Pneumoperitoneum upregulates preproendothelin-1 messenger RNA

P53 related apoptosis in kidneys in CO₂ pneumoperitoneum rat model: an immunohistochemical study

Laparoscopic surgery techniques have been increasingly preferred to classic laparotomy by surgeons since 1987. However, this method may have some side effects on different intraabdominal organs including kidneys. The aim of this study is to evaluate the effects of different pressures of CO2 on p53 related apoptosis in kidneys. Totally 24 male rats were divided into four equal groups. CO2 is insufflated into rats' intraabdominal cavity in two different pressures of 10 and 20 mmHg during 1 h. However, in sham group, only cannula was inserted, but no gas was insufflated. After 1 h, 30 min reperfusion was applied. At last, the kidneys were excised and p53 expression and apoptosis were evaluated immunohistochemically. All the data revealed that the number of apoptotic cell in kidney' tubular cells significantly increases in proportion to CO2 pressure level. On the other hand, p53 expression was detected only in the highest pressure. Because the low CO2 pressured group' rats had no p53 expression in kidneys, we suggest that this method can be safely used for abdominal surgery. At the same time, increasing in the number of apoptotic cells parallel to pressure also suggest that CO2 pressure level and application time are very important parameters during CO2 pneumoperitoneum.

Effect of intra-abdominal pressure on hepatic microcirculation: implications of the endothelin-1 receptor

OBJECTIVE

To investigate the effect of endothelin receptor A (ET(A)) and endothelin receptor B (ET(B)) blockade on liver microcirculation and oxygenation during intra-abdominal pressure (IAP) increase.

METHODS

Fifteen anesthetized pigs were randomized to receive either nonselective endothelin-1 (ET-1) blocker tezosentan (TG, n = 7) or saline (CG, n = 8). Helium was insufflated to increase IAP from 0 to 25 mmHg. Stroke volume variability was maintained ≤ 12% with colloid infusion. Total liver blood flow (TLBF), hepatic microcirculatory blood flow (MBF), hepatic tissue oxygenation (HpO(2)), hyaluronic acid and plasma disappearance rate (PDR) of indocyanine green (ICG) were recorded.

RESULTS

TLBF remained mostly unaltered in both groups at low IAP and decreased only in CG at the IAP of 25 mmHg. As IAP increased, a significant decline in MBF was observed without correlation with cardiac output or TLBF. In CG, HpO(2) decreased as early as IAP of 10 mmHg to high levels of pressure. However, in TG the decrease was significant only at the IAP of 25 mmHg. PDR of ICG decreased in both groups at IAP of 25 mmHg (P = 0.046 and P = 0.009 in TG and CG, respectively). These changes correlated with MBF (r = 0.793).

CONCLUSION

Blocking ET(A) and ET(B) receptors partially protects sinusoidal circulation and tissue oxygenation against stress induced by high IAP.

The hepatorenal reflex contributes to the induction of oliguria during pneumoperitoneum in the rat

BACKGROUND

Hepatic blood flow is known to decrease during pneumoperitoneum. Studies have shown that such changes affect kidney urinary output through the sympathetic pathway known as the hepatorenal reflex. This study investigated the potential role of the hepatorenal reflex in pneumoperitoneum-induced oliguria. The authors hypothesized that oliguria detectable during pneumoperitoneum is caused by activation of the hepatorenal reflex.

METHODS

Denervation of the sympathetic nervous structure was performed in 15 rats by applying 1 ml of 90 % aqueous phenol solution circumferentially to the portal vein and vena cava area at their entrance to the liver. The same was applied to only the peritoneum in 15 nondenervated rats. After 2 weeks, the rats were divided into three subgroups (5 rats per subgroup) that were exposed respectively to carbon dioxide-induced pneumoperitoneum at 0, 10, and 15 mmHg for 2 h. Statistical analysis was performed using Student's t test and analyses of variance.

RESULTS

Denervation did not affect the preinsufflation parameters. The denervated and the nondenervated 0-mmHg subgroups presented with similar parameters. The postinsufflation mean urine output was significantly lower in the nondenervated than in the denervated 10- and 15-mmHg subgroups (p = 0.0097). The denervated rats had a final creatinine clearance 29 % lower than the preinsufflation value (p = 0.83), whereas the nondenervated animals presented a 79 % drop in creatinine clearance (p = 0.02).

CONCLUSION

The study findings indicate that the hepatorenal reflex plays an important role in the pathophysiology of oliguria that occurs during pneumoperitoneum in the rat.

Understanding Intra-Abdominal Hypertension

Received November 10, 2009. Received Revised June 17, 2010. Submitted June 21, 2010. Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are highly morbid conditions that are common and underrecognized in the intensive care unit. Intra-abdominal hypertension affects the critically ill patient population and is not solely limited to the trauma and surgical subgroups. The recognition of IAH and ACS as distinct clinical states has become more apparent. Extensive bench and clinical research has shed significant light into the definition, incidence, etiology, physiology, clinical manifestations, and treatment strategies. Although further research into this morbid condition is needed, improvement in recognition is a critical first step. This review aims to scrutinize the basic science and clinical literature available on this condition in a surgically focused, organ-system-based approach.

Effect of pneumoperitoneum on renal tissue oxygenation and blood flow in a rat model

OBJECTIVES

To determine the correlation between the renal blood flow (RBF) and tissue oxygenation (PO(2)) at varying intra-abdominal pressures (IAPs) and to compare the effects on renal blood flow from carbon dioxide-induced pneumoperitoneum.

METHODS

Carbon dioxide pneumoperitoneum was established in Sprague-Dawley rats (n = 6). Licox oxygen/temperature tissue probes were laparoscopically inserted into the renal parenchyma, with the renal PO(2) and RBF recorded every 30 seconds while the IAP was gradually increased. Microprobes measuring the RBF, mean arterial pressures and serum pH were placed into the parenchyma to compare the effects of carbon dioxide pneumoperitoneum (n = 7) with that of open surgery (n = 6) and medical air pneumoperitoneum (n = 6).

RESULTS

Renal PO(2) was inversely related to the IAP (P < .001). Despite the reduction in IAP, the renal PO(2) in the recovery phase was lower than at baseline (P = .045). The renal PO(2) and RBF changed in a virtually identical pattern at varying levels of IAP (P > .05). The RBF significantly declined with a pneumoperitoneal pressure of 15 and 20 mm Hg (P = .022), regardless of the gas used to create the pneumoperitoneum. A partial reversal of the RBF occurred with a decrease of the IAP. The RBF in the open surgical arm remained unchanged. Although both the serum pH and the mean arterial pressure were inversely proportional to the IAP (P < .001), the mean arterial pressure was depressed to the greatest extent in the medical air group (P = .02).

CONCLUSIONS

These results have demonstrated that elevated IAP secondary to pneumoperitoneum causes significant renal hypoxia and decreased RBF. Additionally, this experiment has demonstrated the use of the Licox probes in monitoring the renal PO(2) and established a novel method for evaluating the effects of IAP on the kidney.

Renal apoptosis following carbon dioxide pneumoperitoneum in a rat model

PURPOSE

Laparoscopically recruited kidneys regain normal function more slowly than laparotomy harvested organs for several possible reasons. We investigated the effects of CO(2) induced pneumoperitoneum on kidney function, as reflected by blood and urine creatinine levels, and its relation with renal cell apoptosis.

MATERIALS AND METHODS

CO(2) pneumoperitoneum was established in anesthetized Wistar male rats that were randomly allocated at 6 per group into 1 of 6 groups with an intraperitoneal pressure of 0 (control), 5, 8, 12, 15 or 18 mm Hg. Pressure was maintained for 60 minutes in all groups. Three additional groups were subjected to 30-minute pneumoperitoneum at 0, 12 and 18 mm Hg, respectively. The rats were kept alive for the ensuing 24 hours, after which blood and urine creatinine were analyzed and the abdominal organs were harvested. Various areas of the organs were analyzed for apoptotic cells using the TUNEL method. Cells were randomly counted in 10 eyeshots in 3 sections each using an ocular micrometer.

RESULTS

Creatinine levels in blood and urine changed as pressure and pneumoperitoneum duration progressed. Isolated TUNEL positive nuclei were detected in the outer medulla and the cortex of control kidneys. There was a significantly higher number of TUNEL positive nuclei in the cortex and the medulla of all pressurized kidneys (p <0.05), which increased in parallel with increasing intraperitoneal pressure and pneumoperitoneum exposure time.

CONCLUSIONS

The CO(2) pneumoperitoneum gradient and its duration affect renal function and induce apoptosis. This could be a mechanism involved in renal delayed graft dysfunction in recipients of laparoscopically harvested kidneys.

[Immune response during laparoscopic and open living donor nephrectomy. An experimental pig model]

INTRODUCTION

It's been demonstrated laparoscopic access determines a lower surgical stress, by measurement of several markers as different interleuquines (IL) or C-reactive protein (CRP). Endothelin 1 (ET-1) is a powerful vasoconstrictor produced in renal endothelium scarcely studied in laparoscopy. The objective of this study is to analyze immune response during laparoscopic and open donor nephrectomy, in a porcine experimental model by means of measuring IL-2, 10, tumoral necrosis factor alpha (TNFalpha), CRP and ET-1.

METHODS

Twenty pigs underwent left nephrectomy, 10 by laparoscopy and 10 by open approach in an experimental model. Both groups were monitorized IL-2, 10, TNF alpha, ET-1 at basal, immediately post surgery, first, third, fifth and seventh days after procedure.

RESULTS

The comparative analysis between groups demonstrated a significant increase in levels of CRP (1.44+/-0.88 vs 1.32+/-0.14 mg/dl, p=0.046), TNF alpha (131.14+/-41.37 vs 57.19+/-23.71 pg/ml, p>0.001) and ET-1 (0.91+/-0.49 vs 0.56+/-0.5 fmol/ml, p=0.001) of open nephrectomy group, as a higher levels of IL-2 in laparoscopic group.

CONCLUSIONS

Open donor nephrectomy determines a higher immune response than laparoscopic approach. The importance of this fact over the ischemia-reperfusion syndrome or the immediate function of graft is not clearly established.

Adverse effects of pneumoperitoneum on renal function: involvement of the endothelin and nitric oxide systems

Increased intra-abdominal pressure (IAP) during laparoscopy adversely affects kidney function. The mechanism underlying this phenomenon is largely unknown. This study was designed to investigate the involvement of endothelin (ET)-1 and nitric oxide (NO) systems in IAP-induced renal dysfunction. Rats were subjected to IAP of 14 mmHg for 1 h, followed by a deflation for 60 min (recovery). Four additional groups were pretreated with 1) ABT-627, an ET(A) antagonist; 2) A-192621, an ET(B) antagonist; 3) nitroglycerine; and 4) N(G)-nitro-L-arginine methyl ester, a NO synthase inhibitor, before IAP. Urine flow rate (V), absolute Na+ excretion (U(Na)V), glomerular filtration rate (GFR), and renal plasma flow (RPF) were determined. Significant reductions in kidney function and hemodynamics were observed when IAP was applied. V decreased from 8.1 +/- 1.0 to 5.8 +/- 0.5 microl/min, U(Na)V from 1.08 +/- 0.31 to 0.43 +/- 0.10 microeq/min, GFR from 1.84 +/- 0.12 to 1.05 +/- 0.06 ml/min (-46.9 +/- 2.7% from baseline), and RPF from 8.62 +/- 0.87 to 3.82 +/- 0.16 ml/min (-54 +/- 3.5% from baseline). When the animals were pretreated with either ABT-627 or A-192621, given alone or combined, the adverse effects of IAP on GFR, RPF, V, and U(Na)V were significantly augmented. When the animals were pretreated with nitroglycerine, the adverse effects of pneumoperitoneum on GFR and RPF were substantially improved. In contrast, pretreatment with N(G)-nitro-L-arginine methyl ester remarkably aggravated pneumoperitoneum-induced renal dysfunction. In conclusion, decreased renal excretory function and hypofiltration are induced by increased IAP. These effects are related to impairment of renal hemodynamics and could be partially ameliorated by pretreatment with nitroglycerine and aggravated by NO and ET blockade.

Immunohumoral response during laparoscopic and open living donor nephrectomy: an experimental model

Measurement of interleukins (IL) and C-reactive protein (CRP) have demonstrated that a laparoscopic approach may induce less surgical stress than an open approach. The potential influence of this observation in living donor nephrectomy has scarcely been analyzed. The aim of the study was to analyze the immunohumoral response induced by laparoscopic versus open donor nephrectomy in an experimental model. Twenty pigs underwent left nephrectomy, 10 by laparoscopy and 10 by an open approach. In both groups the following parameters were measured: CRP, IL-2, IL-10, tumour necrosis factor alpha (TNF alpha), and endothelin-1 (ET-1). The determinations were done at different times: basal, immediately as well as on the first, third, fifth, and seventh days after the procedure. A comparative analysis between groups demonstrated a significant increases among the open group in the following markers: CRP (1.44 +/- 0.88 vs 1.32 +/- 0.14 mg/dL, P = .046); TNF alpha (131.14 +/- 41.37 vs 57.19 +/- 23.71 pg/mL; P > .001); and ET-1 (0.91 +/- 0.49 vs 0.56 +/- 0.5 fmol/mL; P = .001). The laparoscopic group showed higher levels of IL-2 than the open group. In conclusion, open donor nephrectomy produced a greater immunohumoral response than a laparoscopic approach. The influence of these observations on ischemia-reperfusion injury or on immediate graft function after kidney transplantation has not been clearly established.

[Comparative analysis about hemodynamic and renal blood flow effects during open versus laparoscopic nephrectomy. An experimental study]

BACKGROUND

The increase of intraabdominal pressure to 10 mmHg provokes a decrease of renal blood flow (RBF). Pneumoperitoneum during laparoscopic techniques with intra-abdominal pressure (IAP) to 15 mmHg, results in a decrease in RBF, urine output and glomerular filtration rate (GFR).

PURPOSE

Analyze the changes in RBF, urine output an GFR in a porcine experimental model during open vs laparoscopic nephrectomy.

MATERIALS AND METHODS

30 pigs (medium weigh= 22.6+3.2 Kg) were divided into two groups: Laparoscopic nephrectomy was performed using 15 pigs and open nephrectomy in 15 pigs, following a living donor nephrectomy autotransplantation model. Study parameters were urine volume and GFR baseline values, 30 and 60 minutes during nephrectomy. RBF was measured using an electromagnetic flow catheter around the main renal artery during the initial 60 minutes of nephrectomy.

RESULTS

The laparoscopic technique was associated with a significant reduction of RBF (80+2.7 vs 262+3 ml/min) (p<0.005), diuresis (42%) and GFR (38%), vs the open group.

CONCLUSIONS

Laparoscopic nephrectomy involves a significant reduction of RBF, GFR and diuresis, which is potentially transcendent in living donor nephrectomy and kidney transplantation.

Laparoscopic donor nephrectomy gene expression profiling reveals upregulation of stress and ischemia associated genes compared to control kidneys

We compared gene expression profiles from six donor kidneys prior to surgical manipulation to six kidneys removed after laparoscopic donor nephrectomy (LDN) and several hours of CO2 pneumoperitoneum. Biopsies were obtained from renal cortex and hybridized to Affymetrix HG-U133A GeneChips. For control kidneys, we identified 1380 genes present on all six samples that had a signal intensity >1,000. Functional classification of these revealed genes for cellular signaling (201; 15%), regulation of transcription (156; 11%), cellular transport (144; 10%) and cellular metabolism (111; 8%). A class comparison between the controls and LDN kidneys yielded 865 differentially expressed genes. Functional classification of the 502 genes differentially upregulated in LDN kidneys identified associations with apoptosis, cell adhesion, cell signaling, regulation of cell growth/proliferation, immune/inflammation, ischemia/stress response and proteolysis/peptidolysis. These data demonstrate an altered renal transcriptome induced by several hours of CO2 pneumoperitoneum and laparoscopic surgery characterized by upregulation of ischemia and injury associated genes.