ABSTRACT
STUDY DESIGN: In Vitro cell culture study. PURPOSE: This study aims to investigate the impact of transforming growth factor-beta1 (TGF-β1) and lovastatin on differentiating human mesenchymal stem cells (MSCs) toward nucleus pulposus (NP)-like phenotype. OVERVIEW OF LITERATURE: MSCs offer a cell source to the cell-based therapy for intervertebral disc degeneration. TGF-β1 is used to induce MSCs to differentiate into NP-like cells; however, an undesired expression of collagen type I has been reported. Statins reportedly stimulate expression of bone morphogenetic protein-2 (BMP-2) and promote the chondrogenic phenotype to NP cells. However, the effects of statins with or without TGF-β1 on the differentiation of MSCs into NP-like cells remain unclear. METHODS: Human MSCs were treated with TGF-β1 alone, lovastatin alone, and simultaneous or sequential treatment with TGF-β1 and lovastatin. After the proposed stimulation, the total RNA was extracted to assess the expression profile of NP cells-specific genes. Hematoxylin–eosin staining was used for examining the microscopic morphology. Furthermore, we detected the syntheses of S-100 protein, aggrecan, and collagen type II in the extracellular matrix using immunohistochemical staining. RESULTS: Simultaneous or sequential treatment of TGF-β1 and lovastatin could further augment the BMP-2 overexpression compared with lovastatin-alone treatment. However, the mRNA expression of aggrecan and collagen type II was not compatible with the expression level of BMP-2. Immunohistochemical studies revealed compatible production of aggrecan, collagen type II, and S-100 protein in all three groups treated with lovastatin. Cells in groups treated with lovastatin were less populated than that in the group treated with TGF-β1 alone. CONCLUSIONS: This study demonstrates a promising role of lovastatin in inducing human MSCs into NP-like cells. However, further optimization of cell density before lovastatin treatment, treatment duration, and combination with TGF-β1 are warranted to attain better stimulatory effects.
ABSTRACT
PURPOSE: Many studies supported that vegetarians have a lower risk of cardiac diseases and mortality, partly due to better blood pressure and serum cholesterol profiles. However, the inflammatory markers, especially lipoprotein-associated phospholipase A2 (Lp-PLA2), have not been well-studied. This study aimed to compare inflammatory markers and conventional risk factors between vegetarians and omnivores. MATERIALS AND METHODS: One hundred and seventy-three vegetarians and 190 omnivores were studied. Fasting blood samples were obtained to compare levels of glucose, total cholesterol, triacylglycerol, high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol, homocysteine, Lp-PLA2 activity, and high-sensitivity C-reactive protein (hs-CRP). RESULTS: Vegetarians had higher serum levels of the following markers: hs-CRP (1.8 +/- 3.4 vs. 1.2 1.8 mg/L, respectively; p = 0.05), homocysteine (9.39 +/- 3.22 vs. 7.62 +/- 2.41 micromol/L, respectively; p < 0.01), and triacylglycerol (96.91 +/- 59.56 vs. 84.66 +/- 43.24 mg/dL, respectively; p < 0.05). Vegetarians also had lower levels of Lp-PLA2 (18.32 +/- 7.19 10-3 micromol/min/mL vs. 20.22 8.13 10-3 micromol/min/mL; p < 0.05), total cholesterol (180.62 +/- 36.55 mg/dL vs. 192.73 +/- 36.57 mg/dL; p < 0.01), LDL cholesterol (118.15 +/- 32.8 vs. 126.41 +/- 34.28 mg/dL; p < 0.05), and HDL cholesterol (55.59 +/- 13.30 vs. 62.09 +/- 14.52 mg/dL, p < 0.01). Multivariate analyses demonstrated that a vegetarian diet increases the chances for high serum hs-CRP and low Lp-PLA2 activity. CONCLUSION: In addition to lower total cholesterol, LDL-cholesterol, and HDL-cholesterol, Taiwanese female vegetarians have lower serum Lp-PLA2 activity but higher levels of hs-CRP, homocysteine, and triacylglyerol. It might be due to geographic differences of vegetarian diets, and further studies are needed.