Oxidants as important determinants of renal apoptosis during pneumoperitoneum: a study in an isolated perfused rat kidney model

Mediators of Regional Kidney Perfusion during Surgical Pneumo-Peritoneum Creation and the Risk of Acute Kidney Injury—A Review of Basic Physiology

Acute kidney injury (AKI), especially if recurring, represents a risk factor for future chronic kidney disease. In intensive care units, increased intra-abdominal pressure is well-recognized as a significant contributor to AKI. However, the importance of transiently increased intra-abdominal pressures procedures is less commonly appreciated during laparoscopic surgery, the use of which has rapidly increased over the last few decades. Unlike the well-known autoregulation of the renal cortical circulation, medulla perfusion is modulated via partially independent regulatory mechanisms and strongly impacted by changes in venous and lymphatic pressures. In our review paper, we will provide a comprehensive overview of this evolving topic, covering a broad range from basic pathophysiology up to and including current clinical relevance and examples. Key regulators of oxidative stress such as ischemia-reperfusion injury, the activation of inflammatory response and humoral changes interacting with procedural pneumo-peritoneum formation and AKI risk will be recounted. Moreover, we present an in-depth review of the interaction of pneumo-peritoneum formation with general anesthetic agents and animal models of congestive heart failure. A better understanding of the relationship between pneumo-peritoneum formation and renal perfusion will support basic and clinical research, leading to improved clinical care and collaboration among specialists.

Effects of pneumoperitoneum with carbon dioxide on renal and hepatic functions in rats

Introduction

Laparoscopic surgery is a preferred method based on its many benefits. However, increasing abdominal pressure by CO₂ insufflation during the implementation of this technique poses challenges.

Aim

To determine the degree of renal and liver injury that occurs in a pneumoperitoneum (PP) model of prolonged CO₂ insufflation.

Material and methods

Twenty-one female Sprague Dawley rats were separated randomly into three groups. Group 1 was the control group and given anesthesia for 3 h. In group 2, PP was administered under anesthesia for 1 h. In the last group, PP was administered under anesthesia to animals for 3 h. We measured renal and liver injury biomarkers and made a histopathological evaluation to estimate the degree of injury and assessed the correlation of biomarkers including kidney injury molecule-1 (KIM-1) with histopathological findings.

Results

Histopathological analysis according to the kidney ischemia tubular damage score showed a statistically significant difference between the 3 groups (p < 0.001). There was an increase in KIM-1 levels in the groups, although it was not statistically significant (p = 0.062, p = 0.156, p = 0.350 respectively). According to the correlation test in this research, KIM-1 results had a statistically significant association with creatinine, urea, aspartate aminotransferase and alanine aminotransferase levels in all control and study groups.

Conclusions

According to our results, the increase in KIM-1 was correlated with Cr levels and compatible with histopathological analysis. Moreover, intra-abdominal pressure statistically significantly increased the degree of kidney injury and there was not a significant increase in the levels of KIM-1. There was no difference in liver damage between groups.

Renal Physiology and Robotic Urological Surgery

The use of robotic-assisted laparoscopic techniques has transformed the face of urological surgery in the last decade, with demonstrable benefits over both unassisted laparoscopic and traditional open approaches. For example, robotic-assisted partial nephrectomy is associated with lower morbidity, improved convalescence, reduced postoperative pain, shorter length of hospital stay, and a superior cosmetic result when compared to an open procedure. This review discusses the various perioperative influences on the renal physiology of patients undergoing robotic-assisted urological procedures.

The effects of prolonged CO2 insufflation on kidney function in a rat pneumoperitoneum model

INTRODUCTION

Pneumoperitoneum (PP) is known to cause ischemia in kidneys and other intra-abdominal organs because of decreased splanchnic blood flow.

AIM

We aimed to determine the degree of renal injury that occurs due to a PP and prolonged PP. We measured renal injury biomarkers and made a histopathological evaluation to estimate the degree of injury and assessed the correlation of biomarkers with histopathological findings.

MATERIAL AND METHODS

Twenty-one female Sprague Dawley rats were separated randomly into three groups. Group 1 was the control group and was given anesthesia for 3 h. In group 2, a PP was administered under anesthesia for 1 h. A pneumoperitoneum was administered under anesthesia to animals in group 3 for 3 h.

RESULTS

Pathological analysis showed a significant statistical difference between the 3 groups. In particular, neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C (Cys C) levels at the 24^th h and preoperative mean urea levels showed a significant difference between the groups. The 24^th-hour NGAL level in group 3 was significantly higher than that of group 1. The preoperative Cys C level was higher in group 1 than in either group 2 or 3. Cys C was decreased significantly in group 1 and increased significantly in both groups 2 and 3.

CONCLUSIONS

The increase in NGAL and Cys C levels directly correlated with the duration of PP and intra-abdominal pressure, and they are therefore good biomarkers in diagnosing acute renal injury in the early phase. Serum creatinine level is not a good biomarker in the early phase of renal injury.

Effect of Pneumoperitoneum on Renal Function and Physiology in Patients Undergoing Robotic Renal Surgery

Laparoscopic and minimally-invasive robotic access has transformed the delivery of urological surgery. While associated with numerous desirable outcomes including shorter post-operative stay and faster return to preoperative function, these techniques have also been associated with increased morbidity such as reduced renal blood flow and post-operative renal dysfunction. The mechanisms leading to these renal effects complex and multifactorial, and have not been fully elucidated. However they are likely to include direct effects from raised intra-abdominal pressure, and indirect effects secondary to carbon dioxide absorption, neuroendocrine factors and tissue damage from oxidative stress. This review summarises these factors, and highlights the need for further work in this area, to direct novel therapies and guide alterations in technique with the aim of reducing renal dysfunction post-laparoscopic and robotic surgery.

An update to the toxicological profile for water-soluble and sparingly soluble tungsten substances

Tungsten is a relatively rare metal with numerous applications, most notably in machine tools, catalysts, and superalloys. In 2003, tungsten was nominated for study under the National Toxicology Program, and in 2011, it was nominated for human health assessment under the US Environmental Protection Agency's (EPA) Integrated Risk Information System. In 2005, the Agency for Toxic Substances and Disease Registry (ATSDR) issued a toxicological profile for tungsten, identifying several data gaps in the hazard assessment of tungsten. By filling the data gaps identified by the ATSDR, this review serves as an update to the toxicological profile for tungsten and tungsten substances. A PubMed literature search was conducted to identify reports published during the period 2004-2014, in order to gather relevant information related to tungsten toxicity. Additional information was also obtained directly from unpublished studies from within the tungsten industry. A systematic approach to evaluate the quality of data was conducted according to published criteria. This comprehensive review has gathered new toxicokinetic information and summarizes the details of acute and repeated-exposure studies that include reproductive, developmental, neurotoxicological, and immunotoxicological endpoints. Such new evidence involves several relevant studies that must be considered when regulators estimate and propose a tungsten reference or concentration dose.

Acute kidney injury induced by various pneumoperitoneum pressures in a rabbit model of mild and severe hydronephrosis

OBJECTIVE

Increased pneumoperitoneum pressure during laparoscopic surgery can result in acute kidney injury. We aimed to clarify whether intraabdominal pressure tolerance is modified in various degrees of unilateral kidney hydronephrosis in rabbits.

METHODS

A total 90 rabbits were randomly allocated to three groups (group PN, PM and PS, i.e. rabbits with no, mild and severe hydronephrosis, respectively, subjected to intraabdominal pressures). Rabbits in group PM (n=30) and group PS (n=30) underwent a surgical procedure inducing a mild or severe left hydronephrosis. Rabbits in all groups were then allocated to 5 subgroups. Then, they were subjected to intraabdominal pressures of 0, 6, 9, 12, and 15 mm Hg, respectively. Acute kidney injury was assessed by measuring serum creatinine (Scr), blood urea nitrogen (BUN), tubular cell apoptosis, kidney injury molecule-1 (KIM-1) and cysteine-rich 61 (Cyr-61/CCN1) expression.

RESULTS

Acute kidney injury with increased tubular apoptosis and KIM-1 and Cyr-61 expression occurred when intraabdominal pressure reached 15, 15 and 9 mm Hg in PN, PM and PS groups, respectively. The Scr and BUN levels were similar in all groups.

CONCLUSIONS

In rabbits, kidneys with severe hydronephrosis were more likely to suffer acute injury when they were exposed to pneumoperitoneal pressure.

Does prolonged pneumoperitoneum affect the kidney? Oxidative stress, stereological and electron microscopy study in a rat model

PURPOSE

Pneumoperitoneum (Pp) at 12 to 15 mmHg in rats is associated with kidney damage. However, Pp at 8 mmHg is now known to best correlate to working pressures used in humans. Thus the aim of this work was to study the kidney of rats submitted to prolonged Pp at 8 mmHg.

MATERIALS AND METHODS

Rats were divided into a Sham group (n = 14), submitted to anesthesia, and a Pp group (n = 14), submitted to Pp at 8 mmHg, followed by deflation. In both groups, 7 animals were immediately killed and their kidneys were used for oxidative stress analyses. The remaining 7 rats in each group were evaluated after 6 weeks for the number of glomeruli and podocyte morphology.

RESULTS

For all analyzed parameters Sham and Pp groups presented no statistical difference.

CONCLUSION

When submitted to adequate Pp pressures (8 mmHg), no kidney damage occurs in rats.