Clinical hypertension is associated with raised serum IgG antibodies. However, whether antibodies are causative agents in hypertension remains unknown. We investigated whether hypertension in mice is associated with B-cell activation and IgG production and moreover whether B-cell/IgG deficiency affords protection against hypertension and vascular remodeling. Angiotensin II (Ang II) infusion (0.7 mg/kg per day; 28 days) was associated with (1) a 25% increase in the proportion of splenic B cells expressing the activation marker CD86, (2) an 80% increase in splenic plasma cell numbers, (3) a 500% increase in circulating IgG, and (4) marked IgG accumulation in the aortic adventitia. In B-cell–activating factor receptor–deficient (BAFF-R ^−/− ) mice, which lack mature B cells, there was no evidence of Ang II–induced increases in serum IgG. Furthermore, the hypertensive response to Ang II was attenuated in BAFF-R ^−/− (Δ30±4 mm Hg) relative to wild-type (Δ41±5 mm Hg) mice, and this response was rescued by B-cell transfer. BAFF-R ^−/− mice displayed reduced IgG accumulation in the aorta, which was associated with 80% fewer aortic macrophages and a 70% reduction in transforming growth factor-β expression. BAFF-R ^−/− mice were also protected from Ang II–induced collagen deposition and aortic stiffening (assessed by pulse wave velocity analysis). Finally, like BAFF-R deficiency, pharmacological depletion of B cells with an anti-CD20 antibody attenuated Ang II–induced hypertension by ≈35%. Hence, these studies demonstrate that B cells/IgGs are crucial for the development of Ang II–induced hypertension and vessel remodeling in mice. Thus, B-cell–targeted therapies—currently used for autoimmune diseases—may hold promise as future treatments for hypertension.

The gut microbiome and intestinal dysfunction have emerged as potential contributors to the development of cardiovascular disease (CVD). Alterations in gut microbiome are well documented in hypertension, atherosclerosis, and heart failure and have been investigated as a therapeutic target. However, a perhaps underappreciated but related role for intestinal barrier function has become evident. Increased intestinal permeability is observed in patients and mouse models of CVD. This increased intestinal permeability can enhance systemic inflammation, alter gut immune function, and has been demonstrated as predictive of adverse cardiovascular outcomes. The goal of this review is to examine the evidence supporting a role for intestinal barrier function in cardiovascular disease and its prospect as a novel therapeutic target. We outline key studies that have investigated intestinal permeability in hypertension, coronary artery disease, atherosclerosis, heart failure, and myocardial infarction. We highlight the central mechanisms involved in the breakdown of barrier function and look at emerging evidence for restored barrier function as a contributor to promising treatment strategies such as short chain fatty acid, probiotic, and renin angiotensin system-targeted therapeutics. Recent studies of more selective targeting of the intestinal barrier to improve disease outcomes are also examined. We suggest that although current data supporting a contribution of intestinal permeability to CVD pathogenesis are largely associative, it appears to be a promising avenue for further investigation. Additional studies of the mechanisms of barrier restoration in CVD and testing of intestinal barrier-targeted compounds will be required to confirm their potential as a new class of CVD therapeutic.

Diabetes and its complications, including impaired wound healing, present a critical clinical challenge and burden for the U.S. healthcare system, with costs of over USD 13 billion annually. Hyperglycemia and chronic inflammation in diabetic wounds increase reactive oxygen species (ROS) production, inducing oxidative stress and perpetuating inflammation, which delays healing. This study investigates inflammation, oxidative stress, and the roles of cellular populations in a diabetic wound healing mouse model (db/db). Given that diabetes leads to persistent inflammation and impaired fibroblast function, we also examined how diabetes influences superoxide production in dermal fibroblasts. Blood, dermal fibroblasts, and wound tissue were collected from 12-week-old female diabetic (Db) and heterozygous (Hz) mice. Electron paramagnetic resonance (EPR) spectroscopy revealed higher superoxide levels in diabetic blood, dermal fibroblasts, and wounds compared to controls. In diabetic wounds, immunohistochemistry and flow cytometry showed increased leukocyte infiltration and reduced macrophage presence, with a higher proportion of pro-inflammatory Ly6C^hi macrophages. These results suggest that elevated superoxide production and persistent inflammation contribute to impaired fibroblast function and delayed wound healing in diabetes. By identifying the contributions of ROS and Ly6C^hi macrophages to oxidative stress and chronic inflammation, this study offers insights into therapeutic strategies. These findings highlight the importance of addressing systemic oxidative stress alongside localized inflammation to improve wound healing outcomes in diabetic patients and advance diabetic wound care strategies.

Nicotinamide adenine dinucleotide phosphate oxidases (NOX) are enzymes that generate reactive oxygen species (ROS). NOX2 activity in the vascular wall is elevated in hypercholesterolemia, and contributes to oxidative stress and atherogenesis. Here we examined the role of another NOX isoform, NOX1, in atherogenesis in apolipoprotein E-knockout (APOE^−/−) mice fed a Western diet for 14 weeks. Although NOX1 mRNA expression was unchanged in aortas from APOE^−/− versus wild-type mice, expression of the NOX1-specific organizer, NOXO1, was diminished, consistent with an overall reduction in NOX1 activity in APOE^−/− mice. To examine the impact of a further reduction in NOX1 activity, APOE^−/− mice were crossed with NOX1^−/y mice to generate NOX1^−/y/APOE^−/− double-knockouts. NOX1 deficiency in APOE^−/− mice was associated with 30–50% higher plasma very-low-density lipoprotein (VLDL)/LDL and triglyceride levels (P < 0.01). Vascular ROS levels were also elevated by twofold in NOX1^−/y/APOE^−/− versus APOE^−/− mice (P < 0.05), despite no changes in expression of other NOX subunits. Although en face analysis of the descending aorta revealed no differences in plaque area between NOX1^−/y/APOE^−/− and APOE^−/− mice, intimal thickening in the aortic sinus was increased by 40% (P < 0.05) in the double-knockouts. Moreover, NOX1 deficiency was associated with a less stable plaque phenotype; aortic sinus lesions contained 60% less collagen (P < 0.01), 40% less smooth muscle (P < 0.01), and 2.5-fold higher levels of matrix metalloproteinase-9 (P < 0.001) than lesions in APOE^−/− mice. Thus, these data, which suggest a protective role for NOX1 against hyperlipidemia and atherosclerosis in APOE^−/− mice, highlight the complex and contrasting roles of different NOX isoforms (e.g., NOX2 versus NOX1) in vascular pathology.

Aims. To date, the ROS-generating capacities of macrophages in different activation states have not been thoroughly compared. This study is aimed at determining the nature and levels of ROS generated following stimulation with common activators of M1 and M2 macrophages and investigating the potential for this to impact fibrosis.Results. Human primary and THP-1 macrophages were treated with IFN-γ+LPS or IL-4-activating stimuli, and mRNA expression of established M1 (CXCL11, CCR7, IL-1β) and M2 (MRC-1, CCL18, CCL22) markers was used to confirm activation. Superoxide generation was assessed by L-012-enhanced chemiluminescence and was increased in both M(IFN-γ+LPS) and M(IL-4) macrophages, as compared to unpolarised macrophages (MΦ). This signal was attenuated with NOX2 siRNA. Increased expression of the p47phox and p67phox subunits of the NOX2 oxidase complex was evident in M(IFN-γ+LPS) and M(IL-4) macrophages, respectively. Amplex Red and DCF fluorescence assays detected increased hydrogen peroxide generation following stimulation with IL-4, but not IFN-γ+LPS. Coculture with human aortic adventitial fibroblasts revealed that M(IL-4), but not M(IFN-γ+LPS), enhanced fibroblast collagen 1 protein expression. Macrophage pretreatment with the hydrogen peroxide scavenger, PEG-catalase, attenuated this effect.Conclusion. We show that superoxide generation is not only enhanced with stimuli associated with M1 macrophage activation but also with the M2 stimulus IL-4. Macrophages activated with IL-4 also exhibited enhanced hydrogen peroxide generation which in turn increased aortic fibroblast collagen production. Thus, M2 macrophage-derived ROS is identified as a potentially important contributor to aortic fibrosis.