Chronic inflammation and atherosclerosis : A critical role for renin angiotensin system that is activated by lifestyle-related diseases

The Relationship between Vitamin D and Coronary Artery Ectasia in Subjects with a Normal C-Reactive Protein Level

Background and Objectives

Vitamin D is generally known to be closely related to inflammation. The effects of vitamin D on coronary artery disease (CAD) are not fully explained. Nowadays, coronary artery ectasia (CAE) cases are common and are regarded as being a kind of CAD. We aimed to investigate, in a case-control study, the relationship between vitamin D and CAE without an associated inflammatory process.

Subjects and Methods

This study population included 201 patients (CAE group, 121 males; mean age, 61.2±6.4 years) with isolated CAE; and 197 healthy individuals (control group, 119 males; mean age, 62.4±5.8 years), comprising the control group, who had normal coronary arteries. These participants concurrently underwent routine biochemical tests, tests for inflammatory markers, and tests for 25-OH vitamin D in whole-blood draws. These parameters were compared.

Results

There are no statistical significance differences among the groups for basic clinical characteristics (p>0.05). Inflammatory markers were recorded and compared to exclude any inflammatory process. All of them were similar, and no statistical significance difference was found. The average parathyroid hormone (PTH) level of patients was higher than the average PTH level in controls (41.8±15.1 pg/mL vs. 19.1±5.81 pg/mL; p<0.001). Also, the average 25-OH vitamin D level of patients was lower than the average 25-OH vitamin D level of controls (14.5±6.3 ng/mL vs. 24.6±9.3 ng/mL; p<0.001). In receiver operating characteristic curve analysis, the observed cut-off value for vitamin D between the control group and patients was 10.8 and 85.6% sensitivity and 75.2% specificity (area under the curve: 0.854, 95% confidence interval: 0.678-0.863).

Conclusion

We found that there is an association between vitamin D and CAE in patients who had no inflammatory processes. Our study may provide evidence for the role of vitamin D as a non-inflammatory factor in the pathophysiology of CAE.

Angiotensin II type 1 receptor antagonist attenuates lacrimal gland, lung, and liver fibrosis in a murine model of chronic graft-versus-host disease

Chronic graft-versus-host disease (cGVHD), a serious complication following allogeneic HSCT (hematopoietic stem cell transplantation), is characterized by systemic fibrosis. The tissue renin-angiotensin system (RAS) is involved in the fibrotic pathogenesis, and an angiotensin II type 1 receptor (AT1R) antagonist can attenuate fibrosis. Tissue RAS is present in the lacrimal gland, lung, and liver, and is known to be involved in the fibrotic pathogenesis of the lung and liver. This study aimed to determine whether RAS is involved in fibrotic pathogenesis in the lacrimal gland and to assess the effect of an AT1R antagonist on preventing lacrimal gland, lung, and liver fibrosis in cGVHD model mice. We used the B10.D2→BALB/c (H-2^d) MHC-compatible, multiple minor histocompatibility antigen-mismatched model, which reflects clinical and pathological symptoms of human cGVHD. First, we examined the localization and expression of RAS components in the lacrimal glands using immunohistochemistry and quantitative real-time polymerase chain reaction (PCR). Next, we administered an AT1R antagonist (valsartan; 10 mg/kg) or angiotensin II type 2 receptor (AT2R) antagonist (PD123319; 10 mg/kg) intraperitoneally into cGVHD model mice and assessed the fibrotic change in the lacrimal gland, lung, and liver. We demonstrated that fibroblasts expressed angiotensin II, AT1R, and AT2R, and that the mRNA expression of angiotensinogen was greater in the lacrimal glands of cGVHD model mice than in controls generated by syngeneic-HSCT. The inhibition experiment revealed that fibrosis of the lacrimal gland, lung, and liver was suppressed in mice treated with the AT1R antagonist, but not the AT2R antagonist. We conclude that RAS is involved in fibrotic pathogenesis in the lacrimal gland and that AT1R antagonist has a therapeutic effect on lacrimal gland, lung, and liver fibrosis in cGVHD model mice. Our findings point to AT1R antagonist as a possible target for therapeutic intervention in cGVHD.