Understanding the Impact of Preservation Methods on the Integrity and Functionality of Placental Allografts.

INTRODUCTION: Human placental membranes (hPMs) have a long history in treating burns and wounds. The composition of hPMs includes structural matrix, growth factors, and neonatal cells, all of which contribute to their regenerative potential. However, most hPM products are devitalized after dehydration and irradiation. We compared the functionality of single-layer viable cryopreserved human amniotic membrane (vCHAM) with multilayer devitalized dehydrated human amnion/chorion membrane (dHACM) in wound-relevant models to determine the effect of different processing methods on hPMs. METHODS: Viable cryopreserved human amniotic membrane and dHACM were compared with fresh hPM for structural integrity and viability. Viable cell persistence in vCHAM over time was evaluated in vitro and in vivo in a diabetic chronic wound mouse model. Proliferation of cells within fresh hPM and vCHAM was evaluated with bromodeoxyuridine and Ki-67 staining, and proliferation of isolated cells in culture was evaluated. Growth factor release over time and in vitro response to chronic wound stimuli (tumor necrosis factor α, lipopolysaccharide, and hypoxia) were used to compare the functionality of vCHAM and dHACM. RESULTS: The structure and thickness of fresh hPM were retained in vCHAM but were compromised in dHACM. Similar to fresh hPM, vCHAM contained viable cells, whereas dHACM did not. Cells in vCHAM remained viable after 4 and 7 days in culture and in an in vitro chronic wound environment and after 4 and 8 days in vivo after application to a mouse chronic wound. Staining for bromodeoxyuridine and Ki-67 did not reveal proliferative cells within fresh hPM and vCHAM. However, isolated cells proliferated in culture. Viable cryopreserved human amniotic membrane increased platelet-derived growth factor BB, hepatocyte growth factor, and epidermal growth factor levels over time and responded to chronic wound stimuli in vitro by significantly increasing levels of vascular endothelial growth factor and prostaglandin E2. Dehydrated human amnion/chorion membrane showed no significant accumulation of growth factors and did not respond to chronic wound stimuli. CONCLUSIONS: These results indicate that vCHAM retains intact, native matrix, and viable, active cells and responds to chronic wound stimuli in vitro. The inclusion of multiple layers of hPM does not compensate for structural degradation and loss of viability caused by dehydration as evidenced by a lack of functional response by dHACM. The clinical significance of these results remains to be answered.

Biomarker correlates with response to NY-ESO-1 TCR T cells in patients with synovial sarcoma.

Autologous T cells transduced to express a high affinity T-cell receptor specific to NY-ESO-1 (letetresgene autoleucel, lete-cel) show promise in the treatment of metastatic synovial sarcoma, with 50% overall response rate. The efficacy of lete-cel treatment in 45 synovial sarcoma patients (NCT01343043) has been previously reported, however, biomarkers predictive of response and resistance remain to be better defined. This post-hoc analysis identifies associations of response to lete-cel with lymphodepleting chemotherapy regimen (LDR), product attributes, cell expansion, cytokines, and tumor gene expression. Responders have higher IL-15 levels pre-infusion (p = 0.011) and receive a higher number of transduced effector memory (CD45RA- CCR7-) CD8 + cells per kg (p = 0.039). Post-infusion, responders have increased IFNγ, IL-6, and peak cell expansion (p < 0.01, p < 0.01, and p = 0.016, respectively). Analysis of tumor samples post-treatment illustrates lete-cel infiltration and a decrease in expression of macrophage genes, suggesting remodeling of the tumor microenvironment. Here we report potential predictive and pharmacodynamic markers of lete-cel response that may inform LDR, cell dose, and strategies to enhance anticancer efficacy.

Soluble Factors Released by Endogenous Viable Cells Enhance the Antioxidant and Chemoattractive Activities of Cryopreserved Amniotic Membrane.

Objective: Regulation of oxidative stress and recruitment of key cell types are activities of human amniotic membrane (hAM) that contribute to its benefits for wound treatment. Progress in tissue preservation has led to commercialization of hAM. The majority of hAM products are devitalized with various degrees of matrix alteration. Data show the importance of hAM matrix preservation, but little is known about the advantages of retaining viable endogenous cells. In this study, we compared the antioxidant and chemoattractive properties of viable intact cryopreserved hAM (int-hAM) and devitalized cryopreserved hAM (dev-hAM) to determine the benefits of cell preservation. Approach: We evaluated the ability of int-hAM and dev-hAM to protect fibroblasts from oxidant-induced cell damage, to suppress oxidants, and to recruit fibroblasts and keratinocytes in vitro. Results: Both the int-hAM-derived conditioned medium (CM) and the int-hAM tissue rescued significantly more fibroblasts from oxidant-induced damage than dev-hAM (844% and 93% more, respectively). The int-hAM CM showed a 202% greater antioxidant capacity than dev-hAM. The int-hAM CM enhanced the recruitment of fibroblasts and normal and diseased keratinocytes to a greater extent than dev-hAM (1,555%, 315%, and 151% greater, respectively). Innovation and Conclusion: Int-hAM, in which all native components are preserved, including endogenous viable cells, demonstrated a significantly greater antioxidant and fibroblast and keratinocyte chemoattractive potential compared to dev-hAM, in which viable cells are destroyed. The release of soluble factors that protect fibroblasts from oxidative injury by hAM containing viable cells is a mechanism of hAM antioxidant activity, which is a novel finding of this study.

Angiogenic Potential of Cryopreserved Amniotic Membrane Is Enhanced Through Retention of All Tissue Components in Their Native State.

Objective: Chronic wounds have inadequate microvasculature (or blood vessels), resulting in poor healing. Both fresh human amniotic membrane (hAM) containing viable cells and devitalized hAM have been shown to stimulate angiogenesis in chronic wounds. However, the importance of retaining viable endogenous cells on the angiogenic activity of hAM remains unknown. To understand their role, we compared the angiogenic potential of intact cryopreserved hAM containing viable cells (int-hAM) with devitalized cryopreserved hAM (dev-hAM). Approach: The effects of conditioned medium (CM) derived from int-hAM and dev-hAM on endothelial cell migration and tube formation were compared. Int-hAM and dev-hAM CM and tissues were tested for key angiogenic factors, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and platelet-derived growth factor-BB (PDGF-BB) after 7 days in culture. The role of VEGF in int-hAM-mediated tube formation was analyzed through inhibition of its activity by anti-VEGF antibody. Results: CM from int-hAM showed greater endothelial cell recruitment and tube formation compared with dev-hAM. Significantly higher levels of VEGF were detected in int-hAM CM after 1 week compared with dev-hAM CM. Int-hAM tissue also had significantly greater expression of VEGF and bFGF relative to dev-hAM. A similar trend was observed for PDGF-BB. Neutralization of VEGF in int-hAM CM significantly inhibited tube formation compared with int-hAM CM alone. Innovation and Conclusion: Preservation of all native hAM components, including viable endogenous cells, enhances the angiogenic effect of cryopreserved hAM. This effect is mediated through higher levels of angiogenic factors, especially VEGF, produced by int-hAM.

Retention of Endogenous Viable Cells Enhances the Anti-Inflammatory Activity of Cryopreserved Amnion.

Objective: Human amniotic membrane (hAM) has been used to treat wounds for more than 100 years. However, widespread use of fresh hAM has been limited due to its short shelf life and safety concerns. To overcome these concerns, different preservation methods have been introduced. The majority of these methods result in devitalized hAM (dev-hAM). Recently, we developed a cryopreservation method that retains all hAM components intact (int-hAM), including viable endogenous cells. To understand the advantages of retaining viable cells in preserved hAM, we compared the anti-inflammatory properties of int-hAM and dev-hAM. Approach: The tissue composition of int-hAM and dev-hAM was compared with fresh hAM through histology and cell viability analysis. We also evaluated the ability of int-hAM and dev-hAM to regulate tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), and IL-10 release when co-cultured with immune cells; to produce prostaglandin E2 (PGE2) on TNF-α stimulation; and to inhibit proteases. Results: Int-hAM maintained the structural and cellular integrity of fresh hAM. Int-hAM had >80% cell viability post-thaw and remained viable for at least a week in culture. Viable cells were not detected in dev-hAM. Compared with dev-hAM, int-hAM showed significantly greater downregulation of TNF-α and IL-1α, upregulation of PGE2 and IL-10, and stronger inhibition of collagenase. Innovation and Conclusion: A new cryopreservation method has been developed to retain all native components of hAM. For the first time, we show that viable endogenous cells significantly augment the anti-inflammatory activity of cryopreserved hAM.

UV-Induced Wnt7a in the Human Skin Microenvironment Specifies the Fate of Neural Crest-Like Cells via Suppression of Notch.

Multipotent stem cells with neural crest-like properties have been identified in the dermis of human skin. These neural crest stem cell (NCSC)-like cells display self-renewal capacity and differentiate into neural crest derivatives, including epidermal pigment-producing melanocytes. NCSC-like cells share many properties with aggressive melanoma cells, such as high migratory capabilities and expression of the neural crest markers. However, little is known about which intrinsic or extrinsic signals determine the proliferation or differentiation of these neural crest-like stem cells. Here we show that, in NCSC-like cells, Notch signaling is highly activated, similar to melanoma cells. Inhibition of Notch signaling reduced the proliferation of NCSC-like cells, induced cell death, and downregulated noncanonical Wnt5a, suggesting that the Notch pathway contributes to the maintenance and motility of these stem cells. In three-dimensional skin reconstructs, canonical Wnt signaling promoted the differentiation of NCSC-like cells into melanocytes. This differentiation was triggered by the endogenous Notch inhibitor Numb, which is upregulated in the stem cells by Wnt7a derived from UV-irradiated keratinocytes. Together, these data reveal a cross talk between the two conserved developmental pathways in postnatal human skin, and highlight the role of the skin microenvironment in specifying the fate of stem cells.

Alternative functional in vitro models of human intestinal epithelia.

Physiologically relevant sources of absorptive intestinal epithelial cells are crucial for human drug transport studies. Human adenocarcinoma-derived intestinal cell lines, such as Caco-2, offer conveniences of easy culture maintenance and scalability, but do not fully recapitulate in vivo intestinal phenotypes. Additional sources of renewable physiologically relevant human intestinal cells would provide a much needed tool for drug discovery and intestinal physiology. We compared two alternative sources of human intestinal cells, commercially available primary human intestinal epithelial cells (hInEpCs) and induced pluripotent stem cell (iPSC)-derived intestinal cells to Caco-2, for use in in vitro transwell monolayer intestinal transport assays. To achieve this for iPSC-derived cells, intestinal organogenesis was adapted to transwell differentiation. Intestinal cells were assessed by marker expression through immunocytochemical and mRNA expression analyses, monolayer integrity through Transepithelial Electrical Resistance (TEER) measurements and molecule permeability, and functionality by taking advantage the well-characterized intestinal transport mechanisms. In most cases, marker expression for primary hInEpCs and iPSC-derived cells appeared to be as good as or better than Caco-2. Furthermore, transwell monolayers exhibited high TEER with low permeability. Primary hInEpCs showed molecule efflux indicative of P-glycoprotein (Pgp) transport. Primary hInEpCs and iPSC-derived cells also showed neonatal Fc receptor-dependent binding of immunoglobulin G variants. Primary hInEpCs and iPSC-derived intestinal cells exhibit expected marker expression and demonstrate basic functional monolayer formation, similar to or better than Caco-2. These cells could offer an alternative source of human intestinal cells for understanding normal intestinal epithelial physiology and drug transport.