Gonzalez-Covarrubias, V. | bioRxiv Science

bioRxiv2023

Physical performance and telomere length in older adults

BackgroundThe fast-paced aging demographic prompts studying risk factors and markers that could predict healthy aging. Telomere length shows promise for assessing a broad spectrum of aging-related phenotypes. Aim of the studyTo assess the association between physical performance and telomere length in Mexican older adults. MethodsIn this observational cross-sectional study, we recruited 323 older adults affiliated with the Instituto Mexicano del Seguro Social (IMSS) and members of the "Cohort of Obesity, Sarcopenia, and Frailty of Older Mexican Adults (COSFOMA). To assess physical performance, we used the Short Physical Performance Battery (SPPB) and stratified individuals into two groups according to their SPPB score into low [≤]7 (L-SPPB) and high >7 (H-SPPB). Absolute telomere length (aTL) was determined by using qPCR. Next, we classified individuals according to their aTL into short [≤]4.22 kb (S-TL) and long >4.22 kb (L-TL). For both SPPB and aTL categories, we calculated the mean and adjusted mean by sex, age, marital status, education, remunerated work, smoking, drinking, cognitive decline, depression, and polypharmacy with 95% CI, including the lower and upper CI (LCImeanUCI). We estimated the effect size between physical performance and telomere length with Cohens d for unequal group sizes. Also, we calculated the odds ratio with 95% confidence intervals, including the lower and upper CI (LCIORUCI) for physical performance according to telomere length categories. ResultsParticipants in the low physical performance category had significantly shorter telomeres (4.14.44.7 mean and 3.54.04.5 kb adjusted mean, p<0.001), in opposition to the high physical performance category (score >7) with longer telomeres (5.55.75.9 mean and 4.75.35.8 kb adjusted mean, p<0.001), with a medium-to-high telomere length effect size (d= 0.762). Finally, the odds of being classified in the low physical activity category increased 2.13.66.1 times per kb of telomere (adjOR 1.73.36.3, p<0.001) compared to the high physical activity group (p<0.001). ConclusionDecreased physical functioning is associated with lower telomere length. Absolute telomere length (aTL) as a possible biomarker for differential diagnosis of healthy and unhealthy aging should be explored further.

genetics↗

bioRxiv2019

Whole genomic sequencing as a tool for diagnosis of drug and multidrug-resistance tuberculosis in an endemic region in Mexico

BackgroundWhole genome sequencing (WGS) has been proposed as a tool for diagnosing drug resistance in tuberculosis. However, reports of its effectiveness in endemic countries with important numbers of drug resistance are scarce. The goal of this study was to evaluate the effectiveness of this procedure in isolates from a tuberculosis endemic region in Mexico. MethodsWGS analysis was performed in 81 tuberculosis positive clinical isolates with a known phenotypic profile of resistance against first-line drugs (isoniazid, rifampin, ethambutol, pyrazinamide and streptomycin). Mutations related to drug resistance were identified for each isolate; drug resistant genotypes were predicted and compared with the phenotypic profile. Genotypes and transmission clusters based on genetic distances were also characterized. FindingsPrediction by WGS analysis of resistance against isoniazid, rifampicin, ethambutol, pyrazinamide and streptomycin showed sensitivity values of 84%, 96%, 71%, 75% and 29%, while specificity values were 100%, 94%, 90%, 90% and 98%, respectively. Prediction of multidrug resistance showed a sensitivity of 89% and specificity of 97%. Moreover, WGS analysis revealed polymorphisms related to second-line drug resistance, enabling classification of eight and two clinical isolates as pre- and extreme drug-resistant cases, respectively. Four lineages were identified in the population (L1, L2, L3 and L4). The most frequent of these was L4, which included 90% (77) of the isolates. Six transmission clusters were identified; the most frequent was TC6, which included 13 isolates with a L4.1.1 and a predominantly multidrug-resistant condition. ConclusionThe results illustrate the utility of WGS for establishing the potential for prediction of resistance against first and second line drugs in isolates of tuberculosis from the region. They also demonstrate the feasibility of this procedure for use as a tool to support the epidemiological surveillance of drug- and multidrug-resistant tuberculosis.

microbiology↗