Scaffolds of recombinant spider silk protein (spidroin) and hyaluronic acid (HA) hydrogel hold promise in combination with cell therapy for spinal cord injury. However, little is known concerning the human immune response to these biomaterials and grafted human neural stem/progenitor cells (hNPCs). Here, we analyzed short- and long-term in vitro activation of immune cells in human peripheral blood mononuclear cells (hPBMCs) cultured with/without recombinant spidroins, HA hydrogels, and/or allogeneic hNPCs to assess potential host–donor interactions. Viability, proliferation and phenotype of hPBMCs were analyzed using NucleoCounter and flow cytometry. hPBMC viability was confirmed after exposure to the different biomaterials. Short-term (15 h) co-cultures of hPBMCs with spidroins, but not with HA hydrogel, resulted in a significant increase in the proportion of activated CD69⁺ CD4⁺ T cells, CD8⁺ T cells, B cells and NK cells, which likely was caused by residual endotoxins from the Escherichia coli expression system. The observed spidroin-induced hPBMC activation was not altered by hNPCs. It is resource-effective to evaluate human compatibility of novel biomaterials early in development of the production process to, when necessary, make alterations to minimize rejection risk. Here, we present a method to evaluate biomaterials and hPBMC compatibility in conjunction with allogeneic human cells.

Imagine the profits in quality of life that can be made by treating inherited diseases early in life, maybe even before birth! Immense cost‐savings can also be made by treating diseases promptly. Hence, prenatal stem cell therapy holds great promise for developing new and early stage treatment strategies for several diseases. Successful prenatal stem cell therapy would represent a major step forward in the management of patients with hematological, metabolic, or immunological disorders. However, treatment before birth has several limitations, including ethical issues. In this review, we summarize the past, the present, and the future of prenatal stem cell therapy, which includes an overview of different stem cell types, preclinical studies, and clinical attempts treating various diseases. We also discuss the current challenges and future strategies for prenatal stem cell therapy and also new approaches, which may lead to advancement in the management of patients with severe incurable diseases. Stem Cells Translational Medicine 2019

Congenital malformations are the leading cause of deaths during the neonatal period. Infants with prenatally diagnosed soft tissue defects may benefit from readily available autologous tissue for surgical implantation perinatally. In this study we investigated the cell content of amniotic fluid (AF) and its suitability for isolation and expansion of autologous cells for clinical use. Second trimester AF was obtained at routine amniocentesis at mean gestational week+day 16+2 ( n =54). To investigate the cell content, freshly harvested AF cells (AFC) were analyzed for different cell lineages by flow cytometry. To evaluate the isolation and expansion potential of AFC, isolation by plastic adherence was evaluated with three cell culture media and positive selection of CD117, CD133, CD271, and fibroblast cells were evaluated with minimum essential medium alpha culture media. Both the positive (+) and the negative (−) fractions were analyzed. Surface expression, senescence, immunogenicity, colony forming, proliferation, and differentiation capacity was examined. In the nonhematopoietic, nonendothelial fraction of freshly harvested AF ( n =17), 0.13% cells were CD73 ⁺ /CD117 ⁺ and 0.12% CD73 ⁺ /CD271 ⁺ . AF displayed large donor variability with varying isolation and expansion success ( n =30). The proliferative, differentiative, colony forming capacity and time before senescence also showed high variance. AFC had a preference for osteogenic rather than adipogenic lineages. Most culture-expanded AFC expressed mesenchymal but not hematopoietic surface epitopes. AFC expanded in Dulbecco's modified Eagle's medium showed higher immunogenic characteristics. This study shows that AF is a heterogeneous cell source, with high donor variation. Therefore, it may not be the best source for autologous cell therapy.

Urological reconstructive surgery is sometimes hampered by a lack of tissue. In some cases, autologous urothelial cells (UCs) are not available for cell expansion and ordinary tissue engineering. In these cases, we wanted to explore whether autologous mesenchymal stem cells (MSCs) from bone marrow could be used to create urological transplants. MSCs from human bone marrow were cultured in vitro with medium conditioned by normal human UCs or by indirect co-culturing in culture well inserts. Changes in gene expression, protein expression and cell morphology were studied after two weeks using western blot, RT-PCR and immune staining. Cells cultured in standard epithelial growth medium served as controls. Bone marrow MSCs changed their phenotype with respect to growth characteristics and cell morphology, as well as gene and protein expression, to a UC lineage in both culture methods, but not in controls. Urothelial differentiation was also accomplished in human bone marrow MSCs seeded on a three-dimensional poly(ε-caprolactone) (PCL)–collagen construct. Human MSCs could easily be harvested by bone marrow aspiration and expanded and differentiated into urothelium. Differentiation could take place on a three-dimensional hybrid PCL-reinforced collagen-based scaffold for creation of a tissue-engineered autologous transplant for urological reconstructive surgery.