Autologous human plasma in stem cell culture and cryopreservation in the creation of a tissue-engineered vascular graft

Microliter Whole Blood Neutrophil Assay Preserving Physiological Lifespan and Functional Heterogeneity

For in vitro neutrophil functional assays, neutrophils are typically isolated from whole blood, having the target cells exposed to an artificial microenvironment with altered kinetics. Isolated neutrophils exhibit limited lifespans of only a few hours ex vivo, significantly shorter than the 3-5 day lifespan of neutrophils in vivo. In addition, due to neutrophils' inherently high sensitivity, neutrophils removed from whole blood exhibit stochastic non-specific activation that contributes to assay variability. Here, a method - named "µ-Blood" - is presented that enables functional neutrophil assays using a microliter of unprocessed whole blood. µ-Blood allows multiple phenotypic readouts of neutrophil function (including cell/nucleus morphology, motility, recruitment, and pathogen control). In µ-Blood, neutrophils show sustained migration and limited non-specific activation kinetics (<0.1% non-specific activation) over 3-6 days. In contrast, neutrophils isolated using traditional methods show increased and divergent activation kinetics (10-70% non-specific activation) in only 3 h. Finally, µ-Blood allows the capture and quantitative comparison of distinct neutrophil functional heterogeneity between healthy donors and cancer patients in response to microbial stimuli with the preserved physiological lifespan over 6 days.

A Single Injection of ADRCs Does Not Prevent AAA Formation in Rats in a Randomized Blinded Design

There is a pressing need for alternative medical treatments for abdominal aortic aneurysms (AAAs). Mesenchymal regenerative cells derived from adipose tissue (ADRCs) have shown potential in modulating the inflammation and immune responses that drive AAA progression. We hypothesized that ADRCs could reduce inflammation and preserve vascular integrity, potentially slowing the progression of AAA. In our study, subcutaneous adipose tissue was harvested from male Sprague Dawley rats, from which ADRCs were isolated. AAA was induced in these rats using intraluminal porcine pancreatic elastase, followed by intravenous administration of either ADRCs (106 cells) or saline (0.1 mL). We monitored the progression of AAA through weekly ultrasound, and the rats were sacrificed on day 28 for histological analysis. Our results showed no significant difference in the inner abdominal aortic diameter at day 28 between the control group (172% ± 73%, n = 17) and the ADRC-treated group (181% ± 75%, n = 15). Histological analyses of AAA cross-sections also revealed no significant difference in the infiltration of neutrophils or macrophages between the two groups. Furthermore, the integrity and content of elastin in the tunica media were similar between groups. These findings indicate that a single injection of ADRCs does not inhibit the development of AAA in rats in a randomized blinded study.

Microliter whole blood neutrophil assay preserving physiological lifespan and functional heterogeneity

For in vitro neutrophil functional assays, neutrophils are typically isolated from whole blood, having the target cells exposed to an artificial microenvironment with altered kinetics. Isolated neutrophils exhibit limited lifespans of only a few hours ex vivo, significantly shorter than the 3-5 day lifespan of neutrophils in vivo. In addition, due to neutrophil inherently high sensitivity, neutrophils removed from whole blood exhibit stochastic non-specific activation that contributes to assay variability. Here we present a method - named micro-Blood - that enables functional neutrophil assays using a microliter of unprocessed whole blood. micro-Blood allows multiple phenotypic readouts of neutrophil function (including cell/nucleus morphology, motility, recruitment, and pathogen control). In micro-Blood, neutrophils show sustained migration and limited non-specific activation kinetics (<0.1% non-specific activation) over 3-6 days. In contrast, neutrophils isolated using traditional methods show increased and divergent activation kinetics (10-70% non-specific activation) in only 3 h. Finally, micro-Blood allows the capture and quantitative comparison of distinct neutrophil functional heterogeneity between healthy donors and cancer patients in response to microbial stimuli with the preserved physiological lifespan over 6 days.

In Vitro Neutrophil-Bacteria Assay in Whole Blood Microenvironments with Single-Cell Confinement

Blood is a common medium through which invasive bacterial infections disseminate in the human body. In vitro neutrophil-bacteria assays allow flexible mechanistic studies and screening of interventional strategies. In standard neutrophil-bacteria assays, both the immune cells and microorganisms are typically interrogated in an exogenous, homogeneous, bulk fluid environment (e.g., culture media or bacterial broth in microtiter plates), lacking the relevant physicochemical factors in the heterogenous blood-tissue microenvironment (e.g., capillary bed) with single-cell confinement. Here we present an in vitro neutrophil-bacteria assay by leveraging an open microfluidic model known as "μ-Blood" that supports sub-microliter liquid microchannels with single-cell confinement. In this study we compare the exogenous and endogenous fluids including neutrophils in RPMI (standard suspension cell culture media) and whole blood in response to Staphylococcus aureus ( S. aureus , a gram-positive, non-motile bacterium) in phosphate buffered saline (PBS), Mueller Hinton Broth (MHB), and human serum. Our results reveal a significant disparity between the exogenous and endogenous fluid microenvironments in the growth kinetics of bacteria, the spontaneous generation of capillary (i.e., Marangoni) flow, and the outcome of neutrophil intervention on the spreading bacteria.

FACTORS INFLUENCING POST- CRYOPRESERVED CD34+ CELLS VIABILITY IN THE HARVESTED PRODUCTS OF AUTOLOGOUS HAEMATOPOIETIC STEM CELLS

The cryopreservation process of stem cells potentially cause the loss of CD34+ cells. The aim of this study is to evaluate association of patient, graft and technical characteristics with post cryopreserved CD34+ cells viability among lymphoproliferative disease namely multiple myeloma (MM) and lymphoma patients at Hospital Universiti Sains Malaysia (USM). This retrospective study was conducted in the Transplant Unit. A search of the hospital data (2008-2018) to identify 132 patients for both MM and lymphoma who underwent autologous peripheral blood haematopoietic stem cells (APBSC) mobilisation, and were successfully harvested and cryopreserved. Selected patients' profile as well as selected parameters of stem cell mobilization and cryopreservation were obtained from laboratory information system (LIS), record unit and the Transplant Unit. Multiple logistic regression (MLR) was used to find significant associated factors and p <0.05 was considered significant. The mean age of the patients was 39 years old with almost equal gender distribution and majority were lymphoma patients, 96 (72.7%) while 36 (27.3%) were multiple myeloma (MM) patients. The significant influencing factors of post-cryopreserved CD34+ cells viability were pre-cryopreserved CD34+ cell viability, total nucleated cells (TNC), and anti-platelet and antibiotics usage. Patients who are not on anti-platelet and have higher pre-cryopreserved CD34+ cells viability have higher chance for good post-cryopreserved CD34+ cells viability. While, those patients with higher TNC and on antibiotics have lower chance for good post cryopreserved CD34+ cells viability. This study showed patients who are not on anti-platelet and antibiotics will have higher probability of achieving good post cryopreserved CD34+ cells viability. The APBSC products with higher pre-cryopreserved CD34+ cells viability and lower TNC will achieve better post-cryopreserved CD34+ cells viability. The addition of extra plasma to the APBSC products is recommended to reduce the TNC.

Vascular Remodeling of Clinically Used Patches and Decellularized Pericardial Matrices Recellularized with Autologous or Allogeneic Cells in a Porcine Carotid Artery Model

Background: Cardiovascular surgery is confronted by a lack of suitable materials for patch repair. Acellular animal tissues serve as an abundant source of promising biomaterials. The aim of our study was to explore the bio-integration of decellularized or recellularized pericardial matrices in vivo. Methods: Porcine (allograft) and ovine (heterograft, xenograft) pericardia were decellularized using 1% sodium dodecyl sulfate ((1) Allo-decel and (2) Xeno-decel). We used two cell types for pressure-stimulated recellularization in a bioreactor: autologous adipose tissue-derived stromal cells (ASCs) isolated from subcutaneous fat of pigs ((3) Allo-ASC and (4) Xeno-ASC) and allogeneic Wharton’s jelly mesenchymal stem cells (WJCs) ((5) Allo-WJC and (6) Xeno-WJC). These six experimental patches were implanted in porcine carotid arteries for one month. For comparison, we also implanted six types of control patches, namely, arterial or venous autografts, expanded polytetrafluoroethylene (ePTFE Propaten® Gore®), polyethylene terephthalate (PET Vascutek®), chemically stabilized bovine pericardium (XenoSure®), and detoxified porcine pericardium (BioIntegral® NoReact®). The grafts were evaluated through the use of flowmetry, angiography, and histological examination. Results: All grafts were well-integrated and patent with no signs of thrombosis, stenosis, or aneurysm. A histological analysis revealed that the arterial autograft resembled a native artery. All other control and experimental patches developed neo-adventitial inflammation (NAI) and neo-intimal hyperplasia (NIH), and the endothelial lining was present. NAI and NIH were most prominent on XenoSure® and Xeno-decel and least prominent on NoReact®. In xenografts, the degree of NIH developed in the following order: Xeno-decel > Xeno-ASC > Xeno-WJC. NAI and patch resorption increased in Allo-ASC and Xeno-ASC and decreased in Allo-WJC and Xeno-WJC. Conclusions: In our setting, pre-implant seeding with ASC or WJC had a modest impact on vascular patch remodeling. However, ASC increased the neo-adventitial inflammatory reaction and patch resorption, suggesting accelerated remodeling. WJC mitigated this response, as well as neo-intimal hyperplasia on xenografts, suggesting immunomodulatory properties.

A humoral solution: Autologous blood products and tissue repair

Autologous blood-derived products (ABP) are the focus of growing scientific interest and are investigated and used for multiple medical indications. ABPs hold promise thanks to their availability, ease of preparation, and low risk of adverse allogenic reaction, hypersensitivity, and contamination. Compositional analysis of ABPs reveals a diverse mixture of cellular components, cytokines and growth factors that play roles in healing processes such as tissue proliferation and angiogenesis, modulation of the local environment through chemotaxis and regulation of inflammation and the extracellular matrix, as well as several immunomodulatory actions. Thus, the administration of ABP induces supraphysiological levels of components necessary for orchestrating reparative efforts in currently difficult-to-treat medical conditions. In this article, we review the variety of autologous blood-derived products, their composition, current clinical uses, regulatory climate, and mechanisms of action.