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Individuals with type 2 diabetes mellitus (T2DM) are at an increased risk for heart failure, yet preventive cardiac care is suboptimal in this population. Pyridoxamine (PM), a vitamin B6 analog, has been shown to exert protective effects in metabolic and cardiovascular diseases. In this study, we aimed to investigate whether PM limits adverse cardiac remodeling and dysfunction in rats who develop T2DM. Male rats received a standard chow diet or Western diet (WD) for 18 weeks to induce prediabetes. One WD group received additional PM (1 g/L) via drinking water. Glucose tolerance was assessed with a 1 h oral glucose tolerance test. Cardiac function was evaluated using echocardiography and hemodynamic measurements. Histology on left ventricular (LV) tissue was performed. Treatment with PM prevented the increase in fasting plasma glucose levels compared to WD-fed rats (p < 0.05). LV cardiac dilation tended to be prevented using PM supplementation. In LV tissue, PM limited an increase in interstitial collagen deposition (p < 0.05) seen in WD-fed rats. PM tended to decrease 3-nitrotyrosine and significantly lowered 4-hydroxynonenal content compared to WD-fed rats. We conclude that PM alleviates interstitial fibrosis and oxidative stress in the hearts of WD-induced prediabetic rats. [ABSTRACT FROM AUTHOR]

Ameloblasts are the specialized dental epithelial cell type responsible for enamel formation. Following completion of enamel development in humans, ameloblasts are lost and biological repair or regeneration of enamel is not possible. In the past, in vitro models to study dental epithelium and ameloblast biology were limited to freshly isolated primary cells or immortalized cell lines, both with limited translational potential. In recent years, large strides have been made with the development of induced pluripotent stem cell and organoid models of this essential dental lineage – both enabling modeling of human dental epithelium. Upon induction with several different signaling factors (such as transforming growth factor and bone morphogenetic proteins) these models display elevated expression of ameloblast markers and enamel matrix proteins. The advent of 3D bioprinting, and its potential combination with these advanced cellular tools, is poised to revolutionize the field – and its potential for tissue engineering, regenerative and personalized medicine. As the advancements in these technologies are rapidly evolving, we evaluate the current state-of-the-art regarding in vitro cell culture models of dental epithelium and ameloblast lineage with a particular focus toward their applicability for translational tissue engineering and regenerative/personalized medicine. Future perspectives for in vitro modeling of dental epithelium and ameloblasts. Development of iPSC and organoid models that can reliably generate dental epithelium and ameloblast-like cells, together with advances in 3D bioprinting, provide promising tools for enamel research. Advanced models will provide new avenues for development of enamel repair/regeneration approaches, for testing of dental materials or drugs, studying host-pathogen and/or cell-cell interactions, in vitro modeling of enamel diseases (e.g. amelogenesis imperfecta) and developing novel insights in fundamental tooth biology (e.g. regulation of amelogenesis, lineage specification). Abbreviations: iPSC: induced pluripotent stem cells; TO: tooth organoids; DE: dental epithelium; AB: ameloblast. [ABSTRACT FROM AUTHOR]

Background: Dysregulation of the endo-lysosomal–autophagy pathway has been identified as a critical factor in the pathology of various demyelinating neurodegenerative diseases, including peripheral neuropathies. This pathway plays a crucial role in transporting newly synthesized myelin proteins to the plasma membrane in myelinating Schwann cells, making these cells susceptible to lysosome-related dysfunctions. Nevertheless, the specific impact of lysosomal dysfunction in Schwann cells and its contribution to neurodegeneration remain poorly understood. Methods: We aim to mimic lysosomal dysfunction in Schwann cells using chloroquine, a lysosomal dysfunction inducer, and to monitor lysosomal leakiness, Schwann cell viability, and apoptosis over time. Additionally, due to the ethical and experimental issues associated with cell isolation and the culturing of human Schwann cells, we use human dental pulp stem cell-derived Schwann cells (DPSC-SCs) as a model in our study. Results: Chloroquine incubation boosts lysosomal presence as demonstrated by an increased Lysotracker signal. Further in-depth lysosomal analysis demonstrated an increased lysosomal size and permeability as illustrated by a TEM analysis and GAL3-LAMP1 staining. Moreover, an Alamar blue assay and Caspase-3 staining demonstrates a reduced viability and increased apoptosis, respectively. Conclusions: Our data indicate that prolonged lysosomal dysfunction leads to lysosomal permeability, reduced viability, and eventually apoptosis in human DPSC-SCs. [ABSTRACT FROM AUTHOR]

Endurance exercise training is a promising cardioprotective strategy in type 2 diabetes mellitus (T2DM), but the impact of its intensity is not clear. We aimed to investigate whether and how isocaloric moderate-intensity exercise training (MIT) and high-intensity interval exercise training (HIIT) could prevent the adverse cardiac remodeling and dysfunction that develop T2DM in rats. Male rats received a Western diet (WD) to induce T2DM and underwent a sedentary lifestyle (n = 7), MIT (n = 7) or HIIT (n = 8). Insulin resistance was defined as the HOMA-IR value. Cardiac function was assessed with left ventricular (LV) echocardiography and invasive hemodynamics. A qPCR and histology of LV tissue unraveled underlying mechanisms. We found that MIT and HIIT halted T2DM development compared to in sedentary WD rats (p < 0.05). Both interventions prevented increases in LV end-systolic pressure, wall thickness and interstitial collagen content (p < 0.05). In LV tissue, HIIT tended to upregulate the gene expression of an ROS-generating enzyme (NOX4), while both modalities increased proinflammatory macrophage markers and cytokines (CD86, TNF-α, IL-1β; p < 0.05). HIIT promoted antioxidant and dicarbonyl defense systems (SOD2, glyoxalase 1; p < 0.05) whereas MIT elevated anti-inflammatory macrophage marker expression (CD206, CD163; p < 0.01). We conclude that both MIT and HIIT limit WD-induced T2DM with diastolic dysfunction and pathological LV hypertrophy, possibly using different adaptive mechanisms. [ABSTRACT FROM AUTHOR]

The use of doxorubicin (DOX) chemotherapy is restricted due to dose-dependent cardiotoxicity. Pyridoxamine (PM) is a vitamin B6 derivative with favorable effects on diverse cardiovascular diseases, suggesting a cardioprotective effect on DOX-induced cardiotoxicity. The cardioprotective nature of PM was investigated in a rat model of DOX-induced cardiotoxicity. Six-week-old female Sprague Dawley rats were treated intravenously with 2 mg/kg DOX or saline (CTRL) weekly for eight weeks. Two other groups received PM via the drinking water next to DOX (DOX+PM) or saline (CTRL+PM). Echocardiography, strain analysis, and hemodynamic measurements were performed to evaluate cardiac function. Fibrotic remodeling, myocardial inflammation, oxidative stress, apoptosis, and ferroptosis were evaluated by various in vitro techniques. PM significantly attenuated DOX-induced left ventricular (LV) dilated cardiomyopathy and limited TGF-β1-related LV fibrotic remodeling and macrophage-driven myocardial inflammation. PM protected against DOX-induced ferroptosis, as evidenced by restored DOX-induced disturbance of redox balance, improved cytosolic and mitochondrial iron regulation, and reduced mitochondrial damage at the gene level. In conclusion, PM attenuated the development of cardiac damage after DOX treatment by reducing myocardial fibrosis, inflammation, and mitochondrial damage and by restoring redox and iron regulation at the gene level, suggesting that PM may be a novel cardioprotective strategy for DOX-induced cardiomyopathy. [ABSTRACT FROM AUTHOR]

Macrophages play major roles in the pathophysiology of various neurological disorders, being involved in seemingly opposing processes such as lesion progression and resolution. Yet, the molecular mechanisms that drive their harmful and benign effector functions remain poorly understood. Here, we demonstrate that extracellular vesicles (EVs) secreted by repair‐associated macrophages (RAMs) enhance remyelination ex vivo and in vivo by promoting the differentiation of oligodendrocyte precursor cells (OPCs). Guided by lipidomic analysis and applying cholesterol depletion and enrichment strategies, we find that EVs released by RAMs show markedly elevated cholesterol levels and that cholesterol abundance controls their reparative impact on OPC maturation and remyelination. Mechanistically, EV‐associated cholesterol was found to promote OPC differentiation predominantly through direct membrane fusion. Collectively, our findings highlight that EVs are essential for cholesterol trafficking in the brain and that changes in cholesterol abundance support the reparative impact of EVs released by macrophages in the brain, potentially having broad implications for therapeutic strategies aimed at promoting repair in neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

Leukocyte- and Platelet-Rich Fibrin (L-PRF) is a second-generation platelet concentrate that is prepared directly from the patient's own blood. It is widely used in the field of regenerative medicine, and to better understand its clinical applicability we aimed to further explore the biological properties and effects of L-PRF on cells from the central and peripheral nervous system. To this end, L-PRF was prepared from healthy human donors, and confocal, transmission, and scanning electron microscopy as well as secretome analysis were performed on these clots. In addition, functional assays were completed to determine the effect of L-PRF on neural stem cells (NSCs), primary cortical neurons (pCNs), and peripheral dorsal root ganglion (DRG) neurons. We observed that L-PRF consists of a dense but porous fibrin network, containing leukocytes and aggregates of activated platelets that are distributed throughout the clot. Antibody array and ELISA confirmed that it is a reservoir for a plethora of growth factors. Key molecules that are known to have an effect on neuronal cell functions such as brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF) were slowly released over time from the clots. Next, we found that the L-PRF secretome had no significant effect on the proliferative and metabolic activity of NSCs, but it did act as a chemoattractant and improved the migration of these CNS-derived stem cells. More importantly, L-PRF growth factors had a detrimental effect on the survival of pCNs, and consequently, also interfered with their neurite outgrowth. In contrast, we found a positive effect on peripheral DRG neurons, and L-PRF growth factors improved their survival and significantly stimulated the outgrowth and branching of their neurites. Taken together, our study demonstrates the positive effects of the L-PRF secretome on peripheral neurons and supports its use in regenerative medicine but care should be taken when using it for CNS applications. [ABSTRACT FROM AUTHOR]

Exercise training is an encouraging approach to treat cardiac dysfunction in type 2 diabetes (T2DM), but the impact of its intensity is not understood. We aim to investigate whether and, if so, how moderate-intensity training (MIT) and high-intensity interval training (HIIT) alleviate adverse cardiac remodeling and dysfunction in rats with T2DM. Male rats received standard chow (n = 10) or Western diet (WD) to induce T2DM. Hereafter, WD rats were subjected to a 12-week sedentary lifestyle (n = 8), running MIT (n = 7) or HIIT (n = 7). Insulin resistance and glucose tolerance were assessed during the oral glucose tolerance test. Plasma advanced glycation end-products (AGEs) were evaluated. Echocardiography and hemodynamic measurements evaluated cardiac function. Underlying cardiac mechanisms were investigated by histology, western blot and colorimetry. We found that MIT and HIIT lowered insulin resistance and blood glucose levels compared to sedentary WD rats. MIT decreased harmful plasma AGE levels. In the heart, MIT and HIIT lowered end-diastolic pressure, left ventricular wall thickness and interstitial collagen deposition. Cardiac citrate synthase activity, mitochondrial oxidative capacity marker, raised after both exercise training modalities. We conclude that MIT and HIIT are effective in alleviating diastolic dysfunction and pathological cardiac remodeling in T2DM, by lowering fibrosis and optimizing mitochondrial capacity. [ABSTRACT FROM AUTHOR]

A hallmark of multiple sclerosis (MS) is the formation of multiple focal demyelinating lesions within the central nervous system (CNS). These lesions mainly consist of phagocytes that play a key role in lesion progression and remyelination, and therefore represent a promising therapeutic target in MS. We recently showed that unsaturated fatty acids produced by stearoyl-CoA desaturase-1 induce inflammatory foam cell formation during demyelination. These fatty acids are elongated by the "elongation of very long chain fatty acids" proteins (ELOVLs), generating a series of functionally distinct lipids. Here, we show that the expression and activity of ELOVLs are altered in myelin-induced foam cells. Especially ELOVL6, an enzyme responsible for converting saturated and monounsaturated C16 fatty acids into C18 species, was found to be up-regulated in myelin phagocytosing phagocytes in vitro and in MS lesions. Depletion of Elovl6 induced a repair-promoting phagocyte phenotype through activation of the S1P/PPAR? pathway. Elovl6-deficient foamy macrophages showed enhanced ABCA1-mediated lipid efflux, increased production of neurotrophic factors, and reduced expression of inflammatory mediators. Moreover, our data show that ELOVL6 hampers CNS repair, as Elovl6 deficiency prevented demyelination and boosted remyelination in organotypic brain slice cultures and the mouse cuprizone model. These findings indicate that targeting ELOVL6 activity may be an effective strategy to stimulate CNS repair in MS and other neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) are used for regenerative therapy. Dental pulp MSCs make extracted wisdom teeth a useful resource in humans. Preclinical validation of regenerative therapies requires large animal models such as the sheep. Since stem cells can be retrieved from the dental pulp of ovine incisors, the best age to extract a maximal volume of dental pulp needs to be defined. The objective of this ex vivo study was to quantify incisors dental pulp volume, in sheep of various age. Three jaws were dedicated to histology (one per age group); the others were imaged with a computed tomography scanner [3 years‐old (n = 9), 4 (n = 3) and 6 (n = 5)]. The incisors dental pulp volume was measured after 3D reconstruction. Multiple linear regression showed that dental pulp volume of ovine incisors decreases with age (β‐estimate = −3.3; p < 0.0001) and teeth position from the more central to the more lateral (β‐estimate = −4.9; p = 0.0009). Weight was not a relevant variable in the regression model. The dental pulp volume ranged from 36.7 to 19.6 mm3 in 3‐year‐old sheep, from 23.6 to 11.3 in 4‐year‐old sheep, and from 19.4 to 11.5 in 6‐year‐old sheep. The pulp volume of the most central teeth (first intermediate) was significantly higher than the most lateral teeth (corner). Haematoxylin–Eosin–Safran of the whole incisors, and of isolated dental pulps demonstrated a similar morphology to that in humans. The first intermediate incisor of 3‐year‐old sheep should be selected preferentially in preclinical research to retrieve the highest volume of dental pulp. [ABSTRACT FROM AUTHOR]

Foamy macrophages containing abundant intracellular myelin remnants are an important pathological hallmark of multiple sclerosis. Reducing the intracellular lipid burden in foamy macrophages is considered a promising therapeutic strategy to induce a phagocyte phenotype that promotes central nervous system repair. Recent research from our group showed that sustained intracellular accumulation of myelin-derived lipids skews these phagocytes toward a disease-promoting and more inflammatory phenotype. Our data now demonstrate that disturbed lipophagy, a selective form of autophagy that helps with the degradation of lipid droplets, contributes to the induction of this phenotype. Stimulating autophagy using the natural disaccharide trehalose reduced the lipid load and inflammatory phenotype of myelin-laden macrophages. Importantly, trehalose was able to boost remyelination in the ex vivo brain slice model and the in vivo cuprizone-induced demyelination model. In summary, our results provide a molecular rationale for impaired metabolism of myelin-derived lipids in macrophages, and identify lipophagy induction as a promising treatment strategy to promote remyelination. Abbreviations: Baf: bafilomycin a1; BMDM: bone marrow-derived macrophage; CD68: CD68 antigen; CNS: central nervous system; LD: lipid droplet; LIPE/HSL: lipase, hormone sensitive; LPS: lipopolysaccharide; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MBP: myelin basic protein; MGLL: monoglyceride lipase; MS: multiple sclerosis; NO: nitric oxide; NOS2/iNOS: nitric oxide synthase 2, inducible; ORO: oil red o; PNPLA2: patatin-like phospholipase domain containing 2; PLIN2: perilipin 2; TEM: transmission electron microscopy; TFEB: transcription factor EB; TOH: trehalose. [ABSTRACT FROM AUTHOR]

Blood-based (BB) biomarkers for Aβ and tau can indicate pathological processes in the brain, in the early pathological, even pre-symptomatic stages in Alzheimer's disease. However, the relation between BB biomarkers and AD-related processes in the brain in the earliest pre-pathology stage before amyloid pathology develops, and their relation with total brain concentrations of Aβ and tau, is poorly understood. This stage presents a critical window for the earliest prevention of AD. Preclinical models with well-defined temporal progression to robust amyloid and tau pathology provide a unique opportunity to study this relation and were used here to study the link between BB biomarkers with AD-related processes in pre- and pathological stages. We performed a cross-sectional study at different ages assessing the link between BB concentrations and AD-related processes in the brain. This was complemented with a longitudinal analysis and with analysis of age-related changes in a small cohort of human subjects. We found that BB-tau concentrations increased in serum, correlating with progressive development of tau pathology and with increasing tau aggregates and p-tau concentrations in brain in TauP301S mice (PS19) developing tauopathy. BB-Aβ42 concentrations in serum decreased between 4.5 and 9 months of age, correlating with the progressive development of robust amyloid pathology in APP/PS1 (5xFAD) mice, in line with previous findings. Most importantly, BB-Aβ42 concentrations significantly increased between 1.5 and 4.5 months, i.e., in the earliest pre-pathological stage, before robust amyloid pathology develops in the brain, indicating biphasic BB-Aβ42 dynamics. Furthermore, increasing BB-Aβ42 in the pre-pathological phase, strongly correlated with increasing Aβ42 concentrations in brain. Our subsequent longitudinal analysis of BB-Aβ42 in 5xFAD mice, confirmed biphasic BB-Aβ42, with an initial increase, before decreasing with progressive robust pathology. Furthermore, in human samples, BB-Aβ42 concentrations were significantly higher in old (> 60 years) compared to young (< 50 years) subjects, as well as to age-matched AD patients, further supporting age-dependent increase of Aβ42 concentrations in the earliest pre-pathological phase, before amyloid pathology. Also BB-Aβ40 concentrations were found to increase in the earliest pre-pathological phase both in preclinical models and human subjects, while subsequent significantly decreasing concentrations in the pathological phase were characteristic for BB-Aβ42. Together our data indicate that BB biomarkers reflect pathological processes in brain of preclinical models with amyloid and tau pathology, both in the pathological and pre-pathological phase. Our data indicate a biphasic pattern of BB-Aβ42 in preclinical models and a human cohort. And most importantly, we here show that BB-Aβ increased and correlated with increasing concentrations of Aβ in the brain, in the earliest pre-pathological stage in a preclinical model. Our data thereby identify a novel critical window for prevention, using BB-Aβ as marker for accumulating Aβ in the brain, in the earliest pre-pathological stage, opening new avenues for personalized early preventive strategies against AD, even before amyloid pathology develops. [ABSTRACT FROM AUTHOR]

Many critically ill patients infected with SARS-CoV-2 have been submitted to an intensive care unit (ICU). Patients with a SARS-CoV-2 infection that survive critical illness are confronted with months of physical impairments. To maximize recovery, it is important to understand the musculoskeletal involvement in critically ill patients infected with SARS-CoV-2. The aim of the present study was to assess the myocellular changes in SARS-CoV-2 patients that occur throughout the first week of ICU admission. In n = 22 critically ill patients infected with SARS-CoV-2, a biopsy sample from the vastus lateralis muscle was obtained at day 1–3 and day 5–8 following ICU admission. Fluorescence microscopy was used to assess type I and type II muscle fiber size and distribution, myonuclear content, and muscle tissue capillarization. Transmission electron microscopy was used to support quantitative data at an ultrastructural level. Changes in type I and type II muscle fiber size showed large inter-individual variation. The average change in type I fiber size was +309 ± 1834 µm2, ranging from −2129 µm2 (−31%) to +3375 µm2 (+73%). The average change in type II fiber size was −224 ± 1256 µm2, ranging from −1410 µm2 (−36%) to +2592 µm2 (+48%). Ultrastructural observations showed myofibrillar and hydropic degeneration, and fiber necrosis. This study shows that ICU patients admitted with SARS-CoV-2 suffer from substantial muscle fiber damage during ICU admission. These results are a call for action towards more specialized rehabilitation programs for patients admitted to the ICU with SARS-CoV-2 infection. [ABSTRACT FROM AUTHOR]

Purpose: To report on a cohort of patients referred to a tertiary center because of neuropathic pain after dental implant placement. Materials and Methods: This retrospective study of pain after dental implant placement involved a minimum follow-up of 12 months after the initial diagnosis of neuropathic pain or persistent, uncontrolled postoperative pain at the Department of Oral and Maxillofacial Surgery, Leuven University, Leuven, Belgium, from January 2013 to June 2014. Results: Following clinical and radiologic examination, the cause of pain was established in 17 of 26 patients, while the cause was unknown in 9 of 26 patients. Regular implants were placed in the mandibles of 18 patients; in the remaining 8 patients, 6 received regular implants and 2 received a zygoma implant in the maxilla. Surgical management alone brought relief to 2 patients, surgical and pharmacologic management did so for 12 patients, and pharmacologic management alone brought relief for 10 patients. Conclusions: Early removal of an at-risk implant seems justified, preferably within 48 hours after placement. No treatment, either surgical or medical, seems to cure neuropathic pain, but amitriptyline appears to be associated with consistent improvement in symptoms. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to assess whether cone beam computed tomography (CBCT) may be used for clinically reliable alveolar bone quality assessment in comparison to its clinical alternatives, multislice computed tomography and the gold standard (micro-CT). Materials and methods: Six dentate mandibular bone samples were scanned with seven CBCT devices (ProMax 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170, Carestream 9300, Scanora 3D, I-CAT Next generation), one micro-CT scanner (SkyScan 1174) and one MSCT machine (Somatom Definition Flash) using two protocols (standard and high-resolution). MSCT and CBCT images were automatically spatially aligned on the micro-CT scan of the corresponding sample. A volume of interest was manually delineated on the micro-CT image and overlaid on the other scanning devices. Alveolar bone structures were automatically extracted using the adaptive thresholding algorithm. Based on the resulting binary images, an automatic 3D morphometric quantification was performed in a CT-Analyser (Bruker, Kontich, Belgium). The reliability and measurement errors were calculated for each modality compared to the gold standard micro-CT. Results: Both MSCT and CBCT were associated with a clinically and statistically (P <0.05) significant measurement error. Bone quantity-related morphometric indices (bone volume fraction 8.41% min to 17.90% max, bone surface density -0.47 mm-1 min to 0.16 mm-1 max and trabecular thickness 0.15 mm min to 0.31 mm max) were significantly (P <0.05) overestimated, resulting in significantly (P <0.05) closer trabecular pores (total porosity percentage -8.41% min to -17.90% max and fractal dimension 0.08 min to 0.17 max) in all scanners compared to micro-CT. However, the structural pattern of the alveolar bone remained similar compared to that of the micro-CT for the Pro Max 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170 and Carestream 9300. On the other hand, the Scanora 3D, i-CAT Next Generation, standard and high-resolution MSCT displayed an overrated bone quantity and aberrant structural pattern compared to other scanning devices. The calculation of morphometric indices had an overall high reliability (intraclass correlation coefficient [ICC] 0.62 min to 0.99 max), except for the i-CAT Next Generation CBCT (ICC 0.26 min to 0.86 max) and standard resolution MSCT (ICC 0.10 min to 0.62 max). Conclusions: This study demonstrated that most CBCT machines may be able to quantitatively assess alveolar bone quality, with a level of accuracy and reliability that approaches micro-CT. One may therefore propose to extrapolate this to clinical CBCT imaging, certainly when there is a need for implant rehabilitation in dentate jaw bones. [ABSTRACT FROM AUTHOR]

Purpose: To determine the accuracy of the latest cone beam computed tomography (CBCT) machines in comparison to multi-slice computer tomography (MSCT) and micro computed tomography (micro- CT) for objectively assessing trabecular and cortical bone quality prior to implant placement. Materials and methods: Eight edentulous human mandibular bone samples were scanned with seven CBCT scanners (3D Accuitomo 170, i-CAT Next Generation, ProMax 3D Max, Scanora 3D, Cranex 3D, Newtom GiANO and Carestream 9300) and one MSCT system (Somatom Definition Flash) using the clinical exposure protocol with the highest resolution. Micro-CT (SkyScan 1174) images served as a gold standard. A volume of interest (VOI) comprising trabecular and cortical bone only was delineated on the micro-CT. After spatial alignment of all scan types, micro-CT VOIs were overlaid on the CBCT and MSCT images. Segmentation was applied and morphometric parameters were calculated for each scanner. CBCT and MSCT morphometric parameters were compared with micro-CT using mixed-effect models. Intraclass correlation analysis was used to grade the accuracy of each scanner in assessing trabecular and cortical quality in comparison with the gold standard. Bone structure patterns of each scanner were compared with micro-CT in 2D and 3D to facilitate the interpretation of the morphometric analysis. Results: Morphometric analysis showed an overestimation of the cortical and trabecular bone quantity during CBCT and MSCT evaluation compared to the gold standard micro-CT. The trabecular thickness (Tb.Th) was found to be significantly (P < 0.05) different and the smallest overestimation was found for the ProMax 3D Max (180 μm), followed by the 3D Accuitomo 170 (200 μm), Carestream 9300 (220 μm), Newtom GiANO (240 μm), Cranex 3D (280 μm), Scanora 3D (300 μm), high resolution MSCT (310 μm), i-CAT Next Generation (430 μm) and standard resolution MSCT (510 μm). The underestimation of the cortical thickness (Ct.Th) in ProMax 3D Max (-10 μm), the overestimation in Newtom GiANO (10 μm) and the high resolution MSCT (10 μm) were neglible. However, a significant overestimation (P < 0.05) was found for 3D Accuitomo 170 (110 μm), Scanora 3D (140 μm), standard resolution MSCT (150 μm), Carestream 9300 (190 μm), Cranex 3D (190 μm) and i-CAT Next Generation (230 μm). Comparison of the 2D network and 3D surface distance confirmed the overestimation in bone quantity, but only demonstrated a deviant trabecular network for the i-CAT Next Generation and the standard resolution MSCT. Intraclass correlation coefficients (ICCs) showed a significant (P < 0.05) high intra-observer reliability (ICC > 0.70) in morphometric evaluation between micro-CT and commercially available CBCT scanners (3D Accuitomo 170, Newtom GiANO and ProMax 3D Max). The ICC for Tb.Th and Ct.Th were 0.72 and 0.98 (3D Accuitomo 170), 0.71 and 0.96 (Newtom GiANO), and 0.87 and 0.92 (ProMax 3D Max), respectively. Conclusions: High resolution CBCT offers a clinical alternative to MSCT to objectively determine the bone quality prior to implant placement. However, not all tested CBCT machines have sufficient resolution to accurately depict the trabecular network or cortical bone. [ABSTRACT FROM AUTHOR]

Insight into human tooth epithelial stem cells and their biology is sparse. Tissue-derived organoid models typically replicate the tissue’s epithelial stem cell compartment. Here, we developed a first-in-time epithelial organoid model starting from human tooth. Dental follicle (DF) tissue, isolated from unerupted wisdom teeth, efficiently generated epithelial organoids that were long-term expandable. The organoids displayed a tooth epithelial stemness phenotype similar to the DF’s epithelial cell rests of Malassez (ERM), a compartment containing dental epithelial stem cells. Single-cell transcriptomics reinforced this organoid-ERM congruence, and uncovered novel, mouse-mirroring stem cell features. Exposure of the organoids to epidermal growth factor induced transient proliferation and eventual epithelial-mesenchymal transition, highly mimicking events taking place in the ERM in vivo. Moreover, the ERM stemness organoids were able to unfold an ameloblast differentiation process, further enhanced by transforming growth factor-β (TGFβ) and abrogated by TGFβ receptor inhibition, thereby reproducing TGFβ's known key position in amelogenesis. Interestingly, by creating a mesenchymal-epithelial composite organoid (assembloid) model, we demonstrated that the presence of dental mesenchymal cells (i.e. pulp stem cells) triggered ameloblast differentiation in the epithelial stem cells, thus replicating the known importance of mesenchyme-epithelium interaction in tooth development and amelogenesis. Also here, differentiation was abrogated by TGFβ receptor inhibition. Together, we developed novel organoid models empowering the exploration of human tooth epithelial stem cell biology and function as well as their interplay with dental mesenchyme, all at present only poorly defined in humans. Moreover, the new models may pave the way to future tooth-regenerative perspectives. [ABSTRACT FROM AUTHOR]

Mandibular repositioning devices (MRDs) increase the patency of the upper airway by repositioning the mandible forward, resulting in displacement of the oropharyngeal tissues preventing upper airway collapsibility. Mandibular anterior repositioning is counteracted by muscle force from the temporalis muscle. A 39-year-old man had an osteolytic lesion with fracture of the coronoid process of the mandible secondary to wearing a MRD for sleep apnea. Continuous stress generated on the coronoid process temporalis muscle resulted in osteolysis and fracture of the coronoid process on the patient's right side, resulting in swelling and limited ability to open his mouth. The patient was managed with intravenous antibiotics to control the osteomyelitis and surgical debridement, with removal of the coronoid process of the mandible. It is unclear why the fracture only occurred on the right side. Pathologic fracture of the coronoid process due to chronic stress and secondary osteomyelitis is a rare severe complication of treatment for obstructive sleep apnea syndrome with a MRD. [ABSTRACT FROM AUTHOR]

Background: Head and neck cancer (HNC) is one of the most common cancers, associated with a huge mortality and morbidity. In order to improve patient outcomes, more efficient and targeted therapies are essential. Bone marrow-derived mesenchymal stromal cells (BM-MSCs) express tumour homing capacity, which could be exploited to target anti-cancer drug delivery to the tumour region and reduce adverse side-effects. Nevertheless, dental pulp stromal cells (DPSCs), an MSC-like population present in teeth, could offer important clinical benefits because of their easy isolation and superior proliferation compared to BM-MSCs. Therefore, we aimed to elucidate the tumour homing and safe usage of DPSCs to treat HNC. Methods: The in vivo survival as well as the effect of intratumourally administered DPSCs on tumour aggressiveness was tested in a HNC xenograft mouse model by using bioluminescence imaging (BLI), (immuno)histology and qRT-PCR. Furthermore, the in vitro and in vivo tumour homing capacity of DPSCs towards a HNC cell line were evaluated by a transwell migration assay and BLI, respectively. Results: Intratumourally injected DPSCs survived for at least two weeks in the tumour micro-environment and had no significant influence on tumour morphology, growth, angiogenesis and epithelial-to-mesenchymal transition. In addition, DPSCs migrated towards tumour cells in vitro, which could not be confirmed after their in vivo intravenous, intraperitoneal or peritumoural injection under the tested experimental conditions. Conclusions: Our research suggests that intratumourally delivered DPSCs might be used as safe factories for the continuous delivery of anti-cancer drugs in HNC. Nevertheless, further optimization as well as efficacy studies are necessary to understand and improve in vivo tumour homing and determine the optimal experimental set-up of stem cell-based cancer therapies, including dosing and timing. [ABSTRACT FROM AUTHOR]

This review aimed to present studies that prospectively investigated biological effects in patients following diagnostic dentomaxillofacial radiology (DMFR). Literature was systematically searched to retrieve all studies assessing radiobiological effects of using X-ray imaging in the dentomaxillofacial area, with reference to radiobiological outcomes for other imaging modalities and fields. There is a lot of variability in the reported radiobiological assessment methods and radiation dose measures, making comparisons of radiobiological studies challenging. Most radiological DMFR studies are focusing on genotoxicity and cytotoxicity, data for 2D dentomaxillofacial radiographs, albeit with some methodological weakness biasing the results. For CBCT, available evidence is limited and few studies include comparative data on both adults and children. In the future, one will have to strive towards patient-specific measures by considering age, gender and other individual radiation sensitivity-related factors. Ultimately, future radioprotection strategies should build further on the concept of personalized medicine, with patient-specific optimization of the imaging protocol, based on radiobiological variables. [ABSTRACT FROM AUTHOR]

Tailored hydrogels mimicking the native extracellular environment could help overcome the high variability in outcomes within regenerative endodontics. This study aimed to evaluate the effect of the chemokine-binding and antimicrobial polymer, chlorite-oxidized oxyamylose (COAM), on the microstructural properties of fibrin and self-assembling peptide (SAP) hydrogels. A further goal was to assess the influence of the microstructural differences between the hydrogels on the in vitro behavior of human dental pulp stem cells (hDPSCs). Structural and mechanical characterization of the hydrogels with and without COAM was performed by atomic force microscopy and scanning electron microscopy to characterize their microstructure (roughness and fiber length, diameter, straightness, and alignment) and by nanoindentation to measure their stiffness (elastic modulus). Then, hDPSCs were encapsulated in hydrogels with and without COAM. Cell viability and circularity were determined using confocal microscopy, and proliferation was determined using DNA quantification. Inclusion of COAM did not alter the microstructure of the fibrin hydrogels at the fiber level while affecting the SAP hydrogel microstructure (homogeneity), leading to fiber aggregation. The stiffness of the SAP hydrogels was sevenfold higher than the fibrin hydrogels. The viability and attachment of hDPSCs were significantly higher in fibrin hydrogels than in SAP hydrogels. The DNA content was significantly affected by the hydrogel type and the presence of COAM. The microstructural stability after COAM inclusion and the favorable hDPSCs' response observed in fibrin hydrogels suggest this system as a promising carrier for COAM and application in endodontic regeneration. [ABSTRACT FROM AUTHOR]

Background: Bone-to-implant contact ratio (BIC%) plays a critical role in secondary stability of osseointegrated dental implants. The aim of this study was to identify the correlation of 2D/3D micro-CT images with histology as a gold standard for evaluating BIC% and to investigate the influence of the platelet-rich plasma (PRP) and platelet-poor plasma (PPP) on 3D BIC% following delayed implant placement with delayed loading (DIP+DL). Methods: Nine beagle dogs were recruited. Following bilateral extraction of mandibular 3rd premolar, 4th premolar, and 1st molar, 54 screw-type titanium implants were inserted and randomly divided into one control and two test groups based on a split-mouth design. The control group involved DIP+DL (n = 18) and both test groups included DIP+DL with local application of PRP (n = 18) and PPP (n = 18). A BIC analysis was performed utilizing 2D histomorphometry and 2D/3D micro-CT. Following identification of correlation between histology and 2D/3D micro-CT images, a 3D micro-CT assessment of the 3D BIC% at three follow-up time-points (1, 3, and 6 months) was carried out for observing the influence of PRP and PPP on BIC. Results: The 2D micro-CT BIC% values revealed a strong positive correlation with histology (r = 0.98, p < 0.001) and a moderate correlation existed with 3D micro-CT (r = 0. 67, p = 0.005). BIC levels at 1 month and combined influence of PPP and PRP irrespective of time-points revealed significantly higher 3D BIC% compared to the control. However, a reduction in 3D BIC% was observed at the 3rd and 6th month. No significant difference was observed between both PRP and PPP. Conclusions: Both 2D and 3D micro-CT demonstrated a potential to be utilized as a complimentary method for assessing BIC compared to the histological gold standard. Overall, both PRP and PPP significantly facilitated bone healing and osseointegration with a higher 3D BIC at follow-up. However, their influence was reduced as the observation period was increased. [ABSTRACT FROM AUTHOR]

Background: Early detection of marginal bone loss is vital for treatment planning and prognosis of teeth and implant. This study was conducted to assess diagnostic accuracy of CBCT compared to intra-oral (IO) radiography for detection, classification, and measurement of peri-implant bone defects in an animal model. Methods: Fifty-four mandible blocks with implants were harvested from nine male health adult beagle dogs with acquisition of IO, CBCT and micro-CT images from all samples. Peri-implant bone defects from 16 samples were diagnosed using micro-CT and classified into 3 defect categories: dehiscence (n = 5), infrabony defect (n = 3) and crater-like defect (n = 8). Following training and calibration of the observers, they asked to detect location (mesial, distal, buccal, lingual) and shape of the defect (dehiscence, horizontal defect, vertical defect, carter-like defect) utilizing both IO and CBCT images. Both observers assessed defect depth and width on IO, CBCT and micro-CT images at each side of peri-implant bone defect via CT-analyzer software. Data were analyzed using SPSS software and a p value of < 0.05 was considered as statistically significant. Results: Overall, there was a high diagnostic accuracy for detection of bone defects with CBCT images (sensitivity: 100%/100%), while IO images showed a reduction in accuracy (sensitivity: 69%/63%). Similarly, diagnostic accuracy for defect classification was significantly higher for CBCT, whereas IO images were unable to correctly identify vestibular dehiscence, with incorrect assessment of half of the infrabony defects. For accuracy of measuring defect depth and width, a higher correlation was observed between CBCT and gold standard micro-CT (r = 0.91, 95% CI 0.86–0.94), whereas a lower correlation was seen for IO images (r = 0.82, 95% CI 0.67–0.91). Conclusions: The diagnostic accuracy and reliability of CBCT was found to be superior to IO imaging for the detection, classification, and measurement of peri-implant bone defects. The application of CBCT adds substantial information related to the peri-implant bone defect diagnosis and decision-making which cannot be achieved with conventional IO imaging. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs) are of interest for a wide variety of biomedical applications. A major limitation for the clinical use of EVs is the lack of standardized methods for the fast and reproducible separation and subsequent detection of EV subpopulations from biofluids, as well as their storage. To advance this application area, fluorescence-based characterization technologies with single-EV resolution, such as high-sensitivity flow cytometry (HS-FCM), are powerful to allow assessment of EV fractionation methods and storage conditions. Furthermore, the use of HS-FCM and fluorescent labeling of EV subsets is expanding due to the potential of high-throughput, multiplex analysis, but requires further method development to enhance the reproducibility of measurements. In this study, we have applied HS-FCM measurements next to standard EV characterization techniques, including nanoparticle tracking analysis, to compare the yield and purity of EV fractions obtained from lipopolysaccharide-stimulated monocytic THP-1 cells by two EV isolation methods, differential centrifugation followed by ultracentrifugation and the exoEasy membrane affinity spin column purification. We observed differences in EV yield and purity. In addition, we have investigated the influence of EV storage at 4°C or -80°C for up to one month on the EV concentration and the stability of EV-associated fluorescent labels. The concentration of the in vitro cell derived EV fractions was shown to remain stable under the tested storage conditions, however, the fluorescence intensity of labeled EV stored at 4°C started to decline within one day. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to describe nerve fibres around osseointegrated implants in humans. Materials and methods: Twelve mechanically failed implants, retrieved from 10 patients were collected from three dental centres over a period of 5 years. After implant removal, decalcified semi-thin sections (0.5 µm) were stained with thionic methylene blue for light microscopic analysis. In addition, an ultrastructural analysis was performed on serial ultra-thin sections (0.06 µm) using transmission electron microscopy. Results: Both myelinated and unmyelinated nerve fibres could be identified inside the Haversian canals of the osteonal bone near the implant threads. Myelinated fibres were also located at the woven bone around the implant. However, no differentiated nerve endings could be observed around the implants. Conclusions: This study shows the presence of nerve fibres in human peri-implant bone. Previous studies in animals showed that those fibres participate in the process of bone modelling and remodelling. Yet, the role of peri-implant bone innervation in the osseoperception phenomenon cannot be ruled out since the mechanism of mechanoreception in bone is not fully understood. [ABSTRACT FROM AUTHOR]

Our published images not only show the presence of carbon particles in the syncytiotrophoblast but also in the stroma of the villous placental tissue indicating that few particles can bypass the outermost cellular layer. Our paper sought to investigate whether combustion-derived particles are present in placental tissue and whether the placental black carbon load is related to ambient residential black carbon exposure during gestation. By demonstrating, for the first time ever, the presence of black carbon particles in the human placenta, we contributed reliably to the understanding of possible particle translocation towards the fetus and insights into preventable adverse health effects that could potentially harm the next generation. Second, we now show the transfer of air pollution-derived particles towards the fetal circulation by identifying black carbon particles in the central core of the chorionic villous tissue, more specifically inside the fetal capillaries, as visualized in Fig. [Extracted from the article]

In this study, the effects of moderate intense endurance exercise on heart and kidney function and morphology were studied in a thoracic inferior vena cava constricted (IVCc) rat model of abdominal venous congestion. After IVC surgical constriction, eight sedentary male Sprague-Dawley IVCc rats (IVCc-SED) were compared to eight IVCc rats subjected to moderate intense endurance exercise (IVCc-MOD). Heart and kidney function was examined and renal functional reserve (RFR) was investigated by administering a high protein diet (HPD). After 12 weeks of exercise training, abdominal venous pressure, indices of body fat content, plasma cystatin C levels, and post-HPD urinary KIM-1 levels were all significantly lower in IVCc-MOD versus IVCc-SED rats (P < 0.05). RFR did not differ between both groups. The implementation of moderate intense endurance exercise in the IVCc model reduces abdominal venous pressure and is beneficial to kidney function. [ABSTRACT FROM AUTHOR]

Background and Objective: While osseointegration following various dental implant placement protocols has been extensively investigated, the neurohistological integration has received little attention. The primary aim of this study was to compare the myelinated nerve fibers density in peri‐implant bone tissue following various implant placement protocols. The secondary aim assessed the effect of follow‐up on peri‐implant nerve fibers density. Methods: Ten beagle dogs randomly received 68 commercially pure titanium implants in the mandibular premolar or molar region bilaterally following extraction utilizing one of the six treatment protocols: (a) immediate implant placement (IIP) and immediate loading (IL); (b) IIP and delayed loading (DL); (c) IIP and left unloaded (UL); (d) delayed implant placement (DIP) and IL; (e) DIP and DL; and (f) DIP and UL. Histomorphometric analysis of the peri‐implant myelinated nerve fibers was performed in a 300 μm peri‐implant zone at the cervical, middle, and apical level following implant placement. The follow‐up assessment involved longitudinal observation at 3 months following each implant treatment protocol and at 6 months for IIP+IL and IIP+DL protocols. Results: The influence of different treatment protocols, including the fixed effects of implant groups (IIP+IL, IIP+DL, IIP+UL, DIP+IL, DIP+DL, DIP+UL) and regions (cervical, middle, apical), was examined via a linear mixed model. The IIP+IL group showed a significantly higher myelinated nerve density compared to the IIP+UL and DIP+UL group. Peri‐implant nerve re‐innervation was significantly higher (P =.002) in the apical region compared to the cervical region. After immediate implant placement, the IL group showed a significantly (P =.03) higher density of myelinated nerve fibers compared to DL. No significant (P =.19) effect of follow‐up on nerve density was observed. Conclusion: The immediate implant placement and loading protocol showed most beneficial effect on peri‐implant innervation with highest myelinated nerve density in the apical region. A longer loading time had no influence on the peri‐implant nerve density. [ABSTRACT FROM AUTHOR]

Growing evidence supports the role of advanced glycation end products (AGEs) in the development of diabetic vascular complications and cardiovascular diseases (CVDs). We have shown that high-molecular-weight AGEs (HMW-AGEs), present in our Western diet, impair cardiac function. Whether HMW-AGEs affect vascular function remains unknown. In this study, we aimed to investigate the impact of chronic HMW-AGEs exposure on vascular function and structure. Adult male Sprague Dawley rats were daily injected with HMW-AGEs or control solution for 6 weeks. HMW-AGEs animals showed intracardiac pressure overload, characterized by increased systolic and mean pressures. The contraction response to PE was increased in aortic rings from the HMW-AGEs group. Relaxation in response to ACh, but not SNP, was impaired by HMW-AGEs. This was associated with reduced plasma cyclic GMP levels. SOD restored ACh-induced relaxation of HMW-AGEs animals to control levels, accompanied by a reduced half-maximal effective dose (EC50). Finally, collagen deposition and intima-media thickness of the aortic vessel wall were increased with HMW-AGEs. Our data demonstrate that chronic HMW-AGEs exposure causes adverse vascular remodelling. This is characterised by disturbed vasomotor function due to increased oxidative stress and structural changes in the aorta, suggesting an important contribution of HMW-AGEs in the development of CVDs. [ABSTRACT FROM AUTHOR]

Background/Aims: High-molecular-weight advanced glycation end-products (HMW-AGEs) are abundantly present in our Western diet. There is growing evidence reporting that HMWAGEs contribute to the development of cardiovascular dysfunction in vivo, next to the wellknown low-molecular-weight AGEs. The goal of our study is to assess the ultrastructure and function of cardiomyocytes after chronic exposure to HMW-AGEs. A better understanding of underlying mechanisms is essential to create new opportunities for further research on the specific role of HMW-AGEs in the development and progression of cardiovascular diseases. Methods: Adult male rats were randomly assigned to daily intraperitoneal injection for six weeks with either HMW-AGEs (20 mg/kg/day) or a control solution. Hemodynamic measurements were performed at sacrifice. Single cardiomyocytes from the left ventricle were obtained by enzymatic dissociation through retrograde perfusion of the aorta. Unloaded cell shortening, time to peak and time to 50% relaxation were measured during field stimulation and normalized to diastolic length. L-type Ca2+ current density (ICaL) and steady-state inactivation of ICaL were measured during whole-cell ruptured patch clamp. Myofilament functional properties were measured during whole-cell ruptured patch clamp. Myofilament functional properties were measured in membrane-permeabilized cardiomyocytes. Ultrastructural examination of cardiac tissue was performed using electron microscopy. Results: Rats injected with HMW-AGEs displayed in vivo cardiac dysfunction, characterized by significant changes in left ventricular peak rate pressure rise and decline accompanied with an increased heart mass. Single cardiomyocytes isolated from the left ventricle revealed concentric hypertrophy, indicated by the increase in cellular width. Unloaded fractional cell shortening was significantly reduced in cells derived from the HMW-AGEs group and was associated with slower kinetics. Peak L-type Ca2+ current density was significantly decreased in the HMW-AGEs group. L-type Ca2+ channel availability was significantly shifted towards more negative potentials after HMW-AGEs injection. The impact of HMW-AGEs on myofilament function was measured in membrane-permeabilized cardiomyocytes showing a reduction in passive force, maximal Ca2+ activated force and rate of force development. Ultrastructural examination of cardiac tissue demonstrated adverse structural remodeling in HMW-AGEs group characterized by a disruption of the cyto-architecture, a decreased mitochondrial density and altered mitochondrial function. Conclusion: Our data indicate that HMW-AGEs induce structural and functional cellular remodeling via a different working mechanism as the well-known LMW-AGEs. Results of our research open the door for new strategies targeting HMW-AGEs to improve cardiac outcome. [ABSTRACT FROM AUTHOR]

Background and Purpose: Up to 50–60% of all cancer patients receive radiotherapy as part of their treatment strategy. However, the mechanisms accounting for increased vascular risks after irradiation are not completely understood. Mitochondrial dysfunction has been identified as a potential cause of radiation-induced atherosclerosis. Materials and Methods: Assays for apoptosis, cellular metabolism, mitochondrial DNA content, functionality and morphology were used to compare the response of endothelial cells to a single 2 Gy dose of X-rays under basal conditions or after pharmacological treatments that either reduced (EtBr) or increased (rosiglitazone) mitochondrial content. Results: Exposure to ionizing radiation caused a persistent reduction in mitochondrial content of endothelial cells. Pharmacological reduction of mitochondrial DNA content rendered endothelial cells more vulnerable to radiation-induced apoptosis, whereas rosiglitazone treatment increased oxidative metabolism and redox state and decreased the levels of apoptosis after irradiation. Conclusion: Pre-existing mitochondrial damage sensitizes endothelial cells to ionizing radiation-induced mitochondrial dysfunction. Rosiglitazone protects endothelial cells from the detrimental effects of radiation exposure on mitochondrial metabolism and oxidative stress. Thus, our findings indicate that rosiglitazone may have potential value as prophylactic for radiation-induced atherosclerosis. [ABSTRACT FROM AUTHOR]

The brain's endogenous capacity to restore damaged myelin deteriorates during the course of demyelinating disorders. Currently, no treatment options are available to establish remyelination. Chronic demyelination leads to damaged axons and irreversible destruction of the central nervous system (CNS). We identified two promising therapeutic candidates which enhance remyelination: oncostatin M (OSM), a member of the interleukin-6 family, and downstream mediator tissue inhibitor of metalloproteinases-1 (TIMP-1). While remyelination was completely abrogated in OSMRß knockout (KO) mice, OSM overexpression in the chronically demyelinated CNS established remyelination. Astrocytic TIMP-1 was demonstrated to play a pivotal role in OSM-mediated remyelination. Astrocyte-derived TIMP-1 drove differentiation of oligodendrocyte precursor cells into mature oligodendrocytes in vitro. In vivo, TIMP-1 deficiency completely abolished spontaneous remyelination, phenocopying OSMRß KO mice. Finally, TIMP-1 was expressed by human astrocytes in demyelinated multiple sclerosis lesions, confirming the human value of our findings. Taken together, OSM and its downstream mediator TIMP-1 have the therapeutic potential to boost remyelination in demyelinating disorders. [ABSTRACT FROM AUTHOR]

Assessing the possible biological effects of exposure to low doses of ionizing radiation (IR) is one of the prime challenges in radiation protection, especially in medical imaging. Today, radiobiological data on cone beam CT (CBCT) related biological effects are scarce. In children and adults, the induction of DNA double strand breaks (DSBs) in buccal mucosa cells and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxo-dG) and antioxidant capacity in saliva samples after CBCT examination were examined. No DNA DSBs induction was observed in children nor adults. In children only, an increase in 8-oxo-dG levels was observed 30 minutes after CBCT. At the same time an increase in antioxidant capacity was observed in children, whereas a decrease was observed in adults. Our data indicate that children and adults react differently to IR doses associated with CBCT. Fully understanding these differences could lead to an optimal use of CBCT in different age categories as well as improved radiation protection guidelines. [ABSTRACT FROM AUTHOR]

Macrophages play a major role in the removal of foreign materials, including nano-sized materials, such as nanomedicines and other nanoparticles, which they accumulate very efficiently. Because of this, it is recognized that for a safe development of nanotechnologies and nanomedicine, it is essential to investigate potential effects induced by nano-sized materials on macrophages. To this aim, in this work, a recently established model of primary murine alveolar-like macrophages was used to investigate macrophage responses to two well-known nanoparticle models: 50 nm amino-modified polystyrene, known to induce cell death via lysosomal damage and apoptosis in different cell types, and 50 nm silica nanoparticles, which are generally considered non-toxic. Then, a time-resolved study was performed to characterize in detail the response of the macrophages following exposure to the two nanoparticles. As expected, exposure to the amino-modified polystyrene led to cell death, but surprisingly no lysosomal swelling or apoptosis were detected. On the contrary, a peculiar mitochondrial membrane hyperpolarization was observed, accompanied by endoplasmic reticulum stress (ER stress), increased cellular reactive oxygen species (ROS) and changes of metabolic activity, ultimately leading to cell death. Strong toxic responses were observed also after exposure to silica, which included mitochondrial ROS production, mitochondrial depolarization and cell death by apoptosis. Overall, these results showed that exposure to the two nanoparticles led to a very different series of intracellular events, suggesting that the macrophages responded differently to the two nanoparticle models. Similar time-resolved studies are required to characterize the response of macrophages to nanoparticles, as a key parameter in nanosafety assessment. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the peri‐implant trabecular bone volume and architecture changes with 6‐month follow‐up after local application of platelet‐rich plasma (PRP) and platelet‐poor plasma (PPP) using high‐resolution micro‐CT. Material and methods: Seventy‐two dental implants were placed into healed mandibular sites of 9 beagle dogs. Implants were randomly divided into 4 groups following a split‐mouth design: control I; control II; PPP; and PRP. Primary and secondary stabilities were assessed using resonance frequency analyses. At 1, 3, and 6 months after implant loading, trabecular structural parameters were evaluated at 0.5, 1, and 1.5 mm away from implants using micro‐CT (voxel = 20 μm). Results: Primary and secondary stabilities were equivalent in all conditions. PPP and PRP groups showed higher bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) but lower trabecular separation (Tb.Sp) and total porosity percentage (Po (tot)) at all 3 time points. A significant decrease in BV/TV and Tb.Th was found for the control groups after 3 months of healing, while this was not observed in both the PPP and PRP groups. However, no distinct difference was found between the PRP and PPP groups over time. Moreover, as the investigated distance from the implant surface increased, BV/TV and Po (tot) within the same group and time point stayed the same, yet Tb.Th and Tb.Sp continued to increase. Conclusions: Platelet‐rich plasma and PPP with conventional implant placement lead to similar primary and secondary implant stability, but improved peri‐implant bone volume and structural integration. The present research does not seem to suggest a different bone remodeling pattern when using PRP or PPP. [ABSTRACT FROM AUTHOR]

Purpose: To determine the incidence, size, location, course, and content of the superior genial spinal foramen and its bony canal. Materials and Methods: Three hundred eighty dry human cadaver mandibles were morphometrically analyzed by measuring the distance from the foramen to the mandibular base and the size of the foramen and bony canal. Radiologically, the course of the bony canal and its relation to the mandibular incisive canal were investigated after injecting contrast medium (Omnipaque) in the superior genial spinal foramen and the incisive canal at the level of the mental foramen or by inserting a thin metal wire into the bony canal. Dissection was performed on another 10 intact cadaver mandibles. Results: A distinct foramen was present in 98% of all dry specimens studied. Its general form was round or flattened funnel-shaped. Upon microanatomic dissection, a distinct branch of the lingual artery and the lingual nerve entering the superior genial spinal foramen were found. Conclusions: The superior genial spinal foramen is present in most human mandibles and appears to be the entrance of a true lingual neurovascular bundle passing into the bone via a well-defined bony canal toward the buccal side. This implies that surgery and more specifically implant placement at the mandibular midline may carry some risk of neurovascular damage. [ABSTRACT FROM AUTHOR]

Stroke is the second most common cause of death and permanent disability. It is characterized by loss of neural tissue in which inflammation plays a crucial role in both the acute contribution to ischemic damage as in the late-stage impact on post-ischemic tissue regeneration. Microglia play a key role in the inflammatory stroke microenvironment as they can adapt a disease-promoting pro-inflammatory- or pro-regenerative phenotype thereby contributing to the exacerbation or alleviation of ischemic damage, respectively. Triggering receptor expressed on myeloid cells 2 (TREM2) is a cell surface receptor which in the central nervous system is mainly expressed on microglia. This receptor has been shown to play an essential role in microglial phagocytosis and function but its contribution in stroke pathobiology remains unclear. TREM2 was shown to be activated by nucleotides and lipid mediators, key factors that are secreted in the extracellular stroke environment by apoptotic neurons and cell/myelin debris. These factors in turn stimulate TREM2 signaling which mediates microglial migration toward- and phagocytosis of myelin debris and apoptotic cells. Moreover, microglial TREM2 appears to counteract the toll-like receptor response, thereby decreasing the production of pro-inflammatory cytokines. Finally, TREM2 is involved in microglial migration, survival, and is suggested to directly stimulate pro-regenerative phenotype shift. Therefore, this receptor is an attractive target for microglial modulation in the treatment of ischemic stroke and it provides additional information on microglial effector functions. This short review aims to elaborate on these TREM2-mediated microglial functions in the pathobiology and resolving of ischemic stroke. [ABSTRACT FROM AUTHOR]

Objectives: Matrix metalloproteinase (MMP) expression has been associated with tissue development, invasive cancer cell behavior, and inflammation. The associations of increased expression of MMPs with diseases have led to intensive research activities to develop MMP inhibitors. Here, the questions are addressed which associations between increased levels of any MMP with dental diseases may be cause or consequence, whether MMP levels may be of diagnostic value and whether and which MMP inhibitors need further investigations for use in dental diseases. Methods: To study the role of MMPs and to discriminate between cause or consequence, the literature about measurements of MMPs and about the use of inhibitory drugs and genetic knockout animal models in dentistry was compared. Results: The only FDA-approved treatment with MMP inhibitors is tetracyclines for periodontitis, whereas a diagnostic test for activated MMP-8 in oral fluids is valued in practical periodontology. The MMP literature in dentistry is artificially skewed to the gelatinases MMP-2 and MMP-9 and to enamelysin, alias MMP-20. The basis for this observation is, respectively, the widely used and sensitive technique of gelatin zymography and enamel proteins as substrates of MMP-20. Studies on additional MMPs are gaining interest in dentistry and MMP inhibitors may provide new applications. In addition, drugs with proven effects for the treatment of dental diseases may be found to act through MMP inhibition. Conclusion and relevance: In conclusion, research on MMPs and inhibitors may provide practical applications beyond diagnosis and treatment of periodontitis and will be, directly or indirectly, beneficial for patients with dental or periodontal diseases. [ABSTRACT FROM AUTHOR]

Despite the high prevalence and devastating outcome, only a few treatment options for cerebral ischemic stroke exist. Based on the nitric oxide (NO)-stimulating capacity of Non-pulsed Sinusoidal Electromagnetic Field (NP-SEMF) and the possible neuroprotective role of NO in ischemic stroke, we hypothesized that NP-SEMF is able to enhance survival and neurological outcome in a rat model of cerebral ischemia. The animals, in which ischemic injury was induced by occlusion of both common carotid arteries, received 20 min of NP-SEMF of either 10 or 60 Hz daily for 4 days. NP-SEMF dramatically increased survival, reduced the size of the infarcted brain area and significantly improved the neurological score of the surviving rats. Corresponding to previous reports, NP-SEMF was able to induce NO production in vitro. The importance of NO as a key signaling molecule was highlighted by inhibition of the NP-SEMF beneficial effects in the rat stroke model after blocking NO synthase (NOS). Our results indicate for the first time that NP-SEMF exposure (13.5 mT at 60 and 10 Hz) improves the survival and neurological outcome of rats subjected to cerebral ischemia and that this effect is mediated by NO, underlining the great therapeutic potential of NP-SEMF as a therapy for ischemic stroke. [ABSTRACT FROM AUTHOR]

A 51-year-old male was routinely biopsied during a paraspinal muscle study. The biopsy sample was taken from the right erector spinae muscle at the fourth lumbar vertebra. The patient had no history of (diagnosed) major back trauma. The obtained sample was histologically analyzed (hematoxylin and eosin, safranin O), and complementary magnetic resonance imaging was performed. The biopsied sample contained chondroid tissue. Based on its location, the biopsy sample was appointed as chondroid metaplasia. Although chondroid metaplasia is not uncommon in humans, this is the first report of chondroid metaplasia within the paraspinal connective tissue. We propose a novel mechanism to explain the paraspinal chrondrogenic changes, related to spinal degeneration. [ABSTRACT FROM AUTHOR]

Pathologies of the central nervous system are characterized by loss of brain tissue and neuronal function which cannot be adequately restored by endogenous repair processes. This stresses the need for novel treatment options such as cell-based therapies that are able to restore damaged tissue or stimulate repair. This study investigated the neuroregenerative potential of the conditioned medium of human dental pulp stem cells (CM-hDPSCs) on neural stem cell (NSC) proliferation and migration as well as on neurite outgrowth of primary cortical neurons (pCNs). Additionally, the effect of leukocyte- and platelet-rich fibrin (L-PRF) priming on the neuroregenerative potential of the hDPSC secretome on NSCs and pCNs was evaluated. L-PRF contains factors that enhance stem cell-induced regeneration, but its effect on hDPSC-mediated neuroregeneration is unknown. This study demonstrated that CM-hDPSCs enhanced neuritogenesis. Moreover, CM-hDPSCs had a chemoattractant effect on NSCs. Although priming hDPSCs with L-PRF increased brain-derived neurotrophic factor secretion, no additional effects on the paracrine-mediated repair mechanisms were observed. These data support the neuroregenerative potential of hDPSCs, and although priming had no additional effect, the potential of L-PRF-primed hDPSCs on distinct regenerative mechanisms remains to be clarified. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to evaluate objectively the effectiveness of photobiomodulation therapy (PBMT) for the prevention of acute radiation dermatitis (ARD) by using biophysical skin measurements.Methods: A randomized, placebo-controlled trial with 120 breast cancer patients who underwent an identical radiotherapy (RT) regimen post-lumpectomy was performed (TRANSDERMIS trial). Patients were randomized to receive PBM (808 nm CW/905 nm pulsed, 168 mW/cm2, spot size 19.6 cm2, fluence 4 J/cm2) or placebo treatments from the first day of RT (2×/week). Biophysical skin measurements were collected to assess the skin pigmentation and barrier function. Measurements were collected at the first day of RT, a RT dose of 40 Gray (Gy), and the end of RT (66 Gy).Results: The incidence of moist desquamation was significantly higher in the control than in the PBMT group at the end of RT (30 vs. 7%, respectively, odds ratio = 6, p = 0.004). The biophysical skin measures showed that the mean percentage change from the baseline transepidermal water loss (TEWL), erythema, and melanin values was significantly higher in the control than in the PBMT group at the end of RT (ps < 0.05). Logistic regression analysis revealed that the risk on moist desquamation was significantly increased for patients with a large (> 800 cc) breast volume (odds ratio = 4, p = 0.017).Conclusions: This is the first randomized controlled trial demonstrating by objective measurements that PBMT is effective in reducing the incidence of moist desquamation in breast cancer patients undergoing RT. Additionally, a large breast volume is an important risk factor for the development of moist desquamation. [ABSTRACT FROM AUTHOR]

Background: To assess the reproducibility of landmarks in three dimensions that determine the Frankfort horizontal plane (FH) as well as two new landmarks, and to evaluate the angular differences of newly introduced planes to the FH. Methods: Three-dimensional (3D) surface models were created from CBCT scans of 26 dry human skulls. Porion (Po), orbitale (Or), internal acoustic foramen (IAF), and zygomatico-maxillary suture (ZyMS) were indicated in the software by three observers twice with a 4-week interval. Angles between two FHs (FH 1: Or-R, Or-L, mid-Po; FH 2: Po-R, Po-L, mid-Or) and between FHs and new planes (Plane 1-6) were measured. Coordinates were exported to a spreadsheet. A statistical analysis was performed to define the landmark reproducibility and 3D angles. Results: Intra- and inter-observer landmark reproducibility showed mean difference more than 1 mm for x-coordinates of all landmarks except IAF. IAF showed significantly better reproducibility than other landmarks (P < 0.0018). The mean angular difference between FH 1 and FH 2 was 0.7 degrees. Plane 3, connecting Or-R, Or-L and mid-IAF, and Plane 4, connecting Po-R, Po-L and mid-ZyMS, both showed an angular difference of less than 1 degree when compared to FHs. Conclusions: This study revealed poor reproducibility of the traditional FH landmarks on the x-axis and good reproducibility of a new landmark tested to replace Po, the IAF. Yet, Or showed superior results compared to ZyMS. The potential of using new horizontal planes was demonstrated. Future studies should focus on identification of a valid alternative for Or and ZyMS and on clinical implementation of the findings. [ABSTRACT FROM AUTHOR]

Pancreatic islets (PIs) transplantation is an alternative approach for the treatment of severe forms of type 1 diabetes (T1D). To monitor the success of transplantation, it is desirable to follow the location of engrafted PIs non-invasively. In vivo magnetic resonance imaging (MRI) of transplanted PIs is a feasible cell tracking method; however, this requires labeling with a suitable contrast agent prior to transplantation. We have tested the feasibility of cationic magnetoliposomes (MLs), compared to commercial contrast agents (Endorem and Resovist), by labeling insulinoma cells and freshly isolated rat PIs. It was possible to incorporate Magnetic Ressonance (MR)-detectable amounts of MLs in a shorter time (4 h) when compared to Endorem and Resovist. MLs did not show negative effects on the PIs' viability and functional parameters in vitro. Labeled islets were transplanted in the renal sub-capsular region of healthy mice. Hypointense contrast in MR images due to the labeled PIs was detected in vivo upon transplantation, while MR detection of PIs labeled with Endorem and Resovist was only possible after the addition of transfection agents. These findings indicate that MLs are suitable to image PIs, without affecting their function, which is promising for future longitudinal pre-clinical and clinical studies involving the assessment of PI transplantation. [ABSTRACT FROM AUTHOR]

Due to the restricted intrinsic capacity of resident chondrocytes to regenerate the lost cartilage postinjury, stem cell-based therapies have been proposed as a novel therapeutic approach for cartilage repair. Moreover, stem cell-based therapies using mesenchymal stem cells (MSCs) or induced pluripotent stem cells (iPSCs) have been used successfully in preclinical and clinical settings. Despite these promising reports, the exact mechanisms underlying stem cell-mediated cartilage repair remain uncertain. Stem cells can contribute to cartilage repair via chondrogenic differentiation, via immunomodulation, or by the production of paracrine factors and extracellular vesicles. But before novel cell-based therapies for cartilage repair can be introduced into the clinic, rigorous testing in preclinical animal models is required. Preclinical models used in regenerative cartilage studies include murine, lapine, caprine, ovine, porcine, canine, and equine models, each associated with its specific advantages and limitations. This review presents a summary of recent in vitro data and from in vivo preclinical studies justifying the use of MSCs and iPSCs in cartilage tissue engineering. Moreover, the advantages and disadvantages of utilizing small and large animals will be discussed, while also describing suitable outcome measures for evaluating cartilage repair. [ABSTRACT FROM AUTHOR]