Clinical Significance of Serum Kallistatin and ENOX1 Levels in Patients with Coronary Heart Disease

Unravelling the Role of Serum Kallistatin on Cardiorenal Outcomes in Kidney Transplant Survivors

INTRODUCTION

Kallistatin, a serine protease inhibitor, has been implicated in cardiovascular and renal protection. This study investigates its association with clinical characteristics and outcomes in long-term kidney transplant recipients (KTRs).

METHODS

In this longitudinal observational cohort study, we enrolled 101 KTRs between September 2016 and October 2017. The median (interquartile range) time post-transplant was 52 (36-97) months, and the follow-up time was 83 (41-85) months. All patients had documented graft function of ≥24 months and no record of acute rejection or active or chronic infection at presentation. Serum kallistatin and high-sensitivity interleukin-6 were measured at baseline using commercially available enzyme-linked immunosorbent assays. A control group of 32 healthy volunteers was also recruited.

RESULTS

Higher serum kallistatin levels were observed in KTRs compared to healthy controls (15.9 vs. 13.8 µg/mL; p = 0.007). Concentrations were lower in diabetic versus non-diabetic KTR (14.8 vs. 16.4 µg/mL; p = 0.021). A significant interaction between diabetic status and body mass index indicated a positive association with kallistatin levels only in diabetic KTRs (p = 0.046). Linear mixed models assessing estimated glomerular filtration rate (eGFR) change over time showed improved fit after kallistatin was included in a base model with age, sex, and baseline eGFR (p = 0.024). Cox regression showed that higher kallistatin levels were associated with an increased risk of graft loss (HR: 1.120; p = 0.049), but also remained independent of time after transplantation (HR: 1.147; p = 0.030). No association was observed for all-cause mortality. The best performance was estimated for kallistatin models adjusting for time post-transplant (c-index 0.779) and diabetic status (c-index 0.707).

CONCLUSION

This study highlights the complex interactions between kallistatin, renal function, and cardiometabolic status in stable, long-term KTRs. Higher kallistatin levels are associated with an increased risk of graft loss in non-diabetic patients while showing a protective effect in diabetic patients. These findings support integrated management of cardio-reno-metabolic health in KTRs.

Probing the familial ties between serpin members Kallistatin and PEDF: A comparative analysis review

The serine protease inhibitors (Serpins) represent a diverse protein superfamily that holds paramount significance in governing vital pathophysiological processes. Their influence on critical biological pathways renders serpins highly coveted targets for drug discovery endeavors. Among the numerous members of this family, two distinct proteins, Kallistatin (encoded by the SERPINA4 gene) and Pigment Epithelium-Derived Factor (PEDF, encoded by the SERPINF1 gene), stand out as secreted proteins that are abundantly present in peripheral blood. Kallistatin is a serine protease inhibitor that specifically inhibits human tissue kallikrein, while PEDF is a non-inhibitory member of the serine protease inhibitors superfamily (Lin et al., 2015a; Chao and Chao, 1995 [1,2]). Instead, they exhibit notable anti-angiogenic effects and play pivotal roles in the pathogenesis of metabolic disorders. Extensive research, including our own investigations, has revealed intriguing similarities as well as noteworthy differences between these two proteins. Despite their shared characteristics, the distinctive features of Kallistatin and PEDF render them unique in their respective functions and mechanisms of action. However, a comprehensive literature review comparing their similarities and differences remains elusive. Therefore, the present review aims to systematically delve into and summarize the comparable and contrasting aspects of Kallistatin and PEDF. We will delve into their expression patterns, structural features, and mechanisms of expression regulation. Furthermore, this review will delve into their physiological functions and roles in diseases, the signaling pathways they influence, and their potential clinical applications. By comparing and contrasting these two proteins, we hope to provide a comprehensive understanding of their functions and potential in biomedical research and clinical practice.

Relationship between Serum Kallistatin and Afamin and Anthropometric Factors Associated with Obesity and of Being Overweight in Patients after Myocardial Infarction and without Myocardial Infarction

Extensive clinical and epidemiological evidence has linked obesity to a broad spectrum of cardiovascular disease (CVD), including coronary disease, heart failure, hypertension, cerebrovascular disease, atrial fibrillation, ventricular arrhythmias, and sudden death. In addition, increasing knowledge of regulatory peptides has allowed an assessment of their role in various non-communicable diseases, including CVD. The study assessed the concentration of kallistatin and afamin in the blood serum of patients after a myocardial infarction and without a cardiovascular event, and determined the relationship between the concentration of kallistatin and afamin and the anthropometric indicators of being overweight and of obesity in these groups. Serum kallistatin and afamin were quantified by ELISA tests in a cross-sectional study of 160 patients who were divided into two groups: study group (SG) (n = 80) and another with no cardiovascular event (CG) (n = 80). Serum kallistatin concentration was significantly higher in the SG (p < 0.001), while the level of afamin was significantly lower in this group (p < 0.001). In addition, a positive correlation was observed in the SG between the afamin concentration and the waist to hip ratio (WHR), lipid accumulation product (LAP) and the triglyceride glucose index (TyG index). In the CG, the concentration of kallistatin positively correlated with the LAP and TyG index, while the concentration of afamin positively correlated with all the examined parameters: body mass index (BMI), waist circumference (WC), hip circumference (HC), waist to hip ratio (WHtR), visceral adiposity index (VAI), LAP and TyG index. Serum kallistatin and afamin concentrations are associated with the anthropometric parameters related to being overweight and to obesity, especially to those describing the visceral distribution of adipose tissue and metabolic disorders related to excessive fatness.