Human Tissue Bank Research Articles

Deterioration of neuroimmune homeostasis in Alzheimer’s Disease patients who survive a COVID-19 infection

Growing evidence has implicated systemic infection as a significant risk factor for the development and advancement of Alzheimer’s disease (AD). With the emergence of SARS-CoV-2 (COVID-19) and the resultant pandemic, many individuals from the same aging population vulnerable to AD suffered a severe systemic infection with potentially unidentified long-term consequences for survivors. To study the impact of COVID-19 survival on the brain’s intrinsic immune system in a population also suffering from AD, we profiled post-mortem brain tissue from patients in the UF Neuromedicine Human Brain and Tissue Bank with a diagnosis of AD who survived a COVID-19 infection (COVID-AD) and contrasted our findings with AD patients who did not experience a COVID-19 infection, including a group of brain donors who passed away before arrival of SARS-CoV-2 in the United States. We assessed disease-relevant protein pathology and microglial and astrocytic markers by quantitative immunohistochemistry and supplemented these data with whole tissue gene expression analysis performed on the NanoString nCounter® platform. COVID-AD patients showed slightly elevated Aβ burden in the entorhinal, fusiform, and inferior temporal cortices compared to non-COVID-AD patients, while tau pathology burden did not differ between groups. Analysis of microglia revealed a significant loss of microglial homeostasis as well as exacerbated microgliosis in COVID-AD patients compared to non-COVID-AD patients in a brain region-dependent manner. Furthermore, COVID-AD patients showed reduced cortical astrocyte numbers, independent of functional subtype. Transcriptomic analysis supported these histological findings and, in addition, identified a dysregulation of oligodendrocyte and myelination pathways in the hippocampus of COVID-AD patients. In summary, our data demonstrate a profound impact of COVID-19 infection on neuroimmune and glial pathways in AD patients persisting for months post-infection, highlighting the importance of peripheral to central neuroimmune crosstalk in neurodegenerative diseases.

The Importance of Reconstituting the Bodies of Organ and Tissue Donors: a Look at Human Dignity

Introduction: Family refusal to authorize the donation of human organs and tissues has remained high over the years. Among the many reasons for not donating, we highlight the lack of information about the process and the family’s lack of knowledge about the donor’s wishes in life, as well as other issues, such as the appearance of the donor’s body after donation. In this sense, it is necessary to bring to light the aspects that permeate the concepts of death, human dignity, and care for the donor’s image, especially in the case of tissue donors, where the removal may be more noticeable. Objectives: An integrative literature review (ILR) was carried out, seeking to highlight gaps and characterize the process of donating human organs and tissues, with a focus on the reconstruction of the donor’s body and human dignity. In addition, the aim was to describe the experience of a professional from a human tissue bank (BTH). Methods: Using the PICO strategy, the study’s guiding question was drawn up following an IR carried out over the last 10 years, operationalized by controlled descriptors in the SciELO, LILACS, Google Scholar, and PubMed databases. In addition to the search, an experience report was described on the techniques used to reconstruct the donor’s body after the tissues used by a BTH located in the interior of the state of São Paulo were harvested. Results: Nine specific studies were found on donation and the use of prostheses to reconstruct donated areas. The results show the reasons for family refusal, as well as the care taken by the technical teams in reconstructing donors’ bodies. The family’s concern about the donor’s aesthetic situation influences acceptance for donation, so it is necessary to invest in the safety and quality of the services provided by BTH to reduce family refusal for donation. Conclusion: Clear communication and the safety of the processes involved in the procurement of human organs and tissues proved to be the best way to facilitate donation and could thus increase donations.

The Use of Microbiological Quality Control Techniques Adopted in a Human Tissue Bank

The Brazilian Ministry of Health’s Consolidation Ordinance No. 4 of September 28, 2017, provides the requisites for the evaluation of services for human tissue banks (bancos de tecidos humanos [BTH]) in terms of the microbiological control of environments (ISO 5 classification processing room) and products (culture for aerobic, anaerobic, and fungal pathogens), with a view to guaranteeing harmlessness in tissue transplants. Objectives: To highlight the techniques for microbiological control of distributed tissues adopted by a BTH over 5 years, as well as the results obtained from the application and use of these techniques. Methods: Using standard operating procedures (SOPs), the methodology, and frequency of collections, tests and room cleaning were established in advance. Microbiological cultures were taken from the tissues during all the collections and processing. During tissue processing, fingerprint samples on the processor’s gloves and in the processing room were seeded on blood agar plates. The processing room was cleaned weekly with biguanide and quaternary ammonium. The processing bench was sanitized with sterile 70% alcohol and the microbiological environmental control was carried out every 6 months by a qualified outsourced company. Results: In the period analyzed, the techniques proved effective in 46 (96%) cases, with contamination identified in only two (4%) processed and collected samples. The effectiveness and results were documented. Conclusion: Effective biological quality control methods are legitimately required, but they can be improved, raising the need to develop safe protocols for the quality of services and the safety of transplanted tissues.

Quality and applicability of cadaveric donor eyes for molecular biology research: An Indian experience.

Human ocular tissue banking plays an important part in the advancement of translational research for identifying the molecular processes involved in disease etiology and pathogenesis. Timely obtaining a good-quality ocular tissue from a cadaveric donor is exceedingly difficult, especially in remote areas, with a variable transportation time (within 12-24 h), raising concerns about RNA quality and its subsequent applications. Therefore, we assessed the utility of retinal tissues from cadaver donor and enucleated eyes based on the RNA quality and gene expression by real-time polymerase chain reaction (PCR). Prospective study. Retina tissues were separated from the donor/enucleated eyes received in the eye bank within 24 h of death (n = 15) and within an hour from OR (n = 3), respectively, and stored immediately at -80 degree. RNA was isolated using trizol, and the quantity and quality were assessed using Qubit and agarose gel electrophoresis, respectively. QPCR was performed for measuring the expression of different retinal-specific genes. The cellular viability of the retina was assessed by establishing explant primary cell cultures. The data were calculated as an average of normalised Ct values ± standard error of the mean. RNA obtained from cadaveric tissues despite being partially degraded showed a uniform strong gene expression of several retinal-specific genes such as PAX6, RHO, TUBB3, CRX , and ALDH1L1 . The primary cultures established from cadaveric tissues showed viable cells. The cadaver donor tissues collected within 24 hours of death can be effectively utilized for gene expression profiling.

Morphological evaluation of the amniotic membrane decellularization

Background: Biological materials derived from decellularized tissues could be a good basis for progress in regenerative medicine while maintaining the main components of the extracellular matrix. A promising scaffold for tissue-engineered is the human amniotic membrane. It is one of the oldest biomaterials used for scaffolds. Material and methods: 3 placentas were obtained through Human Tissue Bank. Under sterile condition human amniotic membrane was collected. The human amniotic membrane was treated with 0.5% of sodium dodecyl sulphate (SDS), 1% Triton for 24 and 5 hours. Amniotic membrane decellularization was also carried out in combination with ultrasound bath for 20 minutes 3 times. For morphological and structure evaluation of human amniotic membrane the scanning electron microscopy of native amniotic membrane and histology of decellularized and native amniotic membrane were performed. Results: The human amniotic membrane decellularization process with 0.5% SDS solution and 1% Triton solution showed that decellularization for 24 hours is too aggressive for human amniotic membrane structure. The decellularization for 5h with 1% Triton solution was incomplete. Conclusions: The method of decellularization with 0.5% SDS solution is more suitable for amniotic membrane decellularization and can be performed in only 5 hours. The use of ultrasound bath did not have a significant effect on the obtained results.

Structural and physical characteristics of the dermal decellularized structures evaluation

Introduction: Decellularized biomaterials derived from the biological tissues are ideal for tissue engineering applications because they mimic the biochemical composition of the native tissue. The physical and structural properties of the scaffold are important in the fields of tissue engineering and regenerative medicine. Material and methods: Study material was 20 decellularized dermal grafts. 10 samples were obtained from piglets slaughtered in the slaughterhouse. Other tissues (n=10) were received from the donor from the Human Tissue and Cell Bank of the Republic of Moldova. Extracellular matrices were obtained by decellularization with 0.5% sodium dodecyl sulfate/0.1% EDTA solution. The evaluation of the structural characteristics was carried out by the histological examination with hematoxylin and eosin, scanning electron microscopy and the quantification of the amount of deoxyribonucleic acids. Assessment of the physical characteristics included analysis of extracellular matrix volume porosity, density, and swelling rate. Results: Histological examination revealed fewer cells in decellularized tissues compared to non-decellularized ones. More than 80.5% of nucleic acids were removed from porcine matrix and 82.5% of genetic material – from decellularized human dermal structures. A mean correlation and inverse dependence of -0.43 was shown between porosity and swelling rate of decellularized dermis. Conclusions: The decellularization process significantly (P<0.05) removed the cellular components while preserving the connective three-dimensional structure of the dermal matrices clearly shown by quantification of the amount of DNA and microscopic examination of the structures.

Cryopreservation of human dental roots using vitrification for autologous human tooth tissue banking

This study aims to preliminarily evaluate the feasibility of autologous transplantation of tooth tissues cryopreserved with vitrification, by investigating the influence of cryopreservation with vitrification on human dental root, regarding the morphology, microhardness, cell apoptosis, proliferation and differentiation. Freshly extracted human permanent premolars were collected with crown removed. Dental roots were cryopreserved using a commercial vitrification medium (Kitazatousa). After six-month storage in liquid nitrogen, cryopreserved roots were thawed, and then evaluated using histological and immunohistochemical methods. Microhardness of dentine was measured with a Vickers indenter. Cells in periodontal ligament and dental pulp tissues were isolated and characterized. The proliferation, immunophenotype, apoptosis and differentiation ability of cells isolated from cryopreserved roots were evaluated. The data was analyzed using one-way analysis of variance (ANOVA) and Student's t-test. The gross and histological morphology of dental roots was not significantly changed after vitrification and thawing. A few tiny cracks were found in 3 of all 10 cryopreserved samples. No obvious changes were found in microstructure of dentine under SEM observation. Dental pulp cells and periodontal ligament cells were successfully isolated from tissues of cryopreserved human dental roots. There were also no significant differences of those periodontal ligament cells in the two groups regarding morphology, immunophenotype, viability, proliferation and apoptosis. The osteogenic and adipogenic differentiation capability of periodontal ligament cells was maintained by cryopreservation with vitrification. In the conditions of this study, cryopreservation with vitrification preserves cell survival, hardness and structural integrity of dental roots. Vitrification can be a potential way to preserve tooth tissue for future auto-transplantation and autologous cell therapy.

Epidemiological analysis of corneal donors and patients queuing for keratoplasty

Purpose: To characterize corneal donors and patients on the waiting list for keratoplasty clinically and epidemiologically. Methods: Epidemiological, cross-sectional study with a sample of 1,303 donors and 938 patients on the waiting list were analyzed. Performed in MS State Transplant Center (STC) and the Human Ocular Tissue Bank, from January to June 2019. For the qualitative variables, descriptive analysis was performed. In the quantitative variables, trend and data dispersion measures were analyzed. Results: Of the 2,606 corneas, 31.73% were transplanted, 21.64% of donors were reagents for infectious diseases that contraindicated transplantation, with a higher percentage of reagents in donors aged over 50 years (p <0.001). Keratoconus stood out as the main ocular diagnosis in the frequency distribution. The average age found for patients in the waiting line was 49.05 years. Regarding the average waiting time to perform the transplant, it was 108.46 days for elective transplants and 11.0 days for emergency transplants. Conclusion: More than 40% of the tissues taken from donors were discarded, with emphasis on epithelial defects and reagent serologies. Keratoconus was the main indication of patients queuing for keratoplasty.

Human Brain Banking as a Convergence Platform of Neuroscience and Neuropsychiatric Research

Neuropsychiatric disorders affect hundreds of millions of people and their families worldwide. Many studies have used human postmortem brain samples to decipher the molecular framework of these diseases. These studies uncovered brain-specific genetic and epigenetic patterns using high-throughput sequencing techniques. Therefore, determining the best way to collect human postmortem brain samples, analysing such a large amount of sequencing data, and interpreting these results is critical to advancing the field of neuropsychiatric sciences. By collecting postmortem/biopsied neural tissues and information about the diseases and life of donors, human brain banks support the observation and research of human brain sciences. Furthermore, the construction of large-scale brain banks has promoted the exploration of human brain morphology and function, development and ageing, as well as the mechanism of many neuropsychiatric diseases, which progressively reveal the normal mechanism of human brain activities and lead the direction of the prevention and treatment of neurological diseases. This article introduces the significance of human brain tissue bank construction and the current situation of the human brain tissue bank worldwide, as well as an overview of neurology or neuroscience advanced by using human brain samples.

The Significance of the Nucleic Acid Test (NAT) to Prevent Viral Contamination in Musculoskeletal Tissue Transplantation.

Objective The present study aims to highlight the significance of the nucleic acid test (NAT) for musculoskeletal tissue donation and to compare the sensitivity of this test on the different available platforms. Method The present study is a retrospective survey in a human tissue bank database and an integrative literature review encompassing the last 10 years. The PubMed portal and the SCOPUS, CINAHL, and Web of Science databases were queried for articles. Results We found no specific studies on the use and sensitivity of NAT in braindead tissue donors. The information presented in the present study consists of specific contents intended for the Brazilian Blood Transfusion Network (Hemorrede Transfusional Nacional, in Portuguese) and internal retrospective data from a tissue bank located at a city in the state of São Paulo, Brazil. Conclusions The NAT is effective in blood samples from living patients. However, since biochemical reactions in braindead patients can be different, specific research, platforms, or both are crucial to tissue banks.

Xenopus Oocytes as a Powerful Cellular Model to Study Foreign Fully-Processed Membrane Proteins.

The use of Xenopus oocytes in electrophysiological and biophysical research constitutes a long and successful story, providing major advances to the knowledge of the function and modulation of membrane proteins, mostly receptors, ion channels, and transporters. Earlier reports showed that these cells are capable of correctly expressing heterologous proteins after injecting the corresponding mRNA or cDNA. More recently, the Xenopus oocyte has become an outstanding host–cell model to carry out detailed studies on the function of fully-processed foreign membrane proteins after their microtransplantation to the oocyte. This review focused on the latter overall process of transplanting foreign membrane proteins to the oocyte after injecting plasma membranes or purified and reconstituted proteins. This experimental approach allows for the study of both the function of mature proteins, with their native stoichiometry and post-translational modifications, and their putative modulation by surrounding lipids, mostly when the protein is purified and reconstituted in lipid matrices of defined composition. Remarkably, this methodology enables functional microtransplantation to the oocyte of membrane receptors, ion channels, and transporters from different sources including human post-mortem tissue banks. Despite the large progress achieved over the last decades on the structure, function, and modulation of neuroreceptors and ion channels in healthy and pathological tissues, many unanswered questions remain and, most likely, Xenopus oocytes will continue to help provide valuable responses.

Donation Process and Evaluation of Corneal Tissue in a Slit Lamp

The process of capturing and classifying the viability of corneal tissue for corneal transplantation is complex. The biomicroscopic examination is one of the techniques used to evaluate the quality of corneal tissues. The aim of this study was to analyze the relationship between the evaluation criteria used in biomicroscopic examination using a slit lamp and the classification of the quality of corneal tissue. This is a longitudinal, retrospective cohort study, performed at the Human Ocular Tissue Bank in the state of Rio Grande do Norte, Brazil. The sample consisted of 419 corneas donated between 2005 to 2016. After the evaluation, the 419 corneas were classified as excellent (8 -1.91%), good (217 - 51.79%), regular (85 - 20.29%), and bad (109 - 26.01%). The classification of corneal quality attributed by ophthalmologists considered 13 criteria: senile arch, scars, epithelial defect, epithelial exposure, stromal infiltrate, subepithelial opacity, pterygium, Descemet's folds, stromal edema, stromal streak, cornea guttata, specular reflex, and cell loss endothelial. The quality of the cornea classified as excellent and good showed a statistically significant association (P value < .05) with senile arch, scar, epithelial defect, epithelial exposure, Descemet's folds, stromal edema, stromal streak, cornea guttata, specular reflex, and losses of endothelial cells; they had evaluated criteria that were absent or slightly present. The evaluation of the corneal quality for corneal transplantation should involve the implementation of reliable techniques and trained, qualified professionals. There is a need to create evaluation instruments that consider the criteria according to their degree of interference in the quality of corneal tissue.

Be in it for the Long Haul: A Commentary on Human Tissue Recovery Initiatives

The strong need for a new foundational molecular framework for human nervous system research at the nociceptive level is now matched by comprehensive and quantitative capabilities for analyzing nociceptive tissues such as pathologic peripheral tissue, damaged peripheral nerve, dorsal root ganglia, spinal cord, and brain, where possible. However, this idea must be matched by equally strong organization and infrastructures for multisite tissue recovery, molecular analyses, data sharing, and long-term archiving. Experience from other human tissue analysis projects shows that a decades-long activity may be expected, hence “Be in it for the long haul.” While certain milestones can be met fairly quickly, others aimed at molecular and neuroanatomical characterization of chronic pain disorders will require the sustained attention of the groups involved. This can yield a valuable addition to basic and translational pain research and the development of new treatments whose targets are validated directly in humans. PerspectiveA concerted effort is needed to build human nociceptive tissue banks for multi-omic research. In addition to collecting tissue, a careful characterization of pain problems from donors is essential, as is a parallel effort to assess their concurrent medical problems, medications, and the many variables of general human activity and lifestyle that can impact the results. Given the projected long time frame, in addition to maintaining funding, sustaining motivation and momentum are critical factors for success.

SARS-CoV-2 entry sites are present in all structural elements of the human glossopharyngeal and vagal nerves: Clinical implications.

SummaryBackgroundSevere acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections result in the temporary loss of smell and taste in about one third of confirmed cases.MethodsWe used immunohistochemistry to confirm the presence of ACE2, NRP1 and TMPRSS2 in two cranial nerves (IX and X) that mediate taste where they leave/join the medulla. Samples from three (two paraffin embedded and one frozen) postmortem samples were studied (facial (VII) nerve was not available). We also performed immunohistochemistry using the same antibodies in two human cell lines (oligodendrocytes and fibroblasts), and we isolated RNA from one nerve and performed PCR to confirm the presence of the mRNAs that encode the proteins visualized.FindingsAll three of the proteins (ACE-2, NRP1 and TMPRSS2) required for SARS-CoV-2 infections appear to be present in all cellular components (Schwann cells, axons, vascular endothelium, and connective tissue) of the human IXth and Xth nerves near the medulla. We also found their mRNAs in the nerve and in human oligodendrocytes and fibroblasts which were stained by antibodies directed at the three proteins examined.InterpretationInfection of the IXth and Xth nerves by the SARS-CoV-2 virus is likely to cause the loss of taste experienced by many Covid patients. Migration of the virus from the oral cavity through these nerves to brainstem respiratory centers might contribute to the problems that patients experience.FundingThis study was supported by the Intramural Research Program of the National Institute of Dental and Craniofacial Research (NIDCR), NIH (intramural project no. ZDE000755-01), and the Human Brain Tissue Bank, Semmelweis University, Budapest, Hungary from the Hungarian Brain Research Program (2017-1.2.1-NKP-2017-00002).

Effectiveness of Clinical-Grade Chondroitin Sulfate and Ascorbic Acid in Mitigating Cryoprotectant Toxicity in Porcine Articular Cartilage

High concentrations of cryoprotective agents (CPAs) are required to achieve successful vitrification of articular cartilage; however, CPA cytotoxicity causes chondrocyte death. To reduce CPA toxicity, supplementation with research-grade additives, in particular chondroitin sulfate (CS) and ascorbic acid (AA), have previously been shown to improve chondrocyte recovery and metabolic function after exposure to CPAs at hypothermic conditions. However, it is necessary to evaluate the pharmaceutical equivalent clinical grade of these additives to facilitate the supplementation of additives into future vitrification protocols, which will be designed for vitrifying human articular cartilage in tissue banks. We sought to investigate the effectiveness of clinical-grade CS, AA, and N-acetylcysteine (NAC) in mitigating toxicity to chondrocytes during CPA exposure and removal, and determine whether a combination of two additives would further improve chondrocyte viability. We hypothesized that clinical-grade additives would exert chondroprotective effects comparable to those of research-grade additives, and that this protective effect would be enhanced if two additives were combined when compared with a single additive. The results indicated that both clinical-grade and research-grade additives significantly improved cell viability (p < 0.10) compared with the negative control (CPA with no additives). CS, AA, and NAC+AA increased cell viability significantly (p < 0.10) compared with the negative control. However, NAC, NAC+CS, and CS+AA did not improve cell viability when compared with the negative control (p > 0.10). We demonstrated that supplementation with clinical-grade CS or AA significantly improved chondrocyte viability in porcine cartilage subjected to high CPA concentrations, whereas supplementation with clinical-grade NAC did not benefit chondrocyte viability. Supplementation with clinical-grade additives in CPA solutions can mitigate CPA toxicity, which will be important in translating previously developed effective protocols for the vitrification of articular cartilage to human tissue banks.

Brazilian dentists’ perceptions of using bone grafts: an inland survey

Pre-clinical assessments of bone substitute materials are frequent in the literature, but research papers about the clinical situation of bone graft use and consumer market acceptance are rare. The aim of this study was to evaluate the dental use of bone grafts according to the perception of dentists in the city of Sobral, Brazil. We interviewed 183 professionals and analyzed their professional data, knowledge of the subject, specific use, and opinions on cost-effectiveness and biosafety. Most of the respondents had 10 years’ or less experience in the profession, and lacked specialization though they had been familiar with the subject since they graduated. The most frequently mentioned compositions were ceramics, followed by composites. Only a quarter of the respondents had performed bone grafts, generally with up to 50 cases, with the most frequent applications being using simultaneously with a dental implant, fresh dental sockets and maxillary sinus lifting. Autogenous and xenogeneic grafts were more frequent than alloplastic and allogeneic; ceramics were the most frequently used composition, and the association of bone graft with membrane was more frequent than bone graft alone or associated with autologous fibrin. Professional and patient satisfaction was high, cost was considered moderate, and differences were found regarding patient participation in the choice and country of origin of the product. Bone grafts were used more often in the private than public service. Dentists stated that they follow the instructions. Inflammatory or infectious complications were found to be related to the frequency of the procedure performed and safety regarding the origin. Opinions were favorable regarding the use of grafts derived from animals and unfavorable to grafts derived from cadavers. Very few respondents were registered in human bone tissue banks. The good level of acceptance for dental use of bone grafts in a Brazilian inland city provides a promising scenario for the development of the sector.

Implementation and certification of ISO 9001:2015 seal in human tissue bank HCFMRP-USP.

The Quality Management System has been a management technology applied to guarantee the quality of processes and products of a given organization. Thus, ISO 9001:2015 certification assists organizations that want to develop, implement, maintain, and improve a quality management system to enable process improvements and assessments to meet the needs of its customers. This experience report addresses the implementation and certification of the ISO 9001:2015 quality management seal at the Human Tissue Bank of the Ribeirão Preto Clinical Hospital (HCRP) at the University of São Paulo (USP) at Ribeirão Preto Medical School (FMRP)-Brazil. In 2018, the Human Tissue Bank, in partnership with HCRP, received consultancies from PRIMEMODE. The consulting consisted of visits that elucidated the processes to the employees of the Tissue Bank, enabling them to clarify the applicability of all items of the standard. In March 2019, the Tissue Bank received the audit visit and was certified with the ISO 9001:2015 Seal by the Carlos Alberto Vanzolini Foundation. The Tissue Bank aims to provide human tissues for transplantation and research from organ donors. It has a complex physical structure within the required health and legal standards. Also, now it has a quality management seal. The certification guarantees the process organization and the high quality standard of the supplied tissues.

Determination of antibiotics and detergent residues in decellularized tissue-engineered heart valves using LC-MS/MS.

Residual chemicals that are presented during tissue processing in human tissue banks can be a risk for the allograft recipient. Determine the residual concentrations of the antibiotics and detergent used in the process of human decellularized tissue-engineered heart valves stored in isotonic saline solution up to 18months. A total of 24 human decellularized allografts were stored in sterile sodium chloride and analyzed immediately after the decellularization process (0months) and after storage for 6, 12, and 18months, which includes the use of sodium dodecyl sulfate (SDS) and antibiotics (cefoxitin, vancomycin hydrochloride, lincomycin hydrochloride, polymyxin B sulfate). These valves were used for suitability tests, the zone of inhibition evaluation, and direct contact cytotoxicity assay. The stock solution from 32 valves was used for LC-MS/MS analysis of antibiotics and SDS. Tissue samples from decellularized valves showed a zone of inhibition formation for S. aureus and B. subtilis, suggesting the presence of an inhibitory molecule in the tissue. Cytotoxicity tests were negative. Polymyxin B, vancomycin, and SDS were detected and quantified in human decellularized aortic and pulmonary allografts during all periods of the study. There were no traces of residual cefoxitin and lincomycin in the tissue stock solution. We found residual concentrations of the antibiotics and detergent used in the process of human decellularized tissue-engineered heart valves stored in isotonic saline solution up to 18months.

Human bone and amniotic membrane banking in Bangladesh for grafting: the impact of the international atomic energy agency (IAEA) programme.

The idea of establishing a human tissue bank in Bangladesh was started in 1985. However, in 2003, with the active cooperation of international atomic energy agency (IAEA) and Bangladesh Atomic Energy Commission, a tissue bank laboratory was upgraded as a unit for tissue banking and research. Due to increasing demand of allograft, this unit was transformed as an independent institute "Institute of Tissue Banking and Biomaterial Research (ITBBR)" in 2016. This is the only human tissue bank in Bangladesh, which processes human bone and amniotic membrane to provide safe and cost-effective allografts for transplantation. Importantly, banking of human cranial bone as autograft has also started at ITBBR. These processed grafts are sterilized using gamma radiation according to the IAEA Code of Practice for the radiation sterilization of tissues allografts. The amount of grafts produced by the ITBBR from 2007 to 2018 were 120,800cc of bone chips, 45,420cm2 of amniotic membranes, 277 vials of de-mineralized bone granules (DMB), 95 pieces of massive bones, and 134 pieces of cranial bones. Overall, 112,748cc of bone chips, 40,339cm2 of amniotic membranes, 174 vials of DMB, 44 pieces of massive bones, and 64 pieces of cranial bones were transplanted successfully. Nevertheless, to cope up with the modern advanced concepts of cell and tissue banking for therapeutic purpose, ITBBR is working to set up facilities for skin banking, stem cells banking including amniotic and cord blood derived stem cells and scaffold designing. To ensure the quality, safety, ethical and regulatory issues are sustainable in cell and tissue banking practices, ITBBR always works with the Government of Bangladesh for enhancing the national tissue transplantation programme within the contemporary facilities.

Fabrication of co-cultured tissue constructs using a dual cell seeding compatible cell culture insert with a clip-on scaffold for potential regenerative medicine and toxicological screening applications

Tissue engineering is emerging as a modern medicine fascination towards the establishment of human tissue banks; yet, these approaches typically involve cultures of only one type of cell and, therefore, do not recapitulate the native tissue physiology in toto. Co-culture models, comprised of different cell types, can potentially create the next level of complexity. However, conventional approaches involving multiple cell types and cell culture inserts do have limitations. To this end, here we demonstrate a novel cell culture insert that allows the use of any custom-made scaffold, free-flow of fluids/gases, dual cell seeding on either sides of the insert, easy stacking of multiple inserts and resizing it to any multi-well plate format as well as culture dishes. To prove the concept, electrospun silk fibroin scaffold was clipped onto the insert and was used for co-culturing of keratinocytes and fibroblast cells. The results indicated a successful fabrication of spatially organized skin tissue constructs having epidermal and dermal equivalent histology. Cell-laden inserts were stacked and used for simulated transportation studies. However, the conditions need further fine-tuning. All together, the results indicated that the novel cell culture insert with silk fibroin scaffold could be used as a facile, versatile and scalable approach to fabricate and transport 3D co-cultured tissue constructs in vitro, including but not limited to skin. The resultant tissue constructs can be explored for therapeutic applications, for instance as artificial skin substitute in wound healing, and for toxicological applications, for instance as reconstructed skin tissue model in skin irritation testing.