Biology subjects

Volk, H.-D.

Publications and source records attributed to Volk, H.-D..

3 recordsLinked to original sources

bioRxiv2018

Placental-expanded, mesenchymal cells improve muscle function following hip arthroplasty

BackgroundNo regenerative approach has thus far been shown to be effective in skeletal muscle injuries, despite high frequency and associated functional deficits. We sought to address surgical trauma related muscle injuries using local intraoperative application of allogeneic placenta-derived, mesenchymal-like adherent cells (PLX-PAD), using hip arthroplasty as a standardized injury model, because of the high regenerative and immunomodulatory potency of this cell type.\n\nMethodsOur pilot phase I/IIa study was prospective, randomized, double blind and placebo-controlled. Twenty patients undergoing hip arthroplasty via a direct lateral approach were injected with 3.0x108 or 1.5x108 PLX-PAD or a placebo into the gluteus medius muscle.\n\nResultsWe did not observe any relevant PLX-PAD-related adverse events at the 2-year follow-up. Improved gluteus medius strength was noted as early as week 6 in the treatment-groups. Surprisingly, until week 26 the low-dose outperformed the high-dose group and reached significantly improved strength compared to placebo, mirrored by an increase in muscle volume. Histology indicated accelerated healing after cell therapy. Biomarker studies revealed that low-dose treatment reduced the surgery-related immunological stress reaction more than high-dose. Signs of late-onset immune reactivity after high-dose treatment corresponded to reduced functional improvement.\n\nConclusionAllogeneic PLX-PAD therapy improved strength and volume of injured skeletal muscle with a reasonable safety profile. Outcomes could be positively correlated with the modulation of early postoperative stress-related immunological reactions.\n\nTrial RegistrationClinicalTrials.gov (number NCT01525667) and EudraCT (number 2011-003934-16)\n\nFundingThe study was funded by the Sponsor, Pluristem Therapeutics, the Israeli innovation authority and the German Federal Ministry of Education and Research.\n\nConflict of interestT. Winkler, C. Perka and G.N. Duda are members of a clinical advisory board of Pluristem Ltd for future indications. T. Winkler, C. Perka, G.N. Duda, P. von Roth filed a patent together with Pluristem Ltd. E. Lukasiewicz Hagai, R. Ofir, L. Pinzur and E. Eyal are current or former employees of Pluristem Ltd. T. Winkler, P. Reinke and H.-D. Volk received in the past consulting fees from Pluristem Ltd. but not for this project.

clinical trials↗

bioRxiv2018

High prevalence of S. pyogenes Cas9-specific T cell sensitization within the adult human population - A balanced effector/regulatory T cell response

Summary ParagraphThe field of gene therapy has been galvanized by the discovery of the highly efficient and adaptable site-specific nuclease system CRISPR/Cas9 from bacteria.1,2 Immunity against therapeutic gene vectors or gene-modifying cargo nullifies the effect of a possible curative treatment and may pose significant safety issues.3-5 Immunocompetent mice treated with CRISPR/Cas9-encoding vectors exhibit humoral and cellular immune responses against the Cas9 protein, that impact the efficacy of treatment and can cause tissue damage.5,6 Most applications aim to temporarily express the Cas9 nuclease in or deliver the protein directly into the target cell. Thus, a putative humoral antibody response may be negligible.5 However, intracellular protein degradation processes lead to peptide presentation of Cas9 fragments on the cellular surface of gene-edited cells that may be recognized by T cells. While a primary T cell response could be prevented or delayed, a pre-existing memory would have major impact. Here, we show the presence of a ubiquitous memory/effector T cell response directed towards the most popular Cas9 homolog from Streptococcus pyogenes (SpCas9) within healthy human subjects. We have characterized SpCas9-reactive memory/effector T cells (TEFF) within the CD4/CD8 compartments for multi-effector potency and lineage determination. Intriguingly, SpCas9-specific regulatory T cells (TREG) profoundly contribute to the pre-existing SpCas9-directed T cell immunity. The frequency of SpCas9-reactive TREG cells inversely correlates with the magnitude of the respective TEFF response. SpCas9-specific TREG may be harnessed to ensure the success of SpCas9-mediated gene therapy by combating undesired TEFF response in vivo. Furthermore, the equilibrium of Cas9-specific TEFF and TREG cells may have greater importance in Streptococcus pyogenes-associated diseases. Our results shed light on the T cell mediated immunity towards the much-praised gene scissor SpCas9 and offer a possible solution to overcome the problem of pre-existing immunity.

immunology↗

bioRxiv2018

Distinct housing conditions reveal a major impact of adaptive immunity on the course of obesity-induced type 2 diabetes

Obesity is associated with adipose tissue inflammation, insulin resistance and the development of type 2 diabetes. However, our knowledge is mostly based on conventional murine models and promising pre-clinical studies rarely translated into successful therapies.\n\nThere is a growing awareness of the limitations of studies in laboratory mice, housed in abnormally hygienic specific pathogen-free (SPF) conditions, as relevant aspects of the human immune system remain unappreciated. Here, we assessed the impact of housing conditions on adaptive immunity and metabolic disease processes during high-fat diet. We therefore compared diet-induced obesity in SPF mice with those housed in non-SPF, so called \"antigen exposed\" (AE) conditions. Surprisingly, AE mice fed a high-fat diet maintained increased insulin levels to compensate for insulin resistance, which was reflected in islet hyperplasia and improved glucose tolerance compared to SPF mice. In contrast, we observed higher proportions of effector/memory T cell subsets in blood and liver of high-fat diet AE mice accompanied by the development of nonalcoholic steatohepatitis-like liver pathology. Thus, our data demonstrate the impact of housing conditions on metabolic alterations. Studies in AE mice, in which physiological microbial exposure was restored, could provide a tool for revealing therapeutic targets for immune-based interventions for type 2 diabetes patients.

immunology↗