Association of angiotensin converting enzyme gene insertion/deletion polymorphism and familial hypercholesterolemia in the Saudi population.

BACKGROUND: The study of the association between genotype and phenotype is of great importance for the prediction of multiple diseases and pathophysiological conditions. The relationship between angiotensin converting enzyme (ACE) Insertion/Deletion (I/D) polymorphism and Familial Hypercholesterolemia (FH) has been not fully investigated in all the ethnicities. In this study we sought to determine the frequency of I/D polymorphism genotypes of ACE gene in Saudi patients with FH. RESULTS: This is a case-control study carried out purely in Saudi population. Genomic DNA was isolated from 128 subjects who have participated in this study. ACE gene I/D polymorphism was analyzed by polymerase chain reaction in 64 FH cases and 64 healthy controls. There was no statistically significant difference between the groups with respect to genotype distribution. Furthermore, we did not find any significant difference in the frequency of ACE I/D polymorphism in FH subjects when stratified by gender (p = 0.43). CONCLUSION: Our data suggest that ACE gene I/D polymorphism examined in this study has no role in predicting the occurrence and diagnosis of FH.

Genetic association between vitamin D receptor gene and Saudi patients confirmed with Familial Hypercholesterolemia.

INTRODUCTION: Familial Hypercholesterolemia (FH) is a common condition caused by inherited genetic abnormalities. Inadequate clearance of the circulating low-density lipoproteins (LDL) is the primary cause of the excessive concentrations of LDL seen in FH patients. The relation with vitamin D deficiency and vitamin D receptor (VDR) gene is well documented in the Saudi Arabia. AIM: The aim of this study was to investigate the role of molecular analysis studied between FH patients and fours polymorphisms associated with VDR gene in Saudi Population. METHODS: In this case-control study, 120 patients were selected, and 50 patients were confirmed as FH and 70 subjects were confirmed as healthy controls. Genotyping was performed with polymerase chain reaction followed by restriction fragment length polymorphism analysis using ApaI, BsmI, TaqI and FokI polymorphisms in the VDR gene. RESULTS: The current study results confirmed no association between clinical characteristics studied between FH cases and controls (p>0.05). Hardy Weinberg Equilibrium analysis was present in ApaI and FokI polymorphisms (p<0.05). Only ApaI (C vs A: OR-15.1 (95% CI:5.78-39.41); p<0.001; AC+CC vs AA: OR-6.59 (95% CI:2.42-17.95); p=0.0006) and BsmI (G vs A: OR-2.88 (95% CI:1.54-5.38); p=0.0006 and AG+GG vs AA: OR-3.79 (95% CI:1.72-8.35); p=0.0007) polymorphisms showed both allele and genotype association between FH patients and controls. ANOVA analysis confirmed that TG levels were associated (p=0.02) with combination of heterozygous and homozygous genotypes present in all four polymorphisms studied in this population. CONCLUSION: ApaI and BsmI polymorphisms in the VDR gene showed association with FH patients in the Saudi Population.

In vitro differentiation of human skin-derived multipotent stromal cells into putative endothelial-like cells.

BACKGROUND: Multipotent stem cells have been successfully isolated from various tissues and are currently utilized for tissue-engineering and cell-based therapies. Among the many sources, skin has recently emerged as an attractive source for multipotent cells because of its abundance. Recent literature showed that skin stromal cells (SSCs) possess mesoderm lineage differentiation potential; however, the endothelial differentiation and angiogenic potential of SSC remains elusive. In our study, SSCs were isolated from human neonatal foreskin (hNFSSCs) and adult dermal skin (hADSSCs) using explants cultures and were compared with bone marrow (hMSC-TERT) and adipose tissue-derived mesenchymal stem cells (hADMSCs) for their potential differentiation into osteoblasts, adipocytes, and endothelial cells. RESULTS: Concordant with previous studies, both MSCs and SSCs showed similar morphology, surface protein expression, and were able to differentiate into osteoblasts and adipocytes. Using an endothelial induction culture system combined with an in vitro matrigel angiogenesis assay, hNFSSCs and hADSSCs exhibited the highest tube-forming capability, which was similar to those formed by human umbilical vein endothelial cells (HUVEC), with hNFSSCs forming the most tightly packed, longest, and largest diameter tubules among the three cell types. CD146 was highly expressed on hNFSSCs and HUVEC followed by hADSSCs, and hMSC-TERT, while its expression was almost absent on hADMSCs. Similarly, higher vascular density (based on the expression of CD31, CD34, vWF, CD146 and SMA) was observed in neonatal skin, followed by adult dermal skin and adipose tissue. Thus, our preliminary data indicated a plausible relationship between vascular densities, and the expression of CD146 on multipotent cells derived from those tissues. CONCLUSIONS: Our data is the first to demonstrate that human dermal skin stromal cells can be differentiated into endothelial lineage. Hence, SSCs represents a novel source of stem/stromal cells for tissue regeneration and the vascularization of engineered tissues. Moreover, the CD146 investigations suggested that the microenvironmental niche might contribute to direct stromal cells multipotency toward certain lineages, which warrants further investigation.

Comparative investigation of the differentiation capability of bone-marrow- and adipose-derived mesenchymal stem cells by qualitative and quantitative analysis.

Mesenchymal stem cells (MSCs) hold promise for cell-based therapy in regenerative medicine. To date, MSCs have been obtained from conventional bone marrow via a highly invasive procedure. Therefore, MSCs are now also isolated from sources such as adipose tissue, cord blood and cord stroma, a subject of growing interest. As the characterization and differentiation potential of adipose-derived MSCs (AD-MSCs) and bone-marrow-derived MSCs (BM-MSCs) have not been documented, we have evaluated and compared the characteristics of both MSC types by qualitative and quantitative analyses. Both cell types show similar morphology and surface protein expression, being positive for stromal-associated markers and negative for hematopoietic and endothelial markers. The colony-forming potential of AD-MSCs is distinctly higher than that of BM-MSCs. Nonetheless, similar adipogenic and osteogenic differentiation is observed in both groups of MSCs. Cytochemical qualitative analysis and calcium mineralization demonstrate higher levels toward osteogenic differentiation in BM-MSCs than in AD-MSCs. On the contrary, the percentage of Nile red oil staining for differentiated adipocytes is higher in AD-MSCs than in BM-MSCs. Quantitative real-time polymerase chain reaction shows similar patterns of osteogenic- and adipogenic-associated gene expression in both cell types. Each of theMSCs respond in functional analysis by exhibiting unique properties at the differentiation level according to their micro-environmental niche. Thus, quantitative analysis might be a valuable means of describing stem cell multipotency, in addition to qualitative investigation.

Skin-derived multipotent stromal cells--an archrival for mesenchymal stem cells.

Progenitor stem cells have been identified, isolated and characterized in numerous tissues and organs. However, their therapeutic potential and the use of these stem cells remain elusive except for a few progenitor cells from bone marrow, umbilical cord blood, eyes and dental pulp. The use of bone marrow-derived hematopoietic stem cells (HSC) or mesenchymal stem cells (MSCs) is restricted due to their extreme invasive procedures, low differentiation potential with age and rejection. Thus, we need a clinical grade alternative to progenitor stem cells with a high potential to differentiate, naïve and is relatively easy in in vitro propagation. In this review, we summarize cell populations of adherent and floating spheres derived from different origins of skin, or correctly foreskin, by enzymatic digestion compared with established MSCs. The morphology, phenotype, differentiation capability and immunosuppressive property of the adherent cell populations are comparable with MSCs. Serum-free cultured floating spheres have limited mesodermal but higher neurogenic differentation potential, analogous to neural crest stem cells. Both the populations confirmed their plethora potential in in vitro. Together, it may be noted that the skin-derived adherent cell populations and floating cells can be good alternative sources of progenitor cells especially in cosmetic, plastic and sports regenerative medicine.

Effect of Genetic Variations in the ADIPOQ Gene on Susceptibility to Type 2 Diabetes Mellitus.

Background: ADIPOQ (adiponectin) affects fatty acid oxidation, glucose uptake, and glycogenesis, all of which are involved in the development of diabetes. As a result, ADIPOQ is being studied as a potential gene for type 2 diabetes mellitus (T2DM), which is a polygenic disease with genetic inheritance. This study aims to investigate the genetic variants (rs17846866 and rs1501299) in ADIPOQ gene with T2DM in the Saudi population. Methods: In this study, T2DM patients (n=96) and healthy controls (n=96) were recruited for molecular analysis for rs17846866 and rs1501299 single nucleotide polymorphisms (SNPs). Clinical data were analyzed using t-tests, HWE analysis, and genotype and allele frequencies were calculated for the rs17846866 and rs1501299 SNPs between T2DM cases and controls. ANOVA analysis was also used to investigate the relationship between the SNPs rs17846866 and rs1501299 and T2DM characteristics. Results: The current study results confirmed a positive association between clinical characteristics, HWE analysis, genotype, and allele frequencies in both rs17846466 and rs1501299 SNPs (p<0.05). In T2DM patients, ANOVA analysis with rs17846466 and rs1501299 SNPs in the ADIPOQ gene has no effect on any of the involved parameters (p>0.05). Conclusion: This study concludes as rs17846866 and rs1501299 SNPs were strongly associated in the Saudi population with T2DM patients.

Impact of weight loss predictors in severe-morbid obesity patients in the Saudi population.

Universally, obesity has been affected more than 650 million and converts as global health problem. Obesity is equally affecting starting from children to elder population. Obese subjects are converting into severe obese and then into morbid obesity. Body mass index is proning from 30 to 50 kg/m2 in the adult population. Obesity is connected with the future complications of hypertension, type 2 diabetes mellitus, cardiovascular, stroke, osteoarthritis, obstructive sleep apnea and liver diseases. Loosing of body fat is the only option to avoid obesity and this could be achieved with routine physical activity and diet modifications. Obesity subjects may fail to achieve the daily routine activities or insufficient activity may be involved and finally fail to lose the body fat after the medical course. Then these severe or morbidity obese can be lose with the existing surgery. Currently, Bariatric Surgery (BS) has become the active treatment for long-term weight loss. Various types (Roux-en-Y gastric bypass, sleeve gastrectomy and duodenal switch and the jejunoileal bypass) of BS are performed on the gastrointestinal tract. Throughout the world population, BS has found to be safe in losing the weight and avoiding the future and long-term complications. The prevalence of overweight and obesity in Saudi Arabia is an issue in terms of incidence and health consequences. Maximum obesity studies involved in Saudi Arabia has proven to be develop the long-term complications in the future involving from child to morbid obesity. Limited bariatric studies carried out in the Saudi subjects confirmed as effective tool in lowering the body fat and avoiding the life-threatened complications of human diseases. So, this review recommends BS as effective and safe surgical treatment to lose body fat in the Saudi population. However, post-operative monitoring is mandatory to follow-up.

Analysis of Downs syndrome with molecular techniques for future diagnoses.

Down syndrome (DS) is a genetic disorder appeared due to the presence of trisomy in chromosome 21 in the G-group of the acrocentric region. DS is also known as non-Mendelian inheritance, due to the lack of Mendel's laws. The disorder in children is identified through clinical symptoms and chromosomal analysis and till now there are no biochemical and molecular analyses. Presently, whole exome sequencing (WES) has largely contributed in identifying the new disease-causing genes and represented a significant breakthrough in the field of human genetics and this technique uses high throughput sequencing technologies to determine the arrangement of DNA base pairs specifying the protein coding regions of an individual's genome. Apart from this next generation sequencing and whole genome sequencing also contribute for identifying the disease marker. From this review, the suggestion was to perform the WES is DS children to identify the marker region.

Angiogenic Potential of Human Neonatal Foreskin Stromal Cells in the Chick Embryo Chorioallantoic Membrane Model.

Several studies have demonstrated the multipotentiality of human neonatal foreskin stromal cells (hNSSCs) as being able to differentiate into adipocytes and osteoblasts and potentially other cell types. Recently, we demonstrated that hNSSCs play a role during in vitro angiogenesis and appear to possess a capacity to differentiate into endothelial-like cells; however, their angiogenic potential within an ex vivo environment remains unclear. Current study shows hNSSCs to display significant migration potential in the undifferentiated state and high responsiveness in the in vitro wound healing scratch assay. When hNSSCs were seeded onto the top of the CAM, human von Willebrand factor (hVWF), CD31, smooth muscle actin (SMA), and factor XIIIa positive cells were observed in the chick endothelium. CAMs transplanted with endothelial-differentiated hNSSCs displayed a higher number of blood vessels containing hNSSCs compared to CAMs transplanted with undifferentiated hNSSCs. Interestingly, undifferentiated hNSSCs showed a propensity to differentiate towards ectoderm with indication of epidermal formation with cells positive for CD1a, CK5/6, CK19, FXIIIa, and S-100 cells, which warrant further investigation. Our findings imply a potential angiogenic role for hNSSCs ex vivo in the differentiated and undifferentiated state, with potential contribution to blood vessel formation and potential application in tissue regeneration and vascularization.

Lack of association between UBE2E2 gene polymorphism (rs7612463) and type 2 diabetes mellitus in a Saudi population.

The ubiquitin-conjugating enzyme E2E 2 (UBE2E2) gene plays an important role in insulin synthe-sis and secretion under conditions in which stress to the endoplasmic reticu-lum is increased in ß-cells. In this case-control study, we have selected rs7612462 polymorphism within UBE2E2 gene to identify in a Saudi population the type 2 diabetes mellitus (T2DM) subjects. In total, 376 subjects with T2DM and 380 controls were enrolled in this study. We have collected 5 mL of peripheral blood from each participant for biochemical and molecular analyses. PCR-RFLP was used to generate genotypes at rs7612462 in all of the study subjects. Clinical data and anthropometric measurements of the patients were significantly different from those of the controls (p<0.05). All of the subjects used in this study were non-obese (25

Human stromal (mesenchymal) stem cells from bone marrow, adipose tissue and skin exhibit differences in molecular phenotype and differentiation potential.

Human stromal (mesenchymal) stem cells (hMSCs) are multipotent stem cells with ability to differentiate into mesoderm-type cells e.g. osteoblasts and adipocytes and thus they are being introduced into clinical trials for tissue regeneration. Traditionally, hMSCs have been isolated from bone marrow, but the number of cells obtained is limited. Here, we compared the MSC-like cell populations, obtained from alternative sources for MSC: adipose tissue and skin, with the standard phenotype of human bone marrow MSC (BM-MSCs). MSC from human adipose tissue (human adipose stromal cells (hATSCs)) and human skin (human adult skin stromal cells, (hASSCs) and human new-born skin stromal cells (hNSSCs)) grew readily in culture and the growth rate was highest in hNSSCs and lowest in hATSCs. Compared with phenotype of hBM-MSC, all cell populations were CD34(-), CD45(-), CD14(-), CD31(-), HLA-DR(-), CD13(+), CD29(+), CD44(+), CD73(+), CD90(+),and CD105(+). When exposed to in vitro differentiation, hATSCs, hASSCs and hNSSCs exhibited quantitative differences in their ability to differentiate into adipocytes and to osteoblastic cells. Using a microarray-based approach we have unveiled a common MSC molecular signature composed of 33 CD markers including known MSC markers and several novel markers e.g. CD165, CD276, and CD82. However, significant differences in the molecular phenotype between these different stromal cell populations were observed suggesting ontological and functional differences. In conclusion, MSC populations obtained from different tissues exhibit significant differences in their proliferation, differentiation and molecular phenotype, which should be taken into consideration when planning their use in clinical protocols.

Pleiotropic effects of cancer cells' secreted factors on human stromal (mesenchymal) stem cells.

INTRODUCTION: Studying cancer tumors' microenvironment may reveal a novel role in driving cancer progression and metastasis. The biological interaction between stromal (mesenchymal) stem cells (MSCs) and cancer cells remains incompletely understood. Herein, we investigated the effects of tumor cells' secreted factors as represented by a panel of human cancer cell lines (breast (MCF7 and MDA-MB-231); prostate (PC-3); lung (NCI-H522); colon (HT-29) and head & neck (FaDu)) on the biological characteristics of MSCs. METHODS: Morphological changes were assessed using fluorescence microscopy. Changes in gene expression were assessed using Agilent microarray and qRT-PCR. GeneSpring 12.1 and DAVID tools were used for bioinformatic and signaling pathway analyses. Cell migration was assessed using a transwell migration system. SB-431542, PF-573228 and PD98059 were used to inhibit transforming growth factor ß (TGFß), focal adhesion kinase (FAK), and mitogen activated protein kinase kinase (MAPKK) pathways, respectively. Interleukin-1ß (IL1ß) was measured using ELISA. RESULTS: MSCs exposed to secreted factors present in conditioned media (CM) from FaDu, MDA-MB-231, PC-3 and NCI-H522, but not from MCF7 and HT-29, developed an elongated, spindle-shaped morphology with bipolar processes. In association with phenotypic changes, genome-wide gene expression and bioinformatics analysis revealed an enhanced pro-inflammatory response of those MSCs. Pharmacological inhibitions of FAK and MAPKK severely impaired the pro-inflammatory response of MSCs to tumor CM (approximately 80% to 99%, and 55% to 88% inhibition, respectively), while inhibition of the TGFß pathway was found to promote the pro-inflammatory response (approximately 3-fold increase). In addition, bioinformatics and pathway analysis of gene expression data from tumor cell lines combined with experimental validation revealed tumor-derived IL1ß as one mediator of the pro-inflammatory phenotype observed in MSCs exposed to tumor CM. CONCLUSIONS: Our data revealed tumor-derived IL1ß as one mediator of the pro-inflammatory response in MSCs exposed to tumor CM, which was found to be positively regulated by FAK and MAPK signaling and negatively regulated by TGFß signaling. Thus, our data support a model where MSCs could promote cancer progression through becoming pro-inflammatory cells within the cancer stroma.

Salamander-derived, human-optimized nAG protein suppresses collagen synthesis and increases collagen degradation in primary human fibroblasts.

Unlike humans, salamanders regrow their amputated limbs. Regeneration depends on the presence of regenerating axons which upregulate the expression of newt anterior gradient (nAG) protein. We had the hypothesis that nAG might have an inhibitory effect on collagen production since excessive collagen production results in scarring, which is a major enemy to regeneration. nAG gene was designed, synthesized, and cloned. The cloned vector was then transfected into primary human fibroblasts. The results showed that the expression of nAG protein in primary human fibroblast cells suppresses the expression of collagen I and III, with or without TGF- ß 1 stimulation. This suppression is due to a dual effect of nAG both by decreasing collagen synthesis and by increasing collagen degradation. Furthermore, nAG had an inhibitory effect on proliferation of transfected fibroblasts. It was concluded that nAG suppresses collagen through multiple effects.

Teratoma formation in immunocompetent mice after syngeneic and allogeneic implantation of germline capable mouse embryonic stem cells.

BACKGROUND: Embryonic stem cells (ESCs) have the potential to form teratomas when implanted into immunodeficient mice, but data in immunocompetent mice are limited. We therefore investigated teratoma formation after implantation of three different mouse ESC (mESC) lines into immunocompetent mice. MATERIALS AND METHODS: BALB/c mice were injected with three highly germline competent mESCs (129Sv, BALB/c and C57BL/6) subcutaneously or under the kidney capsule. After 4 weeks, mice were euthanized and examined histologically for teratoma development. The incidence, size and composition of teratomas were compared using Pearson Chi-square, t-test for dependent variables, one-way analysis of variance and the nonparametric Kruskal- Wallis analysis of variance and median test. RESULTS: Teratomas developed from all three cell lines. The incidence of formation was significantly higher under the kidney capsule compared to subcutaneous site and occurred in both allogeneic and syngeneic mice. Overall, the size of teratoma was largest with the 129Sv cell line and under the kidney capsule. Diverse embryonic stem cell-derived tissues, belonging to the three embryonic germ layers, were encountered, reflecting the pluripotency of embryonic stem cells. Most commonly represented tissues were nervous tissue, keratinizing stratified squamous epithelium (ectoderm), smooth muscle, striated muscle, cartilage, bone (mesoderm), and glandular tissue in the form of gut- and respiratory-like epithelia (endoderm). CONCLUSIONS: ESCs can form teratomas in immunocompetent mice and, therefore, removal of undifferentiated ESC is a pre-requisite for a safe use of ESC in cell-based therapies. In addition the genetic relationship of the origin of the cell lines to the ability to transplant plays a major role.

ABCA1 C69T gene polymorphism and risk of type 2 diabetes mellitus in a Saudi population.

Type 2 diabetes mellitus (T2DM) is a disease induced by complex interactions between environmental factors and certain genetic factors. Genetic variants in the Adenosine Binding Cassette Transporter Proteins 1 (ABCA1) have been associated with abnormalities of serum lipid levels of high-density lipoprotein (HDL-C). Decreased serum levels of HDL-C have often been observed in T2DM cases, and this condition has been considered to be involved in the mechanism of insulin resistance (IR). Therefore, we investigated possible association between ABCA1 C69T gene polymorphism and T2DMin a Saudi population. This study was carried out with 380 healthy control subjects and 376 T2DM patients. Genotyping of ABCA1 C69T polymorphism was carried out by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism technique. We observed that the frequency of the T allele of the ABCA1 C69T gene was significantly higher in healthy subjects compared to T2DMpatients (0.28 vs 0.45; p less than 0.0001; OR (95 percent CI) = 0.4624 (0.3732-0.5729), and therefore the T allele may be a protective factor against T2DM in the Saudi population.

Human stromal (mesenchymal) stem cells: basic biology and current clinical use for tissue regeneration.

Human stromal (mesenchymal) stem cells (hMSC) represent a group of non-hematopoietic stem cells present in the bone marrow stroma and the stroma of other organs including subcutaneous adipose tissue, placenta, and muscles. They exhibit the characteristics of somatic stem cells of self-renewal and multi-lineage differentiation into mesoderm-type of cells, e.g., to osteoblasts, adipocytes, chondrocytes and possibly other cell types including hepatocytes and astrocytes. Due to their ease of culture and multipotentiality, hMSC are increasingly employed as a source for cells suitable for a number of clinical applications, e.g., non-healing bone fractures and defects and also non-skeletal degenerative diseases like heart failure. Currently, the numbers of clinical trials that employ MSC are increasing. However, several biological and biotechnological challenges need to be overcome to benefit from the full potential of hMSC. In this current review, we present some of the most important and recent advances in understanding of the biology of hMSC and their current and potential use in therapy.

Derivation of stromal (skeletal and mesenchymal) stem-like cells from human embryonic stem cells.

Derivation of bone forming cells (osteoblasts) from human embryonic stem cells (hESCs) is a prerequisite for their use in clinical applications. However, there is no standard protocol for differentiating hESCs into osteoblastic cells. The aim of this study was to identify the emergence of a human stromal (mesenchymal and skeletal) stem cell (hMSC)-like population, known to be osteoblastic cell precursors and to test their osteoblastic differentiation capacity in ex vivo cultures and in vivo. We cultured hESCs in a feeder-free environment using serum replacement and as suspension aggregates (embryoid bodies; hEBs). Over a 20 day developmental period, the hEBs demonstrated increasing enrichment for cells expressing hMSC markers: CD29, CD44, CD63, CD56, CD71, CD73, CD105, CD106, and CD166 as revealed by immunohistochemical staining and flow cytometry (fluorescence-activated cell sorting) analysis. Ex vivo differentiation of hEBs using bone morphogenic protein 2 (BMP2) combined with standard osteoblast induction medium led to weak osteoblastic induction. Conversely, subcutaneous in vivo implantation of day 20 hEBs in immune deficient mice, mixed with hydroxyapatite/tricalcium phosphate (HA/TCP) as an osteoconductive scaffold, revealed bone and cartilage, and fibrous tissue elements after 8 weeks. These tissues were of human origin and there was no evidence of differentiation to nonmesodermal tissues. hEBs implanted in the absence of HA/TCP formed vacuolated tissue containing glandular, fibrous and muscle-like tissue elements. Conversely, implantation of undifferentiated hESCs resulted in the formation of a teratoma containing a mixture of endodermal, mesodermal, and ectodermal tissues. Our study demonstrates that hMSC-like cells can be obtained from hESCs and they can be induced to form skeletal tissues in vivo when combined with HA/TCP. These findings are relevant for tissue engineering and suggest that differentiated hEBs can provide an unlimited source for functional osteogenic cells.

Human serum is as efficient as fetal bovine serum in supporting proliferation and differentiation of human multipotent stromal (mesenchymal) stem cells in vitro and in vivo.

BACKGROUND: Human multipotent stromal (skeletal, mesenchymal) stem cells (hMSC) are employed in an increasing number of clinical trials for tissue regeneration of age-related degenerative diseases. However, routine use of fetal bovine sera (FBS) for their in vitro expansion is not optimal and may pose a health risk for patients. METHODS: We carried out a side-by-side comparison of the effects of allogenic pooled human serum (HuS) versus FBS on hMSC proliferation and differentiation in vitro and in vivo. As a model for hMSC, we employed telomerase-immortalized hMSC; hMSC-TERT cell line. RESULTS: hMSC-TERT exhibited similar morphology and size when cultured in HuS vs. FBS as assessed by light microscopy and FACS analysis. We did not observe any significant differences in growth rates of hMSC-TERT during short-term (10 days) and long-term (100 days) culture in media supplemented with HuS vs. FBS. hMSC-TERT or primary bone marrow derived hMSC induced to osteoblastic or adipocytic differentiation in the presence of HuS or FBS showed comparable levels of gene expression and protein production of osteoblastic markers (CBFA1/Runx2, alkaline phosphastase, collagen type I and osteocalcin) or adipocytic markers (PPAR-gamma2, lipoprotein lipase (LPL), aP2), respectively. In order to test for the functional capacity of hMSC-TERT that have been maintained in long-term cultures in the presence of HuS vs. FBS, the cells were mixed with hydroxyapatite/tricalcium phosphate (HA/TCP) and implanted subcutaneously in immune deficient mice. hMSC maintained in HuS vs. FBS formed comparable heterotopic bone. DISCUSSION: Human serum can support proliferation and differentiation of hMSC in vitro and can maintain their bone forming capacity in vivo. The use of human serum in cell cultures of hMSC intended for cell-based therapy is preferable.