THE ROLE OF HIGH MOBILITY GROUP BOX-1 PATHOBIOLOGY IN ANGIOTENSIN II-INDUCED ABDOMINAL AORTIC ANEURYSMS

Abdominal aortic aneurysms (AAAs) are permanent luminal dilations of the vessel wall that can result in rupture and death. There is currently no evidence-based treatment to prevent or attenuate the development of this devastating condition. Although vascular inflammation is known to be one of the hallmarks of AAA, underlying mechanisms that initiate inflammatory pathways in the aorta are not clearly known. High-mobility group box 1 (HMGB1), a highly conserved nonhistone DNA-binding nuclear protein, may contribute to vascular diseases. Since whole-body genetic deletion of HMGB1 is embryonic lethal, pharmacological approaches have been used to manipulate HMGB1 in mice. However, it remains desirable to genetically manipulate HMGB1 to further understand its role. In the body of work presented here, we assessed the contributing role of HMGB1 in AAA development and the efficacy of neutralization and a novel antisense oligonucleotides (ASOs) approach to deplete HMGB1 in mice. To examine the role of HMGB1 in AAA development, we assessed the gene expression profile of human and murine aneurysmal samples, indicating a marked upregulation of inflammatory pathways and HMGB1 in the abdominal aorta of diseased tissue. Further validations at the early stages of experimental AAA by utilizing the Angiotensin II (AngII) model also indicated a marked increase of HMGB1 protein abundance in the abdominal aorta of male LDLr-/- mice. To determine the role of HMGB1 inhibition in AngII-induced AAAs, a monoclonal anti-HMGB1 antibody (2G7) or an isotype-matched control were intraperitoneally injected into 8-10-week-old male LDLr-/- mice that were infused with AngII for 28 days. Neutralizing HMGB1 with a low dose did not show a significant decrease in the abdominal aortic diameter of AngII-infused mice. Next, we examined the efficacy of seven different ASOs in reducing HMGB1 protein abundance at selected intervals. Either ASOs or phosphate-buffered saline (PBS) were injected into male C57BL/6J mice (8-10-week-old) at days 0 and 3 in the initial week and then once a week during the remainder of the study. Subsequently, mRNA and protein abundance of HMGB1 were determined in the various tissues. After screening various ASOs to determine the most optimum version and to further investigate the role of systemic HMGB1 inhibition in aneurysm formation, hypercortisolemic male mice fed a Western diet were infused with AngII for four weeks to induce aneurysm and were injected with PBS or HMGB1 ASO. Our results indicated a profound significant attenuation of AAA in ASO administered group. Collectively, our data established that the ASO approach could significantly decrease HMGB1 expression, and its inhibition in an experimental aneurysm model can profoundly attenuate the AngII-induced AAA formation. Further, utilizing an ASO approach to inhibit HMGB1 can provide more clear insights into understanding the biological functions of HMGB1 with strong clinical significance

Calpain Inhibition Attenuates Adipose Tissue Inflammation and Fibrosis in Diet-Induced Obese Mice

Adipose tissue macrophages have been proposed as a link between obesity and insulin resistance. However, the mechanisms underlying these processes are not completely defined. Calpains are calcium-dependent neutral cysteine proteases that modulate cellular function and have been implicated in various inflammatory diseases. To define whether activated calpains influence diet-induced obesity and adipose tissue macrophage accumulation, mice that were either wild type (WT) or overexpressing calpastatin (CAST Tg), the endogenous inhibitor of calpains were fed with high (60% kcal) fat diet for 16 weeks. CAST overexpression did not influence high fat diet-induced body weight and fat mass gain throughout the study. Calpain inhibition showed a transient improvement in glucose tolerance at 5 weeks of HFD whereas it lost this effect on glucose and insulin tolerance at 16 weeks HFD in obese mice. However, CAST overexpression significantly reduced adipocyte apoptosis, adipose tissue collagen and macrophage accumulation as detected by TUNEL, Picro Sirius and F4/80 immunostaining, respectively. CAST overexpression significantly attenuated obesity-induced inflammatory responses in adipose tissue. Furthermore, calpain inhibition suppressed macrophage migration to adipose tissue in vitro. The present study demonstrates a pivotal role for calpains in mediating HFD-induced adipose tissue remodeling by influencing multiple functions including apoptosis, fibrosis and inflammation

A Randomized Trial of Sitagliptin and Spironolactone With Combination Therapy in Hospitalized Adults With COVID-19

COVID-19 may cause respiratory distress syndrome and death. Treatment of COVID-19 to prevent complications remains a priority. Objective Our investigation sought to determine whether combination of spironolactone and sitagliptin could reduce mortality for inpatients with SARS-CoV-2 infection. Methods This single-blind, 4-arm, prospective randomized clinical trial was conducted at Shiraz and Bushehr University of Medical Sciences hospitals between December 2020 and April 2021. We randomized hospitalized adult patients with COVID-19 pneumonia into 4 groups: control, combination therapy, sitagliptin add-on, or spironolactone add-on. The primary outcome was the clinical improvement of the patients in the hospital as measured on an 8-point numerical scale. The secondary outcomes included intubation, ICU admission, end organ damages, CT findings, and paraclinical information. Results A total of 263 admitted patients were randomly assigned to control group (87 patients), combination group (60 patients), sitagliptin group (66 patients), and spironolactone group (50 patients). There were no significant differences in baseline characteristics, except for higher age in control group. The intervention groups, especially combination therapy, had better clinical outcomes (clinical score on fifth day of admission: 3.11 ± 2.45 for controls, 1.33 ± 0.50 for combination, 1.68 ± 1.02 for sitagliptin, and 1.64 ± 0.81 for spironolactone; P = 0.004). However, the mortality rate was lower in patients who received spironolactone (21.84% control, 13.33% combination, 13.64% sitagliptin, 10.00% spironolactone; P = 0.275). Our intervention reduced lung infiltration but not the area of involvement in lungs. Conclusion Sitagliptin and spironolactone can potentially improve clinical outcomes of hospitalized COVID-19 patients