Administration of fenoldopam in critically ill small animal patients with acute kidney injury: 28 dogs and 34 cats (2008-2012)

International Renal Interest Society best practice consensus guidelines for the diagnosis and management of acute kidney injury in cats and dogs

Acute kidney injury (AKI) is defined as an injury to the renal parenchyma, with or without a decrease in kidney function, as reflected by accumulation of uremic toxins or altered urine production (i.e., increased or decreased). AKI might result from any of several factors, including ischemia, inflammation, nephrotoxins, and infectious diseases. AKI can be community- or hospital-acquired. The latter was not previously considered a common cause for AKI in animals; however, recent evidence suggests that the prevalence of hospital-acquired AKI is increasing in veterinary medicine. This is likely due to a combination of increased recognition and awareness of AKI, as well as increased treatment intensity (e.g., ventilation and prolonged hospitalization) in some veterinary patients and increased management of geriatric veterinary patients with multiple comorbidities. Advancements in the management of AKI, including the increased availability of renal replacement therapies, have been made; however, the overall mortality of animals with AKI remains high. Despite the high prevalence of AKI and the high mortality rate, the body of evidence regarding the diagnosis and the management of AKI in veterinary medicine is very limited. Consequently, the International Renal Interest Society (IRIS) constructed a working group to provide guidelines for animals with AKI. Recommendations are based on the available literature and the clinical experience of the members of the working group and reflect consensus of opinion. Fifty statements were generated and were voted on in all aspects of AKI and explanatory text can be found either before or after each statement.

Urine Output Monitoring and Acute Kidney Injury in Non-mammalian Exotic Animal Critical Care

Acute kidney injury (AKI) is a sudden, severe decrease in kidney function which can occur in any species. There are various causes of AKI, some of which are seen in domestic species and some that are unique to birds, reptiles, and amphibians. These species present unique challenges with AKI management, such as differences in anatomy and physiology, intravenous and urinary catheterization, repeated blood sampling, and their tendency to present in advanced states of illness. This article will discuss AKI, diagnosis, treatment, and prognosis for non-mammalian exotic species.

Urine Output Monitoring and Acute Kidney Injury in Mammalian Exotic Animal Critical Care

Acute kidney injury (AKI) is a sudden, severe decrease in kidney function which can occur in any species. There are various causes of AKI, some of which are seen in domestic species and some that are unique to exotics. Exotic animals present unique challenges with AKI management such as differences in anatomy and physiology, intravenous and urinary catheterization, repeated blood sampling, and their tendency to present in advanced states of illness. This article will discuss AKI, diagnosis, treatment, and prognosis for exotic companion mammals. The following article will discuss the same in non-mammalian patients.

Evaluation of presentation, treatment and outcome in hypertensive emergency in dogs and cats: 15 cases (2003-2019)

OBJECTIVES

Hypertensive emergency is well recognised in human medicine, yet there is limited veterinary evidence. This study aimed to determine the presentation, treatment and outcome in dogs and cats with hypertensive emergency.

MATERIALS AND METHODS

A retrospective case series of dogs and cats with hypertensive emergency identified as follows: acute history with non-invasive Doppler systolic blood pressure greater than 180 mmHg and target organ damage including acute onset seizures, altered mentation with or without lateral recumbency or blindness. Data collected included signalment, history, physical examination and clinicopathological findings, systolic blood pressure, antihypertensive treatment and outcome.

RESULTS

Seven dogs and eight cats were included presenting with seizures (n=9), blindness (n=4), altered mentation with (n=2) or without (n=2) lateral recumbency. Median age was 9 years (range 1 to 15) and duration of clinical signs before presentation was 1.5 days (range 1 to 15). Median systolic blood pressure on presentation was 230 mmHg (range 190 to 300). Amlodipine was the most common first-line agent (n=10), followed by hydralazine (n=4) and hypertonic saline (n=1). Aetiology of hypertensive emergency was acute kidney injury (n=9), idiopathic hypertension (n=3), hyperthyroidism (n=1), lymphoma (n=1) and suspected cutaneous and renal glomerular vasculopathy (n=1). Five cats and three dogs survived to discharge with an overall survival of 53.3%.

CLINICAL SIGNIFICANCE

Hypertensive emergencies had various presenting signs in this series. AKI was considered to be the cause of hypertension in the majority of patients. Further evaluation of treatment for hypertensive emergencies is warranted, considering almost half of the cases did not survive to discharge.

Current Status on Canine Foetal Fluid and Adnexa Derived Mesenchymal Stem Cells

Effective standards of care treatment guidelines have been developed for many canine diseases. However, a subpopulation of patients is partially or completely refractory to these protocols, so their owners seek novel therapies such as treatments with MSCs. Although in dogs, as with human medicine, the most studied MSCs sources have been bone marrow and adipose tissue, in recent years, many researchers have drawn attention towards alternative sources, such as foetal adnexa and fluid, since they possess many advantages over bone marrow and adipose tissue. Foetal adnexa and fluid could be considered as discarded material; therefore, sampling is non-invasive, inexpensive and free from ethical considerations. Furthermore, MSCs derived from foetal adnexa and fluid preserve some of the characteristics of the primitive embryonic layers from which they originate and seem to present immune-modulatory properties that make them a good candidate for allo- and xenotransplantation. The aim of the present review is to offer an update on the state of the art on canine MSCs derived from foetal adnexa and fluid focusing on the findings in their clinical setting.

Sequential changes in urine production, glomerular filtration rate, and electrolyte excretion after mannitol administration

Introduction

Acute kidney injury (AKI) leading to severe uremia is associated with high morbidity and mortality. Mannitol is an osmotic diuretic, widely used in the management of AKI, both as a bolus injection and as a constant rate infusion (CRI).

Objectives

To determine the plasma concentration of mannitol after a bolus injection and CRI at the recommended dosages, and to assess the effect of mannitol on renal function variables including urine production, glomerular filtration rate (GFR), and solute excretion.

Methods

Prospective cross‐over design study, using 6 healthy dogs. Each dog underwent 3 protocols with at least a 7‐day washout period between protocols. The first protocol included bolus injection of mannitol, the second protocol included bolus injection followed by CRI of mannitol and the third protocol (control) included injection of 5% dextrose in water (D5W). Urine production, GFR, and fractional excretion (FE) of solutes were measured for 10 hours.

Results

For all protocols, urine production significantly (P < .001) increased after bolus injection, but no significant difference in urine production or GFR was observed among the treatment groups. Mannitol injection increased the FE of sodium and urea nitrogen, but these effects were short‐lived.

Conclusions

Mannitol has minimal effect on urine production and GFR but does increase FE of urea nitrogen and sodium, immediately after bolus injection. Constant rate infusion at a conventional dosage of 1 mg/kg/min cannot maintain these effects in dogs with normal renal function, because mannitol concentration decreases rapidly.

ACVIM consensus statement: Guidelines for the identification, evaluation, and management of systemic hypertension in dogs and cats

An update to the 2007 American College of Veterinary Internal Medicine (ACVIM) consensus statement on the identification, evaluation, and management of systemic hypertension in dogs and cats was presented at the 2017 ACVIM Forum in National Harbor, MD. The updated consensus statement is presented here. The consensus statement aims to provide guidance on appropriate diagnosis and treatment of hypertension in dogs and cats.

Mesenchymal Stem Cells Contribute to Improvement of Renal Function in a Canine Kidney Injury Model

BACKGROUND/AIM

The kidney excretes waste materials and regulates important metabolic functions, and renal disorders constitute a significant medical problem and can result in fatalities. In the present study, mesenchymal stem cells derived from canine umbilical cord blood (cUCB-MSCs) were isolated and evaluated for their ability to improve renal function in a canine model of acute kidney injury (AKI).

MATERIALS AND METHODS

The canine AKI model was developed by i.v. injection of cisplatin and gentamycin into 14 male beagle dogs. cUCB-MSCs were administered into the renal corticomedullary junction following AKI induction. Survival time, clinical signs, blood analysis and histological parameters were analyzed.

RESULTS

The group treated with AKI plus cUCB-MSCs had decreased blood urea nitrogen and creatinine levels, and showed an extended life-span and improved histological manifestations. MSCs were detected around the tubules of these kidneys at the histological level.

CONCLUSION

Taken together, our findings suggest that cUCB-MSCs could be an alternative therapeutic agent for canine AKI.

Effects of fenoldopam on kidney function parameters and its therapeutic efficacy in the management of acute kidney injury in dogs with heatstroke

Background

Acute kidney injury (AKI) is common in dogs, but evidence of efficacy of its treatment is lacking.

Objective

To evaluate the efficacy of fenoldopam in the management of AKI.

Animals

Forty dogs with naturally occurring heatstroke.

Methods

Dogs were prospectively enrolled and divided into treatment and the placebo groups (fenoldopam, constant rate infusion [CRI] of 0.1 µg/kg/min or saline, respectively). Urine production (UP) was measured using a closed system. Urinary clearances were performed at 4, 12, and 24 hours after presentation to estimate the effect of fenoldopam on UP, glomerular filtration rate (GFR) and sodium fractional excretion (NaFE).

Results

At presentation, severity of heatstroke, based on a previously developed scoring system, was similar between the study groups, but was significantly worse in nonsurvivors compared with survivors. Fenoldopam administration was not associated with hypotension. Overt AKI was diagnosed, based on the International Renal Interest Society guidelines in 22/40 (55%) of the dogs. Overall, 14/40 dogs (35%) died, with no significant (P = .507) mortality rate difference between the fenoldopam (6/20 dogs; 30%) and placebo (8/20; 40%) groups. The proportion of dogs with AKI did not differ between the fenoldopam and the placebo groups (9/20; 45% versus 13/20; 65%, respectively; P = .204). There were no differences in UP, GFR, and NaFE between the fenoldopam and the placebo groups.

Conclusion and Clinical Importance

Fenoldopam CRI at 0.1 µg/kg/min did not have a clinically relevant effect on kidney function parameters in dogs with severe heatstroke‐associated AKI.

Acute kidney injury in cats and dogs: A proportional meta-analysis of case series studies

INTRODUCTION

Risk of mortality in the setting of acute kidney injury (AKI) in cats and dogs remains unclear.

OBJECTIVES

To evaluate the incidence of mortality in cats and dogs with AKI based on etiology (i.e. infectious versus non-infectious; receiving dialysis versus conservative treatment).

MATERIALS AND METHODS

Ovid Medline, EMBASE, and LILACS were searched up to July 2016. Articles were deemed eligible if they were case series studies evaluating the incidence of all-cause mortality in cats and dogs with AKI, regardless of etiology or the nature of treatment.

RESULTS

Eighteen case series involving 1,201animalsproved eligible. The pooled proportions for overall mortality were: cats53.1% [95% CI 0.475, 0.586; I2 = 11,9%, p = 0.3352]; dogs 45.0% [95% CI 0.33, 0.58; I2 = 91.5%, P < 0.0001]. A non-significant increase in overall mortality risk was found among dialysed animals relative to those managed with conservative treatment, independent of animal type and the etiology of their AKI. The pooled proportions for overall mortality according to etiology, regardless of treatment type, were: AKI due infectious etiology for cats and dogs, 19.2% [95% CI 0.134, 0.258; I2 = 37.7%, P = 0.0982]; AKI due non-infectious etiology for cats and dogs, 59.9% [95% CI 0.532, 0.663; I2 = 51.0%, P = 0.0211].

CONCLUSION

Our findings suggest higher rates of overall mortality in cats and dogs with AKI due to non-infectious etiologies relative to infectious etiologies, and showed non-significant differences in terms of higher rates associated with dialysis compared to conservative management. Further investigations regarding optimal time to initiate dialysis and the development of clinical models to prognosticate the course of disease and guide optimal treatment initiation for less severe cases of AKI in cats and dogs is warranted.

Recent Perioperative Pharmacological Prevention of Acute Kidney Injury after Cardiac Surgery: A Narrative Review

Acute kidney injury (AKI) is a common and severe complication of cardiac surgery, and related rates of both hospitalization and long-term mortality are increasing. A number of studies have explored the preventive effects of perioperative pharmacological therapy on AKI after cardiac surgery. However, the mechanisms of AKI are multifaceted, and no universal treatment has been confirmed as beneficial. We review and analyze several current perioperative pharmacological therapies for AKI after cardiac surgery to identify promising preventive strategies.

Effect of Fenoldopam Continuous Infusion on Glomerular Filtration Rate and Fractional Excretion of Sodium in Healthy Dogs

BACKGROUND

Acute kidney injury (AKI) is a common problem in small-animal patients and carries a guarded prognosis with substantial morbidity and mortality, particularly in oligoanuric dogs. Fenoldopam, a selective dopamine agonist, has been shown to increase urine output in healthy dogs and cats; however, the mechanism of action is unknown.

HYPOTHESIS/OBJECTIVES

To evaluate the effect of fenoldopam infusion on glomerular filtration rate (GFR) and fractional excretion of sodium (FeNa) in healthy dogs.

ANIMALS

Ten healthy, privately owned dogs.

METHODS

Randomized, crossover design with negative control. Ten healthy dogs were given fenoldopam diluted in 5% dextrose (D5W) as a continuous IV infusion of 0.8 μg/kg/min for 5 hours and a control infusion of D5W alone, 7 days apart. Glomerular filtration rate was measured by exogenous iohexol clearance, beginning 1 hour after the start of the fenoldopam infusion. Fractional excretion of sodium (FeNa) was measured before and after the infusion. Glomerular filtration rate and change in FeNa were compared between treatment days.

RESULTS

Fenoldopam infusion resulted in a significantly increased (P = .0166) GFR (median GFR, 3.33 mL/min/kg) in healthy dogs compared with D5W infusion (median GFR, 2.71 mL/kg/min). Fenoldopam also resulted in a significantly increased (P = .0148) FeNa (mean change, 0.106), whereas infusion of D5W alone did not (mean change, 0.016).

CONCLUSIONS AND CLINICAL IMPORTANCE

In healthy dogs, fenoldopam significantly increased GFR and FeNa compared with infusion of D5W alone. No adverse effects were seen.

Bridging translation for acute kidney injury with better preclinical modeling of human disease

The current lack of effective therapeutics for patients with acute kidney injury (AKI) represents an important and unmet medical need. Given the importance of the clinical problem, it is time for us to take a few steps back and reexamine current practices. The focus of this review is to explore the extent to which failure of therapeutic translation from animal studies to human studies stems from deficiencies in the preclinical models of AKI. We will evaluate whether the preclinical models of AKI that are commonly used recapitulate the known pathophysiologies of AKI that are being modeled in humans, focusing on four common scenarios that are studied in clinical therapeutic intervention trials: cardiac surgery-induced AKI; contrast-induced AKI; cisplatin-induced AKI; and sepsis associated AKI. Based on our observations, we have identified a number of common limitations in current preclinical modeling of AKI that could be addressed. In the long term, we suggest that progress in developing better preclinical models of AKI will depend on developing a better understanding of human AKI. To this this end, we suggest that there is a need to develop greater in-depth molecular analyses of kidney biopsy tissues coupled with improved clinical and molecular classification of patients with AKI.

Inhibiting microRNA-449 Attenuates Cisplatin-Induced Injury in NRK-52E Cells Possibly via Regulating the SIRT1/P53/BAX Pathway

Background

Acute kidney injury (AKI) is quite common in the patients who frequently use the anticancer drug cisplatin. microRNAs (miRNAs) are powerful tools in modulating the expression of key factors in disease progression, but little is known about roles of miRNAs in AKI. This study explored the expression and function of miR-449 in cisplatin-induced AKI.

Material/Methods

Rat renal proximal tubular cell line NRK-52E was used for cisplatin treatment and miR-449 sponge transfection. MTT assay and flow cytometry were performed to detect cell viability and apoptosis in different cell groups. Protein expression of sirtuin 1 (SIRT1), acetylated p53, and BCL-associated X protein (BAX) was detected to deduce the possible regulatory mechanism of miR-449.

Results

Results showed that cisplatin treatment in NRK-52E cells significantly up-regulated miR-449 levels (P<0.05), inhibited cell viability (P<0.05), accelerated cell apoptosis (P<0.05), and changed SIRT1, acetylated p53, and BAX protein levels (P<0.01). However, inhibiting miR-449 by its sponge transfection in cisplatin-treated cells significantly promoted cell viability (P<0.05), suppressed cell apoptosis (P<0.05), elevated SIRT1 expression (P<0.01), and inhibited acetylated p53 and BAX protein levels (P<0.001).

Conclusions

These results indicate that inhibiting miR-449 allows the attenuation of cisplatin-induced injury in NRK-52E cells, suggesting that miR-449 is a potential target for treating AKI. miR-449 regulates the SIRT1/p53/BAX pathway, which may be its possible mechanism in modulating cell apoptosis of cisplatin-induced AKI. Further verification and a thorough understanding are necessary for targeting miR-449 in AKI treatment.