Vascular Calcification Progression Modulates the Risk Associated with Vascular Calcification Burden in Incident to Dialysis Patients

Molecular Mechanism of Calycosin Inhibited Vascular Calcification

Vascular calcification (VC) is a pathological condition frequently observed in cardiovascular diseases. Primary factors contributing to VC are osteogenic differentiation of vascular smooth muscle and hydroxyapatite deposition. Targeted autophagy (a lysosome-mediated mechanism for degradation/recycling of unnecessary cellular components) is a useful approach for inhibiting VC and promoting vascular cell health. Calycosin has been shown to alleviate atherosclerosis by enhancing macrophage autophagy, but its therapeutic effect on VC has not been demonstrated. Using an in vitro model (rat thoracic aortic smooth muscle cell line A7r5), we demonstrated effective inhibition of VC using calycosin (the primary flavonoid component of astragalus), based on the enhancement of autophagic flux. Calycosin treatment activated AMPK/mTOR signaling to induce initiation of autophagy and restored mTORC1-dependent autophagosome-lysosome fusion in late-stage autophagy by promoting soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex formation, thereby preventing stoppage of autophagy in calcified cells. Calycosin substantially reduced degrees of both osteogenic differentiation and calcium deposition in our VC cell model by enhancing autophagy. The present findings clarify the mechanism whereby calycosin mitigates autophagy stoppage in calcified smooth muscle cells and provide a basis for effective VC treatment via autophagy enhancement.

Influence of sodium thiosulfate on coronary artery calcification of patients on dialysis: a meta-analysis

Coronary artery calcification (CAC) is common in dialysis patients and is associated with a higher risk of future cardiovascular events. Sodium thiosulfate (STS) is effective for calciphylaxis in dialysis patients; however, the influence of STS on CAC in dialysis patients remains unclear. This systematic review and meta-analysis were conducted to evaluate the effects of STS on CAC in patients undergoing dialysis. PubMed, Embase, Cochrane Library, CNKI, and Wanfang databases were searched from inception to 22 March 2023 for controlled studies comparing the influence of STS versus usual care without STS on CAC scores in dialysis patients. A random effects model incorporating the potential influence of heterogeneity was used to pool the results. Nine studies, including two non-randomized studies and seven randomized controlled trials, were included in the meta-analysis. Among these, 365 patients on dialysis were included in the study. Compared with usual care without STS, intravenous STS for 3-6 months was associated with significantly reduced CAC scores (mean difference [MD] = -180.17, 95% confidence interval [CI]: -276.64 to -83.70, p < 0.001, I2 = 0%). Sensitivity analysis limited to studies of patients on hemodialysis showed similar results (MD: -167.33, 95% CI: -266.57 to -68.09, p = 0.001; I2 = 0%). Subgroup analyses according to study design, sample size, mean age, sex, dialysis vintage of the patients, and treatment duration of STS also showed consistent results (p for subgroup differences all > 0.05). In conclusion, intravenous STS may be effective in attenuating CAC in dialysis patients.

Moderating Effect of the Lean Tissue Index on the Relationship between the Trabecular Bone Score and Augmentation Index in Dialysis Naïve Patients with Stage 5 Chronic Kidney Disease

Osteopenia, sarcopenia, and increased vascular stiffness are common in patients with chronic kidney disease-mineral bone disorder (CKD-MBD) with protein energy wasting and can lead to worse clinical outcomes. We investigated the potential moderating role of the lean tissue index (LTI) in the relationship between bone microarchitecture and vascular stiffness in dialysis naïve patients with stage 5 CKD. Bioimpedance spectroscopy for evaluating LTI, lumbar spine dual energy X-ray absorptiometry for determining the trabecular bone score (TBS), and arterial applanation tonometry measurements for the central augmentation index, at a heart rate of 75 beats/minute (cAIx75), were simultaneously performed in 117 consecutive patients. A hierarchical regression analysis was conducted to assess the moderating effect of LTI on the relationship between TBS and cAIx75 after adjusting for age and sex. The effect of the interaction between LTI and TBS on cAIx75 was statistically significant (p = 0.030), demonstrating that the cAIx75 tends to decrease more, with the joint effect of LTI and TBS. In the separate analyses, the interaction effect was significant only in women (p = 0.048) and the group of diabetes (p = 0.042). Our study suggests that the evaluation of changes in body composition, bone health, and vascular stiffness needs to be performed simultaneously in patients with advanced-stage CKD. Further research in patients with different stages of CKD warranted to generalize and apply our results to patients in other stages.

The Connubium among diabetes, chronic kidney disease and atrial fibrillation

The burden of cardiovascular comorbid conditions was significantly higher in patients with Atrial Fibrillation (AF); most of them are affected by hypertension, Chronic Kidney Disease (CKD) and/or Diabetes Mellitus (DM). DM represents a well-known risk factor for the development and maintenance of AF; the coexistence of DM and AF is also associated with an increased risk of mortality and stroke. Moreover, DM is currently the main cause of renal impairment and the leading cause of dialysis in the world. The hyperglycemia is responsible for inducing redox imbalance and both systemic and intrarenal inflammation, playing a critical role in the pathogenesis of diabetic kidney disease. Long-term thromboembolic preventive therapy in AF patients with DM and CKD may be more challenging because both DM and CKD have been independently associated with an increased thromboembolic and bleeding risk, which results from the prothrombotic and pro-inflammatory status. Vitamin K Antagonists (VKAs) are characterized by numerous critical issues such as a narrow therapeutic window, increased tissue calcification and an unfavourable risk/benefit ratio with low stroke prevention effect and augmented risk of major bleeding. On the other hand, Direct Oral Anticoagulants (DOACs) are currently contraindicated in dialysis patients even if mounting evidence suggests that they may have a nephroprotective role in AF patients with DM and CKD. Consequently, the choice of anticoagulant therapy in this setting of patient seems to be very challenging. The aim of this review is to investigate the role of DOACs in diabetic patients and its nephroprotective role by reviewing the current literature.

New evidence of direct oral anticoagulation therapy on cardiac valve calcifications, renal preservation and inflammatory modulation

BACKGROUND

Rivaroxaban is a direct inhibitor of activated Factor X (FXa), an anti-inflammatory protein exerting a protective effect on the cardiac valve and vascular endothelium. We compare the effect of Warfarin and Rivaroxaban on inflammation biomarkers and their contribution to heart valve calcification progression and renal preservation in a population of atrial fibrillation (AF) patients with chronic kidney disease (CKD) stage 3b - 4.

METHODS

This was an observational, multicenter, prospective study enrolling 347 consecutive CKD stage 3b - 4 patients newly diagnosed with AF: 247 were treated with Rivaroxaban and 100 with Warfarin. Every 12 months, we measured creatinine levels and cardiac valve calcification via standard trans-thoracic echocardiogram, while plasma levels of inflammatory mediators were quantified by ELISA at baseline and after 24 months.

RESULTS

Over a follow-up of 24 months, long-term treatment with Rivaroxaban was associated with a significative reduction of cytokines. Patients treated with Rivaroxaban experienced a more frequent stabilization/regression of valve calcifications comparing with patients treated with Warfarin. Rivaroxaban use was related with an improvement in kidney function in 87.4% of patients, while in those treated with Warfarin was reported a worsening of renal clearance in 98% of cases. Patients taking Rivaroxaban experienced lower adverse events (3.2% vs 49%, p-value <0.001).

CONCLUSIONS

Our findings suggest that Rivaroxaban compared to Warfarin is associated with lower levels of serum markers of inflammation. The inhibition of FXa may exert an anti-inflammatory effect contributing to reduce the risk of cardiac valve calcification progression and worsening of renal function.