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Background: The great saphenous vein (GSV) has long been recognized as the best conduit for vascular bypass procedures. Concomitant varicose veins disease may be a reason for GSV unavailability either due to dilatation and tortuosity of the vein or due to its destruction during invasive venous treatment. Objectives -to assess the rate of varicose vein patients with concomitant lower extremity arterial disease (LEAD) who have previously lost their GSV due to venous ablation. Material and Methods: A total of 285 patients (76 F, 209 M) with LEAD were consecutively enrolled. A total of 111 patients (222 limbs) underwent a detailed duplex ultrasound of the lower extremity veins for assessing suitability of the GSV as a conduit. We registered presence of varicose veins (VVs), type of previous invasive procedure and availability of saphenous veins as possible grafts. Results: The mean age of screened patients was 70.5 ± 9.1.62 (21.75%) patients had varicose veins or were operated on before due to varicose veins. A total of 42 patients with varicose veins had C2 disease, 10 had C3, 9 had C4 and 1 had C6 according to CEAP classification. A total of 222 lower extremities were examined by duplex ultrasound of which 51 limbs had VVs. Despite the presence of varicose tributaries, the GSV was suitable for bypass in 9 of those lower extremities. The GSV was not available as a conduit in 34 (19.9%) ipsilateral lower extremities in the LEAD with no VVs group and in 42 (82.6%) ipsilateral lower extremities in the LEAD with VVs group ( p = 0.0001). Varicose vein disease was associated with a higher frequency of the GSV unavailability (odds ratio 18.8, 95% confidence interval 8.35-42.35). On the 11 ipsilateral limbs (5% of LEAD patients and 21.6% of LEAD with VVs patients), the GSV was unavailable due to previous venous interventions. Conclusions: Almost 20% of patients may have both LEAD and VVs. Among those with VVs, most have the ipsilateral GSV unavailable as a potential conduit. Additionally, one fifth of limbs with VVs had GSVs destroyed previously due to saphenous ablative procedures.

Background: There are no data on the daily regimen of compression therapy in patients with chronic venous disease. This systematic review aimed to establish the optimal daily duration of compression treatment. Methods: A systematic search of CENTRAL and MEDLINE was performed to identify RCTs, non-RCTs, reviews, systematic reviews, meta-analyses, and guidelines evaluating the use of compression regimens in the treatment of varicose veins. Results: Thirty-two RCTs, three non-RCTs, four observational studies, and two crossover trials reporting the duration and regimes of compression treatment fulfilled the inclusion criteria. The daily duration of compression was reported in patients after invasive treatment, for venous ulcer treatment, in patients with venous symptoms. The quality of the studies varied. We could not conduct a meta-analysis due to the heterogeneity of the research data and their quality. Twenty-three studies reported results of compression usage after invasive procedures. Eight studies reported daily duration regimens in patients with venous ulcers. Nine studies reported the impact of compression on venous symptoms and/or edema or limb volume change. One study was conducted to assess if compression improves QoL in venous patients. While there was a clear difference found in the daily duration depending on the clinical scenario, no data in support of exact regimens were found. Conclusions: There are no reliable data supporting exact daily regimens of compression treatment in various cohorts of CVD patients.

Published scientific evidence demonstrate the current spread of healthcare misinformation in the most popular social networks and unofficial communication channels. Up to 40% of the medical websites were identified reporting inappropriate information, moreover being shared more than 450,000 times in a 5-year-time frame. The phenomenon is particularly spread in infective diseases medicine, oncology and cardiovascular medicine. The present document is the result of a scientific and educational endeavor by a worldwide group of top experts who selected and analyzed the major issues and related evidence-based facts on vein and lymphatic management. A section of this work is entirely dedicated to the patients and therefore written in layman terms, with the aim of improving public vein-lymphatic awareness. The part dedicated to the medical professionals includes a revision of the current literature, summing up the statements that are fully evidence-based in venous and lymphatic disease management, and suggesting future lines of research to fulfill the still unmet needs. The document has been written following an intense digital interaction among dedicated working groups, leading to an institutional project presentation during the Universal Expo in Dubai, in the occasion of the v-WINter 2022 meeting.

Background: Vein-specific inflammation leads to vascular smooth muscle cells proliferation and extracellular matrix degradation of vein wall. This process is known as remodeling and is promoted by "trapped" leukocytes. Monocyte chemoattractant protein 1 (MCP-1) is a chemokine responsible for trafficking of leukocytes from blood to vein wall. The aim of this study was to measure the MCP-1 concentration in varicose veins blood before and after venoactive drug therapy and to compare it with a concentration of blood from varicose veins of subjects who did not receive drug treatment., Methods: Non-randomized comparative study was conducted on 30 patients with primary varicose veins. 20 patients of the study group received diosmin 900 mg/hesperidin 100 mg once daily. 10 controls received no treatment. MCP-1 level was measured (pg/mL) in the blood from varicose veins twice, at the day of inclusion and after 60 days. Legs discomfort related to chronic venous disease (CVD) symptoms was measured with 10-cm Visual Analogue Scale (VAS) at inclusion and at completion of the study., Results: Median (interquartile range, IQR) MCP-1 concentrations in treatment and control groups at inclusion were 171.9 (124.4-216.0) and 157.0 (120.1-163.1), resp., P=0.285. After 60 days of treatment MCP-1 level decreased, but non-significantly to 152.3 (124.1-178.3). In patients who did not receive treatment chemokine level slightly increased to 163.0 (134.0-172.9). Median changes over time were -6.6 (-30.9-7.4) and 10.6 (-3.7-19.2) in the study and control groups, resp. (P=0.048). After 60 days in 12 of 19 and 2 of 9 patients of treatments and control groups MCP-1 decreased (P=0.103). Odds ratio for MCP-1 decreasing was 9.5 (95% CI 1.1-81.5, P=0.043) for those who received venoactive drug. Mean (± standard deviation [SD]) legs discomfort significantly dropped in the study group from 5.7 (±2.5) to 1.9 (±2.2) (P=0.0003), while in controls no changes were registered: 3.4 (±1.3) and 3.5 (± 1.4), resp., P=0.28). Mean difference of VAS at baseline and at follow-up was -3.5 (±2.6) and 0.9 (±2.1), resp. (P<0.0001)., Conclusions: Plasma concentration of MCP-1 in varicose veins blood demonstrates a tendency to decrease under two months treatment with a venoactive drug. Future studies are needed to reveal a possible role of MCP-1 as a target considering its role in varicose veins pathogenesis.

Consultation prioritization is fundamental in optimal healthcare management and its performance can be helped by artificial intelligence (AI)-dedicated software and by digital medicine in general. The need for remote consultation has been demonstrated not only in the pandemic-induced lock-down but also in rurality conditions for which access to health centers is constantly limited. The term "AI" indicates the use of a computer to simulate human intellectual behavior with minimal human intervention. AI is based on a "machine learning" process or on an artificial neural network. AI provides accurate diagnostic algorithms and personalized treatments in many fields, including oncology, ophthalmology, traumatology, and dermatology. AI can help vascular specialists in diagnostics of peripheral artery disease, cerebrovascular disease, and deep vein thrombosis by analyzing contrast-enhanced magnetic resonance imaging or ultrasound data and in diagnostics of pulmonary embolism on multi-slice computed angiograms. Automatic methods based on AI may be applied to detect the presence and determine the clinical class of chronic venous disease. Nevertheless, data on using AI in this field are still scarce. In this narrative review, the authors discuss available data on AI implementation in arterial and venous disease diagnostics and care.

Objective: Compression stockings and bandages are widely used after invasive treatment of varicose veins. The goals of compression after venous interventions are to reduce pain, bruising, and ecchymosis. Nevertheless, patients often report discomfort with the compression. To make postprocedural compression more tolerable, foot-sparing bandages were tested in a randomized clinical trial of noninferiority., Methods: A total of 187 patients were randomized to use class II foot-sparing compression sleeves for the full leg or class II stockings after radiofrequency ablation with concomitant phlebectomy. The primary endpoint was the quality of life, measured using the Chronic Venous Disease Quality of Life Questionnaire 20-item scale 30 days after intervention. The secondary endpoints were pain in the leg and discomfort related to the compression garment, which were assessed using the visual analog scale (VAS) at 2, 7, 14, and 30 days., Results: The global index score of the questionnaire was 66.1 and 70.6 and 83.8 and 87.7 for the sleeve and stocking groups before and 30 days after intervention, respectively (P = .542 and P = .150, respectively). The VAS for pain score in the operated leg was slightly higher in the sleeve group the day after the intervention (score, 2.1 vs 1.6; P = .03). At 7, 14, and 30 days, the VAS for pain scores did not differ significantly (score, 0.7 vs 0.5; 0.5 vs 0.3; and 0.1 vs 0.1, respectively; P = NS for all). The VAS for discomfort score was not significantly different statistically in the study group at 2 days (sleeve, 1.9; vs stocking, 1.4; P = .08) but was higher after 7 days (sleeve, 0.9; vs stocking, 0.6; P = .008). No difference in discomfort was found between the study and control groups at 14 or 30 days (sleeve, 0.6; vs stocking, 0.4; and sleeve, 0.4; vs stocking, 0.4, respectively; P = NS for both)., Conclusions: Quality of life after thermal ablation with phlebectomy improved equivalently in patients who had used class II compression sleeves for full legs and those who had used class II compression stockings. Pain and discomfort were slightly higher in the sleeve group., (Copyright © 2020 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Adeno associated viral (AAV) vectors have emerged as a preferred platform for in vivo gene replacement therapy and represent one of the most promising strategies to treat monogenetic disorders such as hemophilia. However, immune responses to gene transfer have hampered human gene therapy in clinical trials. Over the past decade, it has become clear that innate immune recognition provides signals for the induction of antigen-specific responses against vector or transgene product. In particular, TLR9 recognition of the vector's DNA genome in plasmacytoid dendritic cells (pDCs) has been identified as a key factor. Data from clinical trials and pre-clinical studies implement CpG motifs in the vector genome as drivers of immune responses, especially of CD8 + T cell activation. Here, we demonstrate that cross-priming of AAV capsid-specific CD8 + T cells depends on XCR1 + dendritic cells (which are likely the main cross-presenting cell that cooperates with pDCs to activate CD8 + T cells) and can be minimized by the elimination of CpG motifs in the vector genome. Further, a CpG-depleted vector expressing human coagulation factor IX showed markedly reduced (albeit not entirely eliminated) CD8 + T cell infiltration upon intramuscular gene transfer in hemophilia B mice when compared to conventional CpG + vector (comprised of native sequences), resulting in better preservation of transduced muscle fibers. Therefore, this deimmunization strategy is helpful in reducing the potential for CD8 + T cell responses to capsid or transgene product. However, CpG depletion had minimal effects on antibody responses against capsid or transgene product, which appear to be largely independent of CpG motifs., Competing Interests: RH served on the scientific advisory board or Ally Therapeutics and has been receiving grant funding from Luye R&D, Boston, and Spark Therapeutics. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Bertolini, Shirley, Zolotukhin, Li, Kaisho, Xiao, Kumar and Herzog.)

Limitations to successful gene therapy with adeno-associated virus (AAV) can comprise pre-existing neutralizing antibodies to the vector capsid that can block cellular entry, or inefficient transduction of target cells that can lead to sub-optimal expression of the therapeutic transgene. Recombinant serotype 3 AAV (AAV3) is an emerging candidate for liver-directed gene therapy. In this study, we integrated rational design by using a combinatorial library derived from AAV3B capsids with directed evolution by in vitro selection for liver-targeted AAV variants. The AAV3B-DE5 variant described herein was undetectable in the original viral library but gained a selective advantage upon in vitro passaging in human hepatocarcinoma spheroid cultures. AAV3B-DE5 contains 24 capsid amino acid substitutions compared with AAV3B, distributed among all five variable regions, with strong selective pressure on VR-IV, VR-V, and VR-VII. In vivo , AAV3B-DE5 demonstrated improved human hepatocyte tropism in a liver chimeric mouse model. Importantly, this variant exhibited reduced seroreactivity to human intravenous immunoglobulin (i.v. Ig), as well as individual serum samples from 100 healthy human donors. Therefore, molecular evolution using a combinatorial library platform generated a viral capsid with high hepatocyte tropism and enhanced evasion of pre-existing AAV neutralizing antibodies., (© 2020 The Authors.)

Adeno-associated virus (AAV) vectors are widely used in clinical gene therapy to correct genetic disease by in vivo gene transfer. Although the vectors are useful, in part because of their limited immunogenicity, immune responses directed at vector components have complicated applications in humans. These include, for instance, innate immune sensing of vector components by plasmacytoid dendritic cells (pDCs), which sense the vector DNA genome via Toll-like receptor 9. Adaptive immune responses employ antigen presentation by conventional dendritic cells (cDCs), which leads to cross-priming of capsid-specific CD8 + T cells. In this study, we sought to determine the mechanisms that promote licensing of cDCs, which is requisite for CD8 + T cell activation. Blockage of type 1 interferon (T1 IFN) signaling by monoclonal antibody therapy prevented cross-priming. Furthermore, experiments in cell-type-restricted knockout mice showed a specific requirement for the receptor for T1 IFN (IFNaR) in cDCs. In contrast, natural killer (NK) cells are not needed, indicating a direct rather than indirect effect of T1 IFN on cDCs. In addition, co-stimulation by CD4 + T cells via CD40-CD40L was required for cross-priming, and blockage of co-stimulation but not of T1 IFN additionally reduced antibody formation against capsid. These mechanistic insights inform the development of targeted immune interventions., (Copyright © 2019 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

Clinical data from over two decades, involving more than 3000 treated patients, demonstrate that adeno-associated virus (AAV) gene therapy is a safe, effective, and well-tolerated therapeutic method. Clinical trials using AAV-mediated gene delivery to accessible tissues have led to successful treatments for numerous monogenic disorders and advancements in tissue engineering. Although the US Food and Drug Administration (FDA) has approved AAV for clinical use, systemic administration remains a significant challenge. In this review, we delve into AAV biology, focusing on current manufacturing technologies and transgene engineering strategies. We examine the use of AAVs in ongoing clinical trials for ocular, neurological, and hematological disorders, as well as cancers. By discussing recent advancements and current challenges in the field, we aim to provide valuable insights for researchers and clinicians navigating the evolving landscape of AAV-based gene therapy., (© 2024 International Union of Biochemistry and Molecular Biology.)

We compared the phenotypes of three mutant AAV2 viruses containing mutations in arginine amino acids (R585, R588 and R484) previously shown to be involved in AAV2 heparan sulfate binding. The transduction efficiencies of wild type and mutant viruses were determined in the eye, the brain and peripheral organs following subretinal, striatal and intravenous injection, respectively, in mice and rats. We found that each of the three mutants (the single mutant R585A; the double mutant R585, 588A; and the triple mutant R585, 588, 484A) had a unique phenotype compared to wt and each other. R585A was completely defective for transducing peripheral organs via intravenous injection, suggesting that R585A may be useful for targeting peripheral organs by substitution of peptide ligands in the capsid surface. In the brain, all three mutants displayed widespread transduction, with the double mutant R585, 588A displaying the greatest spread and the greatest number of transduced neurons. The double mutant was also extremely efficient for retrograde transport, while the triple mutant was almost completely defective for retrograde transport. This suggested that R484 may be directly involved in interaction with the transport machinery. Finally, the double mutant also displayed improved transduction of the eye compared to wild type and the other mutants., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: To find out the prevalence and risk factors for abdominal wall hernias in the general Russian population., Methods: 783 residents of Kryukovo rural community (Central Russia) of 10 > years were enrolled. Medical history was taken and clinical examination was performed documenting hernia presence. Ultrasound examination was performed in inconclusive situations. We considered residents with hernias at the time of examination, as well as those who had previously undergone hernia repair, to be hernia positive., Results: There were 298 (38%) men and 485 (62%) women (mean age 49.3). Abdominal wall hernias have been found in 20.9% of population. 31.2% of men and 14.6% of women were affected (p < 0.0001). Umbilical hernias was found in 10.2%, groin hernias in 8.3%, incisional in 2.4% of residents. 72% of individuals with hernia reported local pain. 70% had never asked for medical advice before, 30% had undergone hernia repair before. Male gender, age, family history were confirmed as risk factors for any hernia with OR 3.9, 1.03 and 2.7, respectively (p < 0.01). For groin hernias male gender, age, family history and rough labour were confirmed with ORs 9.2, 1.03, 2.9 (p < 0.01) and 2.1 (p < 0.05). Risk factors for umbilical hernias were male gender with OR 2.2 (p < 0.01), age, family history and BMI with ORs 1.02, 1.8 and 1.08 (p < 0.05)., Conclusions: This study is the first to demonstrate prevalence of abdominal wall hernias and its risk factors in Russia. The results confirm that hernias are common in a general population pointing the need for improvement of surgical activity.

Hepatoxicity associated with recombinant adeno-associated virus gene therapy is being increasingly encountered by hepatologists in tertiary and quaternary referral units due to the recent increase of these therapies for neuromuscular and haematological disorders. The challenges in managing the condition stem from a lack of good-quality evidence on the appropriate protocols for immunosuppressants due to lack of representative animal models. There is a need for protocols for diagnosing and treating hepatotoxicity and this possible with further research to understand the problem and its management. The review also highlights the importance of a multidisciplinary team in managing hepatotoxicity and recommends further research to better identify at-risk individuals, define the extent of the problem and assess the long-term effects of liver injury and immunosuppressants., (© 2024 The Author(s). Journal of Pediatric Gastroenterology and Nutrition published by Wiley Periodicals LLC on behalf of European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Over the past decade, in vivo gene replacement therapy has significantly advanced, resulting in market approval of numerous therapeutics predominantly relying on adeno-associated viral vectors (AAV). While viral vectors have undeniably addressed several critical healthcare challenges, their clinical application has unveiled a range of limitations and safety concerns. This review highlights the emerging challenges in the field of gene therapy. At first, we discuss both the role of biological barriers in viral gene therapy with a focus on AAVs, and review current landscape of in vivo human gene therapy. We delineate advantages and disadvantages of AAVs as gene delivery vehicles, mostly from the safety perspective (hepatotoxicity, cardiotoxicity, neurotoxicity, inflammatory responses etc.), and outline the mechanisms of adverse events in response to AAV. Contribution of every aspect of AAV vectors (genomic structure, capsid proteins) and host responses to injected AAV is considered and substantiated by basic, translational and clinical studies. The updated evaluation of recent AAV clinical trials and current medical experience clearly shows the risks of AAVs that sometimes overshadow the hopes for curing a hereditary disease. At last, a set of established and new molecular and nanotechnology tools and approaches are provided as potential solutions for mitigating or eliminating side effects. The increasing number of severe adverse reactions and, sadly deaths, demands decisive actions to resolve the issue of immune responses and extremely high doses of viral vectors used for gene therapy. In response to these challenges, various strategies are under development, including approaches aimed at augmenting characteristics of viral vectors and others focused on creating secure and efficacious non-viral vectors. This comprehensive review offers an overarching perspective on the present state of gene therapy utilizing both viral and non-viral vectors., (© 2024 Wiley Periodicals LLC.)

Heredity plays an important role in the etiology of varicose veins (VVs). However, the genetic basis underlying this condition remains poorly understood. Our aim was to replicate top association signals from genome-wide association studies (GWASs) for VVs of lower extremities using 2 independent datasets-our sample of ethnic Russian individuals (709 cases and 278 controls) and a large cohort of British residents from UK Biobank (10 861 cases and 397 594 controls). Associations of polymorphisms rs11121615, rs6712038, rs507666, rs966562, rs7111987, rs6062618, and rs6905288 were validated in the UK Biobank individuals at a Bonferroni-corrected significance level. In Russian cohort, only rs11121615 reached a nominal significance level of P < .05. Results of original GWAS and replication studies were combined by a meta-analysis, and polymorphisms listed above as well as rs111434909 and rs4463578 passed a genome-wide significant threshold. Notably, the majority of these polymorphisms were located within or near genes involved in vascular development and remodeling, and regulation of inflammatory response. Our results confirm the role of these polymorphisms in genetic susceptibility to VVs and indicate the revealed genomic regions as good candidates for further fine-mapping studies and functional analysis. Moreover, our findings implicate inflammation and abnormal vascular architecture in VVs pathogenesis., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Heredity is a well-known risk factor for varicose veins, but genetic basis of this condition remains poorly studied. Our aim was to conduct a large-scale genetic association study for primary varicose veins (PVVs) in the population of ethnic Russians. An initial scan using Illumina HumanExome-12 v1.0 BeadChip was performed for 273 patients with PVVs and 250 controls without a history of chronic venous disease and other venous disorders. After quality control and removal of monomorphic markers, 25,424 common and 48,232 rare variants were included in the analysis. 42 single nucleotide polymorphisms (SNPs) were genotyped in the independent replication cohort of 447 PVVs patients and 443 controls. Association of common variants with PVVs was investigated by logistic regression, and the impact of rare variants was analyzed using sequence kernel association test. No effect of low frequency alleles has been revealed in our study. Common variant analysis identified a promising signal at chromosome 6 within classical major histocompatibility complex (MHC) class III subregion. The most strongly associated SNP in a combined analysis that reached a suggestive significance level of 3.2e-05 was polymorphism rs4151657 in the complement factor B gene. Testing for potential pleiotropy with other traits indicated that the same causal variant in this region increases the risk of rheumatoid arthritis and has a negative impact on human height. Our results provide suggestive evidence for the involvement of the MHC class III genes in the pathogenesis of PVVs. Further independent studies are needed to confirm our pilot findings., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Inflammation was shown to be activated in varicose veins, although its role in the development of vein wall transformation remains inconclusive. We aimed to investigate the influence of 13 inflammation-related single nucleotide polymorphisms (SNPs) TNF rs1800629 and rs3093661, IL1A rs1800587, IL1RN rs4251961, IL6 rs1800795 and rs1800796, IFNG rs2430561, IL10 rs1800896, TGFB1 rs1800469, HIF1A rs11549465, NFKB1 rs28362491, and rs4648068 on the risk of primary varicose veins (PVVs) in ethnic Russians. We genotyped 709 patients with PVVs and 278 individuals without a history of chronic venous disease and performed a single SNP and a haplotype analysis. Several associations with P < 0.05 were revealed in our study. Variant allele HIF1A rs11549465 T, TNF rs3093661 A, and NFKB1 rs28362491 ATTG deletion showed the reverse association with PVV risk, and allele IL6 rs1800795 C was associated with the increased risk of the studied pathology. Haplotype analysis revealed associations of TNF haplotypes rs3093661 A-rs1800629 G and IL6 rs1800795 C-rs1800796 G with the decreased and the increased risk of PVVs, correspondingly. However, all the observed associations failed to reach statistical significance after the correction for multiple testing, which was set at a level of 10 -3 due to many tests performed. Our study therefore provides evidence that investigated polymorphisms do not play a major role in susceptibility to PVVs.

Adeno-associated virus (AAV) is a replication-deficient parvovirus that is extensively used as a gene therapy vector. CD8 + T-cell responses against the AAV capsid protein can, however, affect therapeutic efficacy. Little is known about the in vivo mechanism that leads to the crosspriming of CD8 + T cells against the input viral capsid antigen. In this study, we report that the Toll-like receptor 9 (TLR9)-MyD88 pattern-recognition receptor pathway is uniquely capable of initiating this response. By contrast, the absence of TLR2, STING, or the addition of TLR4 agonist has no effect. Surprisingly, both conventional dendritic cells (cDCs) and plasmacytoid DCs (pDCs) are required for the crosspriming of capsid-specific CD8 + T cells, whereas other antigen-presenting cells are not involved. TLR9 signaling is specifically essential in pDCs but not in cDCs, indicating that sensing of the viral genome by pDCs activates cDCs in trans to cross-present capsid antigen during CD8 + T-cell activation. Cross-presentation and crosspriming depend not only on TLR9, but also on interferon type I signaling, and both mechanisms can be inhibited by administering specific molecules to prevent induction of capsid-specific CD8 + T cells. Thus, these outcomes directly point to therapeutic interventions and demonstrate that innate immune blockade can eliminate unwanted immune responses in gene therapy., (© 2017 by The American Society of Hematology.)

Background: Adeno-associated virus (AAV) gene therapy vectors have shown the best outcomes in human clinical studies for the treatment of genetic diseases such as hemophilia. However, these pivotal investigations have also identified several challenges. For example, high vector doses are often used for hepatic gene transfer, and cytotoxic T lymphocyte responses against viral capsid may occur. Therefore, achieving therapy at reduced vector doses and other strategies to reduce capsid antigen presentation are desirable., Methods: We tested several engineered AAV capsids for factor IX (FIX) expression for the treatment of hemophilia B by hepatic gene transfer. These capsids lack potential phosphorylation or ubiquitination sites, or had been generated through molecular evolution., Results: AAV2 capsids lacking either a single lysine residue or 3 tyrosine residues directed substantially higher coagulation FIX expression in mice compared to wild-type sequence or other mutations. In hemophilia B dogs, however, expression from the tyrosine-mutant vector was merely comparable to historical data on AAV2. Evolved AAV2-LiC capsid was highly efficient in hemophilia B mice but lacked efficacy in a hemophilia B dog., Conclusions: Several alternative strategies for capsid modification improve the in vivo performance of AAV vectors in hepatic gene transfer for correction of hemophilia. However, capsid optimization solely in mouse liver may not predict efficacy in other species and thus is of limited translational utility.

Two hundred and twenty eight ethnic Russian individuals from Moscow, Russia, were genotyped at 14 single nucleotide polymorphisms CCL2 A-2578G; VEGFA C-2578A, G-634C, and C+936T; TNF G+419A and G-308A; IL1A G-889A; IL1RN T+1018C; IL6G-174C and G-572C; IFNG T+874A; IL1B C-511T; IL10 A+1082G; TGFB1 C-509T. Genotypes were determined using real-time polymerase chain reaction with TaqMan probes and polymerase chain reaction followed by melting analysis of dual-labeled probe. Genotype distribution was in accordance with Hardy-Weinberg equilibrium for all studied polymorphisms. Genotype data are available in the Allele Frequencies Net Database under identifier AFND 3367 and the population name "Russia Moscow Cytokine"., (Copyright © 2016 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)

The tolerogenic hepatic microenvironment impedes clearance of viral infections but is an advantage in viral vector gene transfer, which often results in immune tolerance induction to transgene products. Although the underlying tolerance mechanism has been extensively studied, our understanding of antigen presentation to transgene product-specific CD4 + T cells remains limited. To address this, we administered hepatotropic adeno-associated virus (AAV8) vector expressing cytoplasmic ovalbumin (OVA) into wt mice followed by adoptive transfer of transgenic OVA-specific T cells. We find that that the liver-draining lymph nodes (celiac and portal) are the major sites of MHC II presentation of the virally encoded antigen, as judged by in vivo proliferation of DO11.10 CD4 + T cells (requiring professional antigen-presenting cells, e.g. , macrophages) and CD4 + CD25 + FoxP3 + Treg induction. Antigen presentation in the liver itself contributes to activation of CD4 + T cells egressing from the liver. Hepatic-induced Treg rapidly disseminate through the systemic circulation. By contrast, a secreted OVA transgene product is presented in multiple organs, and OVA-specific Treg emerge in both the thymus and periphery. In summary, liver draining lymph nodes play an integral role in hepatic antigen presentation and peripheral Treg induction, which results in systemic regulation of the response to viral gene products.

Hemophilia A and B are coagulation disorders resulting from the loss of functional coagulation factor VIII (FVIII) or factor IX proteins, respectively. Gene therapy for hemophilia with adeno-associated virus vectors has shown efficacy in hemophilia B patients. Although hemophilia A patients are more prevalent, the development of therapeutic adeno-associated virus vectors has been impeded by the size of the F8 cDNA and impaired secretion of FVIII protein. Further, it has been reported that over-expression of the FVIII protein induces endoplasmic reticulum stress and activates the unfolded protein response pathway both in vitro and in hepatocytes in vivo , presumably due to retention of misfolded FVIII protein within the endoplasmic reticulum. Engineering of the F8 transgene, including removal of the B domain (BDD-FVIII) and codon optimization, now allows for the generation of adeno-associated virus vectors capable of expressing therapeutic levels of FVIII. Here we sought to determine if the risks of inducing the unfolded protein response in murine hepatocytes extend to adeno-associated virus gene transfer. Although our data show a mild activation of unfolded protein response markers following F8 gene delivery at a certain vector dose in C57BL/6 mice, it was not augmented upon further elevated dosing, did not induce liver pathology or apoptosis, and did not impact FVIII immunogenicity.

Adeno-associated viral (AAV) vectors are currently being tested in multiple clinical trials for liver-directed gene transfer to treat the bleeding disorders hemophilia A and B and metabolic disorders. The optimal viral capsid for transduction of human hepatocytes has been under active investigation, but results across various models are inconsistent. We tested in vivo transduction in "humanized" mice. Methods to quantitate percent AAV transduced human and murine hepatocytes in chimeric livers were optimized using flow cytometry and confocal microscopy with image analysis. Distinct transduction efficiencies were noted following peripheral vein administration of a self-complementary vector expressing a gfp reporter gene. An engineered AAV3 capsid with two amino acid changes, S663V+T492V (AAV3-ST), showed best efficiency for human hepatocytes (~3-times, ~8-times, and ~80-times higher than for AAV9, AAV8, and AAV5, respectively). AAV5, 8, and 9 were more efficient in transducing murine than human hepatocytes. AAV8 yielded the highest transduction rate of murine hepatocytes, which was 19-times higher than that for human hepatocytes. In summary, our data show substantial differences among AAV serotypes in transduction of human and mouse hepatocytes, are the first to report on AAV5 in humanized mice, and support the use of AAV3-based vectors for human liver gene transfer.

Recombinant adeno-associated virus (rAAV) serotype 2, 3 and 8 vectors are the most promising liver-tropic AAV serotype vectors. Liver diseases are significant problems in China. However, to date, few studies on AAV neutralizing antibodies (Nabs) were working with the Chinese population or with the rAAV3 vectors. The present study aimed to determine the prevalence of Nabs in Chinese population against wild-type AAV2, AAV3 and AAV8 capsids as well as additional two AAV3 variants. In addition, we performed a preliminary analysis to investigate the potential influence of traditional Chinese medicine body constitutions on AAV Nabs. Our work demonstrated that the majority of healthy Chinese subjects were positive for AAV Nabs, with the order of AAV2>AAV3=AAVLK03>AAV8. There was no difference between: 1) AAV3 and its variants; 2) male and female subjects; and 3) different age cohorts (≤35, 36-50, and ≥51 years old). People in the Qi-deficiency constitution had significantly increased AAV8 Nabs than people in the Gentleness constitution. Our studies may have impact on the future clinical design of AAV-based gene therapy in the Chinese population.

Compact elliptical galaxies form a rare class of stellar system (~30 presently known) characterized by high stellar densities and small sizes and often harboring metal-rich stars. They were thought to form through tidal stripping of massive progenitors, until two isolated objects were discovered where massive galaxies performing the stripping could not be identified. By mining astronomical survey data, we have now found 195 compact elliptical galaxies in all types of environment. They all share similar dynamical and stellar population properties. Dynamical analysis for nonisolated galaxies demonstrates the feasibility of their ejection from host clusters and groups by three-body encounters, which is in agreement with numerical simulations. Hence, isolated compact elliptical and isolated quiescent dwarf galaxies are tidally stripped systems that ran away from their hosts., (Copyright © 2015, American Association for the Advancement of Science.)

The immune system represents a significant barrier to successful gene therapy with adeno-associated viral (AAV) vectors. In particular, adaptive immune responses to the viral capsid or the transgene product are of concern. The sensing of AAV by toll-like receptors (TLRs) TLR2 and TLR9 has been suggested to play a role in innate immunity to the virus and may also shape subsequent adaptive immune responses. Here, we investigated the functions of TLR2, TLR9 and the downstream signaling adaptor MyD88 in antibody and CD8+ T-cell responses. Antibody formation against the transgene product occurred largely independently of TLR signaling following gene transfer with AAV1 or AAV2 vectors, whereas loss of signaling through the TLR9-MyD88 pathway substantially reduced CD8+ T-cell responses. In contrast, MyD88 (but neither of the TLRs) regulated antibody responses to capsid. B cell-intrinsic MyD88 was required for the formation of anti-capsid IgG2c independently of vector serotype or route of administration. However, MyD88(-/-) mice instead produced anti-capsid IgG1 that emerged with delayed kinetics but nonetheless completely prevented in vivo readministration. We conclude that there are distinct roles for TLR9 and MyD88 in promoting adaptive immune responses to AAV-mediated gene transfer and that there are redundant MyD88-dependent and MyD88-independent mechanisms that stimulate neutralizing antibody formation against AAV., (© 2015 S. Karger AG, Basel.)

Gene therapy is a promising therapeutic approach for genetic and acquired diseases nowadays. Among DNA delivery vectors, recombinant adeno-associated virus (rAAV) is one of the most effective and safest vectors used in commercial drugs and clinical trials. However, the current yield of rAAV biomanufacturing lags behind the necessary dosages for clinical and commercial use, which embodies a concentrated reflection of low productivity of rAAV from host cells, difficult scalability of the rAAV-producing bioprocess, and high levels of impurities materialized during production. Those issues directly impact the price of gene therapy medicine in the market, limiting most patients' access to gene therapy. In this context, the current practices and several critical challenges associated with rAAV gene therapy bioprocesses are reviewed, followed by a discussion of recent advances in rAAV-mediated gene therapy and other therapeutic biological fields that could improve biomanufacturing if these advances are integrated effectively into the current systems. This review aims to provide the current state-of-the-art technology and perspectives to enhance the productivity of rAAV while reducing impurities during production of rAAV., (© 2023 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals LLC.)

Gene transfer with high doses of adeno-associated viral (AAV) vectors has resulted in serious adverse events and even death of the recipients. Toxicity could most likely be circumvented by repeated injections of lower and less toxic doses of vectors. This has not been pursued as AAV vectors induce potent neutralizing antibodies, which prevent cell transduction upon reinjection of the same vector. This review discusses different types of immune responses against AAV vectors and how they offer targets for the elimination or inhibition of vector-specific neutralizing antibodies. Such antibodies can be circumvented by using different virus serotypes for sequential injections, they can be removed by plasmapheresis, or they can be destroyed by enzymatic degradation. Antibody producing cells can be eliminated by proteasome inhibitors. Drugs that inhibit T-cell responses, B-cell signaling, or presentation of the vector's antigens to B cells can prevent or reduce induction of AAV-specific antibodies. Combinations of different approaches and drugs are likely needed to suppress or eliminate neutralizing antibodies, which would then allow for repeated dosing. Alternatively, novel AAV vectors with higher transduction efficacy are being developed and may allow for a dose reduction, although it remains unknown if this will completely address the problem of high-dose adverse events., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Cellular 3D structures, for example, organoids, are an excellent model for studying and developing treatments for various diseases, including hereditary ones. Therefore, they are increasingly being used in biomedical research. From the point of view of safety and efficacy, recombinant adeno-associated viral (rAAV) vectors are currently most in demand for the delivery of various transgenes for gene replacement therapy or other applications. The delivery of transgenes using rAAV vectors to various types of organoids is an urgent task, however, it is associated with a number of problems that are discussed in this review. Cellular heterogeneity and specifics of cultivation of 3D structures determine the complexity of rAAV delivery and are sometimes associated with low transduction efficiency. This review surveys the main ways to solve emerging problems and increase the efficiency of transgene delivery using rAAVs to organoids. A clear understanding of the stage of development of the organoid, its cellular composition and the presence of surface receptors will allow obtaining high levels of organoid transduction with existing rAAV vectors., (© 2022 Wiley Periodicals LLC.)

Over the past years, many significant advances have been made in the field of gene therapy and shown promising results in clinical trials conducted. Gene therapy aims at modifying or replacing a defective, inefficient, or nonfunctional gene with a healthy, functional gene by administration of genome material into the cell to cure genetic diseases. Various methods have been devised to do this by using several viral and non-viral vectors which are either administered by in vivo or ex vivo technique. Viral vectors are best suitable for this therapy due to their potential to invade cells and deliver their genetic material whereas non-viral vectors are less efficient than viral vectors but possess some advantages such as less immunogenic response and large gene carrying capacity. Recent advances in biotechnology such as CRISPR-Cas9 mediated genome engineering and Cancer treatment with Chimeric antigen receptor (CAR) T-cell therapy are addressed in this review. This review article also delves into some recent research studies, gene therapy trials, and its applications, laying out future hopes for gene therapy in the treatment of various diseases namely haemophilia, Muscular dystrophy, SCID, Sickle cell disease, Familial Hypercholesterolemia, Cystic Fibrosis. Additionally, it also includes various nanoformulations and clinical trial data related to gene therapy., Competing Interests: Declarations. Conflict of Interest: None., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Serotonin (5-hydroxytryptamine, 5-HT) is a very important neurotransmitter emerging from the raphe nuclei to several brain regions. Serotonergic neuronal connectivity has multiple functions in the brain. In this study, several techniques were used to trace serotonergic neurons in the dorsal raphe (DR) and median raphe (MnR) that project toward the arcuate nucleus of the hypothalamus (Arc), dorsomedial hypothalamic nucleus (DM), lateral hypothalamic area (LH), paraventricular hypothalamic nucleus (PVH), ventromedial hypothalamic nucleus (VMH), fasciola cinereum (FC), and medial habenular nucleus (MHb). Cholera toxin subunit B (CTB), retro-adeno-associated virus (rAAV-CMV-mCherry), glycoprotein-deleted rabies virus (RV-ΔG), and simultaneous microinjection of rAAV2-retro-Cre-tagBFP with AAV-dio-mCherry in C57BL/6 mice were used in this study. In addition, rAAV2-retro-Cre-tagBFP was microinjected into Ai9 mice. Serotonin immunohistochemistry was used for the detection of retrogradely traced serotonergic neurons in the raphe nuclei. The results indicated that rAAV2-retro-Cre-tagBFP microinjection in Ai9 mice was the best method for tracing serotonergic neuron circuits. All of the previously listed nuclei exhibited serotonergic neuronal projections from the DR and MnR, with the exception of the FC, which had very few projections from the DR. The serotonergic neuronal projections were directed toward the Arc by the subpeduncular tegmental (SPTg) nuclei. Moreover, the RV-ΔG tracer revealed monosynaptic non-serotonergic neuronal projections from the DR that were directed toward the Arc. Furthermore, rAAV tracers revealed monosynaptic serotonergic neuronal connections from the raphe nuclei toward Arc. These findings validate the variations in neurotropism among several retrograde tracers. The continued discovery of several novel serotonergic neural circuits is crucial for the future discovery of the functions of these circuits. RESEARCH HIGHLIGHTS: Various kinds of retrograde tracers were microinjected into C57BL/6 and Ai9 mice. The optimum method for characterizing serotonergic neuronal circuits is rAAV2-retro-Cre-tagBFP microinjection in Ai9 mice. The DR, MnR, and SPTg nuclei send monosynaptic serotonergic neuronal projections toward the arcuate nucleus of the hypothalamus. Whole-brain quantification analysis of retrograde-labeled neurons in different brain nuclei following rAAV2-retro-Cre-tagBFP microinjection in the Arc, DM, LH, and VMH is shown. Differential quantitative analysis of median and dorsal raphe serotonergic neurons emerging toward the PVH, DM, LH, Arc, VMH, MHb, and FC is shown., (© 2024 Wiley Periodicals LLC.)

Recombinant adeno-associated viruses (rAAVs) are promising vectors for the delivery of various genetic constructs into eukaryotic cells. rAAVs have a number of properties that make it possible to successfully use them both in vitro and in vivo. Purification and concentration of rAAV vectors are critical for achieving high viral titer, stability, efficiency, and purity. This review systematically analyses all available purification approaches. The purification methods described in this work differ substantially from each other in mechanisms, efficiency, labor time, and cost. Researchers have to choose a purification algorithm depending on the purpose of their work. We strive to simplify the choice of the necessary and sufficient technique based on the experimental needs and available resources of the laboratory., (© 2022 Wiley Periodicals LLC.)

There is a strong and growing interest in the development and production of gene therapy products, including those utilizing adeno-associated virus (AAV) particles. This is evident with the increase in the number of clinical trials and agency approvals for AAV therapeutics. As bioproduction of AAV viral vectors matures, a quality by design (QbD) approach to process development can aid in process robustness and product quality. Furthermore, it may become a regulatory expectation. The first step in any QbD approach is to determine what physical, chemical, biological, or microbiological property or characteristic product attributes should be controlled within an appropriate limit, range, or distribution to ensure the desired product quality. Then predefined goals are set to allow proactive process development to design in quality. This review lists typical quality attributes used for release testing of AAV viral vectors and discusses these and selected attributes important to extended characterization studies in terms of safety, efficacy, and impact upon the patient immune response., (© 2021 Wiley Periodicals LLC.)

Purpose: Umbilical hernias (UH) have a higher prevalence than previously considered. With the high workload radiologists must endure, UH can be missed when interpreting a computed tomography scan (CT). The clinical implications of its misdiagnosis are yet to be determined. Unreporting could lead to content lesions in surgical approaches and other potential complications. The aim was to determine the prevalence of UH using CT scans, and the incidence of radiological reporting., Methods: A multicenter, cross-sectional study was performed in four tertiary-level hospitals. CT scans were reviewed for abdominal wall defects at the umbilicus, and radiological reports were examined to compare findings. In the case of UH, transversal, anteroposterior, and craniocaudal lengths were obtained., Results: A total of 1557 CTs were included, from which 971 (62.4%, 95% CI 0.59-0.64) had UH. Out of those, 629 (64.8%, 95% CI 0.61-0.67) of the defects were not included in the radiological report. Smaller UH (x̄: 7.7 × 6.0 mm) were more frequently missed. Of the reported UH, 187 (54.7%) included at least one axis measurement, 289 (84.5%) content description, and 146 (42.7%) whether or not there were complication signs., Conclusion: There is a high prevalence of UH, and a high incidence of under-reporting. This raises the question of whether this is a population-based finding or the norm worldwide. The reason of under-reporting and the clinical implications of these must be addressed in further studies., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Recombinant adeno-associated virus, serotype 9 (rAAV9) has shown promise as a gene therapy vector for muscle and central nervous diseases. High-dose requirements of these therapies present critical safety considerations and biomanufacturing challenges. Notably, the reduction of empty capsids (ECs), which lack therapeutic transgene, from rAAV9 products is critical to maximize efficacy. Removal of rAAV ECs from full capsids is a major downstream challenge because of their highly similar biophysical characteristics. Ultracentrifugation (UC) reduces ECs but is laborious and difficult to scale. In this paper, to replace a poorly scalable UC process, we developed an anion exchange (AEX) chromatography for rAAV9 EC reduction from full capsids. AEX load preparation by dilution incurred major product loss. The addition of histidine and surfactants to dilution buffers increased yield and reduced aggregation. Elution salts were screened and sodium acetate was found to maximize yield and EC reduction. The most promising load dilution buffer and elution salt were used in combination to form an optimized AEX method. The process reduced ECs three-fold, demonstrated robustness to a broad range of EC load challenges, and was scaled for large-scale manufacture. Compared to UC, the AEX method simplified scale-up, reduced ECs to comparable levels (20%), afforded similar purity and product quality, and increased yield by 14%., (© 2024 Wiley Periodicals LLC.)

Viral vectors can be utilised to deliver therapeutic genes to diseased cells. Adeno-associated virus (AAV) is a commonly used viral vector that is favoured for its ability to infect a wide range of tissues whilst displaying limited toxicity and immunogenicity. Most humans harbour anti-AAV neutralising antibodies (NAbs) due to subclinical infections by wild-type virus during infancy and these pre-existing NAbs can limit the efficiency of gene transfer depending on the target cell type, route of administration and choice of serotype. Vector administration can also result in de novo NAb synthesis that could limit the opportunity for repeated gene transfer to diseased sites. A number of strategies have been described in preclinical models that could circumvent NAb responses in humans, however, the successful translation of these innovations into the clinical arena has been limited. Here, we provide a comprehensive review of the humoral immune response to AAV gene therapy in the ocular compartment. We cover basic AAV biology and clinical application, the role of pre-existing and induced NAbs, and possible approaches to overcoming antibody responses. We conclude with a framework for a comprehensive strategy for circumventing humoral immune responses to AAV in the future., (© 2021 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.)

Mucopolysaccharidosis type IIIB (MPS IIIB) is an autosomal recessive lysosomal disease caused by defective production of the enzyme α-N-acetylglucosaminidase. It is characterized by severe and complex central nervous system degeneration. Effective therapies will likely target early onset disease and overcome the blood-brain barrier. Modifications of adeno-associated viral (AAV) vector capsids that enhance transduction efficiency have been described in the retina. Herein, we describe for the first time, a transduction assessment of two intracranially administered adeno-associated virus serotype 8 variants, in which specific surface-exposed tyrosine (Y) and threonine (T) residues were substituted with phenylalanine (F) and valine (V) residues, respectively. A double-mutant (Y444 + 733F) and a triple-mutant (Y444 + 733F + T494V) AAV8 were evaluated for their efficacy for the potential treatment of MPS IIIB in a neonatal setting. We evaluated biodistribution and transduction profiles of both variants compared to the unmodified parental AAV8, and assessed whether the method of vector administration would modulate their utility. Vectors were administered through four intracranial routes: six sites (IC6), thalamic (T), intracerebroventricular, and ventral tegmental area into neonatal mice. Overall, we conclude that the IC6 method resulted in the widest biodistribution within the brain. Noteworthy, we demonstrate that GFP intensity was significantly more robust with AAV8 (double Y-F + T-V) compared to AAV8 (double Y-F). This provides proof of concept for the enhanced utility of IC6 administration of the capsid modified AAV8 (double Y-F + T-V) as a valid therapeutic approach for the treatment of MPS IIIB, with further implications for other monogenic diseases., (© 2020. The Author(s), under exclusive licence to Springer Nature Limited.)

The cation channel transient receptor potential melastatin 4 (TRPM4) is a calcium-activated non-selective cation channel and acts in cardiomyocytes as a negative modulator of the L-type Ca 2+ influx. Global deletion of TRPM4 in the mouse led to increased cardiac contractility under β-adrenergic stimulation. Consequently, cardiomyocyte-specific inactivation of the TRPM4 function appears to be a promising strategy to improve cardiac contractility in heart failure patients. The aim of this study was to develop a gene therapy approach in mice that specifically silences the expression of TRPM4 in cardiomyocytes. First, short hairpin RNA miR30 (shRNA miR30 ) sequences against the TRPM4 mRNA were screened in vitro using lentiviral transduction for a stable expression of the shRNA cassettes. Western blot analysis identified three efficient shRNA miR30 sequences out of six, which reduced the endogenous TRPM4 protein level by up to 90 ± 6%. Subsequently, the most efficient shRNA miR30 sequences were delivered into cardiomyocytes of adult mice using adeno-associated virus serotype 9 (AAV9)-mediated gene transfer. Initially, the AAV9 vector particles were administered via the lateral tail vein, which resulted in a downregulation of TRPM4 by 46 ± 2%. Next, various optimization steps were carried out to improve knockdown efficiency in vivo. First, the design of the expression cassette was streamlined for integration in a self-complementary AAV vector backbone for a faster expression. Compared to the application via the lateral tail vein, intravenous application via the retro-orbital sinus has the advantage that the vector solution reaches the heart directly and in a high concentration, and eventually a TRPM4 knockdown efficiency of 90 ± 7% in the heart was accomplished by this approach. By optimization of the shRNA miR30 constructs and expression cassette as well as the route of AAV9 vector application, a 90% reduction of TRPM4 expression was achieved in the adult mouse heart. In the future, AAV9-RNAi-mediated inactivation of TRPM4 could be a promising strategy to increase cardiac contractility in preclinical animal models of acute and chronic forms of cardiac contractile failure.

Haemophilia is at the dawn of a new era in therapeutic management, one that can generate greater protection from bleeding and a functional cure in some individuals. Prior advances in protein engineering and monoclonal antibody technology have facilitated therapeutic options to maintain decreased risk of bleeding and less burdensome treatment. The use of gene transfer, first proposed in 1971 for monogenic diseases, is emerging as an effective long-term treatment for a variety of diseases. Transfer of functional factor VIII (FVIII) and factor IX (FIX) genes has witnessed a series of advances and setbacks since the first non-clinical experiments in animals were initiated nearly 30 years ago. More recently, multiyear therapeutic levels of FVIII and FIX activity have been achieved in human clinical trials, translated into meaningful clinical benefit and a functional cure. While clinical progress has been definitive, many questions remain unanswered as prelicensure phase 3 clinical trials are underway. These unanswered questions translate into a state of uncertainty about the known unknowns and unknown unknowns intrinsic to any new therapeutic platform. Accepting this modality as a means to functionally cure haemophilia also means accepting the uncertainty regarding the biology of viral vector-mediated gene transfer, which remains inadequately understood. Gene therapy is a far more complex biological 'drug' than small molecule and protein drugs, where manufacturing processes and the drugs themselves are now well characterized. Extent of community acceptance of uncertainty and acknowledgement of the need for an uncompromising drive for answers to the unknowns will characterize the introduction of this first generation of gene therapy for haemophilia to the wider patient population in both resource-rich and resource-poor countries., (© 2020 John Wiley & Sons Ltd.)

Recombinant adeno-associated virus (rAAV) is a mammalian virus that has been altered to be used as a gene delivery vehicle. Several changes to the viral genome have made them replication deficient so that this aspect of the viral infection cycle is under full control of the experimenter, while maintaining gene expression machinery. Over the last decades, rAAVs have become the gold standard for studying in vivo gene function and are especially favorable for gene transfer in the central nervous system. AAVs have been proven safe and provide stable gene expression over a long period of time. They are extensively used in preclinical experiments and show great potential for clinical applications. However, the use of AAVs in preclinical settings are often held back due to availability. Waiting lines are long at commercial production facilities, and in-lab production is hindered due to lack of specific laboratory equipment needed. Here we present a novel production method that can be carried out in any molecular biology laboratory using standard laboratory equipment. We provide a simple, fast, and streamlined protocol for production that can result in titers comparable with the more time-consuming iodixanol gradient ultracentrifugation method. The yield using this protocol is high enough for any type of study where AAV is the vector of choice. © 2020 The Authors., (© 2020 The Authors.)

Lentiviral vectors (LV) are efficient vehicles for in vivo gene delivery to the liver. LV integration into the chromatin of target cells ensures their transmission upon proliferation, thus allowing potentially life-long gene therapy following a single administration, even to young individuals. The glycoprotein of the vesicular stomatitis virus (VSV.G) is widely used to pseudotype LV, as it confers broad tropism and high stability. The baculovirus-derived GP64 envelope protein has been proposed as an alternative for in vivo liver-directed gene therapy. Here, we perform a detailed comparison of VSV.G- and GP64-pseudotyped LV in vitro and in vivo. We report that VSV.G-LV transduced hepatocytes better than GP64-LV, however the latter showed improved transduction of liver sinusoidal endothelial cells (LSEC). Combining GP64-pseudotyping with the high surface content of the phagocytosis inhibitor CD47 further enhanced LSEC transduction. Coagulation factor VIII (FVIII), the gene mutated in hemophilia A, is naturally expressed by LSEC, thus we exploited GP64-LV to deliver a FVIII transgene under the control of the endogenous FVIII promoter and achieved therapeutic amounts of FVIII and correction of hemophilia A mice., (© 2024. The Author(s).)

Recent advancements have focused on enhancing factor VIII half-life and refining its delivery methods, despite the well-established knowledge that factor VIII deficiency is the main clotting protein lacking in hemophilia. Consequently, both viral and non-viral delivery systems play a crucial role in enhancing the quality of life for hemophilia patients. The utilization of viral vectors and the manipulation of non-viral vectors through targeted delivery are significant advancements in the field of cellular and molecular therapies for hemophilia. These developments contribute to the progression of treatment strategies and hold great promise for improving the overall well-being of individuals with hemophilia. This review study comprehensively explores the application of viral and non-viral vectors in cellular (specifically T cell) and molecular therapy approaches, such as RNA, monoclonal antibody (mAb), and CRISPR therapeutics, with the aim of addressing the challenges in hemophilia treatment. By examining these innovative strategies, the study aims to shed light on potential solutions to enhance the efficacy and outcomes of hemophilia therapy., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Although therapeutic outcomes have been achieved in hemophilia patients after delivery of clotting factor genes to the liver using adeno-associated virus (AAV) vectors, it is well known that the preclinical results generated from hemophilia animal models have not been directly predictive of successful translation in humans. To address this discrepancy humanized mouse models have recently been used to predict AAV transduction efficiency for human hepatocytes. In this study we evaluated AAV vector transduction from several serotypes in human liver hepatocytes xenografted into chimeric mice. After systemic administration of AAV vectors encoding a GFP transgene in humanized mice, the liver was harvested for either immunohistochemistry staining or flow cytometry assay for AAV human hepatocyte transduction analysis. We observed that AAV7 consistently transduced human hepatocytes more efficiently than other serotypes in both immunohistochemistry assay and flow cytometry analysis. To better assess the future application of AAV7 for systemic administration in the treatment of hemophilia or other liver diseases, we analyzed the prevalence of neutralizing antibodies (NAbs) to AAV7 in sera from healthy subjects and patients with hemophilia. In the general population, the prevalence of NAbs to AAV7 was lower than that of AAV2 or AAV3B. However, a higher prevalence of AAV7 NAbs was found in patients with hemophilia. In summary, results from this study suggest that AAV7 vectors should be considered as an effective vehicle for human liver targeting in future clinical trials.

Purpose: This study aimed to perform a systematic review and meta-analysis comparing the efficacy and safety outcomes of robotic-assisted and laparoscopic techniques for incisional hernia repair., Methods: PubMed, Embase, Scopus, Cochrane databases, and conference abstracts were systematically searched for studies that directly compared robot-assisted versus laparoscopy for incisional hernia repair and reported safety or efficacy outcomes in a follow-up of ≥ 1 month. The primary endpoints of interest were postoperative complications and the length of hospital stay., Results: The search strategy yielded 2104 results, of which four studies met the inclusion criteria. The studies included 1293 patients with incisional hernia repairs, 440 (34%) of whom underwent robot-assisted repair. Study follow-up ranged from 1 to 24 months. There was no significant difference between groups in the incidence of postoperative complications (OR 0.65; 95% CI 0.35-1.21; p = 0.17). The recurrence rate of incisional hernias (OR 0.34; 95% CI 0.05-2.29; p = 0.27) was also similar between robotic and laparoscopic surgeries. Hospital length of stay (MD - 1.05 days; 95% CI - 2.06, - 0.04; p = 0.04) was significantly reduced in the robotic-assisted repair. However, the robot-assisted repair had a significantly longer operative time (MD 69.6 min; 95% CI 59.0-80.1; p < 0.001)., Conclusion: The robotic approach for incisional hernia repair was associated with a significant difference between the two groups in complications and recurrence rates, a longer operative time than laparoscopic repair, but with a shorter length of stay., (© 2023. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Recombinant adeno-associated virus (rAAV) is widely used as an in vivo delivery vector for gene therapy. It is used in a very large dose, and the large quantities required for broad applications present manufacturing challenges. We have developed a synthetic biology platform of constructing cell lines integrated with essential viral genes which can be induced to produce rAAV without plasmid transfection or virus transduction. Through iterative design-construct-characterization cycles, we have showcased the potential of this synthetic cell production system. Systems characterization of the dynamics of viral transcripts and proteins as well as virus assembly and packaging revealed that the expression level and balance of viral genome and capsid protein are keys to not only the productivity but also the full particle content, an important product quality attribute. Boosting cap gene expression by sequential transfection and integration of multiple copies of the cap gene elevated the rAAV titer to levels on a par with traditional plasmid transfection and virus infection. However, overexpression of the cap gene shifted the balance and kinetics of the genome and capsid. We independently tuned the dynamics of genome amplification and capsid protein synthesis by modulating the induction concentration as well as the time profile, and significantly enhanced full particle content while maintaining a high productivity. This strategy of constructing an inducible stable producer cell line is readily adaptable to rAAV vectors of different serotypes and payloads. It can greatly facilitate scalable production of gene therapy vectors., (© 2024 The Authors. Biotechnology Journal published by Wiley-VCH GmbH.)

Recombinant adeno-associated viruses (AAVs) have emerged as a popular tool for gene therapy in the central nervous system (CNS). Given the dense vasculature in the CNS, systemic administration is an appealing approach for achieving a broad distribution of AAV vectors across the CNS. However, the blood-brain barrier (BBB) is a major obstacle that blocks the entry of AAV vectors into the brain and spinal cord. Thus, there is a great need to develop novel AAV vector technology with enhanced BBB penetration. In this chapter, we briefly summarize AAV biology, possible mechanisms for AAV vectors to overcome the BBB and further engineering strategies, and current clinical trials using systemic AAV gene therapy for CNS diseases., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Here, we describe methods for the production of adeno-associated viral (AAV) vectors by transient transfection of HEK293 cells grown in serum-free medium using orbital shaken bioreactors and the subsequent purification of vector particles. The protocol for expression of AAV components is based on polyethyleneimine (PEI)-mediated transfection of a three-plasmid system and is specified for production in milliliter-to-liter scales. After PEI and plasmid DNA (pDNA) complex formation, the diluted cell culture is transfected without a prior concentration step or medium exchange. Following a 7-day batch process, cell cultures are further processed using a set of methods for cell lysis and vector recovery. Methods for the purification of viral particles are described, including immunoaffinity and anion-exchange chromatography, ultrafiltration, as well as digital PCR to quantify the concentration of vector particles., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Gene therapy clinical trials are rapidly expanding for inherited metabolic liver diseases whilst two gene therapy products have now been approved for liver based monogenic disorders. Liver-directed gene therapy has recently become an option for treatment of haemophilias and is likely to become one of the favoured therapeutic strategies for inherited metabolic liver diseases in the near future. In this review, we present the different gene therapy vectors and strategies for liver-targeting, including gene editing. We highlight the current development of viral and nonviral gene therapy for a number of inherited metabolic liver diseases including urea cycle defects, organic acidaemias, Crigler-Najjar disease, Wilson disease, glycogen storage disease Type Ia, phenylketonuria and maple syrup urine disease. We describe the main limitations and open questions for further gene therapy development: immunogenicity, inflammatory response, genotoxicity, gene therapy administration in a fibrotic liver. The follow-up of a constantly growing number of gene therapy treated patients allows better understanding of its benefits and limitations and provides strategies to design safer and more efficacious treatments. Undoubtedly, liver-targeting gene therapy offers a promising avenue for innovative therapies with an unprecedented potential to address the unmet needs of patients suffering from inherited metabolic diseases., (© 2024 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM.)

Recombinant adeno-associated virus (rAAV) is among the most commonly used in vivo gene delivery vehicles and has seen a number of successes in clinical application. Current manufacturing processes of rAAV employ multiple plasmid transfection or rely on virus infection and face challenges in scale-up. A synthetic biology approach was taken to generate stable cell lines with integrated genetic modules, which produced rAAV upon induction albeit at a low productivity. To identify potential factors that restrained the productivity, we systematically characterized virus production kinetics through targeted quantitative proteomics and various physical assays of viral components. We demonstrated that reducing the excessive expression of gene of interest by its conditional expression greatly increased the productivity of these synthetic cell lines. Further enhancement was gained by optimizing induction profiles and alleviating proteasomal degradation of viral capsid protein by the addition of proteasome inhibitors. Altogether, these enhancements brought the productivity close to traditional multiple plasmid transfection. The rAAV produced had comparable full particle contents as those produced by conventional transient plasmid transfection. The present work exemplified the versatility of our synthetic biology-based viral vector production platform and its potential for plasmid- and virus-free rAAV manufacturing., (© 2023 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals LLC.)