Effects of terlipressin on microcirculation of small bowel mesentery in rats with endotoxic shock

Micro-lightguide spectrophotometry assessment of hepatic and intestinal microcirculation in endotoxemic rats during intravenous treatment with angiotensin II

INTRODUCTION

During septic shock, impairment of microcirculation leads to enhanced permeability of intestinal mucosa triggered by generalized vasodilation and capillary leak. Intravenous angiotensin II (AT-II) has been approved for the treatment of septic shock; however, no in-vivo data exist on the influence of AT-II on hepatic and intestinal microcirculation.

MATERIAL AND METHODS

Sixty male Lewis rats were randomly assigned to six study groups (each n = 10): sham, lipopolysaccharide-induced septic shock, therapy with low- or high-dose AT-II (50 or 100 ng/kg/min, respectively), and septic shock treated with low- or high-dose AT-II. After median laparotomy, hepatic and intestinal microcirculation measures derived from micro-lightguide spectrophotometry were assessed for 3 h and included oxygen saturation (SO2), relative blood flow (relBF) and relative hemoglobin level (relHb). Hemodynamic measurements were performed using a left ventricular conductance catheter, and blood samples were taken hourly to analyze blood gasses and systemic cytokines.

RESULTS

AT-II increased mean arterial pressure in a dose-dependent manner in both septic and non-septic animals (p < 0.001). Lower hepatic and intestinal SO2 (both p < 0.001) were measured in animals without endotoxemia who received high-dose AT-II treatment, however, significantly impaired cardiac output was also reported in this group (p < 0.001). In endotoxemic rats, hepatic relBF and relHb were comparable among the treatment groups; however, hepatic SO2 was reduced during low- and high-dose AT-II treatment (p < 0.001). In contrast, intestinal SO2 remained unchanged despite treatment with AT-II. Intestinal relBF (p = 0.028) and interleukin (IL)-10 plasma levels (p < 0.001) were significantly elevated during treatment with high-dose AT-II compared with low-dose AT-II.

CONCLUSIONS

A dose-dependent decrease of hepatic and intestinal microcirculation during therapy with AT-II in non-septic rats was observed, which might have been influenced by a corresponding reduction in cardiac output due to elevated afterload. While hepatic microcirculation was reduced during endotoxemia, no evidence for a reduction in intestinal microcirculation facilitated by AT-II was found. In contrast, both intestinal relBF and anti-inflammatory IL-10 levels were increased during high-dose AT-II treatment.

Addition of terlipressin to norepinephrine in septic shock and effect of renal perfusion: a pilot study

Purpose

Terlipressin improves renal function in patients with septic shock. However, the mechanism remains unclear. Here, we aimed to evaluate the effects of terlipressin on renal perfusion in patients with septic shock.

Materials and Methods

This pilot study enrolled patients with septic shock in the intensive care unit of the tertiary hospital from September 2019 to May 2020. We randomly assigned patients to terlipressin and usual care groups using a 1:1 ratio. Terlipressin was intravenously pumped at a rate of 1.3 μg/kg/hour for 24 h. We monitored renal perfusion using renal contrast-enhanced ultrasound (CEUS). The primary outcome was peak sonographic signal intensity (a renal perfusion parameter monitored by CEUS) at 24 h after enrollment.

Results

22 patients were enrolled in this study with 10 in the terlipressin group and 12 in the usual care group. The baseline characteristics of patients between the two groups were comparable. The peak sonographic signal intensity at 24 h after enrollment in the terlipressin group (60.5 ± 8.6 dB) was significantly higher than that in the usual care group (52.4 ± 7.0 dB; mean difference, 7.1 dB; 95% CI, 0.4–13.9; adjusted p = .04). Patients in the terlipressin group had a lower time to peak, heart rates, norepinephrine dose, and a higher stroke volume at 24 h after enrollment. No significant difference in the urine output within 24 h and incidence of acute kidney injury within 28 days was found between the two groups.

Conclusions

Terlipressin improves renal perfusion, increases stroke volume, and decreases norepinephrine dose and heart rates in patients with septic shock.

Improvement of gut-vascular barrier by terlipressin reduces bacterial translocation and remote organ injuries in gut-derived sepsis

Gut-vascular barrier (GVB) serves as the last barrier to limit the migration of intestinal toxins into the blood circulation. The efficacy of terlipressin (a vasopressin V1 receptor agonist) in reducing GVB and multiple organ damage in gut-derived sepsis is unknown. In this study, we hypothesized that, besides other intestinal barriers, GVB play a key role in gut-derived sepsis and terlipressin improve GVB damage and then reduce bacterial translocation and organ injuries. In vivo, a cecal ligation and puncture mouse model was established. The mice were subjected to examine the damage of GVB determined by intestinal plasmalemma vesicle-associated protein-1(PV-1) and vascular endothelial-cadherin. And the intestinal permeability was assessed by translocation of intestinal bacteria and macromolecules. In vitro, transendothelial electrical resistance (TER) during interleukin (IL)-1β stimulation was measured on endothelial cells with or without small interfering RNA targeting β-catenin (si β-catenin). Terlipressin significantly improved GVB damage and reduced translocation of intestinal macromolecules and bacteria by activating PI3K signaling. Of note, intestinal PV-1 expression was significantly correlated with translocation of macromolecules, and dramatic increase of macromolecules was observed in intestinal tissues whereas fewer macromolecules and bacteria were observed in blood, liver and lung following terlipressin treatment. In vitro, terlipressin restored TER during IL-1β stimulation and si β-catenin transfection blocked the changes delivered by terlipressin. Collectively, terlipressin alleviated GVB damage and subsequent bacterial translocation via blood vessels after sepsis challenge, resulting in reduced distant organ injuries and the responsible mechanisms may involve the activation of PI3K/β-catenin pathway.

Sub-therapeutic vasopressin but not therapeutic vasopressin improves gastrointestinal microcirculation in septic rats: A randomized, placebo-controlled, blinded trial

INTRODUCTION

Sepsis impairs gastrointestinal microcirculation and it is hypothesized that this might increase patient's mortality. Sub-therapeutic vasopressin improves gastric microcirculation under physiologic conditions whereas a therapeutic dosing regimen seems to be rather detrimental. However, the effects of sub-therapeutic vasopressin on gastrointestinal microcirculation in sepsis are largely unknown. Therefore, we conducted this trial to investigate the effect of sub-therapeutic as well as therapeutic vasopressin on gastrointestinal microcirculation in sepsis.

METHODS

40 male Wistar rats were randomized into 4 groups. Colon ascendens stent peritonitis (CASP)-surgery was performed to establish mild or moderate sepsis. 24 hours after surgery, animals received either vasopressin with increasing dosages every 30 min (6.75, 13.5 (sub-therapeutic), 27 mU · kg-1 · h-1 (therapeutic)) or vehicle. Microcirculatory oxygenation (μHBO2) of the colon was recorded for 90 min using tissue reflectance spectrophotometry. Intestinal microcirculatory perfusion (total vessel density (TVD; mm/mm2) and perfused vessel density (PVD; mm/mm2)) were measured using incident dark field-Imaging at baseline and after 60 min.

RESULTS

In mild as well as in moderate septic animals with vehicle-infusion intestinal μHbO2, TVD and PVD remained constant. In contrast, in moderate sepsis, sub-therapeutic vasopressin with 13.5 mU · kg-1 · h-1 elevated intestinal μHBO2 (+ 6.1 ± 5.3%; p < 0.05 vs. baseline) and TVD (+ 5.2 ± 3.0 mm/mm2; p < 0.05 vs. baseline). μHBO2, TVD and PVD were significantly increased compared to moderate sepsis alone. However, therapeutic vasopressin did not change intestinal microcirculation. In mild septic animals sub-therapeutic as well as therapeutic vasopressin had no relevant effect on gastrointestinal microcirculation. Systemic blood pressure remained constant in all groups.

CONCLUSION

Sub-therapeutic vasopressin improves gastrointestinal microcirculatory oxygenation in moderate sepsis without altering systemic blood pressure. This protective effect seems to be mediated by an enhanced microcirculatory perfusion and thereby increased oxygen supply. In contrast, therapeutic vasopressin did not show this beneficial effect.

Terlipressin relieves intestinal and renal injuries induced by acute mesenteric ischemia via PI3K/Akt pathway

Background: To date, the effect of vasopressin on organ damages after acute mesenteric ischemia (MI) remains poorly understood. Aims: To investigate the effect of terlipressin, a selective vasopressin V1 receptor agonist, versus norepinephrine on the intestinal and renal injuries after acute MI, and to explore the underlying mechanism of terlipressin. Methods: Acute MI model was produced by clamping the superior mesenteric artery for 1 hour. Immediately after unclamping, terlipressin or norepinephrine was intravenously administered for 2 hours. Meanwhile, in vitro, RAW264.7 cells were treated with lipopolysaccharide or lipopolysaccharide+terlipressin. In addition, wortmannin was used to determine the role of phosphoinositide 3-kinase (PI3K)/ protein kinase B (Akt) pathway in the potential impacts of terlipressin. Results: MI led to severe hypotension, caused notable intestinal and renal impairments and resulted in high mortality, which were markedly improved by terlipressin or norepinephrine. Terlipressin increased mean arterial pressure, decreased intestinal epithelial cell apoptosis, inhibited the generation of M1 macrophage in intestinal and renal tissues, and hindered the release of inflammatory cytokines after MI. Moreover, in cultured macrophages, terlipressin reduced the mRNA level of specific M1 markers and the release of inflammatory cytokines caused by lipopolysaccharide challenge. Wortmannin decreased the expression of PI3K and Akt induced by terlipressin in cells and in tissues, and abolished the above protective effects conferred by terlipressin. Conclusions: Terlipressin or norepinephrine could effectively improve organ damages and mortality after acute MI. Terlipressin elevates blood pressure and inhibits intestinal epithelial apoptosis and macrophage M1 polarization via the PI3K/Akt pathway.

Evaluation of Neutrophil Gelatinase-Associated Lipocalin as a Predictor of Glomerular Filtration Rate and Amikacin Clearance During Early Rat Endotoxemia: Comparison with Traditional Endogenous and Exogenous Biomarkers

BACKGROUND AND OBJECTIVES

Renal elimination of amikacin and other aminoglycosides is slowed down in sepsis-induced acute kidney injury increasing the risk of adverse effects. Since neutrophil gelatinase-associated lipocalin (NGAL) and aminoglycosides share the mechanisms for renal excretion, the predictive power of NGAL was examined towards the changes in amikacin pharmacokinetics during early endotoxemia in anesthetized Wistar rats.

METHODS

Endogenous biomarkers of inflammation and acute kidney injury were assessed including NGAL in saline-injected controls and two groups of rats challenged with an intravenous injection of bacterial lipopolysaccharide (5 mg/kg)-a fluid-resuscitated group (LPS) and a fluid-resuscitated group infused intravenously with 8 μg/kg/h terlipressin (LPS-T). Sinistrin and amikacin were infused to measure glomerular filtration rate (GFR) and amikacin clearance (CL_am). The investigations included blood gas analysis, chemistry and hematology tests and assessment of urine output, creatinine clearance (CL_cr) and sinistrin clearance (CL_sini).

RESULTS

Within 3 h of injection, systemic and renal inflammatory responses were induced by lipopolysaccharide. Gene and protein expression of NGAL was increased in the kidneys and the concentrations of NGAL in the plasma (pNGAL) and urine rose 4- to 38-fold (P < 0.01). The decreases in CL_am and the GFR markers (CL_cr, CL_sini) were proportional, reflecting the extent to which endotoxemia impaired the major elimination mechanism for the drug. Terlipressin attenuated lipopolysaccharide-induced renal dysfunction (urine output, CL_cr, CL_sini) and accelerated CL_am. The pNGAL showed a strong association with the CL_sini (rs = - 0.77, P < 0.0005). Concerning prediction of CL_am, pNGAL was comparable to CL_cr (mean error - 24%) and inferior to CL_sini (mean error - 6.4%), while the measurement of NGAL in urine gave unsatisfactory results.

CONCLUSIONS

During early endotoxemia in the rat, pNGAL has a moderate predictive ability towards CL_am. Clinical studies should verify whether pNGAL can support individualized dosing of aminoglycosides to septic patients.

A global perspective on vasoactive agents in shock

PURPOSE

We set out to summarize the current knowledge on vasoactive drugs and their use in the management of shock to inform physicians' practices.

METHODS

This is a narrative review by a multidisciplinary, multinational-from six continents-panel of experts including physicians, a pharmacist, trialists, and scientists.

RESULTS AND CONCLUSIONS

Vasoactive drugs are an essential part of shock management. Catecholamines are the most commonly used vasoactive agents in the intensive care unit, and among them norepinephrine is the first-line therapy in most clinical conditions. Inotropes are indicated when myocardial function is depressed and dobutamine remains the first-line therapy. Vasoactive drugs have a narrow therapeutic spectrum and expose the patients to potentially lethal complications. Thus, these agents require precise therapeutic targets, close monitoring with titration to the minimal efficacious dose and should be weaned as promptly as possible. Moreover, the use of vasoactive drugs in shock requires an individualized approach. Vasopressin and possibly angiotensin II may be useful owing to their norepinephrine-sparing effects.

Terlipressin protects intestinal epithelial cells against oxygen-glucose deprivation/re-oxygenation injury via the phosphatidylinositol 3-kinase pathway

Intestinal ischemia/reperfusion (I/R) injury is associated with a high morbidity and mortality. Vasopressin is administered to critically ill patients with potential intestinal I/R. However, the impacts of vasopressin on intestinal epithelia under ischemic/anoxic conditions remain unclear. The aim of the present study was to evaluate the effects of terlipressin, a highly selective vasopressin V1 receptor agonist, on oxygen and glucose deprivation/re-oxygenation (OGD/R)-induced damage in intestinal epithelial cells (IEC-6). IEC-6 cells were subjected to OGD for 4 h, followed by 4 h re-oxygenation. Terlipressin was incubated with cells for 4 h following OGD. Following OGD/R, IEC-6 cell viability, proliferation and apoptosis, as well as cell cycle dynamics, were assessed and the levels of tumor necrosis factor (TNF)-α and 15-F2t-isoprostane in the culture medium were measured. In addition, wortmannin, a specific phosphatidylinositol 3-kinase (PI3K) inhibitor, was administrated to investigate the mechanism of terlipressin action. The results demonstrated that IEC-6 cell viability and proliferation decreased, and cell apoptosis increased, following OGD/R. However, IEC-6 cell cycle dynamics did not significantly change 4 h after OGD. Incubation with 25 nM terlipressin significantly improved cell viability, proliferation and apoptosis. Furthermore, terlipressin inhibited the secretion of TNF-α and 15-F2t-isoprostane from IEC-6 cells following OGD/R. The aforementioned effects of terlipressin were completely abolished following the application of 2 µM wortmannin. Therefore, the current study demonstrated that terlipressin administration following OGD attenuates OGD/R-induced cell damage via the PI3K signaling pathway. These results may help physicians to better understand and more effectively use terlipressin in a clinical setting.

Mechanism of gut barrier failure associated with severe acute pancreatitis

Gut barrier failure is often present in severe acute pancreatitis (SAP), and it increases the gut permeability, leads to translocation of bacteria or endotoxin, causes severe infection and multiple organ dysfunction syndrome, and worsens the course of the disease. The injury of gut barrier may result from the interactions among microcirculation disturbance, ischemia-reperfusion injury, excessive release of inflammatory mediators, apoptosis, flora imbalance and so on. The research on the mechanism of gut barrier failure caused by SAP is of important significance for the treatment of SAP.