Sex differences in urinary biomarkers of vascular and endothelial function in HIV-infected persons receiving antiretroviral therapy

Urine Eicosanoids in the Metabolic Abnormalities, Telmisartan, and HIV Infection (MATH) Trial

OBJECTIVES

Arachidonic acid metabolites (eicosanoids) reflect oxidative stress and vascular health and have been associated with anthropometric measures and sex differences in cross-sectional analyses of HIV-infected (HIV+) persons. Telmisartan is an angiotensin receptor blocker and PPAR-γ agonist with potential anti-inflammatory and metabolic benefits. We assessed telmisartan's effects on urine eicosanoids among HIV+ adults with central adiposity on suppressive antiretroviral therapy enrolled in a prospective clinical trial.

METHODS

Thirty-five HIV+ adults (15 women; 20 men) completed 24 weeks of open-label oral telmisartan 40mg daily. Lumbar computed tomography quantified visceral (VAT) and subcutaneous (SAT) abdominal adipose tissue. Urine F2-isoprostane (F2-IsoP), prostaglandin E2 (PGE-M), prostacyclin (PGI-M), and thromboxane B2 (TxB-M) were quantified at baseline and 24 weeks using gas/liquid chromatography-mass spectroscopy. Mann-Whitney-U tests compared sub-group differences; Spearman's rho assessed correlations between clinical factors and eicosanoid levels.

RESULTS

Median PGE-M increased on telmisartan (p<0.01), with greater changes in men (+4.1 [p = 0.03] vs. +1.0 ng/mg cr in women; between-group p = 0.25) and participants losing >5% VAT (+3.7 ng/mg cr, p<0.01) and gaining >5% SAT (+1.7 ng/mg cr, p = 0.04). Median baseline F2-IsoP and TxB-M were slightly higher in women (both between-group p = 0.08) and did not change on telmisartan.

CONCLUSIONS

Urine PGE-M increased with 24 weeks of telmisartan in virally suppressed, HIV+ adults with central adiposity. Associations with favorable fat redistribution suggest increased PGE-M may reflect a beneficial response.

Urinary eicosanoid metabolites in HIV-infected women with central obesity switching to raltegravir: an analysis from the women, integrase, and fat accumulation trial

Chronic inflammation is a hallmark of HIV infection. Eicosanoids reflect inflammation, oxidant stress, and vascular health and vary by sex and metabolic parameters. Raltegravir (RAL) is an HIV-1 integrase inhibitor that may have limited metabolic effects. We assessed urinary F₂-isoprostanes (F₂-IsoPs), prostaglandin E₂ (PGE-M), prostacyclin (PGI-M), and thromboxane B₂ (TxB₂) in HIV-infected women switching to RAL-containing antiretroviral therapy (ART). Thirty-seven women (RAL = 17; PI/NNRTI = 20) with a median age of 43 years and BMI 32 kg/m² completed week 24. TxB₂ increased in the RAL versus PI/NNRTI arm (+0.09 versus −0.02; P = 0.06). Baseline PGI-M was lower in the RAL arm (P = 0.005); no other between-arm cross-sectional differences were observed. In the PI/NNRTI arm, 24-week visceral adipose tissue change correlated with PGI-M (rho = 0.45; P = 0.04) and TxB₂ (rho = 0.44; P = 0.005) changes, with a trend seen for PGE-M (rho = 0.41; P = 0.07). In an adjusted model, age ≥ 50 years (N = 8) was associated with increased PGE-M (P = 0.04). In this randomized trial, a switch to RAL did not significantly affect urinary eicosanoids over 24 weeks. In women continuing PI/NNRTI, increased visceral adipose tissue correlated with increased PGI-M and PGE-M. Older age (≥50) was associated with increased PGE-M. Relationships between aging, adiposity, ART, and eicosanoids during HIV-infection require further study.

Liquid chromatography-tandem mass spectrometry for the analysis of eicosanoids and related lipids in human biological matrices: a review

Today, there is an increasing number of liquid chromatography tandem-mass spectrometric (LC-MS/MS) methods for the analysis of eicosanoids and related lipids in biological matrices. An overview of currently applied LC-MS/MS methods is given with attention to sample preparation strategies, chromatographic separation including ultra high performance liquid chromatography (UHPLC) and chiral separation, as well as to mass spectrometric detection using multiple reacting monitoring (MRM). Further, the application in recent clinical research is reviewed with focus on preanalytical aspects prior to LC-MS/MS analysis as well as applications in major diseases of Western civilization including respiratory diseases, diabetes, cancer, liver diseases, atherosclerosis, and neurovascular diseases.

Higher serum iron is associated with increased oxidant stress in HIV-infected men

BACKGROUND

F₂-isoprostanes (F₂-IsoP) are oxidant stress biomarkers that are higher in HIV-infected women than men. We explored whether the effect of hemoglobin (Hgb), serum iron, or anemia on F₂-IsoP is different between HIV-infected women and men.

METHODS

Plasma F₂-IsoP were quantified by gas chromatography/mass spectrometry; clinical and laboratory data were collected at enrollment or from the medical record. Multivariable linear regression was used to assess associations between F₂-IsoP and Hgb, anemia as a dichotomous variable, and serum iron with adjustment for age, sex, race, body mass index, CD4 lymphocyte count, self-reported current smoking status, and antiretroviral therapy.

RESULTS

Compared with men, women had lower Hgb [median: 12.7 (interquartile range: 11.8-13.9) vs. 14.9 (13.7-15.8) g/dL, P < 0.001], lower iron levels [75 (47-97) vs. 90 (69-121) µg/dL, P = 0.004], more anemia (29% vs. 10%, P < 0.001), and higher levels of F₂-IsoP [42 (32-62) vs. 36 (25-46) pg/mL, P < 0.001]. The relationship between iron and F₂-IsoP differed significantly between men and women (interaction P = 0.02). Men had a 21% (95% confidence interval: 8 to 36) increase in F₂-IsoP per interquartile increase in iron (P = 0.001), whereas no relationship was seen among women [-4% (-17 to 13, P = 0.65].

CONCLUSIONS

Although women have overall higher F₂-IsoP than men, a relationship between circulating F₂-IsoP and iron levels was observed in men but not in women with HIV infection. The association between female sex and higher F₂-IsoP is not explained by iron or Hgb levels because the association persists when controlling for these factors. The role of iron in oxidant stress and sex-specific differences among HIV-infected individuals require further study.

Targeted chiral analysis of bioactive arachidonic Acid metabolites using liquid-chromatography-mass spectrometry

A complex structurally diverse series of eicosanoids arises from the metabolism of arachidonic acid. The metabolic profile is further complicated by the enantioselectivity of eicosanoid formation and the variety of regioisomers that arise. In order to investigate the metabolism of arachidonic acid in vitro or in vivo, targeted methods are advantageous in order to distinguish between the complex isomeric mixtures that can arise by different metabolic pathways. Over the last several years this targeted approach has become more popular, although there are still relatively few examples where chiral targeted approaches have been employed to directly analyze complex enantiomeric mixtures. To efficiently conduct targeted eicosanoid analyses, LC separations are coupled with collision induced dissociation (CID) and tandem mass spectrometry (MS/MS). Product ion profiles are often diagnostic for particular regioisomers. The highest sensitivity that can be achieved involves the use of selected reaction monitoring/mass spectrometry (SRM/MS); whereas the highest specificity is obtained with an SRM transitions between an intense parent ion, which contains the intact molecule (M) and a structurally significant product ion. This review article provides an overview of arachidonic acid metabolism and targeted chiral methods that have been utilized for the analysis of the structurally diverse eicosanoids that arise.