HIV infection and type 2 diabetes are associated with altered gut microbiota, chronic inflammation, and increased cardiovascular risk. We aimed to investigate the combined effect of these diseases on gut microbiota composition and related metabolites, and a potential relation to endothelial dysfunction in individuals with HIV-infection only (n = 23), diabetes only (n = 16) or both conditions (n = 21), as well as controls (n = 24). Fecal microbiota was analyzed by Illumina sequencing of the 16 S rRNA gene. Markers of endothelial dysfunction (asymmetric dimethylarginine [ADMA]), tryptophan catabolism (kynurenine/tryptophan [KT]-ratio), and inflammation (neopterin) were measured by liquid chromatography-tandem mass spectrometry. The combination of HIV and type 2 diabetes was associated with reduced gut microbiota diversity, increased plasma KT-ratio and neopterin. Microbial genes related to tryptophan metabolism correlated with KT-ratio and low alpha diversity, in particular in HIV-infected with T2D. In multivariate analyses, KT-ratio associated with ADMA (β = 4.58 [95% CI 2.53–6.63], p < 0.001), whereas microbiota composition per se was not associated with endothelial dysfunction. Our results indicate that tryptophan catabolism may be related to endothelial dysfunction, with a potentially detrimental interaction between HIV and diabetes. The potential contribution of gut microbiota and the impact for cardiovascular risk should be further explored in prospective studies powered for clinical end points.

Background As people living with HIV (PLWH) are growing older, there is increased incidence of metabolic diseases, including type 2 diabetes mellitus, for which insulin resistance is a key determinant. In this study, we aimed to investigate risk factors associated with insulin resistance in PLWH. Methods We included well-treated PLWH without hepatitis co-infection, and with available fasting serum insulin and plasma glucose (n = 643) from the Copenhagen Comorbidity in HIV Infection Study. Insulin resistance was calculated using the homeostasis model assessment of insulin resistance (HOMA-IR). We investigated the association between risk factors and high HOMA-IR in a logistic regression model adjusted for age, sex, abdominal obesity, smoking status, and origin. When including use of thymidine analogues and/or didanosine in the model, we also adjusted for time with HIV. Results Median (IQR) age of PLWH was 52 years (46–61), and 87% (n = 557) were male. Median (IQR) HOMA-IR was 1.86 (1.23–3.14) mmol/L × mU/L. Risk factors significantly associated with high HOMA-IR included older age, BMI ≥ 25, abdominal obesity, waist circumference, use of thymidine analogues and/or didanosine, time with HIV, and CD4+ nadir < 200 cells/µL. Conclusions Insulin resistance in PLWH is associated with both use of thymidine analogues and/or didanosine and prior immunodeficiency suggesting that increased attention on blood glucose in these patients could be beneficial.

BackgroundIncreased incidence of cardiovascular diseases (CVD) in both HIV infection and type 2 diabetes (T2D) compared to the general population has been described. Little is known about the combined effect of HIV infection and T2D on inflammation and endothelial function, both of which may contribute to elevated risk of CVD.MethodsCross-sectional study including 50 HIV-infected persons on combination anti-retroviral therapy (cART), with HIV RNA <200 copies/mL (n = 25 with T2D (HIV + T2D+), n = 25 without T2D (HIV + T2D-)) and 50 uninfected persons (n = 22 with T2D (HIV-T2D+) and n = 28 without T2D (HIV-T2D-)). Groups were matched on age and sex.High sensitive C-reactive protein (hsCRP) was used to determine inflammation (cut-off 3 mg/L). The marker of endothelial dysfunction asymmetric dimethylarginine (ADMA) was measured using high performance liquid chromatography. Trimethylamine-N-oxide (TMAO), a microbiota-dependent, pro-atherogenic marker was measured using stable isotope dilution LC/MS/MS.ResultsThe percentage of HIV + T2D+, HIV + T2D-, HIV-T2D+, and HIV-T2D- with hsCRP above cut-off was 50%, 19%, 47%, and 11%, respectively. HIV + T2D+ had elevated ADMA (0.67 μM (0.63-0.72) compared to HIV + T2D- (0.60 μM (0.57-0.64) p = 0.017), HIV-T2D+ (0.57 μM (0.51-63) p = 0.008), and HIV-T2D- (0.55 μM (0.52-0.58) p < 0.001). No differences in TMAO between groups were found. However, a positive correlation between ADMA and TMAO was found in the total population (rs = 0.32, p = 0.001), which was mainly driven by a close correlation in HIV + T2D+ (rs = 0.63, p = 0.001).ConclusionElevated inflammation and evidence of endothelial dysfunction was found in HIV-infected persons with T2D. The effect on inflammation was mainly driven by T2D, while both HIV infection and T2D may contribute to endothelial dysfunction. Whether gut microbiota is a contributing factor to this remains to be determined.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-017-2334-8) contains supplementary material, which is available to authorized users.