Biology subjects

Shandas, R.

Publications and source records attributed to Shandas, R..

2 recordsLinked to original sources

bioRxiv2024

Perivascular adipose tissue remodeling impairs vasoreactivity in thermoneutral-housed rats

ObjectiveVascular pathology, characterized by impaired vasoreactivity and mitochondrial respiration, differs between the sexes. Housing rats under thermoneutral (TN) conditions causes vascular dysfunction and perturbed metabolism. We hypothesized that perivascular adipose tissue (PVAT), a vasoregulatory adipose depot with brown adipose tissue (BAT) phenotype, remodels to a white adipose (WAT) phenotype in rats housed at TN, driving diminished vasoreactivity in a sex-dependent manner. MethodsMale and female Wistar rats were housed at either room temperature (RT) or TN. Endpoints included changes in PVAT morphology, vasoreactivity in vessels with intact PVAT or transferred to PVAT of the oppositely-housed animal, vessel stiffness, vessel mitochondrial respiration and cellular signaling. ResultsRemodeling of PVAT was observed in rats housed at TN; animals in this environment showed PVAT whitening and displayed diminished aortae vasodilation (p<0.05), different between the sexes. Juxtaposing PVAT from RT rats onto aortae from TN rats in females corrected vasodilation (p<0.05); this did not occur in males. In aortae of all animals housed at TN, mitochondrial respiration was significantly diminished in lipid substrate experiments (p<0.05), and there was significantly less expression of peNOS (p<0.001). ConclusionsThese data are consistent with TN-induced remodeling of PVAT, notably associated with sex-specific blunting of vasoreactivity, diminished mitochondrial respiration, and altered cellular signaling.

physiology↗

bioRxiv2022

A Sulfonated Thermoresponsive Injectable Gel for Sequential Release of Therapeutic Proteins to Protect Cardiac Function After a Myocardial Infarction

Myocardial infarction causes cardiomyocyte death and persistent inflammatory responses, which generates adverse pathological remodeling. Delivering therapeutic proteins from injectable materials in a controlled release manner may present an effective biomedical approach for treating this disease. A thermoresponsive injectable gel composed of chitosan, conjugated with poly(N-isopropylacrylamide) and sulfonate groups, was developed for spatiotemporal protein delivery to protect cardiac function after a myocardial infarction. The thermoresponsive gel delivered VEGF, IL-10 and PDGF in a sequential and sustained manner in vitro. An acute myocardial infarction mouse model was used to evaluate polymer biocompatibility and to determine therapeutic effects from the delivery system on cardiac function. Immunohistochemistry showed biocompatibility of the hydrogel, while the controlled delivery of the proteins reduced macrophage infiltration and increased vascularization. Echocardiography showed an improvement in ejection fraction and fractional shortening after injecting the thermal gel and proteins. A factorial design of experiments study was implemented to optimize the delivery system for the best combination and doses of proteins for further increasing stable vascularization and reducing inflammation using a subcutaneous injection mouse model. The results showed that VEGF, IL-10, and FGF-2 demonstrated significant contributions towards promoting long-term vascularization, while PDGFs effect was minimal.

bioengineering↗