A novel rat model of contrast-induced nephropathy based on dehydration

Preventive effect and mechanism of compound Danshen dripping pills on contrast-induced nephropathy after percutaneous coronary interventional

Background

Contrast-induced nephropathy (CIN) is one of the most common complications after coronary stent implantation due to the extensive development of coronary catheterization technology. Compound Danshen dripping pills (CDDP) are clinically used as cardiovascular drugs, relieving systemic inflammatory response. Previous studies have observed that CDDP can decrease CIN incidence after coronary stent implantation with uncertain effectiveness.

Methods

We conducted a prospective, randomized, single-center, single-blind, controlled trial. We enrolled patients 18 years and older with unstable angina pectoris and NSTEMI who underwent PCI at the Tianjin Chest Hospital between November 1, 2021, and November 31, 2022, and followed for 30 days. Patients were randomized to CDDP and hydration therapy (10 capsules three times/day; N = 411) or hydration only (N = 411). The primary outcome was the contrast nephropathy incidence, defined as an elevation in serum creatinine by more than 25% or 44 μmol/L from baseline within 48-72 h of contrast exposure. Secondary outcomes included major adverse cardiovascular events post-surgery and during follow-up.

Results

After 48 h of operation, the two groups had statistical significance in Scr and BUN values (80.0 ± 12.59 vs. 84.43 ± 13.49, P < 0.05; 6.22 ± 1.01 vs. 6.40 ± 0.93, P < 0.05). The difference in Scr in 72 h between the two groups was statistically significant (76.42 ± 10.92 vs. 79.06 ± 11.58, P < 0.05). The CIN incidence was significantly lower in the CDDP group than in the hydration group. The CIN risk was significantly elevated in patients with LVEF <50%, contrast volume ≥160 ml, and hypertension, after 48 and 72 h of operation. The serum inflammation index levels NGAL, TNF-α, oxidative stress indexes SOD, and MDA significantly differed between the two groups. However, there was no significant difference in serum apoptosis indexes Bax, Bcl-2, and Casepase-9.

Conclusions

CDDP pre-treatment could prevent contrast-induced nephropathy. Inflammatory response and oxidative stress could be significant in the CDDP mechanism.

A novel contrast-induced acute kidney injury mouse model based on low-osmolar contrast medium

The contrast-induced acute kidney injury (CI-AKI) has been becoming the third common cause of hospital-acquired acute kidney injury. An ideal animal model is essential for understanding the pathophysiology of CI-AKI. Previous CI-AKI studies were mostly performed on rats with high-osmolar contrast medium (HOCM), which is unsuitable for transgenic researches. This study provides a novel, efficient and reproducible CI-AKI model which was developed in mouse by administrating a low-osmolar contrast medium (LOCM). First of all, we applied the frequently used pretreatments (uninephrectomy and water deprivation), which combined with HOCM on rats could induce CI-AKI, on mice with LOCM. Secondly, we attempted to find a novel pretreatment suitable for mouse and LOCM by combining two classic pretreatments(uninephrectomy, water deprivation and furosemide administration). Finally, we evaluate the kidney damage of the novel model. We found that this mouse model possessed a significant reduction in renal function, severe renal tissue damage, and increased renal tubular cells apoptosis, indicating that LOCM is a feasible inducer for CI-AKI mice model. Taken together, we found that uninephrectomy (UPHT) combined with 24 h water deprivation and furosemide administration 20 min before LOCM (iohexol, 10 ml/kg) application is a feasible pretreatment to establish a novel CI-AKI mouse model.

Rosiglitazone Alleviates Contrast-Induced Acute Kidney Injury in Rats via the PPARγ/NLRP3 Signaling Pathway

Background

This study investigated the effect and mechanism of rosiglitazone on a rat model with contrast-induced acute kidney injury (CI-AKI).

Materials and Methods

The CI-AKI rat model was established from Sprague Dawley rats by furosemide injection (10 ml/kg) to the caudal vein followed by iohexol (11.7 ml/kg). The experimental grouping was randomly allocated into control, model, rosiglitazone, and T0070907 groups. Blood samples were collected from the abdominal aorta. Serum creatinine, urea nitrogen, MDA, and SOD contents were detected by biochemical analysis. TNF-α and IL-10 expression was detected by ELISA. Urine creatinine and urine protein were measured following 24-h urine biochemistry testing. Cell pathology and apoptosis were detected by H&E and TUNEL staining, respectively. PPARγ, NLRP3, eNOS, and caspase-3 mRNA expression were detected by qPCR. Caspase-3 and NLRP3 expression were detected by immunohistochemistry.

Results

The CI-AKI rat model was successfully established because the results showed that compared with control, serum creatinine, urea nitrogen, MDA, SOD, TNF-α, and IL-10, urine creatinine and urine protein levels were significantly increased in the model group, indicating AKI, but was significantly decreased with rosiglitazone treatment, indicating recovery from injury, while opposite results were obtained with SOD. Apoptosis rate was significantly increased in the model group and significantly decreased with rosiglitazone treatment. NLRP3 and eNOS increased significantly in the model group and decreased significantly with rosiglitazone treatment, while opposite results were obtained with PPARγ. NLRP3 and caspase-3 protein expression was significantly increased in the model group and significantly decreased with rosiglitazone treatment.

Conclusion

Rosiglitazone could alleviate acute renal injury in the CI-AKI rat model by regulating the PPARγ/NLRP3 signaling pathway and should be further investigated as a potential treatment in clinical studies.

Fluid administration strategies for the prevention of contrast-associated acute kidney injury

PURPOSE OF REVIEW

The known timing of contrast media exposure in patients identified as high-risk for contrast-associated acute kidney injury (CA-AKI) enables the use of strategies to prevent this complication of intravascular contrast media exposure. Although multiple preventive strategies have been proposed, periprocedural fluid administration remains as the primary preventive strategy. This is a critical review of the current evidence evaluating a variety of fluid administration strategies in CA-AKI.

RECENT FINDINGS

Fluid administration strategies to prevent CA-AKI include comparisons of intravenous (i.v.) to no fluid administration, different fluid solutions, duration of fluid administration, oral hydration, left ventricular end diastolic-pressure guided fluid administration and forced diuresis techniques.

SUMMARY

Despite an abundance of fluid administration trials, it is difficult to make definitive recommendations about preventive fluid administration strategies due to low scientific quality of published studies. The literature supports use of i.v. compared with no fluid administration, especially in high-risk patients undergoing intra-arterial contrast media exposure. Use of isotonic saline is recommended over 0.45% saline or isotonic sodium bicarbonate. Logistical considerations support shortened over longer i.v. fluid administration strategies, despite an absence of evidence of equivalent efficacy. Current literature does not support oral hydration for high-risk patients. The use of tailored fluid administration in heart failure patients and forced diuresis with matching fluid administration are promising new fluid administration strategies.

The Pathophysiology and the Management of Radiocontrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is an impairment of renal function that occurs after the administration of an iodinated contrast medium (CM). Kidney dysfunction in CIN is considered transient and reversible in most cases. However, it is the third most common cause of hospital-acquired acute kidney injury and is associated with increased morbidity and mortality, especially in high-risk patients. Diagnostic and interventional procedures that require intravascular CM are being used with increasing frequency, especially among the elderly, who can be particularly susceptible to CIN due to multiple comorbidities. Therefore, identifying the exact mechanisms of CIN and its associated risk factors is crucial not only to provide optimal preventive management for at-risk patients, but also to increase the feasibility of diagnostic and interventional procedure that use CM. CM induces kidney injury by impairing renal hemodynamics and increasing the generation of reactive oxygen species, in addition to direct cytotoxicity. Periprocedural hydration is the most widely accepted preventive strategy to date. Here, we review the latest research results on the pathophysiology and management of CIN.

Haemodynamic frailty - A risk factor for acute kidney injury in the elderly

Clinical frailty in the elderly is defined by a composite measure of functional psychomotor decline. Herein, we develop the concept of haemodynamic frailty (HDF), a state of increased predisposition to disease prevalent in the elderly and characterised by impairment of the network of compensatory responses governing the defence of circulatory volume and adaptive haemodynamic function. We review the factors predisposing the elderly to HDF, with a focus on the impaired capacity to sustain total body water balance. As a component of HDF, dehydration generates vulnerability to diseases caused by tissue hypoperfusion, including acute kidney injury. We provide a detailed mechanistic explanation of how dehydration and depletion of the intravascular volume impacts on renal blood flow to become an important element of the heightened risk of acute kidney injury (AKI) in the elderly. We bring these mechanistic considerations into the clinical context with reference to examples of how pre-renal (haemodynamic) and intrinsic (involving renal parenchymal damage) AKI risk is elevated in the setting of dehydration. Finally, we present HDF as a state of opportunity to prevent disease, for which diagnostic and interventional standards need to be refined. Further prospective studies are warranted to help clarify the clinical utility of assessing and managing HDF with regard to the mitigation of AKI risk in the elderly.

Erythropoietin Attenuates Experimental Contrast-Induced Nephrology: A Role for the Janus Kinase 2/Signal Transducer and Activator of Transcription 3 Signaling Pathway

The aim of the present study was to investigate the effect of erythropoietin (EPO) on contrast-induced nephrology (CIN) in vivo and in vitro. Male C57BL/6J mice were divided into four groups: control, CIN (iohexol 6.0 g/kg), EPO (3,000 IU/kg), and CIN+EPO. Hematoxylin and eosin (H&E) staining and biochemical index analyses were performed to evaluate renal injury. The cellular proliferation rate was detected using the Cell Counting Kit-8 (CCK-8) assay. In addition, a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and flow cytometric assay were used to assess the apoptosis of tissue and cells, respectively. Renal protein expression associated with apoptosis, pyroptosis, and signaling pathways was determined by Western blot (WB) assays for tissues and cells. The results showed that EPO significantly decreased serum creatinine, blood urea nitrogen, and cystatin C levels and alleviated renal histological changes in vivo. The protein levels of Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway components were overexpressed in the EPO treatment group. Furthermore, EPO suppressed the cell apoptosis and pyroptosis; decreased the protein levels of cleaved caspase-3, Bax, gasdermin D (GSDMD), and caspase-1; and enhanced the expression of Bcl-2. In summary, EPO could exert renoprotective effect by activating the JAK2/STAT3 signaling pathway, which may be a novel potential therapy for the treatment of CIN in the clinic.

CaMKII as a key regulator of contrast-induced nephropathy through mPTP opening in HK-2 cells

Contrast-induced nephropathy (CIN), refers to acute kidney injury observed after administration of contrast media during angiographic or other medical procedures such as urography, and accounting for 12% of all causes of acute renal failure, but no specific prevention or treatment strategy exists for its obscure pathophysiology. The aim of our study was to explore the influence of calcium/calmodulin-dependent protein kinase II (CaMKII) in CIN by using HK-2 cells. Knockdown of CypD was achieved by lentivirus, and CaMKII overexpression by transfection with the plasmid. In this study, we have demonstrated that CypD-mediated mPTP opening triggered mitochondrial dysfunction and tubule cells apoptosis in CIN. We also found that iohexol treatment was associated with mitochondrial ROS overloading, ATP depletion and LDH release. Inhibition of CypD with the pharmacologic inhibitor or knockdown of CypD abrogated mPTP opening, oxidative stress, mitochondria damage, and cell apoptosis induced by iohexol. In addition, we found that inhibition of the CaMKII activity alleviated iohexol-induced CypD expression, whereas also decreased mPTP opening, oxidative stress, mitochondria damage, and cell apoptosis, similarly to the inhibition of CypD did. Moreover, CaMKII overexpression enhanced iohexol-induced mPTP opening, mitochondrial damage and renal tubular epithelial cells apoptosis. These findings first identified the novel role of CaMKII in iohexol-induced tubular cells apoptosis and delineated the CaMKII-CypD/mPTP pathway during contrast-induced tubular cell damage. Hence, these results could provide a new strategy for CIN protection.