Paricalcitol Attenuates Contrast-Induced Acute Kidney Injury by Regulating Mitophagy and Senescence

The connection between autophagy and ferroptosis in AKI: recent advances regarding selective autophagy

Acute kidney injury (AKI) is a significant issue in public health, displaying a high occurrence rate and mortality rate. Ferroptosis, a form of programmed cell death (PCD), is characterized by iron accumulation and intensified lipid peroxidation. Recent studies have demonstrated the pivotal significance of ferroptosis in AKI caused by diverse stimuli, including ischemia-reperfusion injury (IRI), sepsis and toxins. Autophagy, a multistep process that targets damaged organelles and macromolecules for degradation and recycling, also plays an essential role in AKI. Previous research has demonstrated that autophagy deletion in proximal tubules could aggravate tubular injury and renal function loss, indicating the protective function of autophagy in AKI. Consequently, finding ways to stimulate autophagy has become a crucial therapeutic strategy. The recent discovery of the role of selective autophagy in influencing ferroptosis has identified new therapeutic targets for AKI and has highlighted the importance of understanding the cross-talk between autophagy and ferroptosis. This study aims to provide an overview of the signaling pathways involved in ferroptosis and autophagy, focusing on the mechanisms and functions of selective autophagy and autophagy-dependent ferroptosis. We hope to establish a foundation for future investigations into the interaction between autophagy and ferroptosis in AKI as well as other diseases.

P16INK4a deletion alleviates contrast-induced acute kidney injury by ameliorating renal cell apoptosis and suppressing inflammation and oxidative stress

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of hospital-acquired acute kidney injury. Cellular senescence is associated with CI-AKI. P16INK4a (p16) is a cell cycle regulator and link to aging and senescence. We found that the expression of p16 was elevated in CI-AKI renal tissues, however its role in CI-AKI remains insufficiently understood. In this study, we used p16 knockout (p16KO) mice and wild-type (WT) littermates to establish CI-AKI mice model to elucidate the impact of p16 on CI-AKI. The results showed that serum creatinine (SCr), blood urea nitrogen (BUN), and serum neutrophil gelatinase-associated lipocalin (NGAL) levels were markedly reduced in p16KO CI-AKI mice. Both immunohistochemistry and western blot analyses confirmed that p16 knockout alleviated renal cell apoptosis. Furthermore, interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) were attenuated by downregulating NLRP3 and NF-κB inflammasomes. Additionally, ROS levels were diminished via activating Nrf2/Keap-1 pathway in p16KO CI-AKI mice. Collectively, our findings suggest that p16 deletion exerts protective effects against apoptosis, inflammation, and oxidative stress in CI-AKI mice model, p16 deletion might be a potential therapeutic strategy for ameliorating CI-AKI.

JQ1 attenuates contrast-induced acute kidney injury through the upregulation of autophagy and inhibition of inflammation

PURPOSE

Contrast-induced acute kidney injury (CI-AKI) is the third most common cause of hospital-acquired AKI. However, there is a paucity of efficacious interventions for the management of CI-AKI. Here, we aim to investigate the effects of JQ1 in CI-AKI and provide theoretical data and a  foundation for  novel ideas for the clinical treatment of CI-AKI.

METHODS

In this study, we performed in vivo and in vitro experiments with mice and HK2 cells injury models respectively. The levels of serum creatinine (Cr) and blood urea nitrogen (BUN) were determined by an automatic analyzer for the measurements of renal function. The viability of HK-2 cells was analyzed using the Cell Counting Kit-8 (CCK-8) kit. Additionally, the kidney changes in the mice were detected using histopathology (H&E) and immunofluorescent staining. The mRNA and protein expressions were assessed using Quantitative real-time PCR and western blot, respectively. Autophagy and apoptosis was analyzed by Transmission electron microscopy (TEM) and TUNEL assay respectively.

RESULTS

The results demonstrated that JQ1 exhibited potency of attenuating CI-AKI in mouse and HK2 cells. JQ1 increased the expression levels of Atg5, Atg7 and LC3B-II, and decreased the protein levels of p62 in the kidney and HK-2 cells. However, the combined use of JQ1 with chloroquine reversed the effects of JQ1. JQ1 also inhibited the inflammatory cells and downregulated the expression of some inflammatory cytokines (IL-6, IL-1β, TNF-α, and IFN-γ).

CONCLUSION

JQ1 protects against CI-AKI by promoting autophagy and inhibiting inflammation and JQ1 may be a promising therapeutic strategy for CI-AKI.

Suppression of NLRP3 inflammasome activation by astragaloside IV via promotion of mitophagy to ameliorate radiation-induced renal injury in mice

Background

Irradiation (IR) promotes inflammation and apoptosis by inducing oxidative stress and/or mitochondrial dysfunction (MD). The kidneys are rich in mitochondria, and mitophagy maintains normal renal function by eliminating damaged mitochondria and minimizing oxidative stress. However, whether astragaloside IV (AS-IV) can play a protective role through the mitophagy pathway is not known.

Methods

We constructed a radiation injury model using hematoxylin and eosin (HE) staining, blood biochemical analysis, immunohistochemistry, TdT-mediated dUTP nick end labeling (TUNEL) staining, ultrastructural observation, and Western blot analysis to elucidate the AS-IV resistance mechanism for IR-induced renal injury.

Results

IR induced mitochondrial damage; the increase of creatinine (SCr), blood urea nitrogen (BUN) and uric acid (UA); and the activation of NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome and apoptosis in renal tissue. AS-IV administration attenuated the IR-induced MD and reactive oxygen species (ROS) levels in the kidney; enhanced the levels of mitophagy-associated protein [PTEN-induced putative kinase 1 (PINK1)], parkin proteins, and microtubule-associated protein 1 light 3 (LC3) II/I ratio in renal tissues; diminished NLRP3 inflammasome activation-mediated proteins [cleaved cysteinyl aspartate-specific proteinase-1 (caspase-1), interleukin-1β (IL-1β)] and apoptosis-related proteins [cleaved caspase-9, cleaved caspase-3, BCL2-associated X (Bax)]; reduced SCr, BUN, and UA levels; and attenuated the histopathological alterations in renal tissue. Conversely, mitophagy inhibitor cyclosporin A (CsA) suppressed the AS-IV-mediated protection of renal tissue.

Conclusions

AS-IV can strongly diminish the activation and apoptosis of NLRP3 inflammasome, thus attenuating the renal injury induced by radiation by promoting the PINK1/parkin-mediated mitophagy. These findings suggest that AS-IV is a promising drug for treating IR-induced kidney injury.

Effects of paricalcitol combined with hemodiafiltration on bone-metabolism-related indexes in patients with diabetic nephropathy and chronic renal failure

BACKGROUND

Diabetic nephropathy (DN) is frequently seen in the development of diabetes mellitus, and its pathogenic factors are complicated. Its current treatment is controversial, and there is a lack of a relevant efficacy prediction model.

AIM

To determine the effects of paricalcitol combined with hemodiafiltration on bone-metabolism-related indexes in patients with DN and chronic renal failure (CRF), and to construct an efficacy prediction model.

METHODS

We retrospectively analyzed 422 patients with DN and CRF treated in Cangzhou Central Hospital between May 2020 and May 2022. We selected 94 patients who met the inclusion and exclusion criteria. Patients were assigned to a dialysis group (n = 45) and a joint group (n = 49) in relation to therapeutic regimen. The clinical efficacy of the two groups was compared after treatment. The changes in laboratory indexes after treatment were evaluated, and the two groups were compared for the incidence of adverse reactions. The predictive value of laboratory indexes on the clinical efficacy on patients was analyzed.

RESULTS

The dialysis group showed a notably worse improvement in clinical efficacy than the joint group (P = 0.017). After treatment, the joint group showed notably lower serum levels of serum creatinine, uric acid (UA) and blood urea nitrogen (BUN) than the dialysis group (P < 0.05). After treatment, the joint group had lower serum levels of phosphorus, procollagen type I amino-terminal propeptide (PINP) and intact parathyroid hormone than the dialysis group, but a higher calcium level (P < 0.001). Both groups had a similar incidence of adverse reactions (P > 0.05). According to least absolute shrinkage and selection operator regression analysis, UA, BUN, phosphorus and PINP were related to treatment efficacy. According to further comparison, the non-improvement group had higher risk scores than the improvement group (P < 0.0001), and the area under the curve of the risk score in efficacy prediction was 0.945.

CONCLUSION

For treatment of CRF and DN, combined paricalcitol and hemodiafiltration can deliver higher clinical efficacy and improve the bone metabolism of patients, with good safety.

Ox-LDL aggravates contrast-induced injury of renal tubular epithelial cells

Hypercholesterolemia can aggravate contrast-induced acute kidney injury, and the exacerbation of renal tubular epithelial cell (RTEC) injury is a major cause. However, the exact mechanisms remain obscure. Mitophagy, a type of autophagy, selectively eliminates damaged mitochondria and reduces mitochondrial oxidative stress, which is strongly implicated in cell homeostasis and acute kidney injury. Oxidized low-density lipoprotein (Ox-LDL) is accumulated in hypercholesterolemia and has a cytotoxic effect. This study aimed to determine whether and how ox-LDL exacerbates contrast-induced injury in RTECs and to further explore whether PINK1/Parkin-dependent mitophagy is involved in this process. Iohexol and ox-LDL were used alone or in combination to treat HK-2 cells. Rapamycin pretreatment was utilized to enhance mitophagy. Cell viability, apoptosis, mitochondrial membrane potential (MMP) and mitochondrial reactive oxygen species (mtROS) were detected by cell counting kit-8, TUNEL staining, JC-1 kit and MitoSOX fluorescence, respectively. The expression of mitophagy-related proteins (including PINK1, Parkin, and so on) and cleaved caspase-3 was confirmed by western blot. Colocalization of MitoTracker-labeled mitochondria and LysoTracker-labeled lysosomes was observed by fluorescence microscopy to evaluate mitophagy. The results of our study showed that ox-LDL aggravated MMP decline, mtROS release and apoptosis in iohexol-treated HK-2 cells, accompanied by a further increased autophagy level. Enhancement of PINK1/Parkin-dependent mitophagy by rapamycin alleviated apoptosis and mitochondrial injury in HK-2 cells in response to iohexol under ox-LDL condition. Therefore, our findings indicate that ox-LDL aggravates contrast-induced injury of RTECs by increasing mitochondrial damage and mitochondrial oxidative stress, which may be associated with the relative insufficiency of PINK1/Parkin-dependent mitophagy.

Mitochondrial homeostasis: a potential target for delaying renal aging

Mitochondria, which are the energy factories of the cell, participate in many life activities, and the kidney is a high metabolic organ that contains abundant mitochondria. Renal aging is a degenerative process associated with the accumulation of harmful processes. Increasing attention has been given to the role of abnormal mitochondrial homeostasis in renal aging. However, the role of mitochondrial homeostasis in renal aging has not been reviewed in detail. Here, we summarize the current biochemical markers associated with aging and review the changes in renal structure and function during aging. Moreover, we also review in detail the role of mitochondrial homeostasis abnormalities, including mitochondrial function, mitophagy and mitochondria-mediated oxidative stress and inflammation, in renal aging. Finally, we describe some of the current antiaging compounds that target mitochondria and note that maintaining mitochondrial homeostasis is a potential strategy against renal aging.

Research progress on animal models of contrast-induced acute kidney injury

Contrast-induced acute kidney injury (CI-AKI) refers to acute kidney injury that occurs after intravascular contrast media is applied. It is the third most common cause for acute renal failure in hospitalized patients and can cause severe renal impairment and adverse cardiovascular outcomes. In severe cases, it can even lead to the death of the patient. Due to its complicated pathogenesis, the pathogenesis of CI-AKI has not yet been elucidated. Therefore, it is of great significance to further study the pathogenesis for the prevention of CI-AKI. Moreover, a good animal model of CI-AKI is an important tool for in-depth research on the pathogenesis of acute kidney injury induced by contrast agents.

Ioversol Induced Microglia Proinflammatory Activation and Oxidative Stress in Rats

Contrast-induced encephalopathy (CIE) following angiography, though not often and reversible, can in some cases lead to permanent neurological dysfunction. To identify how neuroinflammation is involved in CIE, we investigated microglia responses to a bolus injection of ioversol in the internal carotid artery (ICA) in rats. MicroCT scanning indicated that the injected ioversol was cleared from the rat's brain within 25 min. However, proinflammatory activated and significantly increased microglia were found in the rat occipital cortex at 1 day, and the number of blood vessel-associated microglia was still significantly higher at 3-day post-injection, compared with sham- and PBS-treated rats. Moreover, significantly upregulated malondialdehyde (MDA), downregulated superoxide dismutase (SOD) levels, and elevated proinflammatory cytokines were observed in the brain of rats treated with ioversol. Ioversol administration decreased cell viability of primarily cultured microglia and induced significant proinflammatory activation. Furthermore, ioversol remarkably upregulated astrocytic aquaporin (AQP) 4 expression in the rats brain, and transwell cultures showed significantly enhanced microglia migrating to ioversol-treated endothelial cells. Immediate injection of edaravone dexborneol, a novel antioxidative drug, after ioversol injection effectively rescued ioversol-induced neuroinflammation. Together, these findings suggest that ioversol induced neuroinflammation and oxidative stress in the brain via microglia activation in a direct and indirect manner, which might contribute to the pathogenesis of CIE.

Vitamin D, Cellular Senescence and Chronic Kidney Diseases: What Is Missing in the Equation?

As life expectancy increases in many countries, the prevalence of age-related diseases also rises. Among these conditions, chronic kidney disease is predicted to become the second cause of death in some countries before the end of the century. An important problem with kidney diseases is the lack of biomarkers to detect early damage or to predict the progression to renal failure. In addition, current treatments only retard kidney disease progression, and better tools are needed. Preclinical research has shown the involvement of the activation of cellular senescence-related mechanisms in natural aging and kidney injury. Intensive research is searching for novel treatments for kidney diseases as well as for anti-aging therapies. In this sense, many experimental shreds of evidence support that treatment with vitamin D or its analogs can exert pleiotropic protective effects in kidney injury. Moreover, vitamin D deficiency has been described in patients with kidney diseases. Here, we review recent evidence about the relationship between vitamin D and kidney diseases, explaining the underlying mechanisms of the effect of vitamin D actions, with particular attention to the modulation of cellular senescence mechanisms.

β-Cryptoxanthin Maintains Mitochondrial Function by Promoting NRF2 Nuclear Translocation to Inhibit Oxidative Stress-Induced Senescence in HK-2 Cells

The mechanisms of acute kidney injury and chronic kidney disease remain incompletely revealed, and drug development is a pressing clinical challenge. Oxidative stress-induced cellular senescence and mitochondrial damage are important biological events in a variety of kidney diseases. As a type of carotenoid, β-Cryptoxanthin (BCX) has various biological functions, which means it is a potential therapeutic candidate for the treatment of kidney disease. However, the role of BCX in the kidney is unclear, and the effect of BCX on oxidative stress and cellular senescence in renal cells is also unknown. Therefore, we conducted a series of studies on human renal tubular epithelial (HK-2) cells in vitro. In the present study, we investigated the effect of BCX pretreatment on H₂O₂-induced oxidative stress and cellular senescence and explored the potential mechanism of BCX action. The results showed that BCX attenuated H₂O₂-induced oxidative stress and cellular senescence in HK-2 cells. Moreover, BCX promoted NRF2 nuclear expression, maintained mitochondrial function, and reduced mitochondrial damage in HK-2 cells. In addition, silencing NRF2 altered the protective effect of BCX on mitochondria and significantly reversed the anti-oxidative stress and anti-senescence effects of BCX in HK-2 cells. We concluded that BCX maintained mitochondrial function by promoting NRF2 nuclear translocation to inhibit oxidative stress-induced senescence in HK-2 cells. In light of these findings, the application of BCX might be a promising strategy for the prevention and treatment of kidney diseases.

FFAR4 improves the senescence of tubular epithelial cells by AMPK/SirT3 signaling in acute kidney injury

Acute kidney injury (AKI) is a serious clinical complication with high morbidity and mortality rates. Despite substantial progress in understanding the mechanism of AKI, no effective therapy is available for treatment or prevention. We previously found that G protein-coupled receptor (GPCR) family member free fatty acid receptor 4 (FFAR4) agonist TUG891 alleviated kidney dysfunction and tubular injury in AKI mice. However, the versatile role of FFAR4 in kidney has not been well characterized. In the study, the expression of FFAR4 was abnormally decreased in tubular epithelial cells (TECs) of cisplatin, cecal ligation/perforation and ischemia/reperfusion injury-induced AKI mice, respectively. Systemic and conditional TEC-specific knockout of FFAR4 aggravated renal function and pathological damage, whereas FFAR4 activation by TUG-891 alleviated the severity of disease in cisplatin-induced AKI mice. Notably, FFAR4, as a key determinant, was firstly explored to regulate cellular senescence both in injured kidneys of AKI mice and TECs, which was indicated by senescence-associated β-galactosidase (SA-β-gal) activity, marker protein p53, p21, Lamin B1, phospho-histone H2A.X, phospho-Rb expression, and secretory phenotype IL-6 level. Mechanistically, pharmacological activation and overexpression of FFAR4 reversed the decrease of aging-related SirT3 protein, where FFAR4 regulated SirT3 expression to exhibit anti-senescent effect via Gq subunit-mediated CaMKKβ/AMPK signaling in cisplatin-induced mice and TECs. These findings highlight the original role of tubular FFAR4 in cellular senescence via AMPK/SirT3 signaling and identify FFAR4 as a potential drug target against AKI.

The role of vitamin D on redox regulation and cellular senescence

Vitamin D is considered an essential micronutrient for human health that is metabolized into a multifunctional secosteroid hormone. We can synthesize it in the skin through ultraviolet B (UVB) rays or acquire it from the diet. Its deficiency is a major global health problem that affects all ages and ethnic groups. Furthermore, dysregulation of vitamin D homeostasis has been associated with premature aging, driven by various cellular processes, including oxidative stress and cellular senescence. Various studies have shown that vitamin D can attenuate oxidative stress and delay cellular senescence, mainly by inducing the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and Klotho and improving mitochondrial homeostasis, proposing this vitamin as an excellent candidate for delaying aging. However, the mechanisms around these processes are not yet fully explored. Therefore, in this review, the effects of vitamin D on redox regulation and cellular senescence are discussed to propose new lines of research and clinical applications of vitamin D in the context of age-related diseases.

Cellular senescence: the good, the bad and the unknown

Cellular senescence is a ubiquitous process with roles in tissue remodelling, including wound repair and embryogenesis. However, prolonged senescence can be maladaptive, leading to cancer development and age-related diseases. Cellular senescence involves cell-cycle arrest and the release of inflammatory cytokines with autocrine, paracrine and endocrine activities. Senescent cells also exhibit morphological alterations, including flattened cell bodies, vacuolization and granularity in the cytoplasm and abnormal organelles. Several biomarkers of cellular senescence have been identified, including SA-βgal, p16 and p21; however, few markers have high sensitivity and specificity. In addition to driving ageing, senescence of immune and parenchymal cells contributes to the development of a variety of diseases and metabolic disorders. In the kidney, senescence might have beneficial roles during development and recovery from injury, but can also contribute to the progression of acute kidney injury and chronic kidney disease. Therapies that target senescence, including senolytic and senomorphic drugs, stem cell therapies and other interventions, have been shown to extend lifespan and reduce tissue injury in various animal models. Early clinical trials confirm that senotherapeutic approaches could be beneficial in human disease. However, larger clinical trials are needed to translate these approaches to patient care.

CKD-MBD Biomarkers and CKD Progression: an Analysis by the Joint Model

BACKGROUND

Biomarkers of the CKD- Bone Mineral Disorder (CKD-BMD have been implicated in CKD progression in follow up studies focusing on single measurements of individual biomarkers made at baseline only. The simultaneous relationship between the time trend of these biomarkers over the course of CKD and renal outcomes has never been tested.

METHODS

We applied the Joint Model (JM) to investigate the longitudinal relationship between repeated measurements of CKD-MBD biomarkers and a combined renal endpoint (eGFR reduction >30%, dialysis or transplantation) in 729 stage 2-5 CKD patients over a 36 months follow up.

RESULTS

In the survival sub-model of the JM the longitudinal series of PTH values was directly and independently related to the risk of renal events [HR (1ln PTH) = 2.0 (from 1.5 to 2.8), p<0.001)] and this was also true for repeated measurements of serum phosphate [HR(1mg/dl) = 1.3924 (from 1.1459 to 1.6918), p = 0.001], serum calcium [HR(1mg/dl) = 0.7487 (from 0.5843 to 0.9593), p = 0.022], baseline FGF23 [HR(1pg/ml) = 1.001 (from 1.00 to 1.002), p = 0.045] and 1,25 dihydroxy Vitamin D [HR (1pg/ml) = 0.9796 (from 0.9652 to 0.9942), p = 0.006].

CONCLUSION

Repeated measurements of serum PTH, calcium and phosphate as well as baseline FGF23 and 1,25 dihydroxy vitamin D are independently related with the progression to kidney failure in a cohort of stage 2-5 CKD patients. This longitudinal study generates the hypothesis that interventions at multiple levels on BMD biomarkers can mitigate renal function loss in this population.

Nuclear receptors in renal health and disease

As a major social and economic burden for the healthcare system, kidney diseases contribute to the constant increase of worldwide deaths. A deeper understanding of the underlying mechanisms governing the etiology, development and progression of kidney diseases may help to identify potential therapeutic targets. As a superfamily of ligand-dependent transcription factors, nuclear receptors (NRs) are critical for the maintenance of normal renal function and their dysfunction is associated with a variety of kidney diseases. Increasing evidence suggests that ligands for NRs protect patients from renal ischemia/reperfusion (I/R) injury, drug-induced acute kidney injury (AKI), diabetic nephropathy (DN), renal fibrosis and kidney cancers. In the past decade, some breakthroughs have been made for the translation of NR ligands into clinical use. This review summarizes the current understanding of several important NRs in renal physiology and pathophysiology and discusses recent findings and applications of NR ligands in the management of kidney diseases.

Tolvaptan Improves Contrast-Induced Acute Kidney Injury

OBJECTIVE

Contrast-induced acute kidney injury (CI-AKI) is a serious side effect of contrast media use. The purpose of this study was to investigate the role and mechanism of tolvaptan (TOL) in CI-AKI.

METHODS

24 Wistar male rats were randomly divided into 4 groups (n = 6). And a rat model of CI-AKI was established. Then, the blood and urine of rats in each group were collected to detect relevant parameters. HE staining was utilized for the observation of the pathological changes of rat kidney tissues, TUNEL assay for the detection of tubular cell apoptosis, biochemical detection for the confirmation of oxidative stress level in kidney tissues, and western blot for the test of the expression of apoptotic proteins and the Nrf2 signaling pathway-related proteins in kidney tissues.

RESULTS

TOL could significantly reduce the serum level of urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin and decrease serum Cys-C and urine KIM-1 in CI-AKI rats. The result above meant that TOL could improve kidney injury and reduce tubular cell apoptosis in CI-AKI rats. In addition, TOL contributed to a reduction of oxidative stress level by downregulating myeloperoxidase level and increasing the activities of superoxide dismutase and glutathione peroxidase in the kidney tissue of CI-AKI rats. After the pretreatment of TOL, the expression of proapoptotic proteins cleaved-caspase 3 and BAX, as well as mitochondrial fusion proteins DRP1 and MFN2 was downregulated, while the expression of Bcl-2 and PINK1 was upregulated in the kidney tissue of CI-AKI rats. Further, TOL could activate the Nrf2 signaling pathway, and the Nrf2 inhibitor ML385 reversed the effect of TOL on CI-AKI.

CONCLUSION

TOL can improve CI-AKI by activating the Nrf2/HO-1 signaling pathway, inhibiting oxidative stress response, and reducing tubular cell apoptosis.

The Complex Interplay between Autophagy and NLRP3 Inflammasome in Renal Diseases

Autophagy is a highly conserved process of the eukaryotic cell cycle. It plays an important role in the survival and maintenance of cells by degrading organelles, proteins, and macromolecules in the cytoplasm and the circulation of degraded products. The dysfunction of autophagy can lead to the pathology of many human diseases. The nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome belongs to the family of nucleotide-binding and oligomerization domain-like receptors (NLRs) and can induce caspase-1 activation, thus leading to the maturation and secretion of interleukin-1beta (IL-1β) and IL-18. It has been reported that the interplay between autophagy and NLRP3 inflammasome is involved in many diseases, including renal diseases. In this review, the interplay between autophagy and the NLRP3 inflammasome and the mechanisms in renal diseases are explored to provide ideas for relevant basic research in the future.

Narrative review of recent studies on the role of vitamin D in the prevention of cardiac and renal risk and additional considerations for COVID-19 vulnerability

The role of vitamin D in maintaining a healthy cardiovascular (CV) and the renal system has received increasing attention. Low vitamin D levels are associated with the incidence of hypertension, cardiac remodeling, and chronic congestive heart failure. Low vitamin D levels also influence renal disease progression and albuminuria deterioration. Moreover, recent research indicates that vitamin D deficiency can be a potential risk factor for coronavirus disease-19 (COVID-19) infection and poorer outcomes. Data are inconclusive as to whether supplementation with vitamin D agents reduces CV disease risk or COVID-19 severity. Conversely, in patients with kidney disease, vitamin D supplementation is associated with improved kidney function and albuminuria. This narrative review considers recent data on the effects of vitamin D on the CV and renal system, as well as its possible role regarding COVID-19 complications.

Predictive value of creatine kinase MB for contrast-induced acute kidney injury among myocardial infarction patients

Background

Predictive value of creatine kinase MB (CK-MB) for contrast-induced acute kidney injury (CI-AKI) among myocardial infarction (MI) patients has rarely been reported. We aim to evaluate the predictive value of CK-MB for CI-AKI among MI patients.

Methods

Totally, 1131 MI patients were included from the REduction of rIsk for Contrast-Induced Nephropathy (REICIN) study. The peak CK-MB before coronary angiography (CAG) was chosen. The study population was divided into two groups by log-transformed CK-MB cut-off point. The association between CK-MB and CI-AKI was tested by multivariable logistic regression. CK-MB was integrated with Age, creatinine and ejection fraction (ACEF) score and Mehran risk score (MRS) to evaluate the additive value of CK-MB. The integrated models were validated internally by the bootstrap method and externally by the PREdictive Value of COntrast voluMe to creatinine Clearance Ratio (PRECOMIN) study data set.

Results

Overall, 62(5.48%) patients developed CI-AKI, patients with CK-MB point > 4.7 displayed a higher incidence of CI-AKI than those without (11.9% vs. 4.0%, p < 0.001). CK-MB point > 4.7 was independently associated with CI-AKI (adjusted OR: 3.40, 95% CI: 1.93–5.98, p < 0.001). The additions of CK-MB to ACEF score, Mehran score A and Mehran score B resulted in increases in C-statistics, which ranged from 0.680 to 0.733 (p = 0.046), 0.694 to 0.727 (p = 0.091), 0.704 to 0.734 (p = 0.102), respectively. Internal validation also showed increases in C-statistics, and external validation performed well in discrimination and calibration.

Conclusions

Preprocedural peak CK-MB was a predictor of CI-AKI among MI patients.