The cross-talk between matrix metalloproteinase-9, RANKL/OPG system and cardiovascular risk factors in ovariectomized rat model of postmenopausal osteoporosis

Association of certain biochemical parameters related to bone cycle with genotype in MPS IIIB patients

Background/aim

The aims of this study are to investigate the genotype-phenotype correlation in Sanfilippo type B (MPS IIIB) patients in terms of bone formation/resorption parameters and to determine the release/inhibition of biomarkers accompanying osteoporosis.

Materials and methods

Plasma levels of osteoprotegerin (OPG), matrix metalloproteinases (MMP2 and MMP9), tissue inhibitors of metalloproteinase (TIMP1 and TIMP2) and cathepsin K were examined using the ELISA method for a MPS IIIB patient group and a control group. At the same time, mutations in the NAGLU gene causing the disease were identified by whole exome sequencing, and their correlation with biochemical parameters was investigated.

Results

The enzyme analysis results showed that MMP2, MMP9, TIMP1, and TIMP2 were significantly high in the study group, while cathepsin K was low. OPG levels were similar between the two groups. The genetic analysis of patients with MPS IIIB was performed by sequencing all exons and exon-intron junction regions of the NAGLU gene using a next-generation sequencing (NGS) system. In this way, variations were detected qualitatively with high read depths. The analyses found that only two patients had a previously pathogenically defined alteration. In addition, the impact assessment analyses detected alterations with a modifying effect on protein structure.

Conclusion

The genetic analysis results indicate the need to consider a variation classified as benign in the OMIM database as pathogenic because the variations found in the patients (p.Arg737Gly and p.Trp103Cys) have somehow altered enzyme activity. The mutation p.Trp103Cys, a novel NAGLU gene mutation in the first exon, was detected in one patient; additionally, SIFT and PolyPhen analyses confirmed it as damaging. Further functional analyses of this variation should be conducted to gather more comprehensive information.

Exploring the cytoprotective role of mesenchymal stem Cell-Derived exosomes in chronic liver Fibrosis: Insights into the Nrf2/Keap1/p62 signaling pathway

Hepatic fibrosis is a common pathology present in most chronic liver diseases. Autophagy is a lysosome-mediated intracellular catabolic and recycling process that plays an essential role in maintaining normal hepatic functions. Nuclear factor erythroid 2-like 2 (Nrf2) is a transcription factor responsible for the regulation of cellular anti-oxidative stress response. This study was designed to assess the cytoprotective effect of mesenchymal stem cell-derived exosomes (MSC-exos) on endothelial-mesenchymal transition (EMT) in Carbon Tetrachloride (CCL4) induced liver fibrosis. Rats were treated with 0.1 ml of CCL4 twice weekly for 8 weeks, followed by administration of a single dose of MSC-exos. Rats were then sacrificed after 4 weeks, and liver samples were collected for gene expression analyses, Western blot, histological studies, immunohistochemistry, and transmission electron microscopy. Our results showed that MSC-exos administration decreased collagen deposition, apoptosis, and inflammation. Exosomes modulate the Nrf2/Keap1/p62 pathway, restoring autophagy and Nrf2 levels through modulation of the non-canonical pathway of Nrf2/Keap1/p62. Additionally, MSC-exos regulated miR-153-3p, miR-27a, miR-144 and miRNA-34a expression. In conclusion, the present study shed light on MSC-exos as a cytoprotective agent against EMT and tumorigenesis in chronic liver inflammation.

Advanced Progress of the Relationship Between Antihypertensive Drugs and Bone Metabolism

Hypertension and osteoporosis are common comorbidities among elderly individuals. Drug therapy has been widely used in clinical practice as the preferred antihypertensive treatment. Therefore, antihypertensive drugs have become some of the most commonly prescribed drugs in healthcare settings. However, antihypertensive drugs have different effects on bone metabolism. The results of animal and clinical studies on the effects of antihypertensive drugs on osteoporosis or fracture risk are controversial and have aroused widespread concern among clinicians. Recent studies found that angiotensin receptor blockers, selective β-adrenergic receptor blockers, and thiazide diuretics might improve bone trabecular number and bone mineral density by stimulating osteoblast differentiation, reducing osteoclast generation, and other mechanism. Furthermore, nonselective β-adrenergic receptor blockers and dihydropyridine calcium channel blockers were found to have no significant relationship with bone mineral density or bone strength, and α-adrenergic receptor blockers and loop diuretics might increase fracture risk by decreasing bone mineral density. This article aimed to review previous animal experiments, clinical studies, and meta-analyses focusing on the effects of different antihypertensive drugs on bone metabolism, and to provide a new approach for the prevention and treatment of osteoporosis.

Influencing factors of bone mass abnormalities among postmenopausal women in Tibet, China

BACKGROUND

This study aimed to provide a reference for the prevention and treatment of abnormal bone mass in postmenopausal women by analysing the current situation and influencing factors of bone mass abnormalities in Tibet.

METHODS

A total of 229 postmenopausal Tibetan women were randomly selected from six counties by a multistage cluster random sampling method. Multiple logistic regression was utilized to analyse the status and influencing factors of bone mass abnormalities in postmenopausal Tibetan women.

RESULTS

Among 229 postmenopausal Tibetan women, the prevalence of osteopenia and osteoporosis was 54.6% and 9.6%, respectively. Age {odds ratio (OR) = 0.022 [95% confidence interval (CI) = 0.003 ~ 0.163]}, BMI [OR = 441.902 (20.899,9343.717)], altitude [OR = 18.818 (1.391,254.585)], and creatinine (CREA) levels [OR = 0.895 (0.825 ~ 0.971)] were significantly associated with the risk of osteoporosis.

CONCLUSION

Postmenopausal Tibetan women had high rates of abnormal bone mass. Age, BMI, altitude and CREA levels were associated with osteoporosis. It is suggested that relevant departments should take targeted measures to promote health education on the prevention of osteoporosis in the general population and increase the screening of high-risk groups for osteoporosis to improve the bone health of postmenopausal Tibetan women.

Piezo1-mediated fluid shear stress promotes OPG and inhibits RANKL via NOTCH3 in MLO-Y4 osteocytes

Piezo1, a mechanosensitive ion channel, participates in a variety of biological processes in maintaining bone homeostasis. As the most abundant cells in bones of the mammals, osteocytes play an essential role in bone formation, remodeling, and bone mass maintenance. Here, by exposing MLO-Y4 osteocytes to the fluid shear stress (FSS) microenvironment, we explored the effect of Piezo1-mediated FSS on the expression of the molecules critical to the process of bone formation and resorption, Receptor Activator of Nuclear Factor-Kappa-B Ligand (RANKL) and Osteoprotegerin (OPG). It was found that 9 dyne/cm² loading for 30 minutes showed an upregulation trend on Piezo1 when MLO-Y4 osteocytes were exposed to an FSS microenvironment. FSS promotes the expression of OPG and inhibits the expression of RANKL. The blocker of Piezo1, GsMTx4, downregulates the effect of FSS on the expression of these two molecules. In addition, NOTCH3 was involved in this process. Thus, the results demonstrated that Piezo1-mediated FSS promotes the expression of OPG and inhibits the expression of RANKL via NOTCH3 in MLO-Y4 osteocytes.

The effect of Rutin hydrate on Glucocorticoids induced osteoporosis in mandibular alveolar bone in Albino rats (Radiological, histological and histochemical study)

Background

Glucocorticoids are used in different conditions such as autoimmune disorders and organ transplantation and their administration is the most common cause of secondary osteoporosis. Rutin is a flavonoid found in many plants. Flavonoids are natural products with various therapeutic and biological effects.

Objective

Is to investigate the effect of Rutin Hydrate as a form of Rutin on glucocorticoid induced osteoporosis in mandibular alveolar bone radiologically, histologically and histochemically.

Methods

Twenty-one adult male Albino rats were randomly divided into three groups. Group I (control), group II (osteoporotic) and group III (Rutin Hydrate treated). In both group II and III rats received 21 mg/kg of methylprednisolone daily for four weeks. Then group III received 50 mg/kg of rutin hydrate in distilled water daily for another four weeks. At the end of the experiment, mandibles were dissected for radiographic assessment, then processed for histological and histochemical examination and statistical analysis.

Results

Radiologically, administration of Rutin Hydrate was able to enhance bone density than osteoporotic group. Histological examination revealed preserved cortical bone thickness that had been statistically proved. Apparently normal sized marrow cavities, some plump osteoblasts and normal osteocytes were seen in group III. Histochemical examination showed statistical increase in the area percentage of newly formed collagen in group III than group II.

Conclusions

Rutin Hydrate was able to modify the radiological and histological picture of osteoporotic alveolar bone. This was achieved by the ability of Rutin Hydrate to increase bone density, preserve cortical plates thickness and enhance new collagen formation that was proved histochemically.