Osteoporosis: comparison of genetic and environmental effects determining bone mineral density
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Citation
Abstract
Osteoporosis has affected millions of patients worldwide and is a continuing concern for the increasing ageing population. It is a skeletal disease due to abnormal bone growth and resorption, characterized by low bone mass. Onset could be due to genetics and family history or acquired risk factors like lifestyle, diet, and exercise. As a result, it is important to try to understand the mechanisms of the onset of low bone mineral density so that effective treatment plans and prevention methods can be determined.
The purpose of this study is to compare how the genetic makeup of an individual interacts with one’s environment in the determination of bone mineral density (BMD) and the onset of osteoporosis. This study focused on comparing biochemical markers of osteogenic cells and their mineralization potential between primary and secondary cultures of mesenchymal stem cells (MSC) that were harvested from pelvic bone-marrow remains of patients undergoing hip replacement. We hypothesized that the primary cultures grown out directly after being acquired; should be impacted more directly by comorbidities present at the time of collection while the secondary cultures expanded from the initial marrow stromal cells should show less impact of comorbidities and reflect more closely genetic aspects that affect BMD. It was found that while the secondary cultures overall produced greater values for DNA, ALP, calcium, hydroxyproline, and protein, when samples were normalized the values between the primary and secondary cultures did not show significant differences. This data appeared however to validate our hypothesis since the overall increased growth and mineralization of the secondary cultures showed a loss in their overall correlation to the environmental impacts of smoking and BMI that were observed in the primary cultures.
The second hypothesis explored the specific correlations between the biochemical markers as indices of osteogenic potential of the cultures (DNA, ALP, calcium, hydroxyproline, and total protein) in relation to each other. The hypothesis was mostly supported with positive correlations, between all the features except for that between hydroxyproline and calcium which showed a negative correlation.
Overall, this study demonstrates that although the normalized values between the primary and secondary cultures did not show significant different osteogenic features; it did show the correlations to comorbidities identified in primary cultures were lost upon expansion following sub cultivation. Further studies with larger sample sizes are needed which will provide a more statistically significant conclusion, allowing for further analysis when comparing genetic and environmental effects.