Metformin treatment in diabetes and heart failure: when academic equipoise meets clinical reality

<p>Abstract</p> <p>Objective</p> <p>Metformin has had a 'black box' contraindication in diabetic patients with heart failure (HF), but many believe it to be the treatment of choice in this setting. Therefore, we attempted to conduct a pilot study to evaluate the feasibility of undertaking a large randomized controlled trial with clinical endpoints.</p> <p>Study Design</p> <p>The pilot study was a randomized double blinded placebo controlled trial. Patients with HF and type 2 diabetes were screened in hospitals and HF clinics in Edmonton, Alberta, Canada (population ~1 million). Major exclusion criteria included the current use of insulin or high dose metformin, decreased renal function, or a glycosylated hemoglobin <7%. Patients were to be randomized to 1500 mg of metformin daily or matching placebo and followed for 6 months for a variety of functional outcomes, as well as clinical events.</p> <p>Results</p> <p>Fifty-eight patients were screened over a six month period and all were excluded. Because of futility with respect to enrollment, the pilot study was abandoned. The mean age of screened patients was 77 (SD 9) years and 57% were male. The main reasons for exclusion were: use of insulin therapy (n = 23; 40%), glycosylated hemoglobin <7% (n = 17; 29%) and current use of high dose metformin (n = 12; 21%). Overall, contraindicated metformin therapy was the most commonly prescribed oral antihyperglycemic agent (n = 27; 51%). On average, patients were receiving 1,706 mg (SD 488 mg) of metformin daily and 12 (44%) used only metformin.</p> <p>Conclusion</p> <p>Despite uncertainty in the scientific literature, there does not appear to be clinical uncertainty with regards to the safety or effectiveness of metformin in HF making a definitive randomized trial virtually impossible.</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier: NCT00325910</p

Nck2 promotes human melanoma cell proliferation, migration and invasion in vitro and primary melanoma-derived tumor growth in vivo

<p>Abstract</p> <p>Background</p> <p>Nck1 and Nck2 adaptor proteins are involved in signaling pathways mediating proliferation, cytoskeleton organization and integrated stress response. Overexpression of Nck1 in fibroblasts has been shown to be oncogenic. Through the years this concept has been challenged and the consensus is now that overexpression of either Nck cooperates with strong oncogenes to transform cells. Therefore, variations in Nck expression levels in transformed cells could endorse cancer progression.</p> <p>Methods</p> <p>Expression of Nck1 and Nck2 proteins in various cancer cell lines at different stages of progression were analyzed by western blots. We created human primary melanoma cell lines overexpressing GFP-Nck2 and investigated their ability to proliferate along with metastatic characteristics such as migration and invasion. By western blot analysis, we compared levels of proteins phosphorylated on tyrosine as well as cadherins and integrins in human melanoma cells overexpressing or not Nck2. Finally, in mice we assessed tumor growth rate of human melanoma cells expressing increasing levels of Nck2.</p> <p>Results</p> <p>We found that expression of Nck2 is consistently increased in various metastatic cancer cell lines compared with primary counterparts. Particularly, we observed significant higher levels of Nck2 protein and mRNA, as opposed to no change in Nck1, in human metastatic melanoma cell lines compared with non-metastatic melanoma and normal melanocytes. We demonstrated the involvement of Nck2 in proliferation, migration and invasion in human melanoma cells. Moreover, we discovered that Nck2 overexpression in human primary melanoma cells correlates with higher levels of proteins phosphorylated on tyrosine residues, assembly of Nck2-dependent pY-proteins-containing molecular complexes and downregulation of cadherins and integrins. Importantly, we uncovered that injection of Nck2-overexpressing human primary melanoma cells into mice increases melanoma-derived tumor growth rate.</p> <p>Conclusions</p> <p>Collectively, our data indicate that Nck2 effectively influences human melanoma phenotype progression. At the molecular level, we propose that Nck2 in human primary melanoma promotes the formation of molecular complexes regulating proliferation and actin cytoskeleton dynamics by modulating kinases or phosphatases activities that results in increased levels of proteins phosphorylated on tyrosine residues. This study provides new insights regarding cancer progression that could impact on the therapeutic strategies targeting cancer.</p

Oral abstracts of the 21st International AIDS Conference 18-22 July 2016, Durban, South Africa

The rate at which HIV-1 infected individuals progress to AIDS is highly variable and impacted by T cell immunity. CD8 T cell inhibitory molecules are up-regulated in HIV-1 infection and associate with immune dysfunction. We evaluated participants (n=122) recruited to the SPARTAC randomised clinical trial to determine whether CD8 T cell exhaustion markers PD-1, Lag-3 and Tim-3 were associated with immune activation and disease progression.Expression of PD-1, Tim-3, Lag-3 and CD38 on CD8 T cells from the closest pre-therapy time-point to seroconversion was measured by flow cytometry, and correlated with surrogate markers of HIV-1 disease (HIV-1 plasma viral load (pVL) and CD4 T cell count) and the trial endpoint (time to CD4 count <350 cells/μl or initiation of antiretroviral therapy). To explore the functional significance of these markers, co-expression of Eomes, T-bet and CD39 was assessed.Expression of PD-1 on CD8 and CD38 CD8 T cells correlated with pVL and CD4 count at baseline, and predicted time to the trial endpoint. Lag-3 expression was associated with pVL but not CD4 count. For all exhaustion markers, expression of CD38 on CD8 T cells increased the strength of associations. In Cox models, progression to the trial endpoint was most marked for PD-1/CD38 co-expressing cells, with evidence for a stronger effect within 12 weeks from confirmed diagnosis of PHI. The effect of PD-1 and Lag-3 expression on CD8 T cells retained statistical significance in Cox proportional hazards models including antiretroviral therapy and CD4 count, but not pVL as co-variants.Expression of ‘exhaustion’ or ‘immune checkpoint’ markers in early HIV-1 infection is associated with clinical progression and is impacted by immune activation and the duration of infection. New markers to identify exhausted T cells and novel interventions to reverse exhaustion may inform the development of novel immunotherapeutic approaches

The effect of tetrahydrocannabinol on testosterone among men in the United States: results from the National Health and Nutrition Examination Survey

To determine the association between tetrahydrocannabinol (THC) use and testosterone (T) levels among men in the United States. Using the National Health and Nutrition Examination Survey (NHANES) data from the years 2011-2016, we identified all men 18 years and older who answered the substance use questionnaire and underwent laboratory testing for T. Regular THC users were defined as those who use THC at least one time per month, every month for at least 1 year. Multivariable linear regressions controlling for confounders were then used to determine the relationship between THC use and T levels. Among the 5146 men who met inclusion, 3027 endorsed using THC at least once in their life (ever-user). Nearly half of the THC ever-users (49.3%) were considered regular THC users. Multivariate analysis controlling for age, comorbidities, tobacco use, alcohol use, body mass index (BMI), exercise level, and race revealed a small but statistically significant increase in T among regular THC users at any measured level of use, compared to non-regular THC users (non-users). This increase was characterized by an inverse U-shaped trend with Regular THC users using two-three times per month demonstrating the greatest increase in T (+ 66.77 ng/dL) over non-users. THC use is associated with small increases in testosterone. This increase in T appears to decline as THC use increases, but nevertheless, T is still higher with any amount of regular use when compared to T in non-users. Prospective work is needed to validate the observed increase and to better elucidate the mechanism of impact THC use has on T levels

Insulin and related factors in premenopausal breast cancer risk

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Insulin and related factors in premenopausal breast cancer risk

This article is hosted on a website external to the CBCRA Open Access Archive. Selecting “View/Open” below will launch the full-text article in another browser window

Decline in Serum Testosterone Levels Among Adolescent and Young Adult Men in the USA

Testosterone deficiency has a prevalence of 20% among adolescent and young adult (AYA) males. Although previous studies have shown that total testosterone (TT) levels are declining in the population compared to prior decades, no study has identified TT level trends for AYA males specifically. Using data from the National Health and Nutrition Examination Surveys, we investigated TT levels for 4045 men from 1999 to 2016. After controlling for confounders, we found that mean TT levels declined over time: TT levels were lower in the later (2011–2016) than in the earlier (1999–2000) cycles (all p < 0.001). Elevated body mass index (BMI) was associated with lower TT, but the trend remained significant even among men with normal BMI. Limitations include the influence of confounding variables such as environmental factors and the use of differing assays for TT measurement. Further studies using other data streams are needed to validate these findings. In this report we looked at data for adolescent and young adult men in a US national database on total testosterone (TT) levels. There has been a decline in mean TT levels over the past two decades and TT is lower with progressively higher body mass index. We conclude that TT levels have been declining in young adult men in recent decades. We report declining serum testosterone levels among adolescent and young adult men from 1999 to 2016. Our study has important clinical implications, as low serum testosterone has been associated with underlying comorbidities and potentially higher mortality risk