Angiogenic properties of human placenta-derived adherent cells and efficacy in hindlimb ischemia.

OBJECTIVE: Human placenta-derived adherent cells (PDACs) are a culture-expanded, undifferentiated mesenchymal-like population from full-term placental tissue and were previously shown to possess anti-inflammatory and immunomodulatory properties. PDACs (formulated as PDA-002) are in clinical trials for peripheral arterial disease with diabetic foot ulcer. In the current study, we examined their angiogenic and tissue reparative properties. METHODS: The effects of PDACs on survival and tube formation of human umbilical vein endothelial cells (HUVECs) were tested using conditioned media and noncontact coculture. Angiogenic effects were assessed in the chick chorioallantoic membrane assay. Hindlimb ischemia (HLI) was induced in mice and rats by femoral artery transection, and blood flow and blood vessel density were monitored in vivo by laser Doppler and angiography in the ischemic and control limbs. Tissue damage and regeneration in HLI were examined in histologic sections of quadriceps muscle stained with hematoxylin and eosin, and newly synthesized blood vessels were detected by indoxyl-tetrazolium staining for alkaline phosphatase. RESULTS: PDACs enhanced the survival of serum-starved HUVECs and stimulated HUVEC tube formation, and in the chick chorioallantoic membrane assay, PDACs stimulated blood vessel formation. In HLI, intramuscular administration of PDACs resulted in improved blood flow and vascular density, and in quadriceps muscle, tissue regeneration and increased numbers of blood vessels were observed. CONCLUSIONS: PDACs exhibited various activities consistent with angiogenesis and tissue repair, supporting the continued investigation of this cell therapy as treatment for vascular disease-related indications.

First-in-human evaluation of a hand-held automated venipuncture device for rapid venous blood draws.

Obtaining venous access for blood sampling or intravenous (IV) fluid delivery is an essential first step in patient care. However, success rates rely heavily on clinician experience and patient physiology. Difficulties in obtaining venous access result in missed sticks and injury to patients, and typically require alternative access pathways and additional personnel that lengthen procedure times, thereby creating unnecessary costs to healthcare facilities. Here, we present the first-in-human assessment of an automated robotic venipuncture device designed to safely perform blood draws on peripheral forearm veins. The device combines ultrasound imaging and miniaturized robotics to identify suitable vessels for cannulation and robotically guide an attached needle toward the lumen center. The device demonstrated results comparable to or exceeding that of clinical standards, with a success rate of 87% on all participants (n = 31), a 97% success rate on nondifficult venous access participants (n = 25), and an average procedure time of 93 ± 30 s (n = 31). In the future, this device can be extended to other areas of vascular access such as IV catheterization, central venous access, dialysis, and arterial line placement.

Placenta Derived Adherent Cell (PDAC) Interaction and Response on Extracellular Matrix Isolated from Human Placenta t.

A method was developed to isolate extracellular matrix from the human placenta (pECM). The isolated material is composed primarily of collagen, in addition to, elastin, fibronectin, laminin, and glycosaminoglycans (GAGs). The pECM is isolated as a water insoluble paste. This paste can be molded into sheets, tubes, and other 3-D structures that are stable at room temperature. This report describes the interaction of the pluripotent progenitor cells (PDACs) with the isolated pECM. The stem cells used in this study are of human placental origin (placenta derived adherent cells or PDACs) and have a phenotype described as CD200+, CD105+, CD10+, CD34-, and CD45-. The PDACs bind to and proliferate on the pECM, and are stimulated to secrete soluble fibronectin. They actively assemble the soluble fibronectin into a complex network of detergent-insoluble extracellular matrix fibrils. While proliferating on the pECM, PDACs secrete key cytokines at levels well above that observed on tissue-treated tissue culture plates. These cytokines included monocyte chemoattractant protein (MCP-1), IL-6, and IL-8, all of which are important participants in wound healing processes. These results suggest the feasibility of designing a combination product of pECM with PDACs to augment repair processes in nonhealing deep wounds and in diabetic ulcers.

The Mechanism of Cell Interaction and Response on Decellularized Human Amniotic Membrane: Implications in Wound Healing.

ACELAGRAFT™ (Celgene Cellular Therapeutics, Cedar Knolls, NJ) was developed as a decellularized and dehydrated human amniotic membrane product (DDHAM). The product has demonstrated potential as a wound healing product with several ongoing preclinical and clinical studies in the area of acute and chronic ulcers. Although the mechanism of action of such a decellularized product has not been examined, a detailed study of the ability of fibroblasts to interact with DDHAM and subsequent cellular responses are presented. These studies indicate that the composition of DDHAM is that of an extracellular matrix (ECM)-like material with high collagen content, retaining key bioactive molecules, such as fibronectin, laminin, glycosaminoglycans (GAGs), and elastin. No cytokines or growth factors were identified as one might expect in a nondecellularized amniotic membrane product. Cell assays show that fibroblasts can recognize fibronectin in DDHAM and bind to it via typical integrin-fibronectin interactions. Fibroblasts secrete fibronectin and can actively assemble the soluble fibronectin into a complex extracellular matrix on DDHAM. Fibroblasts are also stimulated by DDHAM to secrete key proinflammatory(IL-1 and IL-6) and chemotactic cytokines or chemokines (proand IL-8) involved in regulating and enhancing wound repair processes. Microarray gene expression studies on fibroblasts bound to DDHAM show increased expression of key wound healing cytokines. Together, these studies provide insight into the mechanisms by which DDHAM may augment the wound healing process.

Human placenta-derived adherent cells induce tolerogenic immune responses.

Human placenta-derived adherent cells (PDAC cells) are a culture expanded, undifferentiated mesenchymal-like population derived from full-term placental tissue, with immunomodulatory and anti-inflammatory properties. PDA-001 (cenplacel-L), an intravenous formulation of PDAC cells, is in clinical development for the treatment of autoimmune and inflammatory diseases. To elucidate the mechanisms underlying the immunoregulatory properties of PDAC cells, we investigated their effects on immune cell populations, including T cells and dendritic cells (DC) in vitro and in vivo. PDAC cells suppressed T-cell proliferation in an OT-II T-cell adoptive transfer model, reduced the severity of myelin oligodendrocyte glycoprotein peptide-induced experimental autoimmune encephalomyelitis and ameliorated inflammation in a delayed type hypersensitivity response model. In vitro, PDAC cells suppressed T-cell proliferation and inhibited Th1 and Th17 differentiation. Analysis of tissues derived from PDAC cell-treated animals revealed diminished CD86 expression on splenic DC, suggesting that they can also modulate DC populations. Furthermore, PDAC cells modulate the differentiation and maturation of mouse bone marrow-derived DC. Similarly, human DC differentiated from CD14(+) monocytes in the presence of PDAC cells acquired a tolerogenic phenotype. These tolerogenic DC failed to induce allogeneic T-cell proliferation and differentiation toward Th1, but skewed T-cell differentiation toward Th2. Inhibition of cyclo-oxygenase-2 activity resulted in a significant, but not complete, abrogation of PDAC cells' effects on DC phenotype and function, implying a role for prostaglandin E2 in PDAC-mediated immunomodulation. This study identifies modulation of DC differentiation toward immune tolerance as a key mechanism underlying the immunomodulatory activities of PDAC cells.