Allogeneic Biomaterials Research Articles

Применение аллогенного диспергированного биоматериала для профилактики рубцовых осложнений при реплантации конечностей (экспериментальное исследование)

Aim: during research study, to identify the nature of cicatricial changes after limb replantation and to study the possibility of preventing fibrosis using an allogeneic biomaterial. Materials and Methods: the research was conducted on 48 male rats (24 each in the control and experimental groups). The operation consisted of a circular incision of soft tissues in the middle third thigh, followed by microvascular stitches of blood vessels, nerves, muscles and skin. In the experimental group, a dispersed allogeneic biomaterial (DAB), which is a sterile powder prepared from decellularized connective tissue, was applied to wound surfaces before stitching. The subjects were withdrawn from the study 7, 14, 30 and 90 days after surgery. Tissue samples from the surgical area were subjected to histology and immunohistochemistry: the expression of transforming growth factor (TGF-β1), tumor necrosis factor (TNF-α), antigen of the main histocompatibility complex (HLA-DR), myosatellitocyte marker (MyoD) was evaluated. Results: in the control group 90 days after surgery, fibroblastic sleeve was found around the vessels and nerves, as well as fibroblast foci between the stitched muscles, therefore, a typical picture of aseptic inflammation. This process was accompanied by high TGF-β1 and HLA-DR expression with low TNF-α expression. In the experimental group, DAB particles were biodegraded by macrophages and resorption. Fibrous membranes around the stitched vessels and nerves consisted of collagen fibers thinner than in the control group. Cicatricial changes were not detected at the sites of muscle stitching. At a later date (30 and 90 days), the vessels and nerves were surrounded by thin collagen fibers. TNF-α expression significantly exceeded that in the control group, while the TGF-β1 and HLA-DR expression remained at a low level. Given time (90 days), a defect cicatrization and a decrease in these cytokines expression were detected in both groups. Starting from the 14th day of the study, MyoD+myosatellitocytes were detected in the subjects of the experimental group, which indicated the muscle fiber regeneration. No MyoD+cells were detected in the subjects of the control group during the study. Conclusion: conducted study showed that aseptic inflammation occured during limb replantation, in the proliferative phase of which fibroblastic sleeve formed around stitched vessels and nerves, as well as fibroblast foci between fragments of stitched muscles, accompanied by high TGF-β1 and HLA-DR expression. The DAB allows to change the wound process course due to the macrophages activation of the proinflammatory phenotype, which is manifested by a significantly higher TNF-α expression, correlating with low TGF-β1 and HLA-DR expression. Under these conditions, vascular fibrosis is inhibited and damaged muscle fibers are regenerated. Thus, the DAB use in limb replantation helps to prevent vascular fibrosis and stimulate progenitor muscle cells. KEYWORDS: replantation, inflammation, fibrosis, allogeneic biomaterial, macrophages, TGF-β1, TNF-α, HLA-DR, myosatellitocytes, MyoD. FOR CITATION: Muslimov S.A., Ibragimov R.K., Lebedeva A.I. Dispersed allogeneic biomaterials for the prevention of cicatricial complications during limb replantation (research study). Russian Medical Inquiry. 2024;8(4):201–207 (in Russ.). DOI: 10.32364/2587- 6821-2024-8-4-3.

Experimental muscle reinnervation by allogeneic biomaterial illustrates restoration of interlevel relations in human body

The objective of our study was to reveal the morphofunctional interactions between allografts and the recipient nervous system from the experimental model of the mimetic musculature reinnervation. Materials and Methods. The experiments were conducted on Chinchilla rabbits (n=36). All animals were subjected to the facial nerve transection. No other manipulations were performed in the Control Group (n=9). In Treatment Group 1 (n=12), an autograft fragment of the masseter muscle with a neurovascular bundle was attached to the denervated buccinator. In Treatment Group 2 (n=15), allogeneic biomaterials – specifically, Regeneration Stimulator and Vasculogenesis Stimulator, were inserted between specified muscles. The animals were removed from the experiment on days 10, 30, 60 and 180. Tissue pieces from the operation zone were analyzed using transmission electron microscopy. Results. It was established that compensatory and restorative processes in the Control Group and Treatment Group 1 end with scarring of the boundary zone and contracture of mimetic muscles. In Treatment Group 2, we observed revascularization of mimetic musculature, as well as axonal ingrowth into the buccinator and restoration of neuromuscular synapses. Conclusion. Allogeneic biomaterial transplantation creates adequate conditions for the restoration of the organ vascular bed and the innervation apparatus of denervated mimetic muscles. The results of our experiments could be regarded as an example of restoring the interlevel relations in the human body following the use of allogeneic biomaterials.

Progress in the study of virus detection methods: The possibility of alternative methods to validate virus inactivation.

Virus inactivation validation studies have been widely applied in the risk assessment of biogenic material-based medical products, such as biological products, animal tissue-derived biomaterials, and allogeneic biomaterials, to decrease the risk of virus transmission. Traditional virus detection methods in an inactivation validation study utilize cell culture as a tool to quantify the infectious virus by observing cytopathic effects (CPEs) after virus inactivation. However, this is susceptible to subjective factors because CPEs must be observed by experts under a microscope during virus titration. In addition, this method is costly and time- and labor-consuming. Molecular biological technologies such as quantitative polymerase chain reaction (qPCR) have been widely used for virus detection but cannot distinguish infectious and noninfectious viruses. Therefore, qPCR cannot be directly applied to virus inactivation validation studies. In this paper, methods to detect viruses and progress in the challenge of differentiating infectious and noninfectious viruses with the combination of pretreatment and qPCR techniques such as the integrated cell culture-qPCR (ICC-qPCR) method are reviewed. In addition, the advantages and disadvantages of each new method, as well as its prospect in virus inactivation validation studies, are discussed.

A quality improvement pilot assessment of the safety and associated outcomes of a viable cryopreserved umbilical tissue allograft as an adjunct surgical wrap in peroneus brevis tendon repair.

Surgical tendon repairs of the lower extremity are frequently associated with post-operative (post-op) risks that result in poor patient outcomes. Initially, increased pain levels may contribute to extended post-op rehabilitation while the development of tissue adhesions and fibrosis limit long-term functionality through reduced range of motion. Several surgical methods describing incorporation of various augmentative graft materials in tendon repair exist. However, reports demonstrating technique and both short- and long-term patient outcomes are lacking. Recently, advances in tissue preservation technology have led to the commercialization of human placental allografts. Of these available allogeneic biomaterials, the components found in human placental membranes may provide anti-inflammatory, antimicrobial, anti-adhesive, and antifibrotic properties to benefit surgical outcomes.Here, the authors introduce and technically describe the use of a viable cryopreserved umbilical tissue (vCUT) (Stravix, Osiris Therapeutics, Inc., Columbia, MD) as a complementary surgical wrap in primary tendon repair, with particular focus on the peroneus brevis. A pilot study was undertaken to assess the safety and potential for secondary rehabilitative outcomes associated with the use of vCUT in 5 tendon repair cases. The use of vCUT as a surgical tendon wrap was evaluated via the following primary endpoints at post-op day 7:1. presence of erythema, tenderness, heat and/or swelling;2. pain score;3. patient use of narcotic medication; and4. the development of adverse events during any point during the post-op course, defined in this study as dehiscence, confirmed infection, fluid collection or drainage.Secondary investigative endpoints included clinical and rehabilitative outcome measures for comparative pain reduction and transition times to both controlled ankle movement (CAM) boot and normal shoe ambulation.All patients were followed for an average of 24.15 months (range 16.75–26.5 months) after surgery. For primary safety measures, erythema, tenderness, drainage, heat, and swelling was absent in all 5 surgical sites. None of the patients required post-op use of narcotics past day 7. The potential for long-term rehabilitative improvement with adjunct use of vCUT was also demonstrated through reduced pain and reduced transition times to functional and non-assisted ambulation in normal shoewear as compared to historical controls managed without vCUT.This surgical technique is simple and safe for patients and preliminary findings have demonstrated favorable clinical and rehabilitative outcomes over historically observed controls.

Human Perinatal‐Derived Biomaterials

Human perinatal tissues have been used for over a century as allogeneic biomaterials. Due to their advantageous properties including angiogenecity, anti-inflammation, anti-microbial, and immune privilege, these tissues are being utilized for novel applications across wide-ranging medical disciplines. Given continued clinical success, increased adoption of perinatal tissues as a disruptive technology platform has allowed for significant penetration into the multi-billion dollar biologics market. Here, we review current progress and future applications of perinatal biomaterials, as well as associated regulatory issues.

Humanized mouse model for assessing the human immune response to xenogeneic and allogeneic decellularized biomaterials.

Current assessment of biomaterial biocompatibility is typically implemented in wild type rodent models. Unfortunately, different characteristics of the immune systems in rodents versus humans limit the capability of these models to mimic the human immune response to naturally derived biomaterials. Here we investigated the utility of humanized mice as an improved model for testing naturally derived biomaterials. Two injectable hydrogels derived from decellularized porcine or human cadaveric myocardium were compared. Three days and one week after subcutaneous injection, the hydrogels were analyzed for early and mid-phase immune responses, respectively. Immune cells in the humanized mouse model, particularly T-helper cells, responded distinctly between the xenogeneic and allogeneic biomaterials. The allogeneic extracellular matrix derived hydrogels elicited significantly reduced total, human specific, and CD4+ T-helper cell infiltration in humanized mice compared to xenogeneic extracellular matrix hydrogels, which was not recapitulated in wild type mice. T-helper cells, in response to the allogeneic hydrogel material, were also less polarized towards a pro-remodeling Th2 phenotype compared to xenogeneic extracellular matrix hydrogels in humanized mice. In both models, both biomaterials induced the infiltration of macrophages polarized towards a M2 phenotype and T-helper cells polarized towards a Th2 phenotype. In conclusion, these studies showed the importance of testing naturally derived biomaterials in immune competent animals and the potential of utilizing this humanized mouse model for further studying human immune cell responses to biomaterials in an invivo environment.