Ageing in patients with chronic HIV infection: impact of hypercoagulation

Age-Associated Gut Dysbiosis, Marked by Loss of Butyrogenic Potential, Correlates With Altered Plasma Tryptophan Metabolites in Older People Living With HIV

BACKGROUND

Imbalance in tryptophan (TRP) metabolism and its neuroactive metabolites, serotonin and kynurenine (KYN), is a known pathogenic mechanism underlying neurocognitive impairment. Gut microbiota plays an important role in TRP metabolism, and the production of these neuroactive molecules affects neurocognitive function. Although both HIV infection and normal aging independently induce gut dysbiosis and influence TRP metabolism, their interactive effects on compositional/functional changes in gut microbiota and consequent alterations in TRP metabolites remain largely undetermined.

METHODS

Older people living with HIV infection (PLWH, aged 50-70 years, n = 22) were enrolled in this cross-sectional pilot study. Metagenomic analysis of fecal microbiome using 16S Ribosomal ribonucleic acid gene sequencing and metabolomics analysis of plasma using mass spectrometry with a reverse-phase iquid chromatography tandem mass spectrometry were performed. Statistical analyses included the univariate linear regression and Spearman correlation analyses.

RESULTS

Age-associated changes in plasma levels of key neuroactive TRP metabolites, serotonin and KYN, were seen in PLWH. Specifically, we observed age-dependent decreases in serotonin and increases in KYN and KYN-to-TRP ratio, indicative of dysfunctional TRP metabolism. Furthermore, the gut dysbiosis seen in older PLWH is characterized by a reduction of Firmicutes/Bacteroidetes ratio and butyrate-producing microbial families Lachnospiraceae and Lactobacillaceae. Of importance, correspondent with gut dysbiosis, increasing age was significantly associated with decreased plasma butyrate levels, which in turn correlated positively with serotonin and negatively with KYN/TRP ratio.

CONCLUSIONS

Age-dependent gut microbial dysbiosis distinguished by a decrease in butyrogenic potential is a key pathogenic feature associated with the shift in TRP metabolism from serotonin to KYN in older PLWH.

An update in toxicology of ageing

The field of ageing research has been rapidly advancing in recent decades and it had provided insight into the complexity of ageing phenomenon. However, as the organism-environment interaction appears to significantly affect the organismal pace of ageing, the systematic approach for gerontogenic risk assessment of environmental factors has yet to be established. This puts demand on development of effective biomarker of ageing, as a relevant tool to quantify effects of gerontogenic exposures, contingent on multidisciplinary research approach. Here we review the current knowledge regarding the main endogenous gerontogenic pathways involved in acceleration of ageing through environmental exposures. These include inflammatory and oxidative stress-triggered processes, dysregulation of maintenance of cellular anabolism and catabolism and loss of protein homeostasis. The most effective biomarkers showing specificity and relevancy to ageing phenotypes are summarized, as well. The crucial part of this review was dedicated to the comprehensive overview of environmental gerontogens including various types of radiation, certain types of pesticides, heavy metals, drugs and addictive substances, unhealthy dietary patterns, and sedentary life as well as psychosocial stress. The reported effects in vitro and in vivo of both recognized and potential gerontogens are described with respect to the up-to-date knowledge in geroscience. Finally, hormetic and ageing decelerating effects of environmental factors are briefly discussed, as well.

Is age and not antiretroviral therapy the strongest risk factor for chronic pain in HIV-infected population?

Background

Chronic pain in HIV-infected patients on effective antiretroviral therapy (ART) limits patients’ normal functioning both somatically and psychologically. The current state of knowledge on the topic is insufficient, with the underlying causes of this pain unexplained. Therefore we analyzed the frequency and factors associated with chronic pain in HIV-infected patients on ART.

Methods

We conducted a prospective, survey study, including consecutive HIV-infected patients under specialist care at the HIV Outpatient Clinic of the Hospital for Infectious Disease in Warsaw between February 2014 and December 2016. During their routine visit all patients who agreed to participate in the study were surveyed using a study questionnaire. For all patients reporting any pain the Brief Pain Inventory (BPI) form and Douleur Neuropathique 4 Questions form (DN4) were completed. Data on history and current ART and laboratory measurements were obtained from electronical database. Chi-squared and Kruskal-Wallis tests were used for group comparison. The potential factors associated with chronic pain were identified via logistic regression models.

Results

In total 196 HIV-infected patients were included in the study, 57 (29,1%) of them reported chronic pain. The reported pain was mostly (75%) limited to a single area of the body. In univariable logistic regression model the odds of chronic pain were significantly higher with increasing age (OR 1.36 [95%CI:1.17–1.58]), time under specialist care (OR 2.25 [95%CI:1.42–35.7]), time on ART (OR2.96 [95%CI:1.60–5.49]), previous ART with zidovudine (OR 2.00[95%CI:1.06–1.55]) and previous treatment with ddI, ddC or d4T (OR4.13 [95%CI:1.92–8.91]). Homosexual route of HIV infection as compared to injecting drug use was decreasing the odds of chronic pain (OR0.33 [95%CI: 014–0.75]). In multivariable analyses, adjusting for all above the only factor associated with chronic pain was age (OR1.28 [95%CI:1.06–1.55]).

Conclusions

The prevalence of chronic pain in the studied population of HIV-infected Polish patients was high. The only risk factor for chronic pain identified was age. With ageing HIV population it is therefore imperative to develop cooperation protocols for specialist HIV treatment clinics, pain treatment clinics, and rehabilitation units.