Renal effects of prostaglandins and cyclooxygenase-2 inhibitors

The physiological basis of renal nuclear medicine

Renal physiology underpins renal nuclear medicine, both academic and clinical. Clearance, an important concept in renal physiology, comprises tissue uptake rate of tracer (tissue clearance), disappearance rate from plasma (plasma clearance), appearance rate in urine (urinary clearance) and disappearance rate from tissue. In clinical research, steady-state plasma clearances of para-amino-hippurate and inulin have been widely used to measure renal blood flow (RBF) and glomerular filtration rate (GFR), respectively. Routinely, GFR is measured at non-steady state as plasma clearance of a filtration agent, such as technetium-99m diethylenetriaminepentaacetic acid. Scaled to three-dimensional whole body metrics rather than body surface area, GFR in women is higher than in men but declines faster with age. Age-related decline is predominantly from nephron loss. Tubular function determines parenchymal transit time, which is important in renography, and the route of uptake of technetium-99m dimercaptosuccinic acid, which is via filtration. Resistance to flow is defined according to the pressure-flow relationship but in renography, only transit time can be measured, which, being equal to urine flow divided by collecting system volume, introduces further uncertainty because the volume is also unmeasurable. Tubuloglomerular feedback governs RBF and GFR, is regulated by the macula densa, mediated by adenosine and renin, and can be manipulated with proximal tubular sodium-glucose cotransporter-2 inhibitors. Other determinants of renal haemodynamics include prostaglandins, nitric oxide and dopamine, while protein meal and amino acid infusion are used to measure renal functional reserve. In conclusion, for measuring renal responses to exogenous agents, steady-state para-amino-hippurate and inulin clearances should be replaced with rubidium-82 and gallium-68 EDTA for measuring RBF and GFR.

Navigating nephrotoxic waters: A comprehensive overview of contrast-induced acute kidney injury prevention

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of acute kidney injury deriving from the intravascular administration of contrast media in diagnostic and therapeutic procedures and leading to longer in-hospital stay and increased short and long-term mortality. Its pathophysiology, although not well-established, revolves around medullary hypoxia paired with the direct toxicity of the substance to the kidney. Critically ill patients, as well as those with pre-existing renal disease and cardiovascular comorbidities, are more susceptible to CI-AKI. Despite the continuous research in the field of CI-AKI prevention, clinical practice is based mostly on periprocedural hydration. In this review, all the investigated methods of prevention are presented, with an emphasis on the latest evidence regarding the potential of RenalGuard and contrast removal systems for CI-AKI prevention in high-risk individuals.

Successful Treatment of Lithium-Induced Nephrogenic Diabetes Insipidus with Celecoxib: A Promising Therapeutic Option

BACKGROUND Nephrogenic diabetic insipidus (NDI) poses a challenge in clinical management, particularly when associated with lithium ingestion. Non-selective non-steroidal anti-inflammatory drugs (NSAIDs) have been widely used for the treatment of numerous diseases worldwide, including NDI. However, many studies have reported the diverse adverse effects of long-term use of non-selective NSAIDs. Celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, is a better drug to relieve pain and inflammation in terms of long-term safety and efficacy than non-selective NSAIDs. Nevertheless, there are few reports describing the effectiveness of celecoxib in treating NDI. CASE REPORT We report a case of a 46-year-old woman with schizophrenia who presented with severe hypernatremia and refractory polyuria due to lithium-induced NDI. Cessation of lithium ingestion and traditional treatments, including trichlormethiazide and desmopressin, yielded minimal improvement in her hypernatremia and polyuria. Her sodium level needed to be strictly controlled with the infusion of dextrose 5% in water. Given the safety of celecoxib, we decided to initiate celecoxib as the treatment of lithium-induced NDI instead of indomethacin. Notably, the introduction of celecoxib led to a substantial and sustained amelioration of polyuria and hypernatremia without any celecoxib-associated adverse effects. Even after transfer to another hospital, stability in serum sodium levels persisted with celecoxib. CONCLUSIONS We presented a case of lithium-induced NDI successfully treated with celecoxib, a selective COX-2 inhibitor. To the best of our knowledge, this is the first reported case of successful treatment of lithium-induced NDI with celecoxib, and suggests celecoxib is a viable therapeutic option warranting further exploration. Physicians should consider its use when faced with the challenging management of lithium-induced NDI.

Cyclooxygenase-2 inhibition prevents renal toxicity but not hypertension during sunitinib treatment

BACKGROUND

Anticancer angiogenesis inhibitors cause hypertension and renal injury. Previously we observed in rats that high-dose aspirin (capable of blocking cyclooxygenase (COX)-1 and-2) was superior to low-dose aspirin (blocking COX-1 only) to prevent these side-effects during treatment with the angiogenesis inhibitor sunitinib, suggesting a role for COX-2. High-dose aspirin additionally prevented the rise in COX-derived prostacyclin (PGI2). Therefore, we studied the preventive effects of selective COX-2 inhibition and the hypothesized contributing role of PGI2 during angiogenesis inhibition.

METHODS

Male WKY rats received vehicle, sunitinib ((SU), 14 mg/kg/day) alone or combined with COX-2 inhibition (celecoxib, 10 mg/kg/day) or a PGI2 analogue (iloprost, 100 μg/kg/day) for 8 days (n = 8-9 per group). Mean arterial pressure (MAP) was measured via radiotelemetry, biochemical measurements were performed via ELISA and vascular function was assessed via wire myography.

RESULTS

SU increased MAP (17±1mmHg versus 3±1mmHg after vehicle on day 4, P < 0.002), which could not be significantly blunted by celecoxib (+12±3mmHg on day 4, P = 0.247), but was temporarily attenuated by iloprost (treatment days 1 + 2 only). Urinary PGI2 (996 ± 112 versus 51 ± 11ng/24h after vehicle, P < 0.001), but not circulating PGI2 increased during SU, which remained unaffected by celecoxib and iloprost. Celecoxib reduced sunitinib-induced albuminuria (0.36 ± 0.05 versus 0.58 ± 0.05mg/24h after SU, P = 0.005). Wire myography demonstrated increased vasoconstriction to endothelin-1 after SU (Emax P = 0.005 versus vehicle), which remained unaffected by celecoxib or iloprost.

CONCLUSION

Selective COX-2 inhibition ameliorates albuminuria during angiogenesis inhibition with sunitinib, which most likely acts independently of PGI2. To combat angiogenesis inhibitor-induced hypertension, dual rather than selective COX-1/2 blockade seems preferential.

Neuroendocrine response to diclofenac in healthy subjects: a pilot study

PURPOSE

The precise effects of non-steroidal anti-inflammatory drugs on the neuroendocrine hydro-electrolytic regulation are not precisely understood. The aim of this pilot study was to evaluate, in healthy subjects, the neuroendocrine response of the antidiuretic system to intravenous diclofenac infusion.

METHODS

For this single-blinded, cross-over study, we recruited 12 healthy subjects (50% women). Test sessions were divided into three observation times (pre-test; test; 48 h post-test), which were repeated equally on two different occasions, with the administration of diclofenac (75 mg in saline solution 0.9% 100 cc) on 1 day, or placebo (saline solution 0.9% 100 cc) on another day. The night before the test the subjects were asked to collect a salivary cortisol and cortisone sample, which was repeated on the night of the procedure session. Serial urine and blood samples were collected on the test day (for osmolality, electrolytes, ACTH, cortisol, copeptin, MR-proADM, MR-proANP; the last three represent more stable and analytically reliable molecules than their respective active peptides). Moreover, the subjects were evaluated with the bioimpedance vector analysis (BIVA) before and after the test. Forty-eight hours after the end of the procedure urine sodium, urine potassium, urine osmolality, serum sodium and copeptin were revaluated together with BIVA.

RESULTS

No significant changes in circulating hormone levels were observed; anyway, 48 h after diclofenac, BIVA showed a significant water retention (p < 0.00001), especially in extracellular fluid (ECF) (16.47 ± 1.65 vs 15.67 ± 1.84, p < 0.001). Salivary cortisol and cortisone tended to increase only the night after placebo administration (p = 0.054 cortisol; p = 0.021 cortisone).

CONCLUSION

Diclofenac resulted in an increased ECF at 48 h, but this phenomenon seems to be associated with a greater renal sensibility to the action of vasopressin rather than with an increase in its secretion. Moreover, a partial inhibitory effect on cortisol secretion can be hypothesized.

The role of Mas receptor on renal hemodynamic responses to angiotensin II administration in chronic renal sympathectomized male and female rats

Background and purpose

Renal hemodynamics is influenced by renal sympathetic nerves and the renin-angiotensin system. On the other hand, renal sympathetic denervation impacts kidney weight by affecting renal hemodynamics. The current study evaluated the role of the Mas receptor on renal hemodynamic responses under basal conditions and in response to angiotensin II (Ang II) in chronic renal sympathectomy in female and male rats.

Experimental approach

Forty-eight nephrectomized female and male rats were anesthetized and cannulated. Afterward, the effect of chronic renal sympathectomy was investigated on hemodynamic parameters such as renal vascular resistance (RVR), mean arterial pressure (MAP), and renal blood flow (RBF). In addition, the effect of chronic sympathectomy on kidney weight was examined.

Findings/Results

Chronic renal sympathectomy increased RVR and subsequently decreased RBF in both sexes. Renal perfusion pressure also increased after sympathectomy in male and female rats, while MAP did not change, significantly. In response to the Ang II injection, renal sympathectomy caused a greater decrease in RBF in all experimental groups, while it did not affect the MAP response. In addition, chronic sympathectomy increased left kidney weight in right nephrectomized rats.

Conclusion and implications

Chronic renal sympathectomy changed systemic/renal hemodynamics in baseline conditions and only renal hemodynamics in response to Ang II administration. Moreover, chronic sympathectomy increased compensatory hypertrophy in nephrectomized rats. These changes are unaffected by gender difference and Mas receptor blocker.

Defining the molecular correlate of arteriolar hyalinosis in kidney disease progression by integration of single cell transcriptomic analysis and pathology scoring

Arteriolar hyalinosis in kidneys is an independent predictor of cardiovascular disease, the main cause of mortality in chronic kidney disease (CKD). The underlying molecular mechanisms of protein accumulation in the subendothelial space are not well understood. Using single cell transcriptomic data and whole slide images from kidney biopsies of patients with CKD and acute kidney injury in the Kidney Precision Medicine Project, the molecular signals associated with arteriolar hyalinosis were evaluated. Co-expression network analysis of the endothelial genes yielded three gene set modules as significantly associated with arteriolar hyalinosis. Pathway analysis of these modules showed enrichment of transforming growth factor beta / bone morphogenetic protein (TGFβ / BMP) and vascular endothelial growth factor (VEGF) signaling pathways in the endothelial cell signatures. Ligand-receptor analysis identified multiple integrins and cell adhesion receptors as over-expressed in arteriolar hyalinosis, suggesting a potential role of integrin-mediated TGFβ signaling. Further analysis of arteriolar hyalinosis associated endothelial module genes identified focal segmental glomerular sclerosis as an enriched term. On validation in gene expression profiles from the Nephrotic Syndrome Study Network cohort, one of the three modules was significantly associated with the composite endpoint (> 40% reduction in estimated glomerular filtration rate (eGFR) or kidney failure) independent of age, sex, race, and baseline eGFR, suggesting poor prognosis with elevated expression of genes in this module. Thus, integration of structural and single cell molecular features yielded biologically relevant gene sets, signaling pathways and ligand-receptor interactions, underlying arteriolar hyalinosis and putative targets for therapeutic intervention.

The Role of Gender Differences and Menopause in Obesity-Related Renal Disease, Renal Inflammation and Lipotoxicity

The pathogenesis of obesity-related-renal disease is unknown. Menopause can promote renal disease in obese women, but this interaction is unclear. In a previous study, we observed that obese male and female mice developed albuminuria, hyperfiltration, and glomerulomegaly, and these changes were more severe in those obese ovariectomized females. In this study, we also evaluated renal inflammation and lipotoxicity in that animal model. For six months, 43 males and 36 females C57BL6/J mice were randomized to standard diet (SD) or high fat diet (HFD). A group of female animals on SD or HFD was ovariectomized to simulate menopause. We evaluated cytokines: NF-κβ p65, IL-1β, MCP-1, TNF-α, total lipid content, lipid classes, and fatty acid profile in total lipid and individual lipid classes in renal tissue and urine. We found that obese males and females showed higher NF-kβ p-65, TNF-α and MCP-1 in renal tissue, and obese females ovariectomized had higher IL-1β and TNF-α compared with not-ovariectomized. Also, obese animals showed lower proinflammatory and higher anti-inflammatory fatty acids in kidney total lipids, while obese females ovariectomized had a more exacerbated pattern. In brief, obesity induces inflammation and an unbalanced lipidic profile in renal tissue. This pattern seems to be enhanced in obesity after menopause.

What is the most effective and safest Non-steroidal anti-inflammatory drug for treating osteoarthritis in patients with comorbidities?

INTRODUCTION

Understanding what the most effective and safe non-steroidal anti-inflammatory drug (NSAID) is for managing osteoarthritis (OA) is complicated. OA is prevalent worldwide and people living with OA commonly have multiple comorbidities. The efficacy and safety of NSAIDs in a patient are influenced by their intrinsic and extrinsic factors. Current guidelines recommend the lowest dose for the shortest duration, monitoring patients for risk factors and comorbidities but generally do not specify, which NSAID is most suitable for a patient with specific comorbidities.

AREAS COVERED

This paper looks at the mechanism of action of all NSAIDs and reviews the current literature concerning their safety in patients with and without comorbidities. Relevant publications were identified by searching PubMed and Cochrane Library using key terms. The search was conducted from inception to 18 July 2023 and included results published before 18 July 2023. The search results and their references were then manually reviewed.

EXPERT OPINION

In the paper, we determine whether the current practice of 'lowest dose for shortest duration' is in fact the best approach for prescribing NSAIDs and identify which NSAIDs are most suitable given a patient's risk factors and comorbidities. Our aim is to help guide health professionals in recommending the most suitable NSAID for each patient.

Genetic and epigenetic background of diabetic kidney disease

Diabetic kidney disease (DKD) is a severe diabetic complication that affects up to half of the individuals with diabetes. Elevated blood glucose levels are a key underlying cause of DKD, but DKD is a complex multifactorial disease, which takes years to develop. Family studies have shown that inherited factors also contribute to the risk of the disease. During the last decade, genome-wide association studies (GWASs) have emerged as a powerful tool to identify genetic risk factors for DKD. In recent years, the GWASs have acquired larger number of participants, leading to increased statistical power to detect more genetic risk factors. In addition, whole-exome and whole-genome sequencing studies are emerging, aiming to identify rare genetic risk factors for DKD, as well as epigenome-wide association studies, investigating DNA methylation in relation to DKD. This article aims to review the identified genetic and epigenetic risk factors for DKD.

Recommendations for the Use of Nonsteroidal Anti-inflammatory Drugs and Cardiovascular Disease Risk: Decades Later, Any New Lessons Learned?

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most prescribed pharmacologic therapies worldwide due to their therapeutic analgesic efficacy and relative tolerability. In the past several decades, various cardiovascular (CV) adverse events have emerged regarding both traditional NSAIDs (tNSAIDs) and cyclo-oxygenase 2 (COX-2) selective (coxibs). This review will provide an updated report on the CV risk profile of NSAIDs, focusing on several of the larger clinical trials, meta-analyses, and registry studies. We aim to provide rheumatologists with a framework for NSAID use in the context of rheumatologic chronic pain management. Recent findings: In patients with and without CV diseases, the use of NSAIDs, both tNSAIDs and coxibs, is associated with an increased risk of adverse CV events, myocardial infarction, heart failure, and cerebrovascular events. These CV risks have increased within weeks of coxib use and higher doses of tNSAIDs. The risk of adverse CV events is heterogenous across NSAIDs; naproxen and low-dose ibuprofen appear to have lower increased CV risk among NSAIDs. A variation in CV risk is associated with multiple factors, including NSAID class, COX-2 selectivity, treatment dose and duration, and baseline patient risk. Summary: Many important questions remain regarding the safety of NSAIDs and whether the culmination of research performed could inform us whether specific patient subtypes or NSAID class may have a more favorable profile. tNSAIDs such as naproxen and low-dose ibuprofen may have a lower CV risk profile, while coxibs have a more favorable GI risk profile. In general, any NSAID can be optimized if used at the lowest effective dose for the shortest amount of time, especially among individuals with increased CV risk.

A Synopsis of Current Theories on Drug-Induced Nephrotoxicity

The overriding goal of the treatment of patients is its effectiveness and safety. However, all medications currently being used also exert some adverse pharmaceutical reactions, which may be regarded as an unintended but inevitable cost of pharmacotherapy. The kidney, as the main organ that eliminates xenobiotics, is an organ especially predisposed and vulnerable to the toxic effects of drugs and their metabolites during their excretion from the body. Moreover, some drugs (e.g., aminoglycosides, cyclosporin A, cisplatin, amphotericin B, and others) have a "preferential" nephrotoxicity potential, and their use is associated with an increased risk of kidney damage. Drug nephrotoxicity is, therefore, both a significant problem and a complication of pharmacotherapy. It should be noted that, currently, there is no generally recognized definition of drug-induced nephrotoxicity and no clear criteria for its diagnosis. This review briefly describes the epidemiology and diagnosis of drug-induced nephrotoxicity and characterizes its pathomechanisms, including immunological and inflammatory disturbances, altered kidney blood flow, tubulointerstitial injury, increased lithogenesis-crystal nephropathy, rhabdomyolysis, and thrombotic microangiopathy. The study also lists the basic drugs with nephrotoxicity potential and provides a short overview of the preventive methods for reducing the risk of drug-related kidney damage developing.

Single-cell profiling of healthy human kidney reveals features of sex-based transcriptional programs and tissue-specific immunity

Knowledge of the transcriptional programs underpinning the functions of human kidney cell populations at homeostasis is limited. We present a single-cell perspective of healthy human kidney from 19 living donors, with equal contribution from males and females, profiling the transcriptome of 27677 cells to map human kidney at high resolution. Sex-based differences in gene expression within proximal tubular cells were observed, specifically, increased anti-oxidant metallothionein genes in females and aerobic metabolism-related genes in males. Functional differences in metabolism were confirmed in proximal tubular cells, with male cells exhibiting higher oxidative phosphorylation and higher levels of energy precursor metabolites. We identified kidney-specific lymphocyte populations with unique transcriptional profiles indicative of kidney-adapted functions. Significant heterogeneity in myeloid cells was observed, with a MRC1+LYVE1+FOLR2+C1QC+ population representing a predominant population in healthy kidney. This study provides a detailed cellular map of healthy human kidney, and explores the complexity of parenchymal and kidney-resident immune cells.

Lessons from 20 years with COX-2 inhibitors: Importance of dose-response considerations and fair play in comparative trials

Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit the enzyme cyclooxygenase (COX), which forms prostaglandins involved in pain and inflammation. COX inhibitors have analgesic and anti-inflammatory effects, but also increase risks for gastrointestinal ulcers, bleeding, and renal and cardiovascular adverse events. Identification of two isoforms of COX, COX-1 and COX-2, led to the development of selective COX-2 inhibitors, which were launched as having fewer gastrointestinal side effects since gastroprotective prostaglandins produced via COX-1 are spared. The balance between COX-1 mediated prothrombotic thromboxane and COX-2 mediated antithrombotic prostacyclin is important for thrombotic risk. An increased risk of suffering myocardial infarction and death with COX-2 inhibitor treatment is well established from clinical trials and observational research. Rofecoxib (Vioxx) was withdrawn from the market for this reason, but the equally COX-2 selective etoricoxib has replaced it in Europe but not in the United States. The "traditional" NSAID diclofenac is as COX-2 selective as celecoxib and increases cardiovascular risk dose dependently. COX inhibitor dosages should be lower in osteoarthritis than in rheumatoid arthritis. Randomized trials comparing COX-2 inhibitors with NSAIDs have exaggerated their gastrointestinal benefits by using maximal NSAID doses regardless of indication, and/or hidden the cardiovascular risk by comparing with COX-2 selective diclofenac instead of low-dose ibuprofen or naproxen. Observational studies show increased cardiovascular risks within weeks of treatment with COX-2 inhibitors and high doses of NSAIDs other than naproxen, which is the safest alternative. COX inhibitors are symptomatic drugs that should be used intermittently at the lowest effective dosage, especially among individuals with an increased cardiovascular risk.

Modified lipid metabolism and cytosolic phospholipase A2 activation in mesangial cells under pro-inflammatory conditions

Diabetic kidney disease is a consequence of hyperglycemia and other complex events driven by early glomerular hemodynamic changes and a progressive expansion of the mesangium. The molecular mechanisms behind the pathophysiological alterations of the mesangium are yet to be elucidated. This study aimed at investigating whether lipid signaling might be the missing link. Stimulation of human mesangial cells with high glucose primed the inflammasome-driven interleukin 1 beta (IL-1β) secretion, which in turn stimulated platelet-derived growth factor (PDGF-BB) release. Finally, PDGF-BB increased IL-1β secretion synergistically. Both IL-1β and PDGF-BB stimulation triggered the formation of phosphorylated sphingoid bases, as shown by lipidomics, and activated cytosolic phospholipase cPLA2, sphingosine kinase 1, cyclooxygenase 2, and autotaxin. This led to the release of arachidonic acid and lysophosphatidylcholine, activating the secretion of vasodilatory prostaglandins and proliferative lysophosphatidic acids. Blocking cPLA2 release of arachidonic acid reduced mesangial cells proliferation and prostaglandin secretion. Validation was performed in silico using the Nephroseq database and a glomerular transcriptomic database. In conclusion, hyperglycemia primes glomerular inflammatory and proliferative stimuli triggering lipid metabolism modifications in human mesangial cells. The upregulation of cPLA2 was critical in this setting. Its inhibition reduced mesangial secretion of prostaglandins and proliferation, making it a potential therapeutical target.

Aspirin Inhibition of Group VI Phospholipase A2 Induces Synthetic Lethality in AAM Pathway Down-Regulated Gingivobuccal Squamous Carcinoma

Background: To elucidate the role of iPLA2/PLA2G6 in gingivobuccal squamous cell carcinoma (GB-SCC) and to ascertain the synthetic lethality-based chemoprevention role of aspirin in arachidonic acid metabolism (AAM) pathway down-regulated GB-SCC. Methods: The in vitro efficacy of aspirin on GB-SCC cells (ITOC-03 and ITOC-04) was assessed by cell proliferation, colony formation, apoptosis, cell migration, cell cycle assay and RNA-seq, while inhibition of PLA2G6 and AAM pathway components was affirmed by qPCR, Western blot and immunofluorescence staining. The in vivo effect of aspirin was evaluated using NOD-SCID mice xenografts and immunohistochemical analysis. Results: We found that aspirin, which has been reported to act through the COX pathway, is inhibiting PLA2G6, and thereby the COX and LOX components of the AAM pathway. The findings were validated using PLA2G6 siRNA and immunohistochemical marker panel. Moreover, a pronounced effect in ITOC-04 cells and xenografts implied aspirin-induced synthetic lethality in the AAM pathway down-regulated GB-SCC. Conclusions: This study reveals that aspirin induces the anti-tumor effect by a previously unrecognized mechanism of PLA2G6 inhibition. In addition, the effect of aspirin is influenced by the baseline AAM pathway status and could guide precision prevention clinical trials of AAM pathway inhibitors.

Hazardous Effect of Low-Dose Aspirin in Patients with Predialysis Advanced Chronic Kidney Disease Assessed by Machine Learning Method Feature Selection

Background: Low-dose aspirin (100 mg) is widely used in preventing cardiovascular disease in chronic kidney disease (CKD) because its benefits outweighs the harm, however, its effect on clinical outcomes in patients with predialysis advanced CKD is still unclear. This study aimed to assess the effect of aspirin use on clinical outcomes in such group. Methods: Patients were selected from a nationwide diabetes database from January 2009 to June 2017, and divided into two groups, a case group with aspirin use (n = 3021) and a control group without aspirin use (n = 9063), by propensity score matching with a 1:3 ratio. The Cox regression model was used to estimate the hazard ratio (HR). Moreover, machine learning method feature selection was used to assess the importance of parameters in the clinical outcomes. Results: In a mean follow-up of 1.54 years, aspirin use was associated with higher risk for entering dialysis (HR, 1.15 [95%CI, 1.10-1.21]) and death before entering dialysis (1.46 [1.25-1.71]), which were also supported by feature selection. The renal effect of aspirin use was consistent across patient subgroups. Nonusers and aspirin users did not show a significant difference, except for gastrointestinal bleeding (1.05 [0.96-1.15]), intracranial hemorrhage events (1.23 [0.98-1.55]), or ischemic stroke (1.15 [0.98-1.55]). Conclusions: Patients with predialysis advanced CKD and anemia who received aspirin exhibited higher risk of entering dialysis and death before entering dialysis by 15% and 46%, respectively.

Pharmacokinetic Behavior and Pharmacokinetic/Pharmacodynamic Integration of Danofloxacin Following Single or Co-Administration with Meloxicam in Healthy Lambs and Lambs with Respiratory Infections

The aim of this study was to determine the pharmacokinetics and pharmacodynamics of danofloxacin (DAN; 6 mg/kg) following subcutaneous administration alone or co-administration with meloxicam (MLX; 1 mg/kg) in healthy lambs and lambs with respiratory infections. The study was carried out using a total of four groups: HD (healthy; n = 6) and ID (infected; n = 7) groups who were administered DAN only, and HDM (healthy; n = 6) and IDM (infected; n = 7) groups who were administered DAN and MLX simultaneously. The plasma concentrations of DAN were determined using high-performance liquid chromatography–UV and analyzed by the non-compartmental method. DAN exhibited a similar elimination half-life in all groups, including both the healthy and infected lambs. The total clearance in the HDM, ID and IDM groups and volume of distribution in the HDM and IDM groups were significantly reduced. MLX in the IDM group significantly increased the area under the curve (AUC) and peak concentration (C_max) of DAN compared to the HD group. The Mannheimia haemolytica, Escherichia coli, and Streptococcus spp. strains were isolated from bronchoalveolar lavage fluid samples of the infected lambs. When co-administration with meloxicam, DAN at a 6 mg/kg dose can provide optimum values of ƒAUC_0–24/MIC (>56 h) and ƒC_max/MIC (>8) for susceptible M. haemolytica isolates with an MIC₉₀ value of 0.25 µg/mL and susceptible E. coli isolates with an MIC value of ≤0.125 µg/mL.

Hepatorenal syndrome: pathophysiology and evidence-based management update

Hepatorenal syndrome (HRS) is a functional renal failure that develops in patients with advanced hepatic cirrhosis with ascites and in those with fulminant hepatic failure. The prevalence of HRS varies among studies but in general it is the third most common cause of acute kidney injury (AKI) in cirrhotic patients after pre-renal azotemia and acute tubular necrosis. HRS carries a grim prognosis with a mortality rate approaching 90% three months after disease diagnosis. Fortunately, different strategies have been proven to be successful in preventing HRS. Although treatment options are available, they are not universally effective in restoring renal function but they might prolong survival long enough for liver transplantation, which is the ultimate treatment. Much has been learned in the last two decades regarding the pathophysiology and management of this disease which lead to notable evolution in the HRS definition and better understanding on how best to manage HRS patients. In the current review, we will summarize the recent advancement in epidemiology, pathophysiology, and management of HRS.

Drug-drug-gene interactions as mediators of adverse drug reactions to diclofenac and statins: a case report and literature review

Concomitant treatment with drugs that inhibit drug metabolising enzymes and/or transporters, such as commonly prescribed statins and nonsteroidal anti-inflammatory drugs (NSAIDs), has been associated with prolonged drug exposure and increased risk of adverse drug reactions (ADRs) due to drug-drug interactions. The risk is further increased in patients with chronic diseases/comorbidities who are more susceptible because of their genetic setup or external factors. In that light, we present a case of a 46-year-old woman who had been experiencing acute renal and hepatic injury and myalgia over two years of concomitant treatment with diclofenac, atorvastatin, simvastatin/fenofibrate, and several other drugs, including pantoprazole and furosemide. Our pharmacogenomic findings supported the suspicion that ADRs, most notably the multi-organ toxicity experienced by our patient, may be owed to drug-drug-gene interactions and increased bioavailability of the prescribed drugs due to slower detoxification capacity and decreased hepatic and renal elimination. We also discuss the importance of CYP polymorphisms in the biotransformation of endogenous substrates such as arachidonic acid and their modulating role in pathophysiological processes. Yet even though the risks of ADRs related to the above mentioned drugs are substantially evidenced in literature, pre-emptive pharmacogenetic analysis has not yet found its way into common clinical practice.

Anti-inflammatory drugs and the renin-angiotensin-aldosterone system: Current knowledge and potential effects on early SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiologic agent of coronavirus disease 19 (COVID-19), and is genetically related to the 2003 SARS and Middle East respiratory syndrome (MERS-CoV) coronaviruses. Recent studies have reported that similar to SARS-CoV, this strain expresses a spike protein (S) with a receptor binding domain (RBD) that binds to angiotensin-converting enzyme 2 (ACE2) - an enzyme expressed mostly in the endothelium, kidneys, heart, gastrointestinal tract and lungs - to facilitate viral entry and intracellular replication. Incidentally, the renin-angiotensin-aldosterone system (RAAS) is integral to physiologic control of both ACE and ACE2 expression, and is an essential system utilized by SARS-CoV-2, albeit with varying schools of thought on how it can affect viral entry. In this paper, we will review current knowledge on the RAAS and how it can be affected by non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroid use at the organ and cellular levels. We will then discuss the relevance of these interactions on organ-specific ACE2 expression, and provide scientific insights on how this mechanism can potentially affect SARS-CoV-2 infection in the early phases of disease. From the standpoint of other known viruses, we will then aim to discuss the potential uses or restrictions of these drugs in viral infection, and provide an update on relevant studies about COVID-19.

The vaso-occlusive pain crisis in sickle cell disease: Definition, pathophysiology, and management

Early diagnosis, treatment, and prevention of a vaso-occlusive crisis (VOC) are critical to the management of patients with sickle cell disease. It is essential to differentiate between VOC-associated pain and chronic pain, hyperalgesia, neuropathy, and neuropathic pain. The pathophysiology of VOCs includes polymerization of abnormal sickle hemoglobin, inflammation, and adhesion. Hydroxyurea, L-glutamine, crizanlizumab, and voxelotor have been approved by the US Food and Drug Administration for reducing the frequency of VOCs; the European Medicines Agency has approved only hydroxyurea. Other novel treatments are in late-stage clinical development in both the United States and the European Union. The development of agents for prevention and treatment of VOCs should be driven by our understanding of its pathophysiology.

PTUPB ameliorates high-fat diet-induced non-alcoholic fatty liver disease via inhibiting NLRP3 inflammasome activation in mice

Non-alcoholic fatty liver disease (NAFLD) affects 25% of the global adult population, and no effective pharmacological treatment has been found. Products of arachidonic acid metabolism have been developed into a novel therapy for metabolic syndrome and diabetes. It has been demonstrated that protective actions of a novel dual cyclooxygenase-2 (COX-2) and soluble epoxide hydrolase (sEH) inhibitor, PTUPB, on the metabolic abnormalities. Here, we investigated the effects of PTUPB on hepatic steatosis in high-fat diet (HFD)-induced obese mice, as well as in hepatocytes in vitro. We found that PTUPB treatment reduced body weight, liver weight, liver triglyceride and cholesterol content, and the expression of lipolytic/lipogenic and lipid uptake related genes (Acc, Cd36, and Cidec) in HFD mice. In addition, PTUPB treatment arrested fibrotic progression with a decrease of collagen deposition and expression of Col1a1, Col1a3, and α-SMA. In vitro, PTUPB decreased palmitic acid-induced lipid deposition and downregulation of lipolytic/lipogenic genes (Acc and Cd36) in hepatocytes. Additionally, we found that PTUPB reduced the production of pro-inflammatory cytokines and suppressed the NLRP3 inflammasome activation in HFD mice and hepatocytes. In conclusion, dual inhibition of COX-2/sEH attenuates hepatic steatosis by inhibiting the NLRP3 inflammasome activation. PTUPB might be a promising potential therapy for liver steatosis associated with obesity.

Nrf2 activation protects against lithium-induced nephrogenic diabetes insipidus

Lithium (Li) is the mainstay pharmacotherapeutic mood stabilizer in bipolar disorder. Its efficacious use is complicated by acute and chronic renal side effects, including nephrogenic diabetes insipidus (NDI) and progression to chronic kidney disease (CKD). The nuclear factor erythroid-derived 2-related factor 2 (Nrf2) pathway senses and coordinates cellular responses to oxidative and electrophilic stress. Here, we identify that graded genetic activation of Nrf2 protects against Li-induced NDI (Li-NDI) and volume wasting via an aquaporin 2-independent mechanism. Renal Nrf2 activity is differentially expressed on functional segments of the nephron, and its activation along the distal tubule and collecting duct directly modulates ion transporter expression, mimicking paradoxical effects of diuretics in mitigating Li-NDI. In addition, Nrf2 reduces cyclooxygenase expression and vasoactive prostaglandin biosynthesis. Pharmacologic activation of Nrf2 confers protective effects, confirming this pathway as a potentially novel druggable target for the prevention of acute and chronic renal sequelae of Li therapy.

Quercetin, a Promising Clinical Candidate for The Prevention of Contrast-Induced Nephropathy

Iodinated contrast media (CM) are the leading cause of acute renal failure of toxic origin. Between 21% and 50% of patients that receive them develop contrast-induced nephropathy (CIN). All prophylactic measures used so far have failed to provide effective prevention. Since oxidative stress is involved in the damage, a possible preventive strategy could be the administration of antioxidant substances, such as quercetin. This compound has shown renoprotective effects in experimental studies. The aim of this study was to evaluate whether quercetin may be helpful in preventing CIN in patients undergoing coronary catheterization. A clinical phase II study was conducted. Patients were distributed in two groups, namely, CM (patients who only received contrast media) and CM+Q (patients who were pretreated with quercetin orally for 3-5 days). Results showed less incidence of CIN in the CM+Q group, possibly due to glomerular protection, evidenced by a lower increase in serum creatinine and albuminuria; and a lower decrease in the glomerular filtration rate (GFR). Furthermore, in this group, the relative risk of developing CIN observed in patients that received a high dose of contrast media was inferior. In conclusion, this is the first study that demonstrates that quercetin is a promising safe candidate in preventing CIN.

Learning Physiology From Inherited Kidney Disorders

The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.

Extracorporeal resuscitation with carbon monoxide improves renal function by targeting inflammatory pathways in cardiac arrest in pigs

Deleterious consequences like acute kidney injury frequently occur upon successful resuscitation from cardiac arrest. Extracorporeal life support is increasingly used to overcome high cardiac arrest mortality. Carbon monoxide (CO) is an endogenous gasotransmitter, capable of reducing renal injury. In our study, we hypothesized that addition of CO to extracorporeal resuscitation hampers severity of renal injury in a porcine model of cardiac arrest. Hypoxic cardiac arrest was induced in pigs. Animals were resuscitated using a conventional [cardiopulmonary resuscitation (CPR)], an extracorporeal (E-CPR), or a CO-assisted extracorporeal (CO-E-CPR) protocol. CO was applied using a membrane-controlled releasing system. Markers of renal injury were measured, and histopathological analyses were carried out. We investigated renal pathways involving inflammation as well as apoptotic cell death. No differences in serum neutrophil gelatinase-associated lipocalin (NGAL) were detected after CO treatment compared with Sham animals (Sham 71 ± 7 and CO-E-CPR 95 ± 6 ng/mL), while NGAL was increased in CPR and E-CPR groups (CPR 135 ± 11 and E-CPR 124 ± 5 ng/mL; P < 0.05). Evidence for histopathological damage was abrogated after CO application. CO increased renal heat shock protein 70 expression and reduced inducible cyclooxygenase 2 (CPR: 60 ± 8; E-CPR 56 ± 8; CO-E-CPR 31 ± 3 µg/mL; P < 0.05). Caspase 3 activity was decreased (CPR 1,469 ± 276; E-CPR 1,670 ± 225; CO-E-CPR 755 ± 83 pg/mL; P < 0.05). Furthermore, we found a reduction in renal inflammatory signaling upon CO treatment. Our data demonstrate improved renal function by extracorporeal CO treatment in a porcine model of cardiac arrest. CO reduced proinflammatory and proapoptotic signaling, characterizing beneficial aspects of a novel treatment option to overcome high mortality.

Lipidomic analysis of urinary exosomes from hereditary α-tryptasemia patients and healthy volunteers

Exosomes are nano‐sized vesicles that are involved in various biological processes including cell differentiation, proliferation, signaling, and intercellular communication. Urinary exosomes were isolated from a cohort of hereditary α‐tryptasemia (HαT) patients and from healthy volunteers. There was a greater number of exosomes isolated from the urine in the HαT group compared to the control volunteers. Here, we investigated the differences in both lipid classes and lipid species within urinary exosomes of the two groups. Lipids were extracted from urinary exosomes and subjected to liquid chromatography mass spectrometry using a targeted approach. Various molecular species of glycerophospholipids, glycerolipids, and sterols were significantly reduced in HαT patients. Out of a possible 1127 lipids, 521 lipid species were detected, and relative quantities were calculated. Sixty‐four lipids were significantly reduced in urinary exosomes of HαT patients compared to controls. All significantly reduced sphingolipids and most of the phospholipids were saturated or mono‐unsaturated lipids. These results suggest exosome secretion is augmented in HαT patients and the lipids within these exosomes may be involved in various biological processes. The unique lipid composition of urinary exosomes from HαT patients will contribute to our understanding of the biochemistry of this disease.

Developmental Pharmacokinetics and Safety of Ibuprofen and Its Enantiomers in the Conventional Pig as Potential Pediatric Animal Model

Pediatric drug development, especially in disease areas that only affect children, can be stimulated by using juvenile animal models not only for general safety studies, but also to gain knowledge on the pharmacokinetic and pharmacodynamic properties of the drug. Recently, the conventional growing piglet has been suggested as juvenile animal model. However, more studies with different classes of drugs are warranted to make a thorough evaluation whether the juvenile pig might be a suitable preclinical animal model. Ibuprofen is one of the most widely used non-steroidal anti-inflammatory drugs in human. The present study determined the PK parameters, gastro-intestinal and renal safety of 5 mg/kg BW ibuprofen after single intravenous, single oral and multiple oral administration to each time eight pigs (four males, four females) aging 1, 4, 8 weeks and 6–7 months. Oral administration was performed via a gastrostomy button. A jugular catheter was used for intravenous administration and blood sampling. To assess NSAID induced renal toxicity, renal function was evaluated using iohexol and p-aminohippuric acid as markers for glomerular filtration rate and renal plasma flow, respectively. After the trial, necropsy and histology was performed to evaluate macroscopic and microscopic gastro-intestinal as well as renal lesions. Both enantiomers, R-ibuprofen and S-ibuprofen, were determined in plasma using an in-house developed and validated UHPLC-MS/MS method. Pharmacokinetic parameters were estimated using compartmental analysis. Clearance and volume of distribution of total ibuprofen and both enantiomers increased with age as was observed in human. The rate of stereochemical conversion decreased with age. Multiple oral dosing decreased the absolute oral bioavailability and maximum plasma concentration of R-ibuprofen and food consumption did not influence drug absorption. Based on the limited available pediatric literature, the current study might suggest the conventional pig as suitable animal model to evaluate NSAIDs for pediatric use.

The Kidney as an Endocrine Organ

The column in this issue is supplied by Vinay Acharya, D.O., and Juan Jose Olivero, M.D. Dr. Acharya is a nephrology fellow at Houston Methodist Hospital. He earned his Doctor of Osteopathic Medicine degree at Arizona College of Osteopathic Medicine and completed an internal medicine residency at Houston Methodist Hospital. Dr. Olivero is a nephrologist at Houston Methodist Hospital and a member of the hospital's Nephrology Training Program. He obtained his medical degree from the University of San Carlos School of Medicine in Guatemala and completed his residency and nephrology fellowship at Baylor College of Medicine in Houston, Texas.

Effect of nonsteroidal anti-inflammatory drugs in children with Bartter syndrome

BACKGROUND

Bartter syndrome (BS) is a salt-wasting tubulopathy with induced expression of cyclooxygenase-2 in the macula densa, leading to increased prostaglandin production and hyperreninemia. Nonsteroidal anti-inflammatory drugs (NSAIDs) are currently used in BS; however, there is limited information on the impact of NSAIDs at treatment initiation or the potential utility of plasma renin level to guide therapy in patients with BS.

METHODS

We included 19 patients with BS treated with NSAIDs between 1994 and 2016. We assessed serum levels of renin, aldosterone, electrolytes, calcium, phosphorus, vitamin D, and intact parathyroid hormone (iPTH) before and after treatment initiation. We also recorded modifications in sodium and potassium supplements and changes in urine calcium.

RESULTS

Median age at diagnosis was 0.9 months [IQR 0-6.9]. Seven patients had BS types 1 or 2, 12 had BS type 3 and two had no mutation identified. There was a trend towards a decrease in sodium chloride supplementation after initiation of NSAIDs. When defining response to treatment based on the normalization of plasma renin level, responders had a greater reduction in their electrolytes supplementation. NSAIDs treatment was associated with a reduction in urine calcium. Before treatment, half of the patients had elevated iPTH, but iPTH normalized following initiation of NSAIDs in all but one patient.

CONCLUSIONS

This study confirms that NSAIDs reduce urine wasting of sodium and calcium in patients with BS. Monitoring serum renin levels may be useful to identify the lowest effective dose of NSAIDs that optimizes reduction of urine electrolyte losses.

Identification and expression of prostaglandin E synthase (PGES) gene in the central nervous system and ovary during ovarian maturation of the female mud crab, Scylla olivacea

Prostaglandins have important physiological roles in marine invertebrates, including larval development and reproduction. The prostaglandin E concentration fluctuates during the ovarian development of crustaceans. The biosynthetic pathway of prostaglandin, however, has not been well studied in portunid crabs, including in the mud crab, Scylla olivacea. In this study, the aim was to investigate the presence of prostaglandin E synthase (PGES), enzyme that catalyzes the terminal conversion in the prostaglandin E2 (PGE₂) biosynthesis, and its gene expression in the central nervous system (CNS) and ovary during ovarian maturation of S. olivacea. cDNA sequence encoding PGES was cloned from the S. olivacea ovary. The PGES transcript of S. olivacea (Scyol-PGES) consists of 1258 nucleotides, which encodes for 420 amino acid PGES protein precursor. Investigation of gene expression by RT-PCR indicated that Scyol-PGES was detected in all organs studied. Based on in situ hybridization, Scyol-PGES was detected in the I to III stages for oocyte development of Stage 3 of ovarian development, and in the CNS, including the various neuronal clusters of the brain. In the ventral nerve cord, the Scyol-PGES gene was expressed in the neurons within the subesophageal, thoracic and abdominal ganglia. The Scyol-PGES gene expression as indicated by relative abundance of mRNA in the Stage 4 of ovarian development was greater than that at Stages 1 to 3 of ovarian development. This is the first report on PGES in the mud crab, S. olivacea, and its gene expression suggested the involvement of PGES in the ovarian development of this species.

Effects of high- and low-dose aspirin on adaptive immunity and hypertension in the stroke-prone spontaneously hypertensive rat

Despite its well-known antithrombotic properties, the effect of aspirin on blood pressure (BP) and hypertension pathology is unclear. The hugely varying doses used clinically have contributed to this confusion, with high-dose aspirin still commonly used due to concerns about the efficacy of low-dose aspirin. Because prostaglandins have been shown to both promote and inhibit T-cell activation, we also explored the immunomodulatory properties of aspirin in hypertension. Although the common preclinical high dose of 100 mg/kg/d improved vascular dysfunction and cardiac hypertrophy, this effect was accompanied by indices of elevated adaptive immunity, renal T-cell infiltration, renal fibrosis, and BP elevation in stroke-prone spontaneously hypertensive rats and in angiotensin II-induced hypertensive mice. The cardioprotective effects of aspirin were conserved with a lower dose (10 mg/kg/d) while circumventing heightened adaptive immunity and elevated BP. We also show that low-dose aspirin improves renal fibrosis. Differential inhibition of the COX-2 isoform may underlie the disparate effects of the 2 doses. Our results demonstrate the efficacy of low-dose aspirin in treating a vast array of cardiovascular parameters and suggest modulation of adaptive immunity as a novel mechanism underlying adverse cardiovascular profiles associated with COX-2 inhibitors. Clinical studies should identify the dose of aspirin that achieves maximal cardioprotection with a new awareness that higher doses of aspirin could trigger undesired autoimmunity in hypertensive individuals. This work also warrants an evaluation of high-dose aspirin and COX-2 inhibitor therapy in sufferers of inflammatory conditions who are already at increased risk for cardiovascular disease.-Khan, S. I., Shihata, W. A., Andrews, K. L., Lee, M. K. S., Moore, X.-L., Jefferis, A.-M., Vinh, A., Gaspari, T., Dragoljevic, D., Jennings, G. L., Murphy, A. J., Chin-Dusting, J. P. F. Effects of high- and low-dose aspirin on adaptive immunity and hypertension in the stroke-prone spontaneously hypertensive rat.

OBE022, an Oral and Selective Prostaglandin F2α Receptor Antagonist as an Effective and Safe Modality for the Treatment of Preterm Labor

Preterm birth is the major challenge in obstetrics, affecting ∼10% of pregnancies. Pan-prostaglandin synthesis inhibitors [nonsteroidal anti-inflammatory drugs (NSAIDs)] prevent preterm labor and prolong pregnancy but raise concerns about fetal renal and cardiovascular safety. We conducted preclinical studies examining the tocolytic effect and fetal safety of the oral prodrug candidate OBE022 [(S)-2-amino-3-methyl-butyric acid (S)-3-{[(S)-3-(biphenyl-4-sulfonyl)-thiazolidine-2-carbonyl]-amino}-3-(4-fluoro-phenyl)-propyl ester] and its parent OBE002 [(S)-3-(biphenyl-4-sulfonyl)-thiazolidine-2-carboxylic acid [(S)-1-(4-fluoro-phenyl)-3-hydroxy-propyl]-amide], both potent and highly selective antagonist of the contractile prostaglandin F_2α (PGF_2α ) receptor (FP). Efficacy of OBE022 and OBE002, alone and in combination with other tocolytics, was assessed in human tissues and pregnant animal models for inhibition of uterine contraction and delay of parturition. Selective safety of OBE022 and/or OBE002, compared with NSAID indomethacin, was assessed on renal function, closure of the ductus arteriosus, and inhibition of platelet aggregation. In in vitro studies, OBE002 inhibited spontaneous, oxytocin- and PGF_2α -induced human myometrial contractions alone and was more effective in combination with atosiban or nifedipine. In in vivo studies, OBE022 and OBE002 reduced spontaneous contractions in near-term pregnant rats. In pregnant mice, OBE022 delayed RU486 [(8S,11R,13S,14S,17S)-11-[4-(dimethylamino)phenyl]-17-hydroxy-13-methyl-17-prop-1-ynyl-1,2,6,7,8,11,12,14,15,16-decahydrocyclopenta[a]phenanthren-3-one] -induced parturition and exerted synergistic effects in combination with nifedipine. OBE022 and/or OBE002 did not show the fetal side effects of ductus arteriosus constriction, impairment of kidney function, or inhibition of platelet aggregation observed with indomethacin. Orally active OBE022 and OBE002 exhibits potent tocolytic effects on human tissues ex vivo and animal models in vivo without causing the adverse fetal side effects seen with indomethacin. Selectively targeting the FP receptor in combination with existing tocolytics may be an effective strategy for preventing or delaying preterm delivery.

Influence of the selective COX-2 inhibitor celecoxib on sex differences in blood pressure and albuminuria in spontaneously hypertensive rats

We previously reported that female spontaneously hypertensive rats (SHR) have greater cyclooxygenase-2 (COX-2) expression in the renal medulla and enhanced urinary excretion of prostaglandin (PG) E₂ (PGE₂) metabolites compared to male SHR. Based on the role of COX-2-derived prostanoids in the regulation of cardiovascular health, the aim of the current study was to test the hypothesis that blood pressure (BP) in female SHR is more sensitive to COX-2 inhibition than in males. Seven week old male and female SHR were implanted with telemetry transmitters for continuous BP recording. After one week of baseline BP recording, male and female SHR were randomized to receive the selective COX-2 inhibitor celecoxib (10 mg/kg/day) or vehicle for six weeks (from 9 to 14 weeks of age). Female SHR had lower BP and albuminuria compared to male SHR as well as enhanced urinary excretion of PGE metabolite (PGEM), 6-keto PGF_1α and thromboxane B₂, indicators of PGE₂, PGI₂ and TXA₂, respectively. Treatment with celecoxib did not significantly alter BP or albuminuria in either female or male SHR. Celecoxib did not change PGs metabolites excretion in male SHR; however, excretion levels of PGEM and 6-keto PGF_1α were reduced in female SHR. COX-2 derived PG can also induce oxidative stress. Markers of oxidative stress (thiobarbituric acid reactive substances (TBARs) and H₂O₂ excretion) were lesser in female SHR versus male SHR. Celecoxib treatment did not significantly change markers of oxidative stress in female SHR, however, urinary TBARs excretion was significantly reduced in male SHR after 6 weeks of treatment with celecoxib. Therefore, although celecoxib treatment appears to have distinct effects on prostanoids levels in female SHR vs. males, it is unlikely that COX-2 contributes to established sex differences in BP in SHR.

Antipyretic therapy: clinical pharmacology

Fever depends on a complex physiologic response to infectious agents and other conditions. To alleviate fever, many medicinal agents have been developed over a century of trying to improve upon aspirin, which was determined to work by inhibiting prostaglandin synthesis. We present the process of fever induction through prostaglandin synthesis and discuss the development of pharmaceuticals that target enzymes and receptors involved in prostaglandin-mediated signal transduction, including prostaglandin H₂ synthase (also known as cyclooxygenase), phospholipase A₂, microsomal prostaglandin E₂ synthase-1, EP receptors, and transient potential cation channel subfamily V member 1. Clinical use of established antipyretics will be discussed as well as medicinal agents under clinical trials and future research.

Intermittent hypoxia alters dose dependent caffeine effects on renal prostanoids and receptors in neonatal rats

Caffeine, one of the most commonly prescribed drugs in preterm neonates, is given in standard or suprapharmacologic doses. Although known as a diuretic, its effects in the neonatal kidneys are not well studied. We tested the hypothesis that neonatal intermittent hypoxia (IH) and high caffeine doses (HCD) alter renal regulators of vasomotor tone and water balance. Newborn rats were randomized to room air, hyperoxia, or IH and treated with standard or high caffeine doses; or placebo saline. Renal prostanoids; histopathology; and cyclooxygenase (COX), prostanoid receptor, and aquaporin (AQP) immunoreactivity were determined. HCD in IH caused severe pathological changes in the glomeruli and proximal tubules, consistent with acute kidney injury. This was associated with reductions in anthropometric growth, PGI_2, and IP, DP, and AQP-4 immunoreactivity, well as a robust increase in COX-2, suggesting that the use of HCD should be avoided in preterm infants who experience frequent IH episodes.

Enhanced hemodynamic responses to angiotensin II in diabetes are associated with increased expression and activity of AT1 receptors in the afferent arteriole

The prevalence of hypertension is about twofold higher in diabetic than in nondiabetic subjects. Hypertension aggravates the progression of diabetic complications, especially diabetic nephropathy. However, the mechanisms for the development of hypertension in diabetes have not been elucidated. We hypothesized that enhanced constrictive responsiveness of renal afferent arterioles (Af-Art) to angiotensin II (ANG II) mediated by ANG II type 1 (AT1) receptors contributes to the development of hypertension in diabetes. In response to an acute bolus intravenous injection of ANG II, alloxan-induced diabetic mice exhibited a higher mean arterial pressure (MAP) (119.1 ± 3.8 vs. 106.2 ± 3.5 mmHg) and a lower renal blood flow (0.25 ± 0.07 vs. 0.52 ± 0.14 ml/min) compared with nondiabetic mice. In response to chronic ANG II infusion, the MAP measured with telemetry increased by 55.8 ± 6.5 mmHg in diabetic mice, but only by 32.3 ± 3.8 mmHg in nondiabetic mice. The mRNA level of AT1 receptor increased by ~10-fold in isolated Af-Art of diabetic mice compared with nondiabetic mice, whereas ANG II type 2 (AT2) receptor expression did not change. The ANG II dose-response curve of the Af-Art was significantly enhanced in diabetic mice. Moreover, the AT1 receptor antagonist, losartan, blocked the ANG II-induced vasoconstriction in both diabetic mice and nondiabetic mice. In conclusion, we found enhanced expression of the AT1 receptor and exaggerated response to ANG II of the Af-Art in diabetes, which may contribute to the increased prevalence of hypertension in diabetes.

Calcineurin inhibitor cyclosporine A activates renal Na-K-Cl cotransporters via local and systemic mechanisms

Calcineurin dephosphorylates nuclear factor of activated T cells transcription factors, thereby facilitating T cell-mediated immune responses. Calcineurin inhibitors are instrumental for immunosuppression after organ transplantation but may cause side effects, including hypertension and electrolyte disorders. Kidneys were recently shown to display activation of the furosemide-sensitive Na-K-2Cl cotransporter (NKCC2) of the thick ascending limb and the thiazide-sensitive Na-Cl cotransporter (NCC) of the distal convoluted tubule upon calcineurin inhibition using cyclosporin A (CsA). An involvement of major hormones like angiotensin II or arginine vasopressin (AVP) has been proposed. To resolve this issue, the effects of CsA treatment in normal Wistar rats, AVP-deficient Brattleboro rats, and cultured renal epithelial cells endogenously expressing either NKCC2 or NCC were studied. Acute administration of CsA to Wistar rats rapidly augmented phosphorylation levels of NKCC2, NCC, and their activating kinases suggesting intraepithelial activating effects. Chronic CsA administration caused salt retention and hypertension, along with stimulation of renin and suppression of renal cyclooxygenase 2, pointing to a contribution of endocrine and paracrine mechanisms at long term. In Brattleboro rats, CsA induced activation of NCC, but not NKCC2, and parallel effects were obtained in cultured cells in the absence of AVP. Stimulation of cultured thick ascending limb cells with AVP agonist restored their responsiveness to CsA. Our results suggest that the direct epithelial action of calcineurin inhibition is sufficient for the activation of NCC, whereas its effect on NKCC2 is more complex and requires concomitant stimulation by AVP.

Histopathological Evaluation of Contrast-Induced Acute Kidney Injury Rodent Models

Contrast-induced acute kidney injury (CI-AKI) can occur in 3–25% of patients receiving radiocontrast material (RCM) despite appropriate preventive measures. Often patients with an atherosclerotic vasculature have to receive large doses of RCM. Thus, animal studies to uncover the exact pathomechanism of CI-AKI are needed. Sensitive and specific histologic end-points are lacking; thus in the present review we summarize the histologic appearance of different rodent models of CI-AKI. Single injection of RCM causes overt renal damage only in rabbits. Rats and mice need an additional insult to the kidney to establish a clinically manifest CI-AKI. In this review we demonstrate that the concentrating ability of the kidney may be responsible for species differences in sensitivity to CI-AKI. The most commonly held theory about the pathomechanism of CI-AKI is tubular cell injury due to medullary hypoxia. Thus, the most common additional insult in rats and mice is some kind of ischemia. The histologic appearance is tubular epithelial cell (TEC) damage; however severe TEC damage is only seen if RCM is combined by additional ischemia. TEC vacuolization is the first sign of CI-AKI, as it is a consequence of RCM pinocytosis and lysosomal fusion; however it is not sensitive as it does not correlate with renal function and is not specific as other forms of TEC damage also cause vacuolization. In conclusion, histopathology alone is insufficient and functional parameters and molecular biomarkers are needed to closely monitor CI-AKI in rodent experiments.

A dual COX-2/sEH inhibitor improves the metabolic profile and reduces kidney injury in Zucker diabetic fatty rat

Cyclooxygenase (COX) and soluble epoxide hydrolase (sEH) inhibitors have therapeutic potential. The present study investigated efficacy of a novel dual acting COX-2/sEH inhibitor, PTUPB in type 2 diabetic Zucker Diabetic Fatty (ZDF) rats. Male ZDF rats were treated with vehicle or PTUPB (10mg/kg/d, i.p.) for 8 weeks. At the end of the 8-week experimental period, ZDF rats were diabetic (fasting blood glucose, 287±45mg/dL) compared to Zucker Diabetic Lean rats (ZDL, 99±6mg/dL), and PTUPB treatment improved glycemic status in ZDF rats (146±6mg/dL). Kidney injury was evident in ZDF compared to ZDL rats with elevated albuminurea (44±4 vs 4±2mg/d) and nephrinurea (496±127 vs 16±4μg/d). Marked renal fibrosis, tubular cast formation and glomerular injury were also present in ZDF compared to ZDL rats. In ZDF rats, PTUPB treatment reduced kidney injury parameters by 30-80% compared to vehicle. The ZDF rats also demonstrated increased inflammation and oxidative stress with elevated levels of urinary monocyte chemoattractant protein-1 excretion (862±300 vs 319±75ng/d), renal macrophage infiltration (53±2 vs 37±4/mm(2)) and kidney malondialdehyde/protein ratio (10±1 vs 5±1μmol/mg). PTUPB treatment decreased these inflammatory and oxidative stress markers in the kidney of ZDF rats by 25-57%. These data demonstrate protective actions of a novel dual acting COX-2/sEH inhibitor on the metabolic abnormalities and kidney function in ZDF rat model of type 2 diabetes.

Mechanisms of triple whammy acute kidney injury

Pre-renal acute kidney injury (AKI) results from glomerular haemodynamic alterations leading to reduced glomerular filtration rate (GFR) with no parenchymal compromise. Renin-angiotensin system inhibitors, such as angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor antagonists (ARAs), non-steroidal anti-inflammatory drugs (NSAIDs) and diuretics, are highly prescribed drugs that are frequently administered together. Double and triple associations have been correlated with increased pre-renal AKI incidence, termed "double whammy" and "triple whammy", respectively. This article presents an integrative analysis of the complex interplay among the effects of NSAIDs, ACEIs/ARAs and diuretics, acting alone and together in double and triple therapies. In addition, we explore how these drug combinations alter the equilibrium of regulatory mechanisms controlling blood pressure (renal perfusion pressure) and GFR to increase the odds of inducing AKI through the concomitant reduction of blood pressure and distortion of renal autoregulation. Using this knowledge, we propose a more general model of pre-renal AKI based on a multi whammy model, whereby several factors are necessary to effectively reduce net filtration. The triple whammy was the only model associated with pre-renal AKI accompanied by a course of other risk factors, among numerous potential combinations of clinical circumstances causing hypoperfusion in which renal autoregulation is not operative or is deregulated. These factors would uncouple the normal BP-GFR relationship, where lower GFR values are obtained at every BP value.

The use of nonsteroidal anti-inflammatory drugs in critically ill horses

OBJECTIVE

To review the physiology of the cyclooxygenase (COX) enzymes with reference to the beneficial effects of nonsteroidal anti-inflammatory drugs (NSAIDs) related to their analgesic and antiendotoxic properties as well as the mechanisms responsible for adverse gastrointestinal, renal, and coagulation effects.

DATA SOURCES

Human and veterinary peer reviewed literature

VETERINARY DATA SYNTHESIS

NSAIDs are frequently administered to critically ill horses for their analgesic and anti-inflammatory effects. However, NSAIDs have significant side effects principally on the gastrointestinal mucosa and kidneys. These side effects may be exacerbated in critically ill horses if they have gastrointestinal damage or are volume depleted

CONCLUSIONS

This review provides important information for equine veterinarians and criticalists on the advantages and disadvantages of using traditional NSAIDs and newer equine COX-2 selective NSAIDs for the management of different conditions in critically ill horses.

Diuretic, anti-inflammatory, and analgesic activities of the ethanol extract from Cynoglossum lanceolatum

ETHNOPHARMACOLOGICAL RELEVANCE

Cynoglossum lanceolatum Forsk. (Boraginaceae) has been used in folk medicine in china to treat acute nephritis, periodontitis, acute submandibular lymphadenitis, snake bite, etc. However, there have been no scientific reports in the modern literature on the diuretic, anti-inflammatory and analgesic effects of this plant. The objective of this study is to evaluate the above activities of the Cynoglossum lanceolatum extract (CLE) in animals.

MATERIALS AND METHODS

The diuretic effect of CLE was assessed in rats and rabbits. The anti-inflammatory activity was evaluated using fresh egg white-induced paw edema in rats, carrageenan-elicited paw edema in adrenalectomized rats, and dimethylbenzene-induced inflammation in mice. The analgesic action was estimated in mice using the acetic acid-induced writhing test and the hot-plate test. In addition, the acute oral toxicity of CLE was studied in mice.

RESULTS

CLE strikingly and dose-dependently increased urine output of rats and rabbits, suppressed fresh egg white-induced paw edema in rats and carrageenan-elicited paw edema in adrenalectomized rats, reduced dimethylbenzene-induced ear edema in mice, inhibited the writhing response in mice, but did not increased reaction time of mice in the hot-plate test. No death of mice was observed when orally administered CLE up to 12g/kg.

CONCLUSIONS

These findings propose that CLE has evident diuretic, anti-inflammatory, and non-central analgesic activities. Furthermore the anti-inflammatory action does not rely on endogenetic glucocorticoids regulated by hypothalamo-pituitary-adrenal axis. On the other hand, CLE also shows a favorable safety.