Biology subjects

Giacca, A.

Publications and source records attributed to Giacca, A..

3 recordsLinked to original sources

bioRxiv2025

Protective effects of central leptin on whole-body energy homeostasis upon acute olanzapine exposure

Second-generation antipsychotic use is associated with severe metabolic side effects such as obesity and type 2 diabetes. Leptin is a hormone that is secreted by adipose tissue, and it acts on the brain to decrease body weight by reducing food intake and stimulating energy expenditure. Leptin also improves glucose and lipid metabolism. We examined the short-term impact of olanzapine, a commonly used second-generation antipsychotic, on the central leptin-mediated regulation of energy balance, lipid metabolism, and hypothalamic kinase activity. Male Sprague Dawley rats were given an acute intracerebroventricular (ICV, 3rd ventricle) injection of either leptin or vehicle, combined with subcutaneous olanzapine or vehicle. As expected, ICV leptin decreased food intake and importantly, olanzapine did not block this effect. Administration of leptin, olanzapine, or their combination reduced the average respiratory exchange ratio (RER) during the light cycle, which indicates that fat oxidation was increased. In the dark cycle, leptin decreased the average RER regardless of olanzapine administration, and in the presence of leptin, olanzapine did not affect the average RER. Leptin did not alter the olanzapine-induced increase in serum triglyceride concentrations. Olanzapine and central leptin treatment differentially activated hypothalamic kinases. In conclusion, regulation of food intake and fuel preference by central leptin is intact following acute olanzapine administration.

neuroscience↗

bioRxiv2021

A Hydrogel Microneedle-assisted Assay Integrating Aptamer Probes and Fluorescence Detection for Reagentless Biomarker Quantification

Analyzing interstitial fluid (ISF) via microneedle (MN) devices enables patient health monitoring in a minimally invasive manner and at point-of-care settings. However, most MN-based diagnostic approaches require complicated fabrication processes or post-processing of the extracted ISF. Here we show in-situ and on-needle measurement of target analytes by integrating hydrogel microneedles (HMN) with aptamer probes as the target recognition elements. Fluorescently tagged aptamer probes are chemically attached to the hydrogel matrix while a crosslinked patch is formed. We use the assay for specific and sensitive quantification of glucose concentrations in an animal model of diabetes to track hypoglycemia, euglycemia, and hyperglycemia conditions. The assay can track the rising and falling concentrations of glucose and the extracted measurements closely match those from the gold standard techniques. The assay enables rapid and reagentless target detection and can be readily modified to measure other target analytes in vivo. Our system has the potential to improve the quality of life of patients who are in need of close monitoring of biomarkers of health and disease.

bioengineering↗

bioRxiv2018

Clusters of fatty acids in the serum triacylglyceride fraction associate with the disorders of type 2 diabetes

AimsOur aim was to examine longitudinal associations of triacylglyceride fatty acid (TGFA) composition with insulin sensitivity (IS) and beta-cell function.\n\nMethodsAdults at-risk for T2D (n=477) had glucose and insulin measured from a glucose challenge at 3 time points over 6 years. The outcome variables Matsuda index (ISI), HOMA2-%S, Insulinogenic Index over HOMA-IR (IGI/IR), and Insulin Secretion-Sensitivity Index-2 (ISSI-2) were computed from the glucose challenge. Gas chromatography quantified TGFA composition from the baseline. We used adjusted generalized estimating equations (GEE) models and partial least squares (PLS) regression for the analysis.\n\nResultsIn adjusted GEE models, four TGFA (14:0, 16:0, 14:1n-7, 16:1n-7 as mol%) had strong negative associations with IS while others (e.g. 18:1n-7, 18:1n-9, 20:2n-6, 20:5n-3) had strong positive associations. Few associations were seen for beta-cell function, except for 16:0, 18:1n-7, and 20:2n-6. PLS analysis indicated four TGFA (14:0, 16:0, 14:1n-7, 16:1n-7) that clustered together and strongly related with lower IS. These four TGFA also correlated highly (r>0.4) with clinically measured TG.\n\nConclusionsWe found that higher proportions of a cluster of four TGFA strongly related with lower IS as well as hypertriglyceridemia, suggesting only a few fatty acids within the TGFA composition may primarily explain lipids role in glucose dysregulation.

epidemiology↗