The Use of Mesenchymal Stromal Cells in the Treatment of Diseases of the Cornea

As a key component of the ocular surface required for vision, the cornea has been extensively studied as a site for cell and tissue-based therapies. Historically, these treatments have consisted of donor corneal tissue transplants, but cultivated epithelial autografts have become established over the last 15 years as a routine treatment for ocular surface disease. Ultimately, these treatments are performed with the intention of restoring corneal transparency and a smooth ocular surface. The degree of success, however, is often dependent upon the inherent level of corneal inflammation at time of treatment. In this regard, the anti-inflammatory and immuno-modulatory properties of mesenchymal stromal cells (MSC) have drawn attention to these cells as potential therapeutic agents for corneal repair. The origins for MSC-based therapies are founded in part on observations of the recruitment of endogenous bone marrow-derived cells to injured corneas, however, an increasing quantity of data is emerging for MSC administered following their isolation and ex vivo expansion from a variety of tissues including bone marrow, adipose tissue, umbilical cord and dental pulp. In brief, evidence has emerged of cultured MSC, or their secreted products, having a positive impact on corneal wound healing and retention of corneal allografts in animal models. Optimal dosage, route of administration and timing of treatment, however, all remain active areas of investigation. Intriguingly, amidst these studies, have emerged reports of MSC transdifferentiation into corneal cells. Clearest evidence has been obtained with respect to expression of markers associated with the phenotype of corneal stromal cells. In contrast, the evidence for MSC conversion to corneal epithelial cell types remains inconclusive. In any case, the conversion of MSC into corneal cells seems unlikely to be an essential requirement for their clinical use. This field of research has recently become more complicated by reports of MSC-like properties for cultures established from the peripheral corneal stroma (limbal stroma). The relationship and relative value of corneal-MSC compared to traditional sources of MSC such as bone marrow are at present unclear. This chapter is divided into four main parts. After providing a concise overview of corneal structure and function, we will highlight the types of corneal diseases that are likely to benefit from the anti-inflammatory and immuno-modulatory properties of MSC. We will subsequently summarize the evidence supporting the case for MSC-based therapies in the treatment of corneal diseases. In the third section we will review the literature concerning the keratogenic potential of MSC. Finally, we will review the more recent literature indicating the presence of MSC-like cells derived from corneal tissue.

Ontology analysis of global gene expression differences of human bone marrow stromal cells cultured on 3D scaffolds or 2D films

Differences in gene expression of human bone marrow stromal cells (hBMSCs) during culture in three-dimensional (3D) nanofiber scaffolds or on two-dimensional (2D) films were investigated via pathway analysis of microarray mRNA expression profiles. Previous work has shown that hBMSC culture in nanofiber scaffolds can induce osteogenic differentiation in the absence of osteogenic supplements (OS). Analysis using ontology databases revealed that nanofibers and OS regulated similar pathways and that both were enriched for TGF-beta and cell-adhesion/ECM-receptor pathways. The most notable difference between the two was that nanofibers had stronger enrichment for cell-adhesion/ECM-receptor pathways. Comparison of nanofibers scaffolds with flat films yielded stronger differences in gene expression than comparison of nanofibers made from different polymers, suggesting that substrate structure had stronger effects on cell function than substrate polymer composition. These results demonstrate that physical (nanofibers) and biochemical (OS) signals regulate similar ontological pathways, suggesting that these cues use similar molecular mechanisms to control hBMSC differentiation. Published by Elsevier Ltd.

Collision tumour involving a rectal gastrointestinal stromal tumour with invasion of the prostate and a prostatic adenocarcinoma

Background: Gastrointestinal stromal tumours (GISTs) are the most common primary mesenchymal neoplasia in the gastrointestinal tract, although they represent only a small fraction of total gastrointestinal malignancies in adults (<2%). GISTs can be located at any level of the gastrointestinal tract; the stomach is the most common location (60-70%), in contrast to the rectum, which is most rare (4%). When a GIST invades into the adjacent prostate tissue, it can simulate prostate cancer. In this study, we report on a case comprising the unexpected collision between a rectal GIST tumour and a prostatic adenocarcinoma. Findings: We describe the complexity of the clinical, endoscopic and radiological diagnosis, of the differential diagnosis based on tumour biopsy, and of the role of neoadjuvant therapy using imatinib prior to surgical treatment. Conclusions: Although isolated cases of coexisting GISTs and prostatic adenocarcinomas have reviously been described, this is the first reported case in the medical literature of a collision tumour involving a rectal GIST and prostatic adenocarcinoma components.

Uptake and intracytoplasmic storage of pigmented particles by human CD34+stromal cells/telocytes: endocytic property of telocytes

We studied the phagocytic-like capacity of human CD34+ stromal cells/telocytes (TCs). For this, we examined segments of the colon after injection of India ink to help surgeons localize lesions identified at endoscopy. Our results demonstrate that CD34+ TCs have endocytic properties (phagocytic-like TCs: phTCs), with the capacity to uptake and store India ink particles. phTCs conserve the characteristics of TCs (long, thin, bipolar or multipolar, moniliform cytoplasmic processes/telopodes, with linear distribution of the pigment) and maintain their typical distribution. Likewise, they are easily distinguished from pigment-loaded macrophages (CD68+ macrophages, with oval morphology and coarse granules of pigment clustered in their cytoplasm). A few c-kit/CD117+ interstitial cells of Cajal also incorporate pigment and may conserve the phagocytic-like property of their probable TC precursors. CD34+ stromal cells in other locations (skin and periodontal tissues) also have the phagocytic-like capacity to uptake and store pigments (hemosiderin, some components of dental amalgam and melanin). This suggests a function of TCs in general, which may be related to the transfer of macromolecules in these cells. Our ultrastructural observation of melanin-storing stromal cells with characteristics of TCs (telopodes with dichotomous branching pattern) favours this possibility. In conclusion, intestinal TCs have a phagocytic-like property, a function that may be generalized to TCs in other locations. This function (the ability to internalize small particles), together with the capacity of these cells to release extracellular vesicles with macromolecules, could close the cellular bidirectional cooperative circle of informative exchange and intercellular interactions.

Role of Stromal Cell-Derived Factor-1 in Neoangiogenesis in Endometriosis Lesions

Endometriosis affects 5-10% of women and is characterized by the growth of endometrial tissue outside of the uterus. Treatment for endometriosis primarily focuses on symptom relief, is short term with severe side effects and often leads to recurrence of the condition. Establishing new blood supply is a fundamental requirement for endometriosis lesions growth. This has led to the idea that antiangiogenic therapy may be a successful approach for inhibiting endometriosis. Recent evidence indicates that endothelial progenitor cells (EPCs) contribute to neoangiogenesis of endometriotic lesions. These EPCs are recruited to the lesion site by stromal cell-derived factor-1 (SDF-1). We hypothesize that SDF-1 is central to the neoangiogenesis and survival of endometriotic lesions and that administration of SDF-1 blocking antibody will inhibit lesion growth by inhibiting angiogenesis in a murine model of endometriosis. Immunohistochemistry for SDF-1 and CD34 was performed on human endometriosis and normal endometrial samples. Quantification of SDF-1 and EPCs was performed in the blood of endometriosis patients and controls using ELISA and flow cytometry, respectively. A new mouse model of endometriosis was developed using BALB/c-Rag2-/-/IL2rg-/- mice to investigate role of SDF-1 in neoangiogenesis. Either SDF-1 blocking antibody or an isotype control was administered on a weekly basis for four weeks. Weekly samples of peripheral blood from mice were analyzed for SDF-1, other cytokines of interest and EPCs. Mice were euthanized at seven weeks to observe lesion growth and blood vessel development. Our results indicate overabundance of SDF-1 and CD34+ progenitor cells in human endometriotic lesions compared to eutopic endometrium. In the mouse model, SDF-1 and circulating EPC levels decreased from pre-treatment levels after one week, and remained constant over the course of the treatment in both SDF-1 blocking antibody and isotype control groups. In the SDF-1 blocking group, reduced vascularity of lesions, identified by immunofluorescence staining for CD31, was revealed compared to isotype controls. These findings suggest that SDF-1 may be responsible for CD34+ progenitor cell recruitment to the neoangiogenic sites in endometriosis. Blocking of SDF-1 reduces neovascularization of human endometriotic lesions in a mouse model. Further studies on blocking SDF-1 in combination with other antiangiogenic agents are needed.

Multi-potent mesenchymal stromal cells in blood.

Peripheral blood-derived multi-potent mesenchymal stromal cells circulate in low number. They share, though not all, but most of the surface markers with bone marrow-derived multi-potent mesenchymal stromal cells, possess diverse and complicated gene expression characteristics, and are capable of differentiating along and even beyond mesenchymal lineages. Although their origin and physio-pathological function are still unclear, their presence in the adult peripheral blood might relate to some interesting but controversial subjects in the filed of adult stem cell biology, such as systemic migration of bone marrow-derived multi-potent mesenchymal stromal cells and the existence of common hematopoietic-mesenchymal precursors. In this review, current studies/knowledge about peripheral blood-derived multi-potent mesenchymal stromal cells is summarized and the above-mentioned topics are discussed.

Ectopic ACTH-syndrome due to a thymic carcinoid tumor

Investigating a recently developed Cushing Syndrome, we diagnosed in a 47-year-old woman an ectopic ACTH syndrome due to a metastatic carcinoid tumor, most likely a thymic carcinoid tumor. Combined therapy with sandostatin and nizoral and later on with sandostatin, metopirone and orimeten, was not able to suppress the hypercortisolism. A few weeks after surgical adrenalectomy, clinical deterioration ensued, culminating in the patient's death 7 months after diagnosis.

ZAP-70 restoration in mice by in vivo thymic electroporation.

Viral and non-viral vectors have been developed for gene therapy, but their use is associated with unresolved problems of efficacy and safety. Efficient and safe methods of DNA delivery need to be found for medical application. Here we report a new monopolar system of non-viral electro-gene transfer into the thymus in vivo that consists of the local application of electrical pulses after the introduction of the DNA. We assessed the proof of concept of this approach by correcting ZAP-70 deficient severe combined immunodeficiency (SCID) in mice. The thymic electro-gene transfer of the pCMV-ZAP-70-IRES-EGFP vector in these mice resulted in rapid T cell differentiation in the thymus with mature lymphocytes detected by three weeks in secondary lymphoid organs. Moreover, this system resulted in the generation of long-term functional T lymphocytes. Peripheral reconstituted T cells displayed a diversified T cell receptor (TCR) repertoire, and were responsive to alloantigens in vivo. This process applied to the thymus could represent a simplified and effective alternative for gene therapy of T cell immunodeficiencies.