Insulin-like growth factor II gene Apa I polymorphism is not associated with endometriosis susceptibility

Relevance of insulin-like growth factor 2 in the etiopathophysiology of diabetic nephropathy: possible roles of phosphatase and tensin homolog on chromosome 10 and secreted protein acidic and rich in cysteine as regulators of repair

BACKGROUND

Diabetic nephropathy (DN) is a devastating complication of diabetes, the exact molecular pathophysiology of which is not well established. Hyperglycemia increases insulin-like growth factors (IGFs), especially IGF2, which acts via the IGF1 receptor present on renal cells. Elevated glucose levels damage the kidney, which is repaired by modulators such as secreted protein acidic and rich in cysteine (SPARC). Hence, it was hypothesized that IGF2 and SPARC may have an important role in the etiology of DN.

METHODS

Human renal biopsies, histopathologically categorized as normal, early Type 2 diabetes mellitus (T2DM), or established DN, were analyzed for the localization and expression of IGF2, its negative regulator phosphatase and tensin homolog on chromosome 10 (PTEN), and SPARC.

RESULTS

Expression of IGF2, PTEN, and SPARC was increased in renal biopsies from T2DM patients compared with normal samples. Although IGF2 protein was increased in biopsies from DN patients, PTEN and SPARC levels were decreased. Real-time reverse transcription-polymerase chain reaction indicated that transcript levels of IGF2 and PTEN were greater than those of β-actin in all human renal biopsy samples.

CONCLUSION

The results suggest the following molecular etiopathophysiology of DN: (i) hyperglycemia upregulates IGF2, which initiates PTEN, a regulator of IGF2 signaling; (ii) loss of this IGF2-PTEN feedback loop causes changes that are characteristic of DN; and (iii) lowered expression of the repair modulator SPARC results in the development and/or progression of DN. Hence, targeting relevant modulators, such as like IGF2, PTEN, and SPARC, may be important in the management of DN.

Functional genetic polymorphisms and female reproductive disorders: part II--endometriosis

BACKGROUND

Endometriosis has a strong genetic component, and numerous genetic studies have been reported.

METHODS

We have systematically reviewed these studies and included 114 in our final selection.

RESULTS

We found no consistent evidence linking endometriosis with specific polymorphisms in genes encoding inflammatory mediators, proteins involved in sex steroid metabolism, vascular function and tissue remodelling. Although a number of polymorphisms have been associated with endometriosis in selected populations, the associations have not been independently confirmed, either because only single studies were carried out on these markers/genes or because other studies reported no association. The most solid evidence linking specific polymorphisms to endometriosis came from studies investigating glutathione-S-transferase, a phase II detoxification enzyme. Carriage of the GSTT1 null deletion variant showed consistent association with endometriosis with a 29% increased risk; however, it cannot be excluded that this result was due to publication bias, and this association should be independently confirmed in large-scale, well-designed case–control studies.

CONCLUSIONS

The evidence of an association between genetic polymorphisms and endometriosis is weak. Carriage of the GSTT1 null deletion may moderately increase the risk of this disease. We suggest that the methodology of association studies should be improved in order to identify and validate associations in endometriosis.