Metabolism of eicosanoids and their action on renal function during ischaemia and reperfusion: the effect of alprostadil

Unveiling the Mysteries of Contrast-Induced Acute Kidney Injury: New Horizons in Pathogenesis and Prevention

The utilization of contrast media (CM) in clinical diagnostic imaging and interventional procedures has escalated, leading to a gradual increase in the incidence of contrast-induced acute kidney injury (CI-AKI). Presently, the scarcity of effective pharmacological treatments for CI-AKI poses significant challenges to clinical management. Firstly, we explore the pathogenesis of CI-AKI in this review. Beyond renal medullary ischemia and hypoxia, oxidative stress, cellular apoptosis, and inflammation, emerging mechanisms such as ferroptosis, release of neutrophil extracellular traps (NETs), and nitrosative stress, which offer promising avenues for the management of CI-AKI, are identified. Secondly, a comprehensive strategy for the early prevention of CI-AKI is introduced. Investigating the risk factors associated with CI-AKI is essential for the timely identification of high-risk groups. Additionally, exploring early sensitive biomarkers is crucial for early diagnosis. A synergistic approach that combines these sensitive biomarkers, CI-AKI risk factors, and disease risk prediction models enhances both the accuracy and efficiency of early diagnostic processes. Finally, we explore recent pharmacological and non-pharmacological interventions for the management of Cl-AKI. Beyond the traditional focus on the antioxidant N-acetylcysteine (NAC), we look at active compounds from traditional Chinese medicine, including tetramethylpyrazine (TMP), salvianolic acid B (Sal B), as well as emerging preventive medications like N-acetylcysteine amide (NACA), alprostadil, and others, which all showed potential benefits in animal and clinical studies for CI-AKI prevention. Furthermore, innovative strategies such as calorie restriction (CR), enhanced external counterpulsation (EECP), and mesenchymal stem cell therapy are highlighted as providing fresh insights into Cl-AKI prevention and management.

The Preventive Effect of Alprostadil on the Contrast-Induced Nephropathy of Coronary Heart Disease Treated by Percutaneous Coronary Intervention in Moderate and High-Risk Population Stratified by Mehran Score

The Mehran risk score (MRS) was used to classify patients with coronary heart disease and evaluate the preventive effect of alprostadil on contrast-induced nephropathy (CIN) after percutaneous coronary intervention. The patients (n = 1146) were randomized into an alprostadil and control group and then divided into 3 groups on the basis of the MRS: low-risk, moderate-risk, and high-risk groups. The primary end point was the occurrence of CIN (alprostadil + hydration vs simple hydration treatment); secondary end points included serum creatinine, blood urea nitrogen, creatinine clearance rate, cystatin C, interleukin-6, C-reactive protein, proteinuria, and differences in the incidence of major adverse events. In the low-risk, moderate-risk, and high-risk groups, the incidence of CIN in the control and alprostadil group was 2.9 versus 2.6% (P = .832), 11.4 versus 4.9% (P = .030), 19.1 versus 7.7% (P = .041), respectively. Multivariate logistic regression analysis showed that alprostadil treatment was a favorable protective factor for moderate-risk and high-risk CIN patients (OR = 0.343, 95% CI: 0.124-0.951, P = .040). Alprostadil can be used as a preventive treatment for moderate- and high-risk CIN patients classified by the MRS. The reduction of CIN by alprostadil may be related to an anti-inflammatory effect.

Protective effects of mitochondrion-targeted peptide SS-31 against hind limb ischemia-reperfusion injury

Hind limb ischemia-reperfusion injury is an important pathology in vascular surgery. Reactive oxygen species are thought to be involved in the pathogenesis of hind limb ischemia-reperfusion injury. SS-31, which belongs to a family of mitochondrion-targeted peptide antioxidants, was shown to reduce mitochondrial reactive oxygen species production. In this study, we investigated whether the treatment of SS-31 could protect hind limb from ischemia-reperfusion injury in a mouse model. The results showed that SS-31 treatment either before or after ischemia exhibited similar protective effects. Histopathologically, SS-31 treatment prevented the IR-induced histological deterioration compared with the corresponding vehicle control. SS-31 treatment diminished oxidative stress revealed by the reduced malondialdehyde level and increased activities and protein levels of Sod and catalase. Cellular ATP contents and mitochondrial membrane potential increased and the level of cytosolic cytC was decreased after SS-31 treatment in this IR model, demonstrating that mitochondria were protected. The IR-induced increase of levels of inflammatory factors, such as Tnf-α and Il-1β, was prevented by SS-31 treatment. In agreement with the reduced cytosolic cytC, cleaved-caspase 3 was kept at a very low level after SS-31 treatment. Overall, the effect of SS-31 treatment before ischemia is mildly more effective than that after ischemia. In conclusion, our results demonstrate that SS-31 confers a protective effect in the mouse model of hind limb ischemia-reperfusion injury preventatively and therapeutically.

Efficacy of alprostadil for preventing of contrast-induced nephropathy: A meta-analysis

Contrast-induced nephropathy (CIN) has become the third-leading cause of hospital-acquired acute renal injury. Although alprostadil has been proposed as an effective preventative measure, this conclusion remains inconsistent. Thus, we performed a meta-analysis of the published studies on this topic to evaluate the preventative effect of alprostadil on CIN. Databases, including PubMed, the Web of Science, Cochrane Library, Wanfang, the China Biological Medicine Database (SinoMed) and the China National Knowledge Infrastructure (CNKI) were systematically searched. Nineteen clinical trials involving 2267 individuals were identified. We utilized a random or a fixed effect model to calculate the pooled odd ratios (ORs) and the standardized mean differences (SMD), respectively. Compared to the control group, the CIN risk decreased significantly in the alprostadil group (P < 0.00001, OR = 0.29, 95% CI = 0.21-0.39). In the subgroup of coronary angiography patients, the use of alprostadil also decreased the risk of CIN (P < 0.00001, OR = 0.27, 95% CI: 0.19-0.39). In conclusion, Alprostadil might be associated with a significant reduction in postcontrast Scr, BUN and CysC level and decrease the incidence of CIN.

Effects of alprostadil and iloprost on renal, lung, and skeletal muscle injury following hindlimb ischemia-reperfusion injury in rats

OBJECTIVES

To evaluate the effects of alprostadil (prostaglandin [PGE1] analog) and iloprost (prostacyclin [PGI2] analog) on renal, lung, and skeletal muscle tissues after ischemia reperfusion (I/R) injury in an experimental rat model.

MATERIALS AND METHODS

Wistar albino rats underwent 2 hours of ischemia via infrarenal aorta clamping with subsequent 2 hours of reperfusion. Alprostadil and iloprost were given starting simultaneously with the reperfusion period. Effects of agents on renal, lung, and skeletal muscle (gastrocnemius) tissue specimens were examined.

RESULTS

Renal medullary congestion, cytoplasmic swelling, and mean tubular dilatation scores were significantly lower in the alprostadil-treated group than those found in the I/R-only group (P<0.0001, P=0.015, and P<0.01, respectively). Polymorphonuclear leukocyte infiltration, pulmonary partial destruction, consolidation, alveolar edema, and hemorrhage scores were significantly lower in alprostadil- and iloprost-treated groups (P=0.017 and P=0.001; P<0.01 and P<0.0001). Polymorphonuclear leukocyte infiltration scores in skeletal muscle tissue were significantly lower in the iloprost-treated group than the scores found in the nontreated I/R group (P<0.0001).

CONCLUSION

Alprostadil and iloprost significantly reduce lung tissue I/R injury. Alprostadil has more prominent protective effects against renal I/R injury, while iloprost is superior in terms of protecting the skeletal muscle tissue against I/R injury.

Prevention of contrast-induced nephropathy with prostaglandin E1 in high-risk patients undergoing percutaneous coronary intervention

PURPOSE

Contrast-induced nephropathy (CIN) is an important complication in the use of iodinated contrast media. The present study aimed to assess the safety and efficacy of prostaglandin E1 (PGE1) in prevention of CIN in patients with high-risk factors undergoing percutaneous coronary intervention (PCI).

METHODS

The study group consisted of 163 patients who had undergone a coronary intervention procedure between January 1, 2012 and October 31, 2012. Study participants were randomly assigned to either the PGE1 group (82 patients) or the control group (81 patients). Patients in the PGE1 group received PGE1 intravenous infusion of 20 ng/kg/min for 6 h before and after the administration of contrast media. The control group received 0.9 % sodium chloride solution for routine hydration only. A nonionic, low-osmolality contrast agent was used in our laboratory at this time. Serum creatinine (Scr) values and estimated glomerular filtration rate were measured before and within 48 h of the administration of contrast agents. CIN was defined as an increase of ≥0.5 mg/dL or ≥ a 25 % increase in Scr concentrations over baseline within 48 h of angiography.

RESULTS

The amount of contrast agent administered was similar for the PGE1 and control groups (156 ± 63 vs. 161 ± 68 mL, P > 0.05). The incidence of CIN was lower in the PGE1 group than in the control group (3.7 vs. 11.1 %, P < 0.05). No serious adverse effects were observed.

CONCLUSIONS

In patients with high-risk factors undergoing PCI, the use of PGE1 for prevention of CIN is safe and efficacious.

Combined use of hydration and alprostadil for preventing contrast-induced nephropathy following percutaneous coronary intervention in elderly patients

Contrast-induced nephropathy (CIN) is a complex syndrome of acute kidney injury that follows exposure to intravascular contrast media. Although a series of preventive measures have been developed, CIN remains a major challenge encountered in elderly patients by interventional cardiologists. No data are currently available concerning the potential effects of the combined use of hydration and alprostadil in the prevention of CIN following percutaneous coronary intervention (PCI) in elderly patients. Therefore, the aim of the present study was to investigate the ability of a combination of hydration and alprostadil to prevent CIN following PCI in elderly patients. From June 1, 2010 to January 31, 2012, 85 elderly patients undergoing PCI were included in the present study. The included patients were randomly allocated into three groups: the control (22 cases), hydration (28 cases) and hydration + alprostadil (35 cases) group. Serum creatinine (SCr) levels were measured prior to PCI and then daily for 3 days following PCI. Creatinine clearance (Ccr) was also calculated. Following investigation of the incidence of CIN, a significant decline in Ccr was observed in the control group but not in the hydration + alprostadil group after PCI. The reduction in the level of Ccr from baseline in the hydration + alprostadil group was the smallest among the three groups. Moreover, the highest incidence of CIN was in the control group (6 cases, 27.27%), followed by the hydration group (3 cases, 10.71%) and the hydration + alprostadil group (1 case, 2.86%). Therefore, the combined use of hydration and alprostadil significantly reduces the incidence of CIN in elderly patients undergoing PCI. Hydration and alprostadil are suggested to act synergistically to protect renal function. In conclusion, the combined use of hydration and alprostadil is more effective in the prevention of CIN in elderly patients undergoing PCI compared with hydration alone.

Lipoxygenase-derived hydroxyeicosatetraenoic acids--novel perioperative markers of early post-transplant allograft function?

BACKGROUND

Active metabolites of arachidonic acid (AA), eicosanoids, strongly influence renal homeostasis. The aims of this study were to measure perioperative variations in lipoxygenase (LOX)-derived 5-, 12- and 15-hydroxyeicosatetraenoic (HETE) acids levels, and to examine whether (i) dynamics of these eicosanoid generation changes during the first 5 min of renal allograft reperfusion, (ii) examined HETE acids may influence perioperative 20-HETE generation, and (iii) LOX HETE may serve as perioperative markers of early post-transplant allograft function.

METHODS

Sixty-nine kidney recipients were divided into early, slow and delayed graft function (EGF, SGF and DGF, respectively) groups. Blood was taken directly before, and in the consecutive minutes of graft reperfusion. HETE concentrations were measured using liquid chromatography. Creatinine levels were measured during the perioperative period, as well as during follow-up visits (first post-transplant year).

RESULTS

Our results demonstrated significant differences in the concentrations and dynamics of HETE changes between the examined groups. Moreover, observed changes in HETE concentrations were strongly associated with post-transplant graft function and perioperative 20-HETE synthesis. Application of cut-off limits for newly introduced markers, that is 71.72 ng/mL for 5-HETE(5), 12.3 ng/mL for 12-HETE△(5-0) and -6.1 ng/mL for 15-HETE△(5-0), resulted in 72.5-81.5% sensitivity and 50-54% specificity for SGF/DGF prediction. Moreover, mixed model analysis revealed that recipients classified according to results of 5-HETE(5) and 15-HETE△(5-0) significantly differ in 1-year post-transplant allograft function (P  =  0.03 and P  < 0.05, respectively), however, not in the frequency of acute rejections' episodes (P = 0.91 and P = 0.31, respectively).

CONCLUSION

We hereby report that human kidney transplantations are accompanied by significant changes in LOX AA metabolism, which strongly influences and predicts early (1 year) post-transplant graft function.

Platelets arachidonic acid metabolism in patients with essential hypertension

Arachidonic acid's (AA) metabolites, eicosanoids, exert a tremendous influence on circulatory and vascular homeostasis, and in humans are generated by many organs and cell types. In this study we wanted to verify whether platelets AA metabolism play a significant role in pathogenesis of essential hypertension (EH). Participants were divided into the study (EH) and the control group. Plasma and urine concentrations of isoprostanes (8-iPF(2alpha)-III) and thromboxane B(2) (TxB(2)) were determined using the ELISA method. The levels of 5- and 12-hydroxyeicosatetraenoic (HETE) acids, generated by platelets, were analysed using RP-HPLC. In a suspension of not stimulated and AA-stimulated platelets TxB(2) level was statistically lower in the study than in the control group (p < 0.0001 and 0.001 respectively). The concentration of 12-HETE was significantly elevated in EH patients compared to the control group; however, only in the non-stimulated conditions (p < 0.05). Plasma and urine F2-isoprostanes levels were significantly higher in hypertensive individuals than in the control group (p < 0.00002 and p < 0.01 respectively). Moreover, EH patients excreted more TxB(2) in urine than normotensive individuals (p < 0.05). Our results highlight the mutual connections between the platelets AA metabolism and indicate its possible role in the pathogenesis of arterial hypertension. Moreover, we hypothesize that platelets AA metabolism may exert a pro-atherosclerotic effect. Finally, we suggest the use of (5-HETE+12-HETE)/TxB(2) parameter in further studies.

Dynamics of thromboxane level changes during early phase of allograft reperfusion

BACKGROUND

Thromboxane (Tx) is a metabolite of arachidonic acid, which exerts a significant influence on kidney homeostasis, and may be involved in the pathogenesis of allograft rejection. The aim of this study was to: examine the dynamics of TxB2 changes during early phase of kidney allograft reperfusion, and analyze whether the observed changes in the concentrations and direction of TxB2 changes, are associated with post-transplant graft function.

METHODS

Sixty-nine transplant recipients were divided into early, slow and delayed graft function group. Blood samples were collected directly before and during first the five minutes of allograft reperfusion. TxB2 concentrations were measured using ELISA. Creatinine and GFR levels were measured on the first, fifth, and 10th post-transplant day.

RESULTS

The results demonstrated that during reperfusion significant differences in TxB2 concentrations occur in all groups. Moreover, significant differences in the concentrations, as well as in the dynamics of TxB2 changes between patients with immediate graft function, and individuals with allograft activation problems, were noticed. These differences were associated with post-transplant graft function.

CONCLUSIONS

Human renal transplantations are accompanied by changes in TxB2 concentrations, and the dynamics of TxB2 changes is associated with early post-transplant graft function. Our results also highlight TxB2 as a potential pre-transplant marker of post-transplant allograft function.

Is it possible to predict the early post-transplant allograft function using 20-HETE measurements? A preliminary report

20-HydroxyEicosaTetraEnoic (20-HETE) acid is an arachidonic acid metabolite that is generated via cytochrome P450 enzymes, and according to the findings from recent studies, may be involved in the pathogenesis of ischemia-reperfusion injury. The aim of this study was to: examine the dynamics of 20-HETE changes during the first 5 min of allograft reperfusion, and analyze whether the observed changes are associated with post-transplant graft function. Sixty-nine renal transplant recipients were divided, according to their outcome, into early, slow and delayed graft function (EGF, SGF, DGF) group. Blood samples were collected directly before and during the first 5 min of allograft reperfusion. 20-HETE concentrations were measured using ELISA. The results demonstrated significant differences in the concentrations and in the dynamics of 20-HETE changes between patients with immediate graft function, and individuals with allograft activation problems. The sensitivity, specificity, positive and negative predictive value of 20-HETEDelta(5-0) parameter in discriminating EGF and SGF from DGF were 69%, 54%, 74% and 48% respectively. Therefore, our results demonstrated that the dynamics of 20-HETE changes, which occurs during early phase of allograft reperfusion, is associated with early post-transplant graft function and also highlighted 20-HETE as a novel clinical marker of post-transplant allograft function.