Evaluation of vascular aging on measures of cardiac function and mechanical efficiency: insights from in-silico modeling.

Introduction: This study evaluated the hypothesis that vascular aging (VA) reduces ventricular contractile function and mechanical efficiency (ME) using the left ventricular pressure-volume (PV) construct. Methods: A previously published in-silico computational model (CM) was modified to evaluate the hypothesis in two phases. In phase I, the CM included five settings of aortic compliance (CA) from normal to stiff, studied at a heart rate of 80 bpm, and phase II included the normal to stiff CA settings evaluated at 60, 100, and 140 bpm. The PV construct provided steady-state and transient data through a simulated vena caval occlusion (VCO). The steady-state data included left ventricular volumes (EDV and ESV), stroke work (SW), and VCO provided the PV area (PVA) data in addition to the three measures of contractile state (CS): end-systolic pressure-volume relationship (ESPVR), dP/dtmax-EDV and preload recruitable stroke work (PRSW). Finally, ME was calculated with the SW/PVA parameter. Results: In phase I, EDV and ESV increased, as did SW and PVA. The impact on the CS parameters demonstrated a small decrease in ESPVR, no change in dP/dtmax-EDV, and a large increase in PRSW. ME decreased from 71.5 to 60.8%, respectively. In phase II, at the normal and stiff CA settings, across the heart rates studied, EDV and ESV decreased, ESPVR and dP/dtmax-EDV increased and PRSW decreased. ME decreased from 76.4 to 62.6% at the normal CA and 65.8 to 53.2% at the stiff CA. Discussion: The CM generated new insights regarding how the VA process impacts the contractile state of the myocardium and ME.

Risk Factors Associated With Atrial Fibrillation in Elderly Patients.

Background: Atrial fibrillation (AF) is the most common arrhythmia with a growing prevalence worldwide, especially in the elderly population. Patients with AF are at higher risk of serious life-threatening events and complications that may lead to long-term sequelae and reduce quality of life. The aim of our study was to examine the association of additional risk factors and comorbid medical conditions with AF in patients 65 years, or older. Methods: We performed a retrospective electronic medical record review of patients aged 65 years and older, who visited our internal medicine office between July 1, 2020 and June 30, 2021. Results: Among 2,433 patients, 418 patients (17.2%) had AF. Our analysis showed that for each unit increased in age, there was a 4.5% increase in the odds of AF (95% confidence interval (CI) 2.2-6.9%; P < 0.001). Compared to patients of Caucasian descent, African-American patients had significantly decreased odds of AF (odds ratio (OR) 0.274, 95% CI 0.141 - 0.531; P < 0.001). Patients with hypertension had 2.241 greater odds of AF (95% CI 1.421 - 3.534; P = 0.001). Additional comorbidities with significantly greater odds of AF included other cardiac arrhythmias (OR 2.523, 95% CI 1.720 - 3.720; P < 0.001), congestive heart failure (OR 3.111, 95% CI 1.674 - 5.784; P < 0.001), osteoarthritis (OR 3.014, 95% CI 2.138 - 4.247; P < 0.001), liver disease (OR 2.129, 95% CI 1.164 - 3.893; P = 0.014), and colorectal disease (OR 1.500 95% CI 1.003 - 2.243; P = 0.048). Comorbidities with significantly decreased odds of AF included other rheumatological disorder (OR 0.144, 95% CI 0.086 - 0.243; P < 0.001), non-steroidal anti-inflammatory drugs (NSAIDs) use (OR 0.206, 95% CI 0.125 - 0.338; P < 0.001), and corticosteroid use (OR 0.553, 95% CI 0.374 - 0.819; P = 0.003). Conclusions: Increasing age, hypertension, presence of other cardiac arrhythmias, congestive heart failure, osteoarthritis, liver disease, and colorectal disease are associated with increased odds of having AF.

B7 immune-checkpoints as targets for the treatment of neuroendocrine tumors.

The B7 family, and their receptors, the CD28 family, are major immune checkpoints that regulate T-cell activation and function. In the present study, we explore the role of two B7 immune-checkpoints: HERV-H LTR-Associating Protein 2 (HHLA2) and B7 Family Member, H4 (B7x), in the progression of gastrointestinal and pancreatic neuroendocrine tumors (GINETs and PNETs). We demonstrated that both HHLA2 and B7x were expressed to a high degree in human GINETs and PNETs. We determined that the expression of B7x and HHLA2 correlates with higher grade and higher incidence of nodal and distant spread. Furthermore, we confirmed that HIF-1α overexpression is associated with the upregulation of B7x both in our in vivo (animal model) and in vitro (cell culture) models. When grown in vitro, islet tumor ß-cells lack B7x expression, unless cultured under hypoxic conditions, which results in both hypoxia-inducible factor 1 subunit alpha (HIF-1α) and B7x upregulation. In vivo, we demonstrated that Men1/B7x double knockout (KO) mice (with loss of B7x expression) exhibited decreased islet ß-cell proliferation and tumor transformation accompanied by increased T-cell infiltration compared with Men1 single knockout mice. We have also shown that systemic administration of a B7x mAb to our Men1 KO mice with PNETs promotes an antitumor response mediated by increased T-cell infiltration. These findings suggest that B7x may be a critical mediator of tumor immunity in the tumor microenvironment of NETs. Therefore, targeting B7x offers an attractive strategy for the immunotherapy of patients suffering from NETs.