Current Stem Cell Clinical Trials and Research Progress

During the last 15-10 years, the interest in stem cells has been growing exponentially because of their self-renewal abilities and high plasticity. The physiologic function of adult stem cells (ASCs) is maintaining tissue homeostasis through cellular damaged or aged turn over, while embryonic stem cells (ESCs) generate all committed cell type of organism. Researchers try to exploit these properties to treat degenerative pathologies, as neurological disorder (Parkinson, Alzheimer, Ataxias, multiple sclerosis ), musculoskeletal disorder (arthrosis, dystrophy, heart failure ), diabetes, eyes disorder (optical nerve or corneal degeneration ),autoimmune disease, renal failure and cancer. Although initial enthusiasm for them potentiality, SCs therapy tire to develop for several reasons. Firstly, self renewal and plasticity are also properties of cancer cells and the possibility to lose control on transplanted SCs could become the worst side effect obtainable. Secondly, in case of allergenic graft will avoid immunorejection by the recipient. Finally, to have ESCs is necessary to manipulate and to sacrifice embryos and scientific, but above all catholic, world identify in this stage of develop a human with same rights of a born man. In this review, we report on recent advances on the clinical trial about stem cells (SCs) therapy. Ours intention is to show all stem cells types disposable and them rational employment in medicine, with focus on treatment benefits and side effects. To give an ethical imprint at the work, we resume the more common clinical practice guidelines in a work track. putamen and caudate nucleus with human embryonic mesencephalic tissue from donors. In the second postoperative year, mean daily L-dopa uptake was decreased by 54% and UPDRS score in off phase was decreased by a mean of 40%. Dopa detection with PET showed a mean 61% increase in the putamen, and 24% increase in the caudate nucleus, compared with preoperative values [91]. A double-blind randomly trial compared transplant of cultured mesencephalic tissue derived from embryos with sham surgery. In 17of the 20 patients fiber outgrowth from the implanted neurons, as indicated by an increase in F-fluorodopa uptake on PET or postmortem examination. However improvements of first year, dystonia and dyskinesias recurred in 15% of the patients who received transplants [92]. An American double-blind trial compared fetal nigral transplantation with placebo. 34 patients with PD were treated and followed for 24 month. There was no significant treatment effect. Although striatal fluorodopa uptake increased, 56% of transplanted patients developed dyskinesia that persisted after dopaminergic medication [93]. Patients with renal cell carcinoma (RCC) treated with reduced intensity conditioning and peripheral blood stem cells and immunosuppression experienced chronic GVHD in 33%. Transplant related mortality was 16% at one year. Complete (n = 4) or partial (n = 24) responses. Factors associated with survival included chronic GVHD. Patients (n = 17) with chronic GVHD and given DLI had a 2 year survival of 70% [124]. HSCT leads to durable responses in a minority of metastatic RCC patients. Appropriate patient selection is paramount. Anemia and decreased performance status may enable risk stratification [125,126]. Treatment of metastatic RCC with HSCT after conditioning with immunosuppression was associated with a graft versus tumor effect [127]. The use of first line high dose chemotherapy (HDC) with AHCT have some effect on overall survival (OS), disease free survival (DFS) and response rate in patients with metastatic breast cancer responding to induction therapy [128,129]. Allogenic SC transplantation (allo SCT) can induce curative graft versus leukemia reactions for hematological malignancies through allogenic immunity. As the gastrointestinal tract is a target of graft versus host disease (GvHD), colorectal cancer has been suggested as a candidate for allo SCT. [130]. Some studies described the feasibility of combination of chemotherapy and SCT for the treatment of ovarian malignancies. 131]