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Background/purpose Patients with periodontal disease have higher dental fear levels, which may have negative effects on their clinical outcome during scaling and root planing (SRP). The present study used the new classification of periodontitis and validated questionnaires to assess the relationship among dental fear, SRP pain and periodontal status. Materials and methods A total of 120 periodontitis patients were enrolled and staging according to the new classification of periodontitis. SRP was performed, and the visual analog scale (VAS) to assess pain was used with every patient after treatment. Questionnaires, including Corah's Dental Anxiety Scale (DAS), Dental Fear Survey (DFS), and short-form Dental Anxiety Inventory (S-DAI) were implemented from the first attendance and subsequent visits after 6 months. The patients were grouped by DAS scores. The statistical analysis was performed using T-test, chi-square, Pearson and Spearman correlative analysis. Results Compared to pre-SRP treatment, the dental fear level on DFS was decreased in the posttreatment period for all periodontitis stages. There were no statistically significant differences in S-DAI and DAS between pretreatment and posttreatment periods in stage I and II; meanwhile, there were statistically differences in stage III and IV. The correlation among periodontitis stages, VAS and dental fear level was significant. The proportion of high periodontitis stages was increased in high dental fear group. Conclusion SRP can reduce dental fear levels in all periodontitis stages, especially in stage III and IV. Correlations exist among periodontal status, dental fear and SRP pain. High dental fear is associated with poor periodontal status.

Background: The present study used the new classification of periodontitis and validated questionnaires to assess the relationship among dental fear, scaling and root planning (SRP) pain and periodontal status for clinical evaluation. Methods: One hundred and twenty periodontitis patients were enrolled for retrospective analysis and staging according to the new classification of periodontitis. All patients included in this study from July 2018 to January 2020 were divided into periodontitis stages. Scaling and root planning (SRP) was performed and Visual analogue scale (VAS) was determined for every patient immediately after SRP. Application of questionnaires including Corah’s Dental Anxiety Scales (DAS), Dental Fear Survey (DFS), and the short-form Dental Anxiety Inventory (S-DAI) were implemented from the first attendance and consequent visits after 6 months. All patient demographic data were collected including age, gender, marital status and education level. The scores of each dental fear scale and combination scales were also recorded. Patients were further subdivided into two categories based on DAS scores (low dental fear group: DAS

Background: The present study used the new classification of periodontitis and validated questionnaires to assess the relationship among dental fear, SRP pain and periodontal status for clinical evaluation.Methods: An amount of 120 periodontitis patients were retrospective analyzed and staged according to the new classification of periodontitis. Scaling and root planning (SRP) was performed and Visual analogue scales (VAS) applied immediately after SRP treatment. Application of questionnaires including Corah’s Dental Anxiety Scales (DAS), Dental Fear Survey (DFS), and the short-form Dental Anxiety Inventory (S-DAI) were adopted at the time of first attendance and consequent visit after 6 months to assess dental fear level. The scores of each dental fear scale and combination scales were recorded. Patients were divided into two categories according to DAS value (low dental fear group: DASResults: Compared to pre-SRP treatment, dental fear level of DFS and combination scales were significantly decreased in post-treatment in all periodontitis stage. There were no statistical significance on dental fear level of S-DAI and DFS between patients pre and post-treatment in periodontitis stage I and II, while statistical significance were shown in stage III and IV. Correlation were statistical significance among dental fear level assessed by DAS, DFS and S-DAI, VAS and periodontitis stages. Significant differences of patient amount were shown between two categories according to DAS.Conclusions: SRP can reduce dental fear level in all periodontitis stages, especially stage III and IV. Correlations exist among periodontal status, dental fear and SRP pain. High dental fear relates to poor periodontal status.

The cardiac transverse (T)-tubule membrane system is the safeguard for cardiac function and undergoes dramatic remodeling in response to cardiac stress. However, the mechanism by which cardiomyocytes repair damaged T-tubule network remains unclear. In the present study, we tested the hypothesis that MG53, a muscle-specific membrane repair protein, antagonizes T-tubule damage to protect against maladaptive remodeling and thereby loss of excitation-contraction coupling and cardiac function. Using MG53-knockout (MG53-KO) mice, we first established that deficiency of MG53 had no impact on maturation of the T-tubule network in developing hearts. Additionally, MG53 ablation did not influence T-tubule integrity in unstressed adult hearts as late as 10 months of age. Following left ventricular pressure overload-induced cardiac stress, MG53 protein levels were increased by approximately three-fold in wild-type mice, indicating that pathological stress induces a significant upregulation of MG53. MG53-deficient mice had worsened T-tubule disruption and pronounced dysregulation of Ca2+ handling properties, including decreased Ca2+ transient amplitude and prolonged time to peak and decay. Moreover, MG53 deficiency exacerbated cardiac hypertrophy and dysfunction and decreased survival following cardiac stress. Our data suggest MG53 is not required for T-tubule development and maintenance in normal physiology. However, MG53 is essential to preserve T-tubule integrity and thereby Ca2+ handling properties and cardiac function under pathological cardiac stress.

Cells sense and transduce mechanical signals through cell-cell adhesions and cell-extracellular matrix adhesions. After birth, contractile force generation and tissue stiffness increase as cardiac output increases to support the needs of the newborn organism. During this postnatal period, the N-cadherin adhesion complex assembles at the intercalated disc (ID) as integrin-fibronectin (FN) adhesions decrease, accompanying the switch from hyperplastic to hypertrophic growth. However, little is known regarding the reciprocity between integrin and N-cadherin adhesions in the regulation of cell cycle withdrawal that occurs in cardiomyocytes after birth. α-catenins function as mechanosensors and transduce the intercellular force from N-cadherin to the actin cytoskeleton. Cardiac-specific αE- and αT-catenins double knockout (DKO) mice exhibit sustained cardiomyocyte proliferation beyond the first week of life. To investigate the role of cell-matrix interactions in DKO hearts, the spatial distribution of integrin-FN complexes was examined at postnatal day (P) 4, P7, P14, and P60. DKO hearts exhibited aberrant N-cadherin localization accompanied by altered distribution of α5/β1 integrin, the primary FN receptor. Normally found at the lateral membrane, α5 and β1 accumulated at the ID while N-cadherin was reduced at the termini. FN matrix assembly, as monitored by immunofluorescent staining and its insolubility in the detergent deoxycholate, was increased in DKO hearts. Meanwhile, focal adhesion kinase (FAK) was activated in early postnatal DKO hearts. Complementary experiments performed with deformable substrata demonstrated that stiffness-mediated proliferation was dependent on FAK activity. Finally, treatment of DKO pups with the lysyl oxidase inhibitor, β-aminopropionitrile (BAPN), was sufficient to reduce cardiomyocyte proliferation to wild-type levels suggesting that matrix assembly and tissue stiffness feedback to promote cardiomyocyte proliferation in DKO hearts. This data demonstrates that α-catenins regulate the balance between cell-cell and cell-matrix adhesions, which, in turn, controls cardiomyocyte proliferation, thus providing a molecular explanation for loss of regenerative potential shortly after birth.

SummaryHeart failure is characterized by the transition from an initial compensatory response to decompensation, which can be partially mimicked by transverse aortic constriction (TAC) in rodent models. Numerous signaling molecules have been shown to be part of the compensatory program, but relatively little is known about the transition to decompensation that leads to heart failure. Here, we show that TAC potently decreases the RBFox2 protein in the mouse heart, and cardiac ablation of this critical splicing regulator generates many phenotypes resembling those associated with decompensation in the failing heart. Global analysis reveals that RBFox2 regulates splicing of many genes implicated in heart function and disease. A subset of these genes undergoes developmental regulation during postnatal heart remodeling, which is reversed in TAC-treated and RBFox2 knockout mice. These findings suggest that RBFox2 may be a critical stress sensor during pressure overload-induced heart failure.

Shortly after birth, muscle cells of the mammalian heart lose their ability to divide. At the same time, the N-cadherin/catenin cell adhesion complex accumulates at the cell termini creating a specialized type of cell-cell contact called the intercalated disc (ICD). To investigate the relationship between ICD maturation and proliferation, αE-catenin (Ctnna1) and αT-catenin (Ctnna3) genes were deleted to generate cardiac-specific α-catenin double knockout (DKO) mice. DKO mice exhibited aberrant N-cadherin expression, mislocalized actomyosin activity, and increased cardiomyocyte proliferation that was dependent on Yap activity. To assess effects on tension, cardiomyocytes were cultured on deformable polyacrylamide hydrogels of varying stiffness. When grown on stiff substrate, DKO cardiomyocytes exhibited increased cell spreading, nuclear Yap, and proliferation. A low dose of either a myosin or RhoA inhibitor was sufficient to block Yap accumulation in the nucleus. Finally, activation of RhoA was sufficient to increase nuclear Yap in wild-type cardiomyocytes. These data demonstrate that α-catenins regulate ICD maturation and actomyosin contractility, which, in turn, controls Yap subcellular localization, thus providing an explanation for the loss of proliferative capacity in the newborn mammalian heart.

Changes in expression and distribution of integrin, fibronectin (FN), and N-cadherin in the postnatal heart accompany the switch from hyperplastic to hypertrophic growth. As FN decreases after birth, N-cadherin/catenin complex accumulates at the cell termini creating a specialized type of cell-cell contact called the intercalated disc (ID). Integrin-FN interactions promote cardiomyocyte and cardiac progenitor cell proliferation. However, little is known regarding the reciprocity between integrin and N-cadherin adhesions in the regulation of myocardial proliferation. Alpha-catenins function as mechanosensors and transduce the intercellular force from N-cadherin to the actin cytoskeleton. To investigate mechanotransduction in the heart, we generated cardiac-specific αE- and αT-catenins double knockout (DKO) mice. The relationship between N-cadherin, integrin, and FN was examined at postnatal day (P) 4, P7, P14, and P60. DKO hearts exhibited aberrant N-cadherin expression accompanied by increased expression of α5/β1 integrin, the primary receptor for FN. Normally found at the lateral membrane, α5 and FN accumulated at the ID along with N-cadherin in DKO hearts. FN-integrin binding leads to the formation of FN fibrils that are initially soluble in the detergent deoxycholate (DOC) but are gradually converted into a stable, DOC-insoluble form that comprises the mature matrix. Both α5 and FN were increased in the DOC-insoluble fraction consistent with enhanced matrix assembly in DKO hearts. Activation of focal adhesion kinase (FAK) and p130CAS were observed in the DKO hearts consistent with increased cell-extracellular matrix interactions. Complementary experiments performed with deformable substrata demonstrated that stiffness-mediated Yap nuclear accumulation was dependent on FAK activity. These data demonstrate that α-catenins regulate the balance between cell-cell and cell-matrix adhesions, which, in turn, controls Yap subcellular localization, thus providing a molecular explanation for loss of regenerative potential in the adult heart.

Heart failure is accompanied by a loss of the orderly disposition of transverse (T)-tubules and a decrease of their associations with the junctional sarcoplasmic reticulum (jSR). Junctophilin-2 (JP2) is a structural protein responsible for jSR/T-tubule docking. Animal models of cardiac stresses demonstrate that down-regulation of JP2 contributes to T-tubule disorganization, loss of excitation-contraction coupling, and heart failure development. Our objective was to determine whether JP2 overexpression attenuates stress-induced T-tubule disorganization and protects against heart failure progression. We therefore generated transgenic mice with cardiac-specific JP2 overexpression (JP2-OE). Baseline cardiac function and Ca(2+) handling properties were similar between JP2-OE and control mice. However, JP2-OE mice displayed a significant increase in the junctional coupling area between T-tubules and the SR and an elevated expression of the Na(+)/Ca(2+) exchanger, although other excitation-contraction coupling protein levels were not significantly changed. Despite similar cardiac function at baseline, overexpression of JP2 provided significantly protective benefits after pressure overload. This was accompanied by a decreased percentage of surviving mice that developed heart failure, as well as preservation of T-tubule network integrity in both the left and right ventricles. Taken together, these data suggest that strategies to maintain JP2 levels can prevent the progression from hypertrophy to heart failure.

Background— Cardiac dysfunction in failing hearts of human patients and animal models is associated with both microtubule densification and transverse-tubule (T-tubule) remodeling. Our objective was to investigate whether microtubule densification contributes to T-tubule remodeling and excitation–contraction coupling dysfunction in heart disease. Methods and Results— In a mouse model of pressure overload–induced cardiomyopathy by transaortic banding, colchicine, a microtubule depolymerizer, significantly ameliorated T-tubule remodeling and cardiac dysfunction. In cultured cardiomyocytes, microtubule depolymerization with nocodazole or colchicine profoundly attenuated T-tubule impairment, whereas microtubule polymerization/stabilization with taxol accelerated T-tubule remodeling. In situ immunofluorescence of heart tissue sections demonstrated significant disorganization of junctophilin-2 (JP2), a protein that bridges the T-tubule and sarcoplasmic reticulum membranes, in transaortic banded hearts as well as in human failing hearts, whereas colchicine injection significantly preserved the distribution of JP2 in transaortic banded hearts. In isolated mouse cardiomyocytes, prolonged culture or treatment with taxol resulted in pronounced redistribution of JP2 from T-tubules to the peripheral plasma membrane, without changing total JP2 expression. Nocodazole treatment antagonized JP2 redistribution. Moreover, overexpression of a dominant-negative mutant of kinesin 1, a microtubule motor protein responsible for anterograde trafficking of proteins, protected against JP2 redistribution and T-tubule remodeling in culture. Finally, nocodazole treatment improved Ca 2+ handling in cultured myocytes by increasing the amplitude of Ca 2+ transients and reducing the frequency of Ca 2+ sparks. Conclusion— Our data identify a mechanistic link between microtubule densification and T-tubule remodeling and reveal microtubule-mediated JP2 redistribution as a novel mechanism for T-tubule disruption, loss of excitation–contraction coupling, and heart failure.

Emerging evidence indicates a critical role for junctophilin-2 (JP2) in T-tubule integrity and assembly of cardiac dyads in adult ventricular myocytes. In the postnatal stage, one of the critical features of myocyte maturation is development of the T-tubule system, though the mechanisms remain poorly understood. In this study, we aim to determine whether JP2 is required for normal cardiac T-tubule maturation.Using in situ confocal imaging of intact murine hearts, we found T-tubules were absent in both left- and right-ventricular myocytes at postnatal Day 8 and did not appear until Day 10. Quantification of T-tubule structural integrity using the T-tubule power (TT(power)) index revealed a progressive increase in TT(power) between postnatal Days 10 and 19. By postnatal Day 19, TT(power) was similar to that in adult murine cardiomyocytes, indicative of a nearly matured T-tubule network. JP2 levels increased dramatically during development, reaching levels observed in adult hearts by postnatal Day 14. Deficiency of JP2, using a mouse model in which a JP2-specific shRNA is expressed during embryonic development, severely impaired T-tubule maturation, with equivalent decreases in the left- and right-ventricular TT(power). We also detected a gradual increase in the density of transverse but not longitudinal tubules during development, and JP2 deficiency abolished the increase in the density of transverse elements. Alterations in T-tubules caused significant reduction in Ca(2+) transient amplitude and marked increase in Ca(2+) release dyssynchrony, Ca(2+) alternans, and spontaneous Ca(2+) waves, leading to contractile failure.Our data identify a critical role for JP2 in T-tubule and excitation-contraction coupling maturation during development.

Cardiac excitation–contraction coupling occurs primarily at the sites of transverse (T)-tubule/sarcoplasmic reticulum junctions. The orderly T-tubule network guarantees the instantaneous excitation and synchronous activation of nearly all Ca2+ release sites throughout the large ventricular myocyte. Because of the critical roles played by T-tubules and the array of channels and transporters localized to the T-tubule membrane network, T-tubule architecture has recently become an area of considerable research interest in the cardiovascular field. This review will focus on the current knowledge regarding normal T-tubule structure and function in the heart, T-tubule remodelling in the transition from compensated hypertrophy to heart failure, and the impact of T-tubule remodelling on myocyte Ca2+ handling function. In the last section, we discuss the molecular mechanisms underlying T-tubule remodelling in heart disease.

Backgrounds Low serum cholesterol levels are associated with cardiac arrhythmias and poor prognosis in patients with chronic heart failure. However, the underlying mechanisms by which decreases in cholesterol content lead to cardiac dysfunction remain unclear. Multiple studies have implicated damage to cardiac transverse (T)-tubules as a key mediator of excitation-contraction (E-C) coupling dysfunction and heart failure. Since the T-tubule membrane system is enriched in cholesterol, we hypothesized that depletion of membrane cholesterol promotes T-tubule remodeling and E-C coupling dysfunction. Methods and results We first examined the impact of membrane cholesterol depletion on T-tubule architecture by treating isolated C57BL/6 murine cardiomyocytes with methyl-β-cyclodextrin (MβCD). T-tubule structural integrity was progressively decreased by MβCD in a concentration- and time-dependent manner. Membrane cholesterol depletion also promoted a severe decrease in the amplitude of Ca 2 + transients and an increase in Ca 2 + release dyssynchrony as well as a significant increase in the frequency of spontaneous Ca 2 + sparks. Reintroduction of cholesterol restored T-tubule integrity and partially restored Ca 2 + handling properties in acutely-treated myocytes and slowed T-tubule deterioration in response to chronic MβCD exposure. Studies were extended to determine the impact of membrane cholesterol depletion on T-tubule structure in intact hearts. In addition to T-tubule remodeling, Langendorff perfusion of MβCD resulted in rapid and severe disruption of the intercellular connections between cardiomyocytes, in particular at intercalated disc regions in intact hearts. Conclusions These data provide the first evidence that cholesterol plays a critical role in maintaining cardiac T-tubule structure as well as the integrity of intercalated discs.

Junctophilin-2 (JP2), a membrane-binding protein that provides a structural bridge between the plasmalemma and sarcoplasmic reticulum, is essential for precise Ca(2+)-induced Ca(2+) release during excitation-contraction coupling in cardiomyocytes. In animal and human failing hearts, expression of JP2 is decreased markedly, but the molecular mechanisms underlying JP2 down-regulation remain incompletely defined. In mouse hearts, ischemia/reperfusion injury resulted in acute JP2 down-regulation, which was attenuated by pretreatment with the calpain inhibitor MDL-28170 or by transgenic overexpression of calpastatin, an endogenous calpain inhibitor. Using a combination of computational analysis to predict calpain cleavage sites and in vitro calpain proteolysis reactions, we identified four putative calpain cleavage sites within JP2 with three N-terminal and one C-terminal cleavage sites. Mutagenesis defined the C-terminal region of JP2 as the predominant calpain cleavage site. Exogenous expression of putative JP2 cleavage fragments was not sufficient to rescue Ca(2+) handling in JP2-deficient cardiomyocytes, indicating that cleaved JP2 is non-functional for normal Ca(2+)-induced Ca(2+) release. These data provide new molecular insights into the posttranslational regulatory mechanisms of JP2 in cardiac diseases.

Transverse tubules (T-tubules) are orderly invaginations of the sarcolemma in mammalian cardiomyocytes. The integrity of T-tubule architecture is critical for cardiac excitation-contraction coupling function. T-tubule remodeling is recognized as a key player in cardiac dysfunction. Early studies on T-tubule structure were based on electron microscopy, which uncovered important information about the T-tubule architecture. The advent of fluorescent membrane probes allowed the application of confocal microscopy to investigations of T-tubule structure. Studies have now been extended beyond single cardiomyocytes to examine the T-tubule network in intact hearts through in situ confocal imaging of Langendorff-perfused hearts. This technique has allowed visualization of T-tubule organization in their natural habitat, avoiding the damage induced by isolation of cardiomyocytes. Additionally, it is possible to obtain T-tubule images in different subepicardial regions in a single intact heart. We review how this state-of-the-art imaging technique has provided important mechanistic insights into maturation of T-tubules in developing hearts and defined the role of T-tubule remodeling in development and progression of heart failure.

A new unsymmetrical photochromic diarylethene, 1-(2,5-dimethyl-3-thienyl)-2-(2-methyl-5-(2,4-difluorophenyl)) perfluorocyclopentene (1a), was synthesized and its optoelectronic properties, such as photochromism in solution as well as in poly-methylmethacrylate (PMMA) amorphous films and fluorescences were investigated. The photochromic reaction kinetics indicated that the cyclization processes of 1a belong to the zeroth order reaction and the cycloreversion process belong to the first order reaction. Using diarylethene 1c/PMMA film as recording medium and a linearly polarized 633 nm laser diode for recording and readout, polarization multiplexed image recording can be carried out in this film, which illustrated that the diarylethene can be potentially used as holographic optical recording medium.