Higher parathyroid hormone levels are associated with increased below-the-knee arterial calcification in type 2 diabetes

Circulating Receptor Activator of Nuclear Factor kB Ligand and triglycerides are associated with progression of lower limb arterial calcification in type 2 diabetes: a prospective, observational cohort study

Background

Lower limb arterial calcification is a frequent, underestimated but serious complication of diabetes. The DIACART study is a prospective cohort study designed to evaluate the determinants of the progression of lower limb arterial calcification in 198 patients with type 2 diabetes.

Methods

Lower limb arterial calcification scores were determined by computed tomography at baseline and after a mean follow up of 31.20 ± 3.86 months. Serum RANKL (Receptor Activator of Nuclear factor kB Ligand) and bone remodeling, inflammatory and metabolic parameters were measured at baseline. The predictive effect of these markers on calcification progression was analyzed by a multivariate linear regression model.

Results

At baseline, mean ± SD and median lower limb arterial calcification scores were, 2364 ± 5613 and 527 respectively and at the end of the study, 3739 ± 6886 and 1355 respectively. Using multivariate analysis, the progression of lower limb arterial log calcification score was found to be associated with (β coefficient [slope], 95% CI, p-value) baseline log(calcification score) (1.02, 1.00–1.04, p < 0.001), triglycerides (0.11, 0.03–0.20, p = 0.007), log(RANKL) (0.07, 0.02–0.11, p = 0.016), previous ischemic cardiomyopathy (0.36, 0.15–0.57, p = 0.001), statin use (0.39, 0.06–0.72, p = 0.023) and duration of follow up (0.04, 0.01–0.06, p = 0.004).

Conclusion

In patients with type 2 diabetes, lower limb arterial calcification is frequent and can progress rapidly. Circulating RANKL and triglycerides are independently associated with this progression. These results open new therapeutic perspectives in peripheral diabetic calcifying arteriopathy.

Trial registration NCT02431234

Abdominal aortic calcification is more severe in unilateral primary aldosteronism patients and is associated with elevated aldosterone and parathyroid hormone levels

Primary aldosteronism (PA) is associated with a higher prevalence of abdominal aortic calcification (AAC). Unilateral and bilateral PA are the most common subtypes of PA. However, no studies have addressed the difference in the prevalence of AAC between the two subtypes. In addition to aldosterone, parathyroid hormone (PTH), an important regulator of calcium metabolism, was also reported to be elevated in individuals with unilateral PA. Therefore, we hypothesized that the prevalence of AAC may be higher in individuals with unilateral PA, which may be related to the plasma aldosterone concentration (PAC) and PTH levels. We included 156 PA patients who underwent adrenal venous sampling and 156 with essential hypertension (EH) matched by age and sex. Of the former, 76 were diagnosed with unilateral PA, and 80 were diagnosed with bilateral PA. The aortic calcification index (ACI) presented the severity of AAC and was measured by adrenal computed tomography scan. Our results showed that compared with the EH group, the prevalence and severity of AAC were higher in PA patients (32.7 vs. 19.6%; 4.32 ± 3.61% vs. 2.53 ± 2.42%, respectively). In the PA subgroup analysis, unilateral PA was associated with a higher and more severe AAC than bilateral PA (40.7 vs. 25.0%; 5.12 ± 4.07% vs. 3.08 ± 2.34%, respectively). Moreover, PAC and PTH levels were higher in individuals with unilateral PA than in those with bilateral PA (P < 0.05). After risk adjustment, multivariate regression analysis revealed that PAC and PTH were positively-associated with AAC in patients with PA (P < 0.05). In conclusion, unilateral PA patients exhibited a higher prevalence of AAC and more severe AAC due to elevated PAC and PTH levels.

Biomarkers of vascular disease in diabetes: the adipose-immune system cross talk

Experimental and clinical studies aimed at investigating the mechanism(s) underlying vascular complications of diabetes indicate that a great number of molecules are involved in the pathogenesis of these complications. Most of these molecules are inflammatory mediators or markers generated by immune or adipose tissue. Some of them, i.e. resistin and sortilin, have been shown to be involved in the cross talk between adipocytes and inflammatory cells. This interaction is an attractive area of research, particularly in type 2 diabetes and obesity. Other proteins, such as adiponectin and visfatin, appear to be more promising as possible vascular markers. In addition, some molecules involved in calcium/phosphorus metabolism, such as klotho and FGF23, have an involvement in the pathogenesis of diabetic vasculopathy, which appears to be dependent on the degree of vascular impairment. Inflammatory markers are a promising tool for treatment decisions while measuring plasma levels of adipokines, sortilin, Klotho and FGF23 in adequately sized longitudinal studies is expected to allow a more precise characterization of diabetic vascular disease and the optimal use of personalized treatment strategies.

Antizyme inhibitor 1 genetic polymorphisms associated with diabetic patients validated in the livers of diabetic mice

Diabetes mellitus (DM) is a complex disease caused by absolute or relative insulin deficiency. The C57BLKsJ-db/db mouse model is a useful animal model for studying type 2 DM (T2DM). The present study investigated the association between an antizyme inhibitor 1 (AZIN1) gene polymorphism (rs1062048) and T2DM susceptibility in 2,270 Taiwanese individuals (570 patients with T2DM and 1,700 controls). Additionally, the present study investigated AZIN1 gene and protein expression in the liver tissues of mice in three age groups (4, 16 and 32 weeks) through reverse transcription-quantitative PCR, western blotting and immunohistochemistry. The data indicated that the genotype frequency distribution of the rs1062048 single-nucleotide polymorphism differed significantly between the patients with T2DM and controls (P<0.05). Furthermore, gene and protein expression levels of AZIN1 were significantly lower in early stage and late stage T2DM mouse liver samples than in control samples. Overall, the data suggested that AZIN1 expression is involved in T2DM development.

Serum concentration and vascular expression of adiponectin are differentially associated with the diabetic calcifying peripheral arteriopathy

BACKGROUND

Medial calcification in diabetes contributes to the arterial occlusive process occurring below the knee level. Adiponectin is an adipokine with atheroprotective properties and possible protective role against arterial calcification. The aim of the study was to investigate, in type 2 diabetes, the link between vascular expression and serum concentration of adiponectin and (1) peripheral arterial calcification and (2) lower limb occlusive arterial disease.

METHODS

Scoring of peripheral vascular calcification and peripheral arterial occlusive disease, using CT-scan and color-duplex ultrasonography respectively, were conducted and explored in relation to serum adiponectin level in a cross sectional study of 197 patients with type 2 diabetes. Vascular adiponectin expression in the arterial wall of diabetic patients with and without medial calcification was evaluated by immunohistochemistry.

RESULTS

Peripheral arterial calcification score was higher in patients with the highest adiponectin concentration. In a multivariate logistic regression analysis, an increase of 1 µg/mL of adiponectin was associated with a 22% increase of arterial calcification (adjusted OR = 1.22; 95% CI 1.03-1.44; p = 0.02). Arterial occlusive score was also higher in patients with adiponectin concentration > median (2.8 ± 4.8 vs 4.2 ± 5.7, p = 0.034). Immunohistochemical analyses showed a strong and specific staining of adiponectin in smooth muscle cells in calcified arteries, with a more pronounced expression of adiponectin in early stages of medial calcification.

CONCLUSIONS

Peripheral arterial calcification is positively associated with circulating adiponectin levels in patients with type 2 diabetes, but vascular adiponectin expression is already observed at early stages of calcification. Adiponectin secretion could be a compensatory mechanism against the calcification process.Trial registration DIACART NCT number: NCT02431234. Registered 30 April 2015.