Responsiveness to metformin in girls with androgen excess: collective influence of genetic polymorphisms

Metformin treatment of juvenile mice alters aging-related developmental and metabolic phenotypes in sex-dependent and sex-independent manners

Metformin has attracted increasing interest for its potential benefits in extending healthspan and longevity. This study examined the effects of early-life metformin treatment on the development and metabolism of C57BL/6 J (B6) mice, with metformin administered to juvenile mice from 15 to 56 days of age. Metformin treatment led to decreased body weight in both sexes (P < 0.05, t-test). At 9 weeks of age, mice were euthanized and organ weights were recorded. The relative weight of retroperitoneal fat was decreased in females, while relative weights of perigonadal and retroperitoneal fat were decreased, and relative liver weight was increased in males (P < 0.05, t-test). Glucose and insulin tolerance tests (GTT and ITT) were conducted at the age of 7 weeks. ANOVA revealed a significant impairment in insulin sensitivity by the treatment, and a significantly interactive effect on glucose tolerance between sex and treatment, underscoring a disparity in GTT between sexes in response to the treatment. Metformin treatment reduced circulating insulin levels in fasting and non-fasting conditions for male mice, with no significant alterations observed in female mice. qRT-PCR analysis of glucose metabolism-related genes (Akt2, Glut2, Glut4, Irs1, Nrip1, Pi3k, Pi3kca, Pkca) in the liver and skeletal muscle reveals metformin-induced sex- and organ-specific effects on gene expression. Comparison with previous studies in heterogeneous UM-HET3 mice receiving the same treatment suggests that genetic differences may contribute to variability in the effects of metformin treatment on development and metabolism. These findings indicate that early-life metformin treatment affects development and metabolism in both sex- and genetics-dependent manners.

Hyperandrogenism and menstrual imbalance are the best predictors of metformin response in PCOS patients

BACKGROUND

Moving from the correlation between insulin-resistance and PCOS, metformin has been administered in some PCOS women improving ovulatory and metabolic functions and decreasing androgen levels. Inconsistency and unpredictability of response to metformin limit its extensive use. Aim of this study was to identify reliable predictors of response to metformin therapy for weight loss and reduction in plasma androgen levels using ANNs (artificial neural networks).

METHODS

One hundred eight consecutive women with PCOS (ESHRE/ASRM 2003 Rotterdam criteria) treated with metformin 1500 mg/day, at inclusion and every 6 months underwent to a complete clinical, endocrine/metabolic assessment and ultrasonographic evaluation. Therapy outcomes were BMI reduction (≥1 kg/m²) in overweight/obese and free-androgen-index (FAI) decrease (≥1%) in hyperandrogenemic women. Semantic connectivity maps (SCMs) were obtained through Auto-CM, a fourth generation ANN, to compare patients' baseline clinical features to the treatment outcomes. Multivariate logistic regression analysis was used to assess the major predictor in drop-out patients and the associated risk.

RESULTS

At 6 months 54 out of 103 (52,4%) obese patients showed BMI reduction and 45 out of 89 (50,6%) hyperandrogenemic women showed FAI decrease. The further response rates at 12 months were 30,6 and 47%, respectively. SCMs showed a clear polarization for both the outcomes with elevated accuracy. Treatment responsiveness resulted strictly related to oligo-amenorrhea and hyperandrogenemia at baseline. In addition, lower serum testosterone levels at baseline were found to be the major predictor of treatment discontinuation.

CONCLUSIONS

In women with PCOS, menstrual pattern imbalance and ovarian androgens excess are the best predictors of metformin response. They may pave the way for a rethinking of the criteria for evaluating hyperandrogenism in order to better define the large population included in the diagnosis of PCOS. Baseline plasma testosterone level can serve as a sensitive marker to predict treatment compliance.

Quantile-Dependent Heritability of Glucose, Insulin, Proinsulin, Insulin Resistance, and Glycated Hemoglobin

BACKGROUND

"Quantile-dependent expressivity" is a dependence of genetic effects on whether the phenotype (e.g., insulin resistance) is high or low relative to its distribution.

METHODS

Quantile-specific offspring-parent regression slopes (βOP) were estimated by quantile regression for fasting glucose concentrations in 6,453 offspring-parent pairs from the Framingham Heart Study.

RESULTS

Quantile-specific heritability (h2), estimated by 2βOP/(1 + rspouse), increased 0.0045 ± 0.0007 (p = 8.8 × 10-14) for each 1% increment in the fasting glucose distribution, that is, h2 ± SE were 0.057 ± 0.021, 0.095 ± 0.024, 0.146 ± 0.019, 0.293 ± 0.038, and 0.456 ± 0.061 at the 10th, 25th, 50th, 75th, and 90th percentiles of the fasting glucose distribution, respectively. Significant increases in quantile-specific heritability were also suggested for fasting insulin (p = 1.2 × 10-6), homeostatic model assessment of insulin resistance (HOMA-IR, p = 5.3 × 10-5), insulin/glucose ratio (p = 3.9 × 10-5), proinsulin (p = 1.4 × 10-6), proinsulin/insulin ratio (p = 2.7 × 10-5), and glucose concentrations during a glucose tolerance test (p = 0.001), and their logarithmically transformed values.

DISCUSSION/CONCLUSION

These findings suggest alternative interpretations to precision medicine and gene-environment interactions, including alternative interpretation of reported synergisms between ACE, ADRB3, PPAR-γ2, and TNF-α polymorphisms and being born small for gestational age on adult insulin resistance (fetal origin theory), and gene-adiposity (APOE, ENPP1, GCKR, IGF2BP2, IL-6, IRS-1, KIAA0280, LEPR, MFHAS1, RETN, TCF7L2), gene-exercise (INS), gene-diet (ACSL1, ELOVL6, IRS-1, PLIN, S100A9), and gene-socioeconomic interactions.

Oncology and Pharmacogenomics Insights in Polycystic Ovary Syndrome: An Integrative Analysis

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. Epidemiological findings revealed that women with PCOS are prone to develop certain cancer types due to their shared metabolic and endocrine abnormalities. However, the mechanism that relates PCOS and oncogenesis has not been addressed. Herein, in this review article the genomic status, transcriptional and protein profiles of 264 strongly PCOS related genes (PRG) were evaluated in endometrial cancer (EC), ovarian cancer (OV) and breast cancer (BC) exploring oncogenic databases. The genomic alterations of PRG were significantly higher when compared with a set of non-diseases genes in all cancer types. PTEN had the highest number of mutations in EC, TP53, in OC, and FSHR, in BC. Based on clinical data, women older than 50 years and Black or African American females carried the highest ratio of genomic alterations among all cancer types. The most altered signaling pathways were p53 in EC and OC, while Fc epsilon RI in BC. After evaluating PRG in normal and cancer tissue, downregulation of the differentially expressed genes was a common feature. Less than 30 proteins were up and downregulated in all cancer contexts. We identified 36 highly altered genes, among them 10 were shared between the three cancer types analyzed, which are involved in the cell proliferation regulation, response to hormone and to endogenous stimulus. Despite limited PCOS pharmacogenomics studies, 10 SNPs are reported to be associated with drug response. All were missense mutations, except for rs8111699, an intronic variant characterized as a regulatory element and presumably binding site for transcription factors. In conclusion, in silico analysis revealed key genes that might participate in PCOS and oncogenesis, which could aid in early cancer diagnosis. Pharmacogenomics efforts have implicated SNPs in drug response, yet still remain to be found.

Common Variants in 22 Genes Regulate Response to Metformin Intervention in Children with Obesity: A Pharmacogenetic Study of a Randomized Controlled Trial

Metformin is a first-line oral antidiabetic agent that has shown additional effects in treating obesity and metabolic syndrome. Inter-individual variability in metformin response could be partially explained by the genetic component. Here, we aimed to test whether common genetic variants can predict the response to metformin intervention in obese children. The study was a multicenter and double-blind randomized controlled trial that was stratified according to sex and pubertal status in 160 children with obesity. Children were randomly assigned to receive either metformin (1g/d) or placebo for six months after meeting the defined inclusion criteria. We conducted a post hoc genotyping study in 124 individuals (59 placebo, 65 treated) comprising finally 231 genetic variants in candidate genes. We provide evidence for 28 common variants as promising pharmacogenetics regulators of metformin response in terms of a wide range of anthropometric and biochemical outcomes, including body mass index (BMI) Z-score, and glucose, lipid, and inflammatory traits. Although no association remained statistically significant after multiple-test correction, our findings support previously reported variants in metformin transporters or targets as well as identify novel and promising loci, such as the ADYC3 and the BDNF genes, with plausible biological relation to the metformin's action mechanism. Trial Registration: Registered on the European Clinical Trials Database (EudraCT, ID: 2010-023061-21) on 14 November 2011 (URL: https://www.clinicaltrialsregister.eu/ctr-search/trial/2010-023061-21/ES).

Metformin therapy for the reproductive and metabolic consequences of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS), the most common hormonal disorder among women of reproductive age, has various metabolic and reproductive consequences. Metformin was originally shown to lower testosterone levels in women with PCOS in the 1990s, an effect presumably related to its insulin sensitising actions. However, the precise mechanisms of metformin action in PCOS remain unclear and there is considerable heterogeneity in the clinical response to this therapy in women with PCOS. Recent evidence indicates that genetic factors may play a significant role in predicting response to metformin therapy in PCOS and future studies are needed to further identify women who are most likely to benefit from this therapy. At present, there is no clear evidence to support broad metformin use in PCOS. Well-designed prospective trials are needed to establish clear benefit for metformin use in the treatment of the reproductive and metabolic consequences associated with PCOS.

Development of Human Membrane Transporters: Drug Disposition and Pharmacogenetics

Membrane transporters play an essential role in the transport of endogenous and exogenous compounds, and consequently they mediate the uptake, distribution, and excretion of many drugs. The clinical relevance of transporters in drug disposition and their effect in adults have been shown in drug–drug interaction and pharmacogenomic studies. Little is known, however, about the ontogeny of human membrane transporters and their roles in pediatric pharmacotherapy. As they are involved in the transport of endogenous substrates, growth and development may be important determinants of their expression and activity. This review presents an overview of our current knowledge on human membrane transporters in pediatric drug disposition and effect. Existing pharmacokinetic and pharmacogenetic data on membrane substrate drugs frequently used in children are presented and related, where possible, to existing ex vivo data, providing a basis for developmental patterns for individual human membrane transporters. As data for individual transporters are currently still scarce, there is a striking information gap regarding the role of human membrane transporters in drug therapy in children.

The role of variants regulating metformin transport and action in women with polycystic ovary syndrome

Aims: Variants in genes encoding metformin transport proteins and the ATM gene are associated with metformin response. We hypothesized that these gene variants contribute to variable metformin treatment response in polycystic ovary syndrome. Materials & methods: The discovery cohort (n = 38) was studied in an open-label study. Results were replicated in two additional cohorts (n = 26 and n = 131). Response was assessed after 3–6 months of treatment with metformin extended-release 1500–2000 mg/day. Results: The rs683369 variant was associated with less weight loss in the discovery cohort (p = 0.003), but these results were not replicated (p = 0.8). There were no differences in glucose parameters, testosterone levels or ovulatory frequency as a function of genotype. Conclusion: Variants in organic ion transporters do not explain the variable metformin response in polycystic ovary syndrome.

Hyperinsulinaemic androgen excess in adolescent girls

Hyperinsulinaemic androgen excess is the most common cause of hirsutism, acne and menstrual irregularity in adolescent girls. Here, we propose that the disorder frequently originates from an absolute or relative excess of lipids in adipose tissue, and from associated changes in insulin sensitivity, gonadotropin secretion and ovarian androgen release. Girls from populations with genotypes attuned to nutritionally harsh conditions seem to be particularly vulnerable to the development of hyperinsulinaemic androgen excess in today's obesogenic environment. We propose that hirsutism, hyperandrogenaemia and menstrual irregularity (≥2 years after menarche) is used as a diagnostic triad for the disorder. No pharmacological therapy has been approved for girls with androgen excess; however, lifestyle intervention is essential to reduce adiposity. In girls without obesity who are not sexually active, insulin sensitization has more broadly normalizing effects than estradiol-progestogen combinations. The early recognition of girls at risk of developing hyperinsulinaemic androgen excess might enable prevention in childhood.

A common gene variant in STK11 is associated with metabolic risk markers and diabetes during gestation

OBJECTIVE

To assess whether the common rs8111699 (C528G) variant in STK11 is related to metabolic risk markers in pregnant women and to gestational diabetes mellitus (GDM).

DESIGN

Cross-sectional study.

SETTING

Hospital.

PATIENT(S)

A total of 561 pregnant women: 318 without and 243 with GDM (National Diabetes Data Group criteria).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURES(S)

rs8111699 variant in STK11 (Taqman technology). Fasting glucose, insulin (homeostatic model assessment of insulin resistance and β-cell function [HOMA-IR and -β]) and C-peptide assessed at 24-28 weeks' gestation.

RESULT(S)

In non-GDM women, the G allele in rs8111699 was associated with lower HOMA-IR (CC: 1.3 ± 0.1 mIU/L; GG: 0.9 ± 0.1 mIU/L) and HOMA-β (CC: 165 ± 20 mIU/L; GG: 118 ± 10 mIU/L). In GDM women, the G allele was related to lower body mass index (BMI; CC: 27.9 ± 1.0 kg/m(2); GG: 24.5 ± 0.6 kg/m(2)) and C-peptide (CC: 2.3 ± 0.1 ng/mL; GG: 1.6 ± 0.1 ng/mL). The GG genotype was less frequently observed in GDM women (18% vs. 26%), particularly in heavier GDM women (BMI > median: 14% vs. 28%).

CONCLUSION(S)

In pregnant women, the G allele for the rs8111699 variant in STK11 is associated with a more favorable metabolic phenotype and may protect against the development of GDM, particularly in heavier women.