Outcome Of Cell-based Therapy Research Articles

Cell Therapies for Parkinson's Disease.

Cell Therapies for Parkinson's Disease.

Abstract 011: ACE2 Gene Transfer Ameliorates Dysfunctions in Hematopoietic Stem/Progenitor Cells of Diabetic Patients

Hematopoietic stem/progenitor cells (HS/PCs) have the propensity of ischemic vascular repair, and this innate vasoprotective function is impaired in diabetes. Angiotensin-converting enzyme (ACE) and ACE-2 are primary enzymes of the cardiovascular-detrimental and protective axes of the renin-angiotensin system, respectively. In this study, we tested the hypothesis that diabetic dysfunction in HS/PCs is due to ACE2/ACE-imbalance, and that increasing ACE2 expression will restore the vasoreparative potential. Lineage- (Lin - ) or CD34 + cells were isolated from the peripheral blood mononuclear cells (MNCs) of nondiabetic subjects (ND), and type 1 or type 2 diabetic (DB) patients (male or female, age 48-76 years, HbA1C 6.5-11.2). ACE and ACE2 activities were measured in lysates of MNCs, Lin - and CD34 + cells by enzyme-selective fluorogenic substrates and inhibitors. Lentiviral ACE2 (LV-ACE2) gene transfer was carried out by spinoculation. Reparative function of Lin - cells was evaluated in Foxn1 nu mice undergoing hind limb ischemia (HLI). Lin - cells with or without ACE2-overexpression were administered (i.m) in the peri-ischemic region, and the blood flow recovery was monitored. Circulating Lin - or CD34 + cells are lower in DB (Lin - ((2±0.2)х10 5 , P<0.04) and CD34 + ((0.6±0.1)х10 3 , P<0.02), n=8) compared to ND group (Lin - (25±4)х10 5 ; CD34 + (2±0.4)х10 3 per 10 6 MNCs, n=8). This was associated with decrease in ACE2 and increase in ACE activity, resulting in 4.5-fold decrease in ACE2/ACE ratio in DB-CD34 + cells (0.4±0.07 vs ND 1.8±0.2, P<0.01, n=6). This was negatively correlated with HbA1C (r 2 =0.89, P<0.01). Administration of ND-Lin - cells has no effect on the blood flow recovery of mice following HLI. In contrast, administration of DB-Lin - cells decreased this recovery (48±6%, n=5, P<0.001 vs ND-Lin - 105±7%). However, treatment with ACE2-overexpressing DB-Lin - cells robustly enhanced blood flow recovery (112±8%, n=4, P<0.001 vs DB). These observations suggest that ACE2/ACE imbalance is correlated with diabetic vasoreparative dysfunction in HS/PCs, and that increasing ACE2 expression reverses the dysfunction. ACE2 gene transfer is a promising approach for enhancing vascularization outcomes of cell-based therapies in diabetic individuals.

Hydrogel depots for local co-delivery of osteoinductive peptides and mesenchymal stem cells

The outcome of cell-based therapies can benefit from carefully designed cell carriers. A multifunctional injectable vehicle for the co-delivery of human mesenchymal stem cells (hMSCs) and osteoinductive peptides is proposed, to specifically direct hMSCs osteogenic differentiation. The osteogenic growth peptide (OGP) inspired the design of two peptides, where the bioactive portion of OGP was flanked by a protease-sensitive linker, or its scrambled sequence, to provide faster and slower release rates, respectively. Peptides were fully characterized and chemically grafted to alginate. Both OGP analogs released bioactive fragments in vitro, at different kinetics, which stimulated hMSCs proliferation and osteogenesis. hMSCs-laden OGP–alginate hydrogels were tested at an ectopic site in a xenograft mouse model. After 4weeks, OGP–alginate hydrogels were more degraded and colonized by vascularized connective tissue than the control (without OGP). hMSCs were able to proliferate, migrate outward the hydrogels, produce endogenous extracellular matrix and mineralize it. Moreover, OGP-groups stimulated hMSCs osteogenesis, as compared with the control. Overall, the ability of the proposed platform to direct the fate of transplanted hMSCs in loco was demonstrated, and OGP-releasing hydrogels emerged as a potentially useful system to promote bone regeneration.

Characterization of articular chondrocytes isolated from 211 osteoarthritic patients

We analyzed specific features of chondrocytes as cellular yield, cell doubling rates and the dependence between these parameters and patient-related data in a set of 211 osteoarthritic (OA) patients undergoing total joint replacement. For each patient the data available were joint type, age and gender. Knee samples chosen randomly among all biopsies were graded according to ICRS score. Patients' age ranged between 30 and 90 years with a mean age of 66 ± 9.7 years. Patients were divided into age classes and statistically significant differences in proliferation rate at passage 1 were found between chondrocytes derived from young and old donors, with the last ones characterized by a lower proliferation rate. A similar trend was observed for proliferation rate at passage 2. For all the samples, cellular yields ranged between 0.1 and 5.5 million cells/g of tissue. No significant correlation was observed between the level of cartilage degeneration (ICRS score) and cellular yield and proliferation rates. However, in samples with a high degree of cartilage degeneration (ICRS score 4) the cellular yield was lower compared to the other three groups (ICRS scores 1-3). In this study we performed a systematic characterization of basic parameters of chondrocytes originating from a wide group of OA patients. Considering the use of autologous chondrocytes in chondral treatments, the characterization of cell basic features may represent an important step to determine the quality of the cell source which is a major determinant in the outcome of cell-based therapies.

Vascular Endothelial Growth Factor Stimulates Endothelial Colony Forming Cells Proliferation and Tubulogenesis by Inducing Oscillations in Intracellular Ca2+ Concentration

Endothelial progenitor cells (EPCs) home from the bone marrow to the site of tissue regeneration and sustain neovascularization after acute vascular injury and upon the angiogenic switch in solid tumors. Therefore, they represent a suitable tool for cell-based therapy (CBT) in regenerative medicine and provide a novel promising target in the fight against cancer. Intracellular Ca(2+) signals regulate numerous endothelial functions, such as proliferation and tubulogenesis. The growth of endothelial colony forming cells (ECFCs), which are EPCs capable of acquiring a mature endothelial phenotype, is governed by store-dependent Ca(2+) entry (SOCE). This study aimed at investigating the nature and the role of VEGF-elicited Ca(2+) signals in ECFCs. VEGF induced asynchronous Ca(2+) oscillations, whose latency, amplitude, and frequency were correlated to the growth factor dose. Removal of external Ca(2+) (0Ca(2+)) and SOCE inhibition with N-(4-[3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl]phenyl)-4-methyl-1,2,3-thiadiazole-5-carboxamide (BTP-2) reduced the duration of the oscillatory signal. Blockade of phospholipase C-γ with U73122, emptying the inositol-1,4,5-trisphosphate (InsP(3))-sensitive Ca(2+) pools with cyclopiazonic acid (CPA), and inhibition of InsP(3) receptors with 2-APB prevented the Ca(2+) response to VEGF. VEGF-induced ECFC proliferation and tubulogenesis were inhibited by the Ca(2+)-chelant, BAPTA, and BTP-2. NF-κB activation by VEGF was impaired by BAPTA, BTP-2, and its selective blocker, thymoquinone. Thymoquinone, in turn, suppressed VEGF-dependent ECFC proliferation and tubulogenesis. These data indicate that VEGF-induced Ca(2+) oscillations require the interplay between InsP(3)-dependent Ca(2+) release and SOCE, and promote ECFC growth and tubulogenesis by engaging NF-κB. This novel signaling pathway might be exploited to enhance the outcome of CBT and chemotherapy.