High Thyrotropin Levels and Risk of Mortality in the Elderly With Subclinical Hypothyroidism: A Systematic Review and Meta-analysis

ObjectiveThis study aims to determine whether elevated endogenous thyrotropin levels contribute to an increased risk of adverse outcomes, such as all-cause mortality in older adults with subclinical hypothyroidism.MethodsEight electronic databases were searched for relevant articles from inception until March 23, 2022. Cohort studies assessing the association between thyrotropin levels and the risk of mortality among older adults aged ≥60 years with subclinical hypothyroidism were eligible. The outcomes of interest were either all-cause or cardiovascular-related mortality. Two independent researchers assessed the eligibility of the studies and collected data through a previously defined data extraction form. The Newcastle-Ottawa Scale was used to evaluate the quality of evidence, and multivariate-adjusted hazard ratios (HRs) (95% Cl) were collected as the necessary risk estimate for synthesis. Random-effects models were applied for meta-analysis.ResultsOverall, 13 studies involving 44 514 participants were included in this meta-analysis. There were no significant differences in the risk of all-cause mortality (pooled HR: 1.18 [95% Cl: 0.95, 1.45], I² = 94%) and cardiovascular-related mortality (pooled HR: 1.08 [95% Cl: 0.94, 1.23], I² = 0%) between euthyroid older adults and older adults with subclinical hypothyroidism. The results remained the same when only older adults with thyrotropin ≥10 mIU/L were assessed (pooled HR for all-cause mortality and cardiovascular-related mortality, respectively: 1.53 [95% Cl: 0.81, 2.88], I² = 22%, 1.35 [95% Cl: 0.63, 2.86], I² = 43%).ConclusionHigh thyrotropin levels are not associated with increased risk for all-cause mortality as well as cardiovascular-related mortality in older adults aged ≥60 years with subclinical hypothyroidism, suggesting an unnecessity in initialing treatment.     

Morphological distance and inter-nest distance account for intra-specific prey overlap in digger wasps (Hymenoptera: Crabronidae)

Although inter-individual diet variation is common in predatory wasp populations, the factors accounting for such variation are still largely unknown. Here, we asked if paired diet dissimilarity in three species of digger wasps correlates with morphological distance and inter-nest distance, two factors previously linked to diet partitioning in vertebrates. Results sharply differed among species and generations. All sampled populations showed significant inter-individual diet variation for prey taxa, but only in half of the cases for prey size. In one generation of two species [Bembix zonata Klug and Stizus continuus (Klug)], similar-sized wasps had similar prey taxonomic spectra (and for S. continuus also similar prey size spectra), a phenomenon which probably reduces intra-specific competition. In addition, B. zonata females nesting closer to each other had more similar prey taxonomic spectra, suggesting that distant females probably hunt on different patches that harbour different prey species. For the females of a further species (Bembix merceti Parker), pairwise size difference and inter-nest distance did not affect prey dissimilarity. Both morphological distance and inter-nest distance are potentially important in shaping the overlap of individual resource use in wasps, though probably only in certain conditions such as a highly clumped distribution of nests and size-related constraints on prey selection.     

Characterization of two peptides isolated from the venom of social wasp Chartergellus communis (Hymenoptera: Vespidae): Influence of multiple alanine residues and C-terminal amidation on biological effects

Chatergellus communis is a wasp species endemic to the neotropical region and its venom constituents have never been described. In this study, two peptides from C. communis venom, denominated Communis and Communis-AAAA, were chemically and biologically characterized. In respect to the chemical characterization, the following amino acid sequences and molecular masses were identified:Communis: Ile-Asn-Trp-Lys-Ala-Ile-Leu-Gly-Lys-Ile-Gly-Lys-COOH (1340.9 Da)Communis-AAAA: Ile-Asn-Trp-Lys-Ala-Ile-Leu-Gly-Lys-Ile-Gly-Lys-Ala-Ala-Ala-Ala-Val-Xle-NH₂ (1836.3 Da).Furthermore, their biological effects were compared, accounting for the differences in structural characteristics between the two peptides. To this end, three biological assays were performed in order to evaluate the hyperalgesic, edematogenic and hemolytic effects of these molecules. Communis-AAAA, unlike Communis, showed a potent hemolytic activity with EC₅₀ = 142.6 μM. Moreover, the highest dose of Communis-AAAA (2nmol/animal) induced hyperalgesia in mice. On the other hand, Communis (10nmol/animal) was able to induce edema but did not present hemolytic or hyperalgesic activity. Although both peptides have similarities in linear structures, we demonstrated the distinct biological effects of Communis and Communis-AAAA. This is the first study with Chartegellus communis venom, and both Communis and Communis-AAAA are unpublished peptides.