Effect of metabolic syndrome and aging on Ca2+ dysfunction in coronary smooth muscle and coronary artery disease severity in Ossabaw miniature swine

BACKGROUND: Metabolic syndrome (MetS) and aging are prevalent risk factors for coronary artery disease (CAD) and contribute to the etiology of CAD, including dysregulation of Ca2+ handling mechanisms in coronary smooth muscle (CSM). The current study tested the hypothesis that CAD severity and CSM Ca2+ dysregulation were different in MetS-induced CAD compared to aging-induced CAD. METHODS: Young (2.5 ± 0.2 years) and old (8.8 ± 1.2 years) Ossabaw miniature swine were fed an atherogenic diet for 11 months to induce MetS and were compared to lean age-matched controls. The metabolic profile was confirmed by body weight, plasma cholesterol and triglycerides, and intravenous glucose tolerance test. CAD was measured with intravascular ultrasound and histology. Intracellular Ca2+ ([Ca2+]i) was assessed with fura-2 imaging. RESULTS: CAD severity was similar between MetS young and lean old swine, with MetS old swine exhibiting the most severe CAD. Compared to CSM [Ca2+]i handling in lean young, the MetS young and lean old swine exhibited increased sarcoplasmic reticulum Ca2+ store release, increased Ca2+ influx through voltage-gated Ca2+ channels, and attenuated sarco-endoplasmic reticulum Ca2+ ATPase activity. MetS old and MetS young swine had similar Ca2+ dysregulation. CONCLUSIONS: Ca2+ dysregulation, mainly the SR Ca2+ store, in CSM is more pronounced in lean old swine, which is indicative of mild, proliferative CAD. MetS old and MetS young swine exhibit Ca2+ dysfunction that is typical of late, severe disease. The more advanced, complex plaques in MetS old swine suggest that the "aging milieu" potentiates effects of Ca2+ handling dysfunction in CAD

Calcium channel Orai1 promotes lymphocyte IL-17 expression and progressive kidney injury

We hypothesized that the store-operated calcium entry (SOCE) channel, Orai1, participates in the activation of Th17 cells and influences renal injury. In rats, following renal ischemia/reperfusion (I/R), there was a rapid and sustained influx of Orai1+ CD4 T cells and IL-17 expression was restricted to Orai1+ cells. When kidney CD4+ cells of post-acute kidney injury (post-AKI) rats were stimulated with angiotensin II and elevated Na+ (10-7 M/170 mM) in vitro, there was an enhanced response in intracellular Ca2+ and IL-17 expression, which was blocked by SOCE inhibitors 2APB, YM58483/BTP2, or AnCoA4. In vivo, YM58483/BTP2 (1 mg/kg) attenuated IL-17+ cell activation, inflammation, and severity of AKI following either I/R or intramuscular glycerol injection. Rats treated with high-salt diet (5-9 weeks after I/R) manifested progressive disease indicated by enhanced inflammation, fibrosis, and impaired renal function. These responses were significantly attenuated by YM58483/BTP2. In peripheral blood of critically ill patients, Orai1+ cells were significantly elevated by approximately 10-fold and Th17 cells were elevated by approximately 4-fold in AKI versus non-AKI patients. Further, in vitro stimulation of CD4+ cells from AKI patients increased IL-17, which was blocked by SOCE inhibitors. These data suggest that Orai1 SOCE is a potential therapeutic target in AKI and CKD progression

Microparticles Produced by the Hydrogel Template Method for Sustained Drug Delivery

Polymeric microparticles have been used widely for sustained drug delivery. Current methods of microparticle production can be improved by making homogeneous particles in size and shape, increasing the drug loading, and controlling the initial burst release. In the current study, the hydrogel template method was used to produce homogeneous poly(lactide-co-glycolide) (PLGA) microparticles and to examine formulation and process-related parameters. Poly(vinyl alcohol) (PVA) was used to make hydrogel templates. The parameters examined include PVA molecular weight, type of PLGA (as characterized by lactide content, inherent viscosity), polymer concentration, drug concentration and composition of solvent system. Three model compounds studied were risperidone, methylprednisolone acetate and paclitaxel. The ability of the hydrogel template method to produce microparticles with good conformity to template was dependent on molecular weight of PVA and viscosity of the PLGA solution. Drug loading and encapsulation efficiency were found to be influenced by PLGA lactide content, polymer concentration and composition of the solvent system. The drug loading and encapsulation efficiency were 28.7% and 82% for risperidone, 31.5% and 90% for methylprednisolone acetate, and 32.2 % and 92 % for paclitaxel, respectively. For all three drugs, release was sustained for weeks, and the in vitro release profile of risperidone was comparable to that of microparticles prepared using the conventional emulsion method. The hydrogel template method provides a new approach of manipulating microparticles

Atherosclerosis imaging with 18F-sodium fluoride PET: state-of-the-art review

Purpose: We examined the literature to elucidate the role of 18F-sodium fluoride (NaF)-PET in atherosclerosis. Methods: Following a systematic search of PubMed/MEDLINE, Embase, and Cochrane Library included articles underwent subjective quality assessment with categories low, medium, and high. Of 2811 records, 1780 remained after removal of duplicates. Screening by title and abstract left 41 potentially eligible full-text articles, of which 8 (about the aortic valve (n = 1), PET/MRI feasibility (n = 1), aortic aneurysms (n = 1), or quantification methodology (n = 5)) were dismissed, leaving 33 published 2010-2012 (n = 6), 2013-2015 (n = 11), and 2016-2018 (n = 16) for analysis. Results: They focused on coronary (n = 8), carotid (n = 7), and femoral arteries (n = 1), thoracic aorta (n = 1), and infrarenal aorta (n = 1). The remaining 15 studies examined more than one arterial segment. The literature was heterogeneous: few studies were designed to investigate atherosclerosis, 13 were retrospective, 9 applied both FDG and NaF as tracers, 24 NaF only. Subjective quality was low in one, medium in 13, and high in 19 studies. The literature indicates that NaF is a very specific tracer that mimics active arterial wall microcalcification, which is positively associated with cardiovascular risk. Arterial NaF uptake often presents before CT-calcification, tends to decrease with increasing density of CT-calcification, and appears, rather than FDG-avid foci, to progress to CT-calcification. It is mainly surface localized, increases with age with a wide scatter but without an obvious sex difference. NaF-avid microcalcification can occur in fatty streaks, but the degree of progression to CT-calcification is unknown. It remains unknown whether medical therapy influences microcalcification. The literature held no therapeutic or randomized controlled trials. Conclusion: The literature was heterogeneous and with few clear cut messages. NaF-PET is a new approach to detect and quantify microcalcification in early-stage atherosclerosis. NaF uptake correlates with cardiovascular risk factors and appears to be a good measure of the body's atherosclerotic burden, potentially suited also for assessment of anti-atherosclerotic therapy

Lipid detection in pig arteries using intravascular photoacoustic imaging

Heart disease is the leading cause of death in the United States and worldwide. Each year over 370,000 people died from coronary artery disease in America. As the primary form of coronary artery disease, atherosclerosis behaves as lipid-rich plaque development inside an artery wall. Vulnerable plaques are those prone to rupture, which may result in thrombus or even death. Typical hallmarks of a vulnerable plaque include thin fibrous cap, a large lipid-rich necrotic core and inflammatory infiltrate. The identification and accurate detection of these lipid depositions in the arterial wall is crucial in the diagnosis of atherosclerosis. However, none of the current clinical imaging tools can provide accurate and reliable detection of the lipid-rich necrotic core in human arteries. Intravascular photoacoustic (IVPA) imaging is an emerging technique that can provide lipid-specific detection with depth resolution. Our research focuses on applying the catheter-based IVPA imaging technique for lipid-laden plaque detection within the artery of an Ossabaw swine model. A high sensitivity IVPA imaging system developed in our lab was performed to imaging the carotid arteries from the pig model ex vivo. The imaging results showed that the exact location and size of the lipid core can be identified, which agrees with the gold standard histology result. We also compared the results of our IVPA system with the commercial near infrared spectroscopy (NIRS) imaging system. They both successfully indicated the lipid appearance at the same location. However, our imaging modality provided more information of the lipid including lipid core size, depth and distribution. This is a significant improvement of plaque burden estimation and the diagnosis of atherosclerosis in the human artery

Animal models for COVID-19:More to the picture than ACE2, rodents, ferrets and non-human 1 primates. A case for porcine respiratory coronavirus and the obese Ossabaw pig

The ongoing COVID-19 pandemic caused by infection with SARS-CoV-2 has created an urgent need for animal models to enable study of basic infection and disease mechanisms and for development of vaccines, therapeutics, and diagnostics. Most research on animal models for COVID-19 has been directed toward rodents, transgenic rodents, and non-human primates. The primary focus has been on the angiotensin-converting enzyme 2 (ACE2), which is a host cell receptor for SARS-CoV-2. Among investigated species, irrespective of ACE2 spike protein binding, only mild (or no) disease has occurred following infection with SARS-CoV-2, suggesting that ACE2 may be necessary for infection but is not sufficient to determine the outcome of infection. The common trait of all species investigated as COVID models is their healthy status prior to virus challenge. In contrast, the vast majority of severe COVID-19 cases occur in people with chronic comorbidities such as diabetes, obesity, and/or cardiovascular disease. Healthy pigs express ACE2 protein that binds the viral spike protein but they are not susceptible to infection with SARS-CoV-2. However, certain pig breeds, such as the Ossabaw pig, can reproducibly be made obese and show most aspects of the metabolic syndrome, thus resembling the more than 80% of the critically ill COVID-19 patients admitted to hospitals. We urge considering infection with porcine respiratory coronavirus of metabolic syndrome pigs, such as the obese Ossabaw pig, as a highly relevant animal model of severe COVID-19.This work was funded by the Technical University of Denmark (DTU) and by an NIH grant to MA and MS (US-NIH-P30-DK097512)

Development and Evaluation of Transferrin-Stabilized Paclitaxel Nanocrystal Formulation

The aim of the present study was to prepare and evaluate a paclitaxel nanocrystal-based formulation stabilized by serum protein transferrin in a non-covalent manner. The pure paclitaxel nanocrystals were first prepared using an antisolvent precipitation method augmented by sonication. The serum protein transferrin was selected for use after evaluating the stabilizing effect of several serum proteins including albumin and immunoglobulin G. The formulation contained approximately 55~60% drug and was stable for at least 3 months at 4 °C. In vivo antitumor efficacy studies using mice inoculated with KB cells demonstrate significantly higher tumor inhibition rate of 45.1% for paclitaxel-transferrin formulation compared to 28.8% for paclitaxel nanosuspension treatment alone. Interestingly, the Taxol® formulation showed higher antitumor activity than the paclitaxel-transferrin formulation, achieving a 93.3% tumor inhibition rate 12 days post initial dosing. However, the paclitaxel-transferrin formulation showed a lower level of toxicity, which is indicated by steady increase in body weight of mice over the treatment period. In comparison, treatment with Taxol® resulted in toxicity issues as body weight decreased. These results suggest the potential benefit of using a serum protein in a non-covalent manner in conjunction with paclitaxel nanocrystals as a promising drug delivery model for anticancer therapy

Effect of Age on Diabetogenicity of Alloxan in Ossabaw Miniature Swine

According to a single study in dogs that was conducted in 1949, the diabetic effects of the β-cell toxin alloxan are dependent on age. The current study examined whether this age-dependence of alloxan is present in the clinically relevant Ossabaw miniature swine (Sus scrofa domestica) model of metabolic syndrome. Juvenile swine (n = 8; age, 4.3 ± 0.2 mo) and adult swine (n = 8; age, 7.4 ± 0.2 mo) received alloxan (average dosage, 140 mg/kg IV) and were placed on a hypercaloric, atherogenic diet for 6 mo. The metabolic syndrome profile was confirmed by measuring body weight, cholesterol, and triglycerides. Intravenous glucose tolerance testing was used to assess glucose clearance and peripheral plasma insulin levels. The β-cell mass was calculated by immunohistochemical staining of pancreatic tissue. Although juvenile and adult swine exhibited comparable severity of metabolic syndrome, adult swine developed impaired glucose clearance and elevated fasting blood glucose levels at 6 mo after alloxan administration on the atherogenic diet. Peripheral plasma insulin levels in juvenile and adult swine were comparable at all time points and lower than in nonalloxan-treated age-matched controls, which is reflected in the lower pancreatic β-cell mass of the 2 treated groups. However, compared with adult pigs, juvenile swine exhibited greater insulin response recovery (complete or partial restoration of peripheral insulin levels to reference values) at 6 mo after alloxan administration. Overall, these results indicate that youth can confer some protection against the diabetogenic effects of alloxan in swine, potentially due in part to the greater insulin response recovery of young pigs. This study supports previous research that the effects of alloxan are dependent on the developmental maturity of the animal

Highly Sensitive Intravascular Photoacoustic Imaging with a Collinear Catheter Probe

A collinear catheter for label-free intravascular photoacoustic imaging was developed with a diameter of 1.6 mm. The collinear overlap between optical and acoustic waves enabled photoacoustic imaging of a human coronary artery from lumen to perivascular fat