Activation of G protein-coupled receptors by ketone bodies: Clinical implication of the ketogenic diet in metabolic disorders

Ketogenesis takes place in hepatocyte mitochondria where acetyl-CoA derived from fatty acid catabolism is converted to ketone bodies (KB), namely β-hydroxybutyrate (β-OHB), acetoacetate and acetone. KB represent important alternative energy sources under metabolic stress conditions. Ketogenic diets (KDs) are low-carbohydrate, fat-rich eating strategies which have been widely proposed as valid nutritional interventions in several metabolic disorders due to its substantial efficacy in weight loss achievement. Carbohydrate restriction during KD forces the use of FFA, which are subsequently transformed into KB in hepatocytes to provide energy, leading to a significant increase in ketone levels known as "nutritional ketosis". The recent discovery of KB as ligands of G protein-coupled receptors (GPCR) - cellular transducers implicated in a wide range of body functions - has aroused a great interest in understanding whether some of the clinical effects associated to KD consumption might be mediated by the ketone/GPCR axis. Specifically, anti-inflammatory effects associated to KD regimen are presumably due to GPR109A-mediated inhibition of NLRP3 inflammasome by β-OHB, whilst lipid profile amelioration by KDs could be ascribed to the actions of acetoacetate via GPR43 and of β-OHB via GPR109A on lipolysis. Thus, this review will focus on the effects of KD-induced nutritional ketosis potentially mediated by specific GPCRs in metabolic and endocrinological disorders. To discriminate the effects of ketone bodies per se, independently of weight loss, only studies comparing ketogenic vs isocaloric non-ketogenic diets will be considered as well as short-term tolerability and safety of KDs

Impact of social determinants on antiretroviral therapy access and outcomes entering the era of universal treatment for people living with HIV in Italy

Background: Social determinants are known to be a driving force of health inequalities, even in high income countries. Aim of our study was to determine if these factors can limit antiretroviral therapy (ART) access, outcome and retention in care of people living with HIV (PLHIV) in Italy. Methods: All ART naïve HIV+ patients (pts) of Italian nationality enrolled in the ICONA Cohort from 2002 to 2016 were included. The association of socio-demographic characteristics (age, sex, risk factor for HIV infection, educational level, occupational status and residency area) with time to: ART initiation (from the first positive anti-HIV test), ART regimen discontinuation, and first HIV-RNA < 50 cp/mL, were evaluated by Cox regression analysis, Kaplan Meier method and log-rank test. Results: A total of 8023 HIV+ pts (82% males, median age at first pos anti-HIV test 36 years, IQR: 29-44) were included: 6214 (77.5%) started ART during the study period. Women, people who inject drugs (PWID) and residents in Southern Italy presented the lowest levels of education and the highest rate of unemployment compared to other groups. Females, pts aged > 50 yrs., unemployed vs employed, and people with lower educational levels presented the lowest CD4 count at ART initiation compared to other groups. The overall median time to ART initiation was 0.6 years (yrs) (IQR 0.1-3.7), with a significant decrease over time [2002-2006 = 3.3 yrs. (0.2-9.4); 2007-2011 = 1.0 yrs. (0.1-3.9); 2012-2016 = 0.2 yrs. (0.1-2.1), p < 0.001]. By multivariate analysis, females (p < 0.01) and PWID (p < 0.001), presented a longer time to ART initiation, while older people (p < 0.001), people with higher educational levels (p < 0.001), unemployed (p = 0.02) and students (p < 0.001) were more likely to initiate ART. Moreover, PWID, unemployed vs stable employed, and pts. with lower educational levels showed a lower 1-year probability of achieving HIV-RNA suppression, while females, older patients, men who have sex with men (MSM), unemployed had higher 1-year risk of first-line ART discontinuation. Conclusions: Despite median time to ART start decreased from 2002 to 2016, socio-demographic factors still contribute to disparities in ART initiation, outcome and durability

An explainable model of host genetic interactions linked to COVID-19 severity

We employed a multifaceted computational strategy to identify the genetic factors contributing to increased risk of severe COVID-19 infection from a Whole Exome Sequencing (WES) dataset of a cohort of 2000 Italian patients. We coupled a stratified k-fold screening, to rank variants more associated with severity, with the training of multiple supervised classifiers, to predict severity based on screened features. Feature importance analysis from tree-based models allowed us to identify 16 variants with the highest support which, together with age and gender covariates, were found to be most predictive of COVID-19 severity. When tested on a follow-up cohort, our ensemble of models predicted severity with high accuracy (ACC = 81.88%; AUCROC = 96%; MCC = 61.55%). Our model recapitulated a vast literature of emerging molecular mechanisms and genetic factors linked to COVID-19 response and extends previous landmark Genome-Wide Association Studies (GWAS). It revealed a network of interplaying genetic signatures converging on established immune system and inflammatory processes linked to viral infection response. It also identified additional processes cross-talking with immune pathways, such as GPCR signaling, which might offer additional opportunities for therapeutic intervention and patient stratification. Publicly available PheWAS datasets revealed that several variants were significantly associated with phenotypic traits such as "Respiratory or thoracic disease", supporting their link with COVID-19 severity outcome.A multifaceted computational strategy identifies 16 genetic variants contributing to increased risk of severe COVID-19 infection from a Whole Exome Sequencing dataset of a cohort of Italian patients

The polymorphism L412F in TLR3 inhibits autophagy and is a marker of severe COVID-19 in males

The polymorphism L412F in TLR3 has been associated with several infectious diseases. However, the mechanism underlying this association is still unexplored. Here, we show that the L412F polymorphism in TLR3 is a marker of severity in COVID-19. This association increases in the sub-cohort of males. Impaired macroautophagy/autophagy and reduced TNF/TNFα production was demonstrated in HEK293 cells transfected with TLR3L412F-encoding plasmid and stimulated with specific agonist poly(I:C). A statistically significant reduced survival at 28 days was shown in L412F COVID-19 patients treated with the autophagy-inhibitor hydroxychloroquine (p = 0.038). An increased frequency of autoimmune disorders such as co-morbidity was found in L412F COVID-19 males with specific class II HLA haplotypes prone to autoantigen presentation. Our analyses indicate that L412F polymorphism makes males at risk of severe COVID-19 and provides a rationale for reinterpreting clinical trials considering autophagy pathways. Abbreviations: AP: autophagosome; AUC: area under the curve; BafA1: bafilomycin A1; COVID-19: coronavirus disease-2019; HCQ: hydroxychloroquine; RAP: rapamycin; ROC: receiver operating characteristic; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; TLR: toll like receptor; TNF/TNF-α: tumor necrosis factor

Determinants of use of the fixed dose combination emtricitabine/rilpivirine/tenofovir (Eviplera) in HIV-infected persons receiving care in Italy

Introduction: Emtricitabine/rilpivirine/tenofovir (EVP) is a fixed-dose combination of antiretrovirals (ARV) approved by the European Medicines Agency in November 2011 and introduced in Italy in February 2013. It is a once-a-day single tablet and is licensed in Europe for use only in ARV-naïve patients with a viral load (VL) ≤100,000 copies/mL. Objective: To identify factors that may be associated with the use of EVP as first-line regimen in HIV-infected individuals starting cART from ARV-naïve in Italy. Methods: Clinical sites in ICONA Foundation Study in which ≥1 person had started EVP were selected for this analysis. From these we included all patients who started an EVP-based cART regimen as well as those starting other cART regimens after the date of introduction of EVP at the site (after February 2013 in any case) and with a VL ≤100,000 copies/mL from ARV-naïve. Characteristics at the time of starting cART were compared using chi-square test and unadjusted and adjusted logistic regression analysis. Factors investigated included: gender, mode of HIV transmission, time from HIV diagnosis, CD4 count, nation of birth, AIDS, HCV-status, age, CD8 count, VL, diabetes, smoking, total and HDL cholesterol, eGFR, blood glucose, level of education and employment and site location. Factors showing unadjusted associations with a p-value of 10% or smaller, were retained in the multivariable model. Results: We identified 183 patients starting EVP and 173 starting the control regimen from 23 sites. The number of patients starting EVP included at each site ranged from 1 to 12 and the number of those starting the control regimen was similar. The most frequently used drugs in the concurrent group were: TDF (75%), FTC (74%), DRV (39%), ATV/r (26%), LPV/r (9%), EFV (13%) and RAL (14%). In univariable analysis, there were differences in median CD4 count (390 cells/mm3 in EVP versus 348 in controls, p=0.002), time from HIV diagnosis to starting cART (11 versus 3 months, p=0.001) and prevalence of students (6% versus 3%, p=0.07). No differences were observed for all other factors examined. The table shows estimates of the odds ratios (OR) for factors included in the multivariable model. Conclusions: CD4 count was higher in EVP-treated patients compared to controls. Guidelines suggest avoiding initiation of EVP in presence of high VL, possibly explaining this residual difference in CD4. There was also a tendency to prescribe EVP to people with perceived lower adherence or hesitant to start or perhaps with a slow progressing disease

Impact of pre-existent drug resistance on virological efficacy of single-tablet regimens in people living with HIV

Despite the wide use of single-tablet regimens (STRs), few real-life data are available regarding the impact of pre-existent drug resistance on virological failure (VF). We aimed to fill this gap by analysing a large cohort of individuals selected from the ARCA database. The impact on VF of pre-existent resistance-associated mutations (RAMs) and cumulative genotypic susceptibility score (cGSS) before STR start was evaluated through survival analysis. Potential emergence of resistance at VF was also evaluated. Overall, 3916 individuals were included, comprising 678 treatment-naïve (G1), 2309 treatment-experienced aviraemic (G2) and 929 viraemic (G3), of whom 65.2% were treated with a STR based on efavirenz (35.2%) or rilpivirine (30.0%). At 2 years after starting a STR, the overall probability of VF was 5.9% in G1, 8.7% in G2 and 20.8% in G3. No impact of pre-existent resistance on VF was found in G1. The probability of VF was higher in patients with cGSS < 3 (reduced susceptibility to at least one drug) than in those with cGSS = 3 (full susceptibility to STR drugs) both in G2 and G3. A higher probability of VF was also found in the presence of pre-existent M184V (alone or in combination with pre-existent thymidine analogue mutations). Among patients who failed STR, a significant emergence of RAMs was found only in those exposed to EFV/FTC/TDF in G3 (specifically K103N and M184V). Our results confirm a high efficacy of STRs in clinical settings. Pre-existent resistance appears to influence virological efficacy of STRs in treatment-experienced individuals (both aviraemic and viraemic). © 2022 Elsevier Ltd and International Society of Antimicrobial Chemotherap