The articular cartilage preservative effects of genistein in an experimental model of knees osteoarthritis

The study aimed to investigate the preservative effects of genistein on articular cartilage in an experimental model of knee osteoarthritis in rats. Thirty male Wistar rats were assigned to 3 equal groups: sham group, osteoarthritis control group (OAG), and genistein-treated osteoarthritis group (GTG). Intra-articular injections of monosodium iodoacetate were used for osteoarthritis induction. After 2 weeks of rest for the induction of the inflammatory process, genistein (30 mg/kg/day) vs. saline gavage was administered for 8 weeks. The expression of matrix metalloproteinase (MMP)-8 and MMP-13, Sox5/Sox6, Indian hedgehog (IHH), and Col2 were evaluated in medial femoral condyle sections by immunohistochemical staining. The number of chondrocytes and cartilage thicknesses were also measured and compared among the groups. No significant change in cartilage thickness was observed in GTG compared with OAG (p = 0.188). Chondrocyte count was significantly higher in the articular cartilage of GTG compared with OAG (p = 0.006). Induction of osteoarthritis significantly increased the expression of MMP-8, MMP-13, and IHH, but decreased Col2, Sox5, and Sox6 expression (p < 0.001); these were partially prevented in the GTG. Our findings support the effectiveness of genistein treatment in the prevention of articular cartilage damage in the experimental model of knee osteoarthritis. The proposed mechanism of action is through the suppression of the MMP, IHH, and Col2 pathways, besides the induction of Sox5 and Sox6 expression. Novelty: Genistein prevents articular cartilage damage in the experimental model of knee osteoarthritis. The osteoprotective effect is manifested by the modulation of expression of MMP, Sox, IHH, and Col2 proteins.

The role of visfatin and resistin in an in vitro model of obesity-induced invasive liver cancer

Obesity is associated with the development of liver disease and its progression to hepatocellular carcinoma. This link may be attributed to adipocytokines such as visfatin and resistin which have been shown to promote liver cancer incidence and progression. Studies have yet to determine the role of visfatin and resistin in liver cancer, specifically in the context of obesity. The objective of this study was to investigate the effect of neutralizing visfatin and resistin in obese (OB) or normal weight (NW) sera to determine the contribution of these proteins in obesity-induced invasive liver cancer. Sera from OB or NW males was used to determine the efficacy of neutralizing visfatin and resistin to reduce the obesity-induced liver cancer phenotype. HepG2 and SNU-449 cells were exposed to OB and NW sera ± antibodies for visfatin or resistin. The neutralizing antibodies differentially suppressed invasion, reactive oxygen species production, and matrix metalloproteinase-9 secretion. These changes corresponded with a decrease in phosphorylated extracellular signal-regulated kinases and protein kinase B in HepG2 cells, but differences were not observed in CAP1 or β-catenin. In conclusion, visfatin and resistin have differential roles in obesity-associated liver cancer and may be potential targets to reverse the impact of obesity on liver cancer progression.

Effect of high-dose vitamin D supplementation in combination with weight loss diet on glucose homeostasis, insulin resistance, and matrix metalloproteinases in obese subjects with vitamin D deficiency: a double-blind, placebo-controlled, randomized clinical trial

As there is limited and inconsistent evidence in potential role of vitamin D on insulin resistance and matrix metalloproteinases, this study aimed to examine the effect of vitamin D supplementation on glucose homeostasis, insulin resistance, and matrix metalloproteinases in obese subjects with vitamin D deficiency. A total of 44 participants with serum 25-hydroxyvitamin D (25(OH)D) level ≤ 50 nmol/L and body mass index (BMI) 30-40 kg/m² were randomly allocated into receiving weight reduction diet with either 50 000 IU vitamin D₃ pearl (n = 22) or placebo (n = 22) once weekly for 12 weeks. Primary outcomes were changes in fasting serum glucose (FSG), homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and matrix metalloproteinases (MMPs). Secondary outcomes were changes in weight, BMI, 25(OH)D, calcium, phosphorous and parathyroid hormone (PTH). Sun exposure and dietary intakes were also assessed. Serum levels of 25(OH)D3 increased significantly with a simultaneous decrease in serum concentration of PTH in the vitamin D group. Weight, BMI, FSG, and MMP-9 decreased significantly in both groups, and there were significant differences in changes in weight, serum 25(OH)D3, PTH, and MMP-9 levels between the groups. Within- and between-groups analysis revealed no significant differences in serum calcium, phosphorous, serum insulin, HOMA-IR, QUICKI, and MMP-2 after intervention. Our results indicated that improvement in vitamin D status resulted in greater reductions in weight and MMP-9 during weight loss. These preliminary results are sufficient to warrant a bigger study group.

The effect of folic acid administration on cardiac tissue matrix metalloproteinase activity and hepatorenal biomarkers in diabetic rats 1

Diabetes mellitus (DM) is a metabolic disorder that causes severe complications. Thus, the aims of this study were to investigate the influence of DM and folic acid treatment on liver and renal biomarkers, and heart remodeling through evaluation of cardiac matrix metalloproteinase (MMP) activity. There were 4 groups: control (physiological saline 1 mL/kg, i.p., 28 days), DM (streptozotocin [STZ] 100 mg/kg in physiological saline, i.p., 1 day), folic acid (FA; 5 mg/kg, i.p., 28 days), and DM+FA (STZ 100 mg/kg, i.p., 1 day and folic acid 5 mg/kg, i.p., 28 days). Our results demonstrated increased aminotransferase and alkaline phosphatase activity, urea and creatinine concentration, and decreased albumin and fibrinogen concentration in the DM group. MMP-2 relative activity was elevated in the DM and FA groups; MMP-9 was decreased in the DM and increased in the FA group. The folic acid treatment of diabetic rats did not change aminotransferase activity; it alleviated the increase in alkaline phosphatase and the decrease in albumin and fibrinogen concentration, and reduced MMP-2 activity; however, it increased urea and creatinine concentration. In conclusion, folic acid treatment of diabetic rats has cardio- and hepato-protective effects. However, its dosing should be carefully considered because of possible renal damage.

Peroxisome proliferator-activated receptors (PPAR) downregulate the expression of pro-inflammatory molecules in an experimental model of myocardial infarction

Myocardial infarction (MI) has been associated with an inflammatory response and a rise in TNF-α, interleukin (IL)-1β, and IL-6. Peroxisome proliferator-activated receptors (PPARs) promote a decreased expression of inflammatory molecules. We aimed to study whether PPAR stimulation by clofibrate decreases inflammation and reduces infarct size in rats with MI. Male Wistar rats were randomized into 3 groups: control, MI + vehicle, and MI + clofibrate (100 mg/kg). Treatment was administered for 3 consecutive days, previous to 2 h of MI. MI induced an increase in protein expression, mRNA content, and enzymatic activity of inducible nitric oxide synthase (iNOS). Additionally, MI incited an increased expression of matrix metalloproteinase (MMP)-2 and MMP-9, intercellular adhesion molecule (ICAM)-1, and IL-6. MI also elevated the nuclear content of nuclear factor-κB (NF-κB) and decreased IκB, both in myocyte nuclei and cytosol. Clofibrate treatment prevented MI-induced changes in iNOS, MMP-2 and MMP-9, ICAM-1, IL-6, NF-κB, and IκB. Infarct size was smaller in clofibrate-treated rats compared to MI-vehicle animals. In silico analysis exhibited 3 motifs shared by genes from renin-angiotensin system, PPARα, iNOS, MMP-2 and MMP-9, ICAM-1, and VCAM-1, suggesting a cross regulation. In conclusion, PPARα-stimulation prevents overexpression of pro-inflammatory molecules and preserves viability in an experimental model of acute MI.

Osteopontin is proteolytically processed by matrix metalloproteinase 9

Osteopontin is robustly upregulated following myocardial infarction (MI), which suggests that it has an important role in post-MI remodeling of the left ventricle (LV). Osteopontin deletion results in increased LV dilation and worsened cardiac function. Thus, osteopontin exerts protective effects post-MI, but the mechanisms have yet to be defined. Matrix metalloproteinases (MMPs) regulate LV remodeling post-MI, and osteopontin is a known substrate for MMP-2, -3, -7, and -9, although the cleavage sites have not been mapped. Osteopontin-derived peptides can exert distinct biological functions that may depend on their cleavage sites. We mapped the MMP-9 cleavage sites via LC-MS/MS analysis using label-free and N-terminal labeling methods, and compared them with those of MMP-2, -3, and -7. Each MMP yielded a unique cleavage profile with few overlapping cleavage sites. Using synthetic peptides, we validated 3 sites for MMP-9 cleavage at amino acid positions 151-152, 193-194, and 195-196. Four peptides were synthesized based on the upstream- and downstream-generated fragments and were tested for biological activity in isolated cardiac fibroblasts. Two peptides increased cardiac fibroblast migration rates post-wounding (p < 0.05 compared with the negative control). Our study highlights the importance of osteopontin processing, and confirms that different cleavage sites generate osteopontin peptides with distinct biological functions.