Pros and Cons of Aspirin Prophylaxis for Prevention of Cardiovascular Events in Kidney Transplantation and Review of Evidence

A Thorough Literature Review of the Potential Benefits and Drawbacks of Long-Term Aspirin Use for the Primary Prevention of Cardiovascular Disease

This article examines the role of aspirin in the primary prevention of cardiovascular disease. It highlights findings from major studies such as ASPREE (ASPirin in Reducing Events in the Elderly), ARRIVE (Aspirin to Reduce Risk of Initial Vascular Events), and ASPREE-XT (ASPirin in Reducing Events in the Elderly - eXTension) , among others. The review focuses on aspirin's role in primary prevention for specific populations including older adults, diabetics, hypertension patients, rheumatoid arthritis patients, kidney transplant recipients, and those with specific lipoprotein(a) genotypes, among other groups. We review these studies, noting aspirin's role in reducing events such as myocardial infarctions and its potential for increasing bleeding risks. The review also considers the implications for patients with kidney disease, referencing the Chronic Renal Insufficiency Cohort (CRIC) study and the International Polycap Study-3 (TIPS-3) trial. Additionally, it addresses the shifting paradigms in guidelines from the US Preventive Services Task Force and other entities, underscoring the importance of individualized aspirin use by balancing benefits against bleeding risks. The article further explores the concept of platelet reactivity, discusses strategies for improving adherence to aspirin therapy, and identifies existing research gaps, such as the phenomenon of aspirin resistance. It concludes by suggesting potential areas for future investigation to enhance understanding and application of aspirin in cardiovascular disease prevention.

Alterations in Energy Metabolism, Mitochondrial Function and Redox Homeostasis in GK Diabetic Rat Tissues Treated with Aspirin

Our recent studies have demonstrated that aspirin treatment prevents inflammatory and oxidative stress-induced alterations in mitochondrial function, improves glucose tolerance and pancreatic endocrine function and preserves tissue-specific glutathione (GSH)-dependent redox homeostasis in Goto-Kakizaki (GK) diabetic rats. In the current study, we have investigated the mechanism of action of aspirin in maintaining mitochondrial bioenergetics and redox metabolism in the liver and kidneys of GK rats. Aspirin reduced the production of reactive oxygen species (ROS) and oxidative stress-induced changes in GSH metabolism. Aspirin treatment also improved mitochondrial respiratory function and energy metabolism, in addition to regulating the expression of cell signaling proteins that were altered in diabetic animals. Ultrastructural electron microscopy studies revealed decreased accumulation of glycogen in the liver of aspirin-treated diabetic rats. Hypertrophic podocytes with irregular fusion of foot processes in the renal glomerulus and detached microvilli, condensed nuclei and degenerated mitochondria observed in the proximal convoluted tubules of GK rats were partially restored by aspirin. These results provide additional evidence to support our previous observation of moderation of diabetic complications by aspirin treatment in GK rats and may have implications for cautious use of aspirin in the therapeutic management of diabetes.

Effect of Aspirin on Mitochondrial Dysfunction and Stress in the Pancreas and Heart of Goto-Kakizaki Diabetic Rats

Our previous study in Goto-Kakizaki (GK) type 2 diabetic rats provided significant evidence that aspirin treatment improves pancreatic β-cell function by reducing inflammatory responses and improving glucose tolerance. In the present study, we aimed to elucidate the mechanism of action of aspirin on the pathophysiology and progression of type 2 diabetic complications in the heart and pancreas of insulin-resistant GK rats. Aspirin treatment demonstrated a reduction in mitochondrial reactive oxygen species (ROS) production and lipid peroxidation, accompanied by improved redox homeostasis. Furthermore, the recovery of metabolic and mitochondrial functions, as well as cytochrome P450 enzyme activities, which were altered in the pancreas and heart of GK rats, were observed. Aspirin treatment brought the activity of CYP 2E1 to the control level in both tissues, whereas the CYP 3A4 level decreased only in the pancreas. This suggests the tissue-specific differential metabolism of substrates in these rats. The recovery of redox homeostasis could be the key target in the improvement of oxidative-stress-dependent alterations in mitochondrial functions which, in turn, facilitated improved energy metabolism in these tissues in the aspirin-treated GK rats. These results may have implications in determining the therapeutic use of aspirin, either alone or in combination with other clinically approved therapies, in insulin-resistant type 2 diabetes.

The Living-Related Kidney Transplant Program in Brunei Darussalam: Lessons Learnt from a Nascent National Program in a Small, Muslim, and Asian Country

Brunei Darussalam commenced its living-related renal transplant program in 2013, with subsequent attainment of independent local capacity and proficiency in 2019. The preliminary outcome from the program has already begun to shape the national nephrology landscape with a 36% increment in transplant rate and mitigation of commercialized transplantations. The blueprint for the program was first laid out in 2010 and thereupon executed in four phases. The first phase involved the gathering of evidence to support the establishment of the national program, through researches investigating feasibility, public opinion, quality of life, graft survival, and cost-effectiveness. The second phase focused on laying the foundation of the program through grooming of local expertise, implementation of legal-ethical frameworks, religious legitimization, and propagation of awareness. The third phase worked on facilitating experiential exposure and strengthening local infrastructure through the upgrading of facilities and the introduction of subsidiary services. The fourth phase was implemented in Brunei in 2013 when foreign personnel worked together with the local team to perform the transplants. Between 2013 and 2019, ten kidney transplants were performed, with two being done in 2018 and three in 2019. We hope to inspire other similar countries to develop their own self-sustainable and independent local program.

Serum Osteocalcin Level is Negatively Associated with Vascular Reactivity Index by Digital Thermal Monitoring in Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES

Osteocalcin is the most abundant noncollagenous protein in bone matrix, which is considered a marker of bone formation. Previous studies indicate that circulating osteocalcin can be expressed by osteoblasts and even by osteoblast-like cells in vessel walls, and it is often associated with arterial stiffness. Our study aims to examine the potential association between osteocalcin levels and endothelial function among kidney transplant (KT) recipients.

MATERIALS AND METHODS

Fasting blood samples were obtained from 68 KT recipients. To measure the endothelial function and vascular reactivity index (VRI), a digital thermal monitoring test (VENDYS) was used. A commercial enzyme-linked immunosorbent assay kit was also utilized to measure serum total osteocalcin levels. In this study, a VRI of less than 1.0 indicated poor vascular reactivity; a VRI of 1.0-2.0 indicated intermediate vascular reactivity; and a VRI of 2.0 or higher indicated good vascular reactivity.

RESULTS

Our findings show that 8 KT recipients (11.8%) had poor vascular reactivity (VRI < 1.0), 26 (38.2%) had intermediate vascular reactivity (1.0 ≤ VRI < 2.0), and 34 (50%) had good vascular reactivity. Increased serum osteocalcin levels (p < 0.001) were found to be associated with poor vascular reactivity. Advanced age (r = -0.361, p = 0.002), serum alkaline phosphate level (r = -0.254, p = 0.037), and log-transformed osteocalcin levels (r = - 0.432, p < 0.001) were identified to be negatively correlated with VRI in KT recipients. Multivariable forward stepwise linear regression analysis revealed that the serum level of osteocalcin (β = -0.391, adjusted R² change = 0.174; p < 0.001) and advanced age (β = -0.308, adjusted R² change = 0.084; p = 0.005) were significantly and independently associated with VRI in KT recipients.

CONCLUSIONS

Higher serum osteocalcin level was associated with lower VRI and poorer endothelial dysfunction among KT recipients.