SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Cell and tissue banking

29

To identify critical elements of physical examination (PE) of potential tissue donors that could help to improve the safety of tissue transplantation. Physical signs were identified that can indicate the presence of a contraindication mentioned in EU Directive 2006/17/EC and that can theoretically be detected at PE. A risk assessment was designed, according to the Failure Mode and Effects Analysis model. Signs were scored on several aspects, taking into account various control measures, either required in the EU Directive or additional non-required measures. 106 signs associated with general and tissue-specific contraindications were identified. Signs of advanced infection with HIV, hepatitis B/C and syphilis (n = 13, 12.3%) can be omitted, since these contraindications will be detected by the required serological testing. With the required control measures, risk priorities are unacceptably “high” for 17.3% of the signs. For 64.5% of the signs, additional control measures are possible, which result in acceptable risk priorities for all signs. This risk management procedure identified the minimal necessary content of PE in potential tissue donors. Furthermore, risks associated with tissue donation were elucidated and possible risk control measures were identified as well as their impact on the safety of tissue transplantation.

Concepts: European Union, Risk, Management, Risk management, Regulation, Risk assessment, Seroconversion, Directive

25

A thick gingival biotype is a requisite for good periodontal health. It has important role in resisting trauma and subsequent gingival recession. The gingival thickness is a significant predictor of clinical outcome of periodontal surgeries. Various surgical procedures are used to increase the gingival thickness. The present study incorporated the innovative step of placement of chorion membrane to objectively evaluate the increase in thickness of gingival biotype during periodontal pocket therapy. The patients in age group between 25 and 45 years with chronic periodontitis, indicated for flap surgery were selected for the study. The sites with pocket depth of 6-8 mm in the mandibular anterior teeth were divided into test and control sites. Periodontal flap surgery was carried at both the sites and chorion membrane was placed at the test sites. The gingival thickness measurement was assessed using a markings marked on injection needle, these markings were read using digital vernier caliper, pre and post operatively. The baseline values of gingival thickness at test site (1.04 ± 0.19 at mid buccal region, 1.24 ± 0.20 at mid papillary) and control site (0.94 ± 0.11 at mid buccal region, 1.14 ± 0.11 at mid papillary region) showed no statistically significant difference. At test sites, 6 weeks post treatment (1.36 ± 0.16 at mid buccal region and 1.48 ± 0.17 at mid papillary region) as compared to control sites (1.06 ± 0.11 at mid buccal region, 1.24 ± 0.11 at mid papillary) showed statistically significant increase in gingival thickness (p ≤ 0.05*). The innovative step of placement of chorion membrane during periodontal pocket therapy facilitated increase in the gingival thickness in the areas with thin gingival biotype.

Concepts: Surgery, Statistical significance, Periodontology, Gingiva, Periodontitis, Periodontal disease, Vernier scale, Caliper

2

The acquisition of brain tissue for research purposes is an important endeavour in research on ageing, pathological diagnosis, and the advancement of treatment of neurological or neurodegenerative diseases. While some tissue samples can be obtained from a living patient, the procurement of a whole brain requires the donation from people after their death. In order to promote positive attitudes towards brain donation, it is essential to understand why people do or do not donate their brain to medical research. In 2018 we undertook a systematic review of the international literature concerning people’s attitudes, motivations, and feelings about brain donation. Five electronic databases were searched: Scopus, PsycINFO, Embase, Medline, and Google Scholar. Search terms included: (“brain donor*” OR “brain donation” OR “brain banking” OR “banking on brain”) AND (attitude* OR motivation* OR decision*“) AND (LIMIT-TO "human”) AND (LIMIT-TO (LANGUAGE, “English”)). Articles were analysed using the Framework for Assessing Qualitative Evaluations and a meta-ethnographic approach. Fourteen articles were included for review. The findings suggest four universal factors informing a person’s decision to donate their brain: (1) contextual knowledge, (2) conceptual understandings, (3) family/friends matter, and (4) personal experience, time and process. The findings also indicate that the way healthcare professionals present themselves can influence people’s feelings and attitudes towards brain donation. Healthcare and research professionals who are involved in brain donation processes must be mindful of the complex and multiple factors that influence donation outcomes. Effective and sensitive communication with potential donors and their family/friends is paramount.

1

Two-step perfusion is considered the gold standard method for isolating hepatocytes from human liver tissue. As perfusion may require a large tissue specimen, which is encapsulated and has accessible vessels for cannulation, only a limited number of tissue samples may be suitable. Therefore, the aim of this work was to develop an alternative method to isolate hepatocytes from non-encapsulated and small samples of human liver tissue. Healthy tissue from 44 human liver resections were graded for steatosis and tissue weights between 7.8 and 600 g were used for hepatocyte isolations. Tissue was diced and underwent a two-step digestion (EDTA and collagenase). Red cell lysis buffer was used to prevent red blood cell contamination and toxicity. Isolated hepatocyte viability was determined by trypan blue exclusion. Western blot and biochemical analyses were undertaken to ascertain cellular phenotype and function. Liver tissue that weighed ≥50 g yielded significantly higher (P < 0.01) cell viability than tissue <50 g. Viable cells secreted urea and displayed the phenotypic hepatocyte markers albumin and cytochrome P450. Presence of steatosis in liver tissue or intra-hepatocellular triglyceride content had no effect on cell viability. This methodology allows for the isolation of viable primary human hepatocytes from small amounts of "healthy" resected liver tissue which are not suitable for perfusion. This work provides the opportunity to increase the utilisation of resection surplus tissue, and may ultimately lead to an increased number of in vitro cellular studies being undertaken using the gold-standard model of human primary hepatocytes.

Concepts: Blood, Red blood cell, Secretion, Cell biology, Liver, Glycogen, Bile, Hepatocyte

1

The use of amniotic membrane in ophthalmic surgery and other surgical procedures in the fields of dermatology, plastic surgery, genitourinary medicine and otolaryngology is on the increase. Furthermore, amniotic membrane and its epithelial and mesenchymal cells have broad use in regenerative medicine and hold great promise in anticancer treatment. Amniotic membrane is a rich source of biologically active factors and as such, promotes healing and acts as an effective material for wound dressing. Amniotic membrane supports epithelialization and exhibits anti-fibrotic, anti-inflammatory, anti-angiogenic and anti-microbial features. Placentas utilised in the preparation of amniotic membrane are retrieved from donors undergoing elective caesarean section. Maternal blood must undergo serological screening at the time of donation and, in the absence of advanced diagnostic testing techniques, 6 months postpartum in order to cover the time window for the potential transmission of communicable diseases. Amniotic membrane is prepared by blunt dissection under strict aseptic conditions, then is typically transferred onto a nitrocellulose paper carrier, usually with the epithelial side up, and cut into multiple pieces of different dimensions. Amniotic membrane can be stored under various conditions, most often cryopreserved in glycerol or dimethyl sulfoxide or their mixture with culture medium or buffers. Other preservation methods include lyophilisation and air-drying. In ophthalmology, amniotic membrane is increasingly used for ocular surface reconstruction, including the treatment of persistent epithelial defects and non-healing corneal ulcers, corneal perforations and descemetoceles, bullous keratopathy, as well as corneal disorders with associated limbal stem cell deficiency, pterygium, conjunctival reconstruction, corneoscleral melts and perforations, and glaucoma surgeries.

Concepts: Medicine, Childbirth, Stem cell, Surgery, Obstetrics, Ophthalmology, Caesarean section, Surgical procedures

0

In this article we describe the organization of post mortem tissue donation in the Netherlands, the average number of tissue donors procured during the years 2015-2019 and the main challenges we face to improve this number. Licensed by the Dutch Ministry of Health, the Dutch Transplant Foundation (NTS) plays a central role in the organization of tissue donation. The NTS works closely with the Dutch hospitals, two tissue banks and a procurement organization. Potential tissue donors are reported to the NTS 24/7. After consulting the Donor Register and relatives give consent for donation, donors are subject to a thorough medical evaluation. If no medical contraindication is mentioned, the donor is approved for tissue donation. Each year, tissues of an average of 1918 donors (112.1 donors Per Million Population) are procured. After procurement of tissues, donor blood and tissues are tested on virology and quality respectively. Based on the test results and the assessment of potential disease transmission, tissues can either be released for transplantation or discarded. In conclusion, the Netherlands has developed a uniform, nationwide approach for safe and efficient post mortem tissue donation in which the NTS plays a central role. In the past 5 years, tissues from a considerable number of donors are procured. The NTS will continue to work together with their partners, by stimulating donor recognition, registration of the donor will, relatives' informed consent and by extending donor selection criteria, for an even more efficient way to help patients on the waiting list for a transplantation.

0

Sperm cryopreservation leads to various structural and functional damages, some of which induce by oxidative stress. The reactive oxygen species (ROS) generates by mitochondria and membrane NADPH oxidases (NOXs). Among the NOXs, only NOX5 has been identified in the cell membrane of human sperm. This study was designed to clarify the possible role of NOX5 on sperm cryoinjury. Forty human semen samples were washed and randomly divided into fresh and cryopreserved groups. Each group was divided into 4 subgroups containing Ham’s F10 (control), 0.1% DMSO (vehicle), 100 nM of PMA (phorbol 12-myristate 13-acetate) and 1 µM of DPI (diphenyleneiodonium), as NOX5 activator and inhibitor. The samples of cryopreserved groups were preserved in liquid nitrogen for 1 month. The sperm kinematics, membrane integrity, ROS production, apoptosis rate, mitochondrial membrane potential (MMP), intracellular ATP and calcium concentration [Ca2+]i were evaluated. The percent of sperm with intact membrane and motile sperm reduced significantly after thawing (p ≤ 0.01). The ROS production (p ≤ 0.01) and the apoptotic rate increased, MMP dissipated, and the percentage of live cells with high [Ca2+]i decreased significantly in the cryopreserved control group relative to the fresh control group. DPI, in contrast to PMA, improved sperm progressive motility (p ≤ 0.01), membrane integrity in fresh and cryopreserved groups and reduced the ROS amount in cryopreserved group (p ≤ 0.01). Apoptotic rate, [Ca2+]i, ATP, and MMP did not change with DPI and PMA in cryopreserved groups. We conclude that NOX5 activity in fresh sperm is low, and it increases during cryopreservation. NOX5 inhibition improves the cryopreserved sperm quality.

0

Acute respiratory infections as one of the most common problems of healthcare systems also can be considered as an important reason for worldwide morbidity and mortality from infectious diseases. Coronaviruses are a group of well-known respiratory viruses that can cause acute respiratory infections. At the current state, the 2019 novel coronavirus is cited as the most worldwide problematic agent for the respiratory system. According to investigations, people with old age and underlying diseases are at higher risk of 2019 novel coronavirus infection. Indeed, they may show a severe form of the disease (with severe acute respiratory infections). Based on the promising role of cell therapy and regenerative medicine approaches in the treatment of several life-threatening diseases, it seems that applying cell-based approaches can also be a hopeful strategy for improving subjects with severe acute respiratory infections caused by the 2019 novel coronavirus. Herein, due to the amazing effects of mesenchymal stem cells in the treatment of various diseases, this review focuses on the auxiliary role of mesenchymal stem cells to reduce inflammatory processes of acute respiratory infections caused by the 2019 novel coronavirus.

0

Despite the wide choice of commercial heart valve prostheses, cryopreserved semilunar allograft heart valves (C-AHV) are required, and successfully transplanted in selected groups of patients. The expiration limit (EL) criteria have not been defined yet. Most Tissue Establishments (TE) use the EL of 5 years. From physiological, functional, and surgical point of view, the morphology and mechanical properties of aortic and pulmonary roots represent basic features limiting the EL of C-AHV. The aim of this work was to review methods of AHV tissue structural analysis and mechanical testing from the perspective of suitability for EL validation studies. Microscopic structure analysis of great arterial wall and semilunar leaflets tissue should clearly demonstrate cells as well as the extracellular matrix components by highly reproducible and specific histological staining procedures. Quantitative morphometry using stereological grids has proved to be effective, as the exact statistics was feasible. From mechanical testing methods, tensile test was the most suitable. Young’s moduli of elasticity, ultimate stress and strain were shown to represent most important AHV tissue mechanical characteristics, suitable for exact statistical analysis. C-AHV are prepared by many different protocols, so as each TE has to work out own EL for C-AHV.

0

Low survival rate of grafted mesenchymal stem cells (MSC) in injured tissue is one of the major limitations of stem cell therapy. One of the most important factors that limits the MSCs survival rate and retention is ischemic stress, which can lead to damage to all components of the cell. In particular, it can damage mitochondria, that play an important role in apoptosis with releasing apoptotic factors. Therefore, we investigated the protective effects of Acetyl-L-carnitine (ALCAR) against serum and glucose deprivation (SGD) in adipose-derived mesenchymal stem cells (AD-MSCs). We measured cell viability, proliferation, and apoptosis in cells experiencing SGD stress for 8 h with exposure to varying concentrations of ALCAR. Results showed that ALCAR protects cells against SGD stress by reducing apoptosis. Its protective effects are associated with reductions in cleaved caspase-3 and attenuation of apoptosis. Result showed that ALCAR exhibits protective effects against SGD-induced damage to AD-MSCs by enhancing the expression of survival signals and by decreasing the expression of death signals.