Endorphins in primate hemorrhagic shock: beneficial action of opiate antagonists

Recurrent pyogenic cholangitis - an independent poor prognostic indicator for resectable intrahepatic cholangiocarcinoma: A propensity score matched analysis

BACKGROUND

Recurrent pyogenic cholangitis (RPC) is a known risk factor for intrahepatic cholangiocarcinoma (ICC), whether it represents a poor prognostic factor remains controversial. The aim of this study was to investigate the post-hepatectomy oncological outcomes of patients with ICC and coexisting RPC.

METHOD

A retrospective analysis with propensity score matching (PSM) was performed for comparison between ICC patient with and without RPC.

RESULTS

There were 143 patients with ICC with a median follow-up of 21 months. RPC was diagnosed in 18% of patients. The time from RPC diagnosis to ICC diagnosis was 137(47-481) months. The 3-year disease-free (DFS) and overall survival for the whole population was 34% and 43% respectively. Preoperative child score, elevated carcinoembryonic antigen, presence of microvascular invasion, multiple tumours, presence of postoperative complications and RPC were independent factors for DFS and OS. After PSM, 60 ICC patients who did not have RPC were compared with 20 ICC patients with RPC. Patients with RPC had significantly worse median DFS (10 vs 23 months, P = 0.020) and OS (15 vs 45 months, P = 0.004) when compared to the patients without RPC.

CONCLUSION

RPC represents a poor prognostic factor affecting outcomes after hepatectomy for patients with ICC.

An Evolving Uncontrolled Hemorrhage Model Using Cynomolgus Macaques

BACKGROUND

Trauma-induced hemorrhagic shock produces hemodynamic changes that often result in a systemic inflammatory response that can lead to multiple organ failure and death. In this prospective study, the pathophysiology of a nonhuman primate uncontrolled hemorrhagic shock model is evaluated with the goal of creating an acute systemic inflammatory syndrome response and a reproducible hemorrhage.

METHODS

Nonhuman primates were divided into 2 groups. A laparoscopic left hepatectomy was performed in groups A and B, 60% and 80%, respectively, resulting in uncontrolled hemorrhage. Resuscitation during the prehospital phase lasted 120 min and included a 0.9% saline bolus at 20 mL/kg. The hospital phase involved active warming, laparotomy, hepatorrhaphy for hemostasis, and transfusion of packed red blood cells (10 mL/kg). The animals were recovered and observed over a 14-day survival period with subsequent necropsy for histopathology.

RESULTS

Baseline demographics and clinical parameters of the two groups were similar. Group A (n = 7) underwent a 57.7% ± 2.4% left hepatectomy with a 33.9% ± 4.0% blood loss and 57% survival. Group B (n = 4) underwent an 80.0% ± 6.0% left hepatectomy with 56.0% ± 3.2% blood loss and 75% survival. Group B had significantly lower hematocrit (P < 0.05) for all postinjury time points. Group A had significantly elevated creatinine on postoperative day 1. Nonsurvivors succumbed to an early death, averaging 36 h from the injury. Histopathologic evaluation of nonsurvivors demonstrated kidney tubular degeneration.

CONCLUSIONS

Nonhuman primates displayed the expected physiologic response to hemorrhagic shock due to liver trauma as well as systemic inflammatory response syndrome with resultant multiple organ dysfunction syndrome and either early death or subsequent recovery. Our next step is to establish a clinically applicable nonhuman primate polytrauma model, which reproduces the prolonged maladaptive immunologic reactivity and end-organ dysfunction consistent with multiple organ failure found in the critically injured patient.

THE IMMEDIATE RESPONSE TO SEVERE SHOCK IN A CANINE MODEL WITH A COMBINATION OF HYPERTONIC-HYPERONCOTIC SOLUTION WITH NALOXONE

To evaluate the acute hemodynamic and acid-base balance effects of hypertonic-hyperoncotic solution (HHS) combined with naloxone in the treatment of hemorrhagic shock in 45 male splenectomized adult mongrel dogs, a severe controlled hemorrhagic shock (20 mmHg mean arterial pressure during 30 min) was established in the groups (n=6) no treatment, shed blood reinfusion, hypertonic-hyperoncotic (saline-dextran) solution alone, naloxone alone (NX), or combination. Interventions included propiopromazine-pentobarbital anesthesia and installation of Swan-Ganz, femoral arterial, and urethral catheters, and exsanguination at 20 mmHg mean arterial pressure during 30 min followed by treatment and observation for 160 min. Fifteen (33%) dogs died before completing the 30-min shock period. Another 33% from the no-treatment group died during the following 90 min. Shed blood improved the cardiac index, arterial pressure, and acid-base balance. NX restored the cardiac index to less than 60% of baseline and reduced vascular resistance. Additionally, NX produced no improvement in acidosis, with 1 dog dead at 95 min posttreatment. HHS restored the cardiac index for 45 min and increased vascular resistance and arterial pressure. Acidosis was not improved. Single-dose HHS combined with naloxone resulted in a high cardiac index, oxygen consumption, and urine output with low peripheral vascular resistance (and no acute mortality) compared with untreated or single-dose groups.

Changes in circulating plasma met-enkephalin concentrations in feline intestinal ischemia--reperfusion

Plasma met-enkephalin-like immunoreactivity (MLI) levels were determined in cats before, during and after 90 min of intestinal ischemia followed by reperfusion and compared with the levels in control cats. Blood pressure and heart rate were registered and small intestinal mucosal lesions were graded. In control animals, the circulation was stable and there were no mucosal injuries. In the shock group, blood pressure decreased, heart rate increased and severe mucosal lesions were found. The circulating MLI levels were significantly higher 30 min after reperfusion of the ischemic intestine in the shock group than in the control group. There were correlations between MLI and tachycardia and hypotension respectively. Met-enkephalin was released in shock animals after reperfusion of the ischemic intestine and may explain naloxone responsiveness in intestinal shock models.

Cardiovascular effects of microinjection of dynorphin fragments into the nucleus of the solitary tract (NTS) are mediated by non-opioid mechanisms

The nucleus of the solitary tract (NTS) is important for the regulation of cardiovascular homeostasis. In the present study we investigated the effect of dynorphin A-(1-13), dynorphin A-(1-17) and dynorphin A-(2-17) microinjected into the NTS on mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV) and left ventricular stroke work (LVSW) following hemorrhage in conscious rats. Following fixed-volume hemorrhage (8 ml/300 g), microinjection of dynorphin A-(2-17) (6 nmol), which is inactive at opioid receptors, into the NTS significantly attenuated the recovery of CO, SV and LVSW following hemorrhage when compared to those animals receiving a microinjection of normal saline (NS) vehicle into the NTS (P < 0.01). NTS microinjection of dynorphin A-(2-17) also increased HR following hemorrhage when compared with the NS group (P < 0.05). No significant effects were observed on CO, SV and LVSW following NTS microinjection of the kappa-opioid agonists, dynorphin A-(1-13) and dynorphin A-(1-17), although dynorphin A-(1-13) microinjection increased HR following hemorrhage when compared with control animals (P < 0.05). Microinjection of all three peptide fragments had no significant effect on MAP when compared with MAP of the control group following hemorrhage. The results of this study suggest that dynorphin A-(2-17) in the NTS can attenuate the compensatory cardiovascular responses to hemorrhage, perhaps via a non-opioid mechanism.

Activation of kappa-opioid receptors in the nucleus ambiguus does not affect cardiovascular function or outcome following acute hemorrhage in the rat

The central cardiovascular response to hemorrhage is believed to be regulated, in part, by specific brain cardioregulatory nuclei, including the nucleus ambiguus (NA) of the hindbrain. Since endogenous opioid peptides and opiate receptors have been localized to this brain region, activation of endogenous opioid systems in the NA may affect the cardiovascular response to acute hemorrhage. The present study examined the effects of intracerebral microinjection of kappa-receptor agonists into the NA prior to acute fixed-volume hemorrhage in awake rats. 15 min prior to fixed volume hemorrhage (7.5 ml/300 g), male Sprague-Dawley rats (n = 59) received a microinjection of either (1) the synthetic kappa-receptor agonist U-50,488H (10 nM) or (2) U-50,488H (100 nM) or (3) the endogenous kappa-receptor agonist dynorphin 1-17 (1 nM) or (4) Des-Tyr dynorphin 2-17, inactive at opiate receptors (1 nM) or (5) equal volume saline. With the exception of the first 10 min post-hemorrhage, where intracerebral injection of both dynorphin 1-17 and dynorphin 2-17 caused a transient suppression of mean arterial blood pressure (P < 0.05 when compared to saline-treated controls), microinjection of the kappa-agonists dynorphin 1-17 or U-50,488H had no effect on blood pressure, heart rate or mortality when compared to control animals. These results suggest that activation of kappa-opiate receptors in the NA does not markedly influence cardiovascular response to acute hemorrhage.

Activation of glucocorticoid receptors and the effect of naloxone during hemorrhagic hypotension

Evidence indicates that endogenous opioid peptides and glucocorticoids participate in the control of cardiovascular regulation during hemorrhagic shock. In the present study, we investigated a possible interaction between brain opioid peptides and adrenal corticosteroids regarding the control of arterial pressure during hemorrhage. The bleeding volumes required to lower arterial pressure to 80, 60 and 40 mmHg were studied in anesthetized sham-operated (SHAM) and adrenalectomized (ADX) rats. I.c.v. administration of 10 micrograms of naloxone resulted in a significant increase in the bleeding volume required to lower arterial pressure from 60 to 40 mmHg in SHAM animals, whereas no effect of naloxone was observed in ADX animals. Replacement therapy with a 100% corticosterone pellet (100 mg, s.c.), but not with a 12.5% corticosterone pellet (12.5 mg corticosterone and 87.5 mg cholesterol, s.c.), resulted in an effect of naloxone on the bleeding volume in ADX animals. The effect of replacement therapy could be inhibited by i.c.v. pretreatment with the synthetic glucocorticoid receptor antagonist, RU38486 (100 ng). These data suggest that (1) opioid mechanisms are involved in the regulation of blood pressure during hemorrhage, and (2) occupancy of glucocorticoid receptors is required for naloxone to exert its hemodynamic effect during hemorrhagic hypotension in ADX rats.

Endogenous opiates: 1986

This is the ninth installment of our annual review of research involving the endogenous opiate peptides. It is restricted to the non-analgesic and behavioral studies of the opiate peptides published in 1986. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic processes; mental illness; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; activity; sex, pregnancy, and development; and some other behaviors.

The effects of naloxone, dexamethasone, deoxycorticosterone and 17-hydroxyprogesterone on blood pressure responses of normal and adrenalectomized rats during hypovolaemic shock

The roles of, and interactions between, steroids and naloxone, an opioid antagonist, in the reversal of experimental hypotensive shock were studied in normal and adrenalectomized rats. In normal rats treated with dexamethasone or deoxycorticosterone or 17-hydroxyprogesterone the hypotension and shock caused by 1% bodyweight and 2% bodyweight haemorrhage could be substantially reversed by naloxone in a dose-related manner. In contrast, the reversal of hypotension by naloxone was markedly less in adrenalectomized rats. It is concluded that there is a co-ordinate release of pressor catecholamines and depressor enkephalins from adrenal glands in hypovolaemic shock. Eventually, the use of naloxone would be of much less value in the treatment of hypotension or shock in patients with Addison's disease.