Effects of high dose octreotide on retrograde bile salt-induced pancreatitis in rats

How Alcohol Induces Human Acute Alcoholic Pancreatitis-Problem Solved?

It has been a puzzle why only a minority of heavy alcohol drinkers develop acute alcoholic pancreatitis. In this review, the sparse data available from published studies were collected and, based on them, a hypothesis was formed. Long-term high alcohol consumption results in lowered cholecystokinin and cholinergic stimulus of the pancreas, and causes concentration and acidification of pancreatic fluid, predisposing to protein secretion. Early during the withdrawal period when returning to a normal or high-fat nonalcoholic diet, there is a relative hyperstimulation of the pancreas, a well-established mechanism that results in experimental acute pancreatitis. Lower, physiological stimulation is enough to start acute pancreatitis, when the secretions cause temporary obstruction in the duct system; the stimulation against temporary obstruction is also well-known to result in experimental acute pancreatitis. The magnitude of alcohol-induced deficits in acinar cell defense mechanisms then finally determines the onset of pancreatitis.

Neuronostatin ameliorates sodium taurocholate-induced acute pancreatitis in rats

BACKGROUND AND AIMS

Neuronostatin is encoded in the preprosomatostatin gene and exerts important physiological actions on neuronal and cardiovascular regulation and metabolism in diverse tissues. An intraperitoneal injection of neuronostatin can induce c-Jun expression in the periphery of pancreatic islets. Because of the relatively high amount of neuronostatin present in the pancreas, it is necessary to investigate the effects of neuronostatin on pancreas. Furthermore, little is known about the effect of neuronostatin on acute pancreatitis.

METHODS

Neuronostatin (30, 60, and 120 nmol) was injected in to the external jugular vein 30 min before retrograde infusion of 2 % sodium taurocholate into the pancreaticobiliary duct. After 6 h, histological damage of the pancreas was evaluated by pancreas weight and paraffin section. A blood sample was collected to determine the serum amylase and lipase activities.

RESULTS

In our findings, neuronostatin groups had a reduction in interstitial edema, acinar cell vacuolization, and inflammatory infiltration of the pancreas compared with the model group. Biochemical data showed that serum amylase and lipase activities were significantly decreased in neuronostatin-pretreated groups by comparison with the model group.

CONCLUSIONS

Histopathologic examination suggests that neuronostatin ameliorated the histological damage of sodium taurocholate-induced acute pancreatitis in rats. The biochemical analysis was consistent with that obtained from histopathologic examination, which was toward a trend of attenuating acute pancreatitis. In summary, neuronostatin might be potentially capable of ameliorating pancreatic damage in acute pancreatitis in rats.

High-dose versus low-dose octreotide in the treatment of acute pancreatitis: a randomized controlled trial

To evaluate the therapeutic efficacy of high-dose octreotide in patients with predicted severe acute pancreatitis (SAP) or SAP, two hundred and thirty-six patients with predicted SAP and 136 patients with SAP were randomized into control, high-dose octreotide (High-O) and low-dose octreotide (Low-O) groups. In addition to the conventional managements administrated in control group, High-O group received an intravenous infusion of octreotide at 50 μg/h × 3d + 25 μg/h × 4d, and Low-O group received octreotide at 25 μg/h × 7d. The major primary outcomes included the numbers of predicted SAP patients which developed SAP after intervention and the number of patients with SAP amelioration. Secondary outcomes included APACHE II, SIRS scores, plasma levels of somatostatin (SST), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6). There were no significant differences between the control and Low-O groups in terms of prevention and treatment for SAP. The incidence of SAP in patients with predicted SAP who received High-O was significantly lower than the Low-O group: 37.5% vs. 59.8%, p=0.005. Compared with Low-O group, the number of SAP patients in the SAP arm in the High-O group was reduced by 29.8%. Plasma levels of SST in both predicted SAP and the SAP patients were efficiently recovered (from 132.71±31.40 pg/ml to 180.00±23.50 pg/ml, p<0.05) after high-dose octreotide supplementation, which concomitantly reduced TNF-α and IL-6 levels. High-dose octreotide administration within 48h after AP onset may efficiently reduce the risk of SAP developing and partly attenuate SAP through raising plasma SST to a normal level and decreasing IL-6 and TNF-α.

Is there a relationship between beginning time and efficiency of octreotide in the treatment of experimental acute pancreatitis?

Purpose

The efficacy of octreotide in the treatment of acute pancreatitis is controversial. Octreotide treatment for acute pancreatitis often shows poor correlation between results obtained in experimental studies and results of clinical trials. In a clinical setting, there is always a delay between the onset of the disease and initiation of the octreotide treatment. The aim of this study is to investigate the relationship between the beginning of treatment and alteration in effectiveness of octreotide.

Methods

Acute pancreatitis was induced by pancreatic duct ligation in 50 rats. The rats were randomly divided into five groups. Octreotide was not used in group 1 (control group). Only single dose (4 µg/kg) octreotide was administered subcutaneously to rats in group 2, having induced pancreatitis. Octreotide treatment was begun at different times (8th, 24th, 48th hour) in three other groups and continued treatment at a dosage of 4 µg/kg t.i.d. The animals were sacrificed at the end of the 72nd hour and blood and tissue samples were collected.

Results

Leukocyte count and plasma amylase values were less in groups 2 and 3. Hemorrhagic focuses were encountered less at pancreas tissues in group 3. Pancreatic necrosis and alveolar capillary basal membrane damage were lower in groups 3 and 4. No difference was found in fasting blood glucose, calcium and hematocrit.

Conclusion

Octreotide had benefical effects in acute pancreatitis when octreotide treatment was begun in the first 24 hours.

Octreotide negates the benefit of galantide when used in the treatment of caerulein-induced acute pancreatitis in mice

BACKGROUND

We have previously shown that galantide, a non-specific galanin receptor antagonist, ameliorates acute pancreatitis (AP) induced in mice. Octreotide, a somatostatin analogue, has been used in the treatment of AP with inconsistent outcomes. This study set out to compare the efficacy of a combined treatment of galantide and octreotide with the efficacy of each agent individually in experimental AP.

METHODS

Acute pancreatitis was induced in mice with 7-hourly caerulein injections. Galantide and/or octreotide were co-administered with each caerulein injection commencing with the first injection. Control animals received galantide, octreotide or saline alone. Pancreata were harvested for histological examination and estimation of myeloperoxidase (MPO) activity. Plasma amylase and lipase activities were measured.

RESULTS

Galantide significantly reduced AP-induced hyperenzymaemia by 39-45%. Octreotide alone, or in combination with galantide, did not significantly alter AP-induced hyperenzymaemia. Plasma enzyme activity in the control groups was comparable with pre-treatment activity. Galantide and octreotide administered individually reduced MPO activity by 79% and 50%, respectively; however their combination was without effect. Galantide, octreotide and their combination significantly reduced the percentage of abnormal acinar cells by 28-45%.

CONCLUSIONS

Treatment with galantide alone ameliorated most of the indices of AP studied, whereas treatment with octreotide reduced pancreatic MPO activity and acinar cell damage. Combining the two peptides appears to negate their individual benefits, which suggests an interaction in their mechanism of action.

The Effect of Octreotide Against Oxidative Damage in Photosensitized Conjunctiva and Cornea of Rabbits

The purpose of this study was to determine the protective effect of octreotide against oxidative damage in rabbit conjunctiva and cornea exposed to ultraviolet radiation. Twenty rabbits weighing 2,500-3,000 g were used and we divided them into 4 groups with randomly selected 5 rabbits. Rabbits were exposed to 2 J/cm(2)/h of ultraviolet A radiation (UVA) in the range 320-405 nm for 12 h per day for 90 days. Group 1 did not receive any treatment or UVA exposure (control group). Group 2 was only exposed to UVA radiation (UVA group). Group 3 received 8-methoxypsoralen and UVA (PUVA group). Group 4 was treated with 8-methoxypsoralen + UVA + octreotide (octreotide group). At the end of 90 days the rabbits were killed by decapitation and then eyes were enucleated. Both eyes of each rabbit were used for histopathologic evaluation. Histopathologic analysis of each group indicated that UVA group and PUVA group showed increasing edema (p<0.01), inflammation (p<0.05), fibroblast proliferation (p<0.05), dysplasia (p<0.05), hyperchromasia (p<0.01) in the conjunctiva. Octreotide group had significant protective effect in comparison with the UVA group and PUVA group. The UVA group and PUVA group showed increasing proliferation (p<0.01), dysplasia (p<0.01), hyperchromasia (p<0.01), pyknosis (p<0.001) and parakeratosis (p<0.01) in the corneal epithelium. Octreotide group showed similar results with control group. We conclude that octreotide which is considered as free radical scavenger protects the eye from the damaging effect of UV exposure.

Octreotide reduces ischaemia-reperfusion injury in the retina

PURPOSE

To investigate the role of octreotide on retinal lipid peroxidation and histopathological changes during ischaemia/reperfusion (I/R).

METHODS

Three groups of seven pigmented guinea pigs each were formed. These represented a control group, an ischaemia group and an ischaemia/octreotide group. One eye of each animal was selected for histopathological evaluation and the other for biochemical assay. Bilateral pressure-induced retinal ischaemia was instigated for 90 min and was followed by 24 hours of reperfusion. Animals in the ischaemia/octreotide and ischaemia groups received either 10 micro g/kg of octreotide or saline, repeated five times at 6-hourly intervals, with the first dose administered 15 min prior to the ischaemic insult. Retinal malondialdehyde (MDA) levels and the thickness of the retinal layers were measured. These were compared with equivalent measurements of the control group.

RESULTS

The mean MDA level increased in the ischaemia group (p < 0.01) but not in the octreotide group (p > 0.05). Significant increases in the thickness of the overall retina (p < 0.01), inner retina (p < 0.05) ganglion cell layer (p < 0.01) inner plexiform layer (p < 0.01) and inner nuclear layer (p < 0.01) were observed in the ischaemia group. No significant difference in thickness was found in any of the layers in the ischaemia/octreotide group.

CONCLUSION

Octreotide reduces the increases in retinal MDA levels and retinal thickness observed during I/R.

Acute pancreatitis

Efforts to unravel the intracellular processes that occur in acute pancreatitis continue. In cerulein pancreatitis, new evidence supports the idea that a very early event is premature trypsinogen activation triggered by lysosomal cathepsin B. Clinicians persist in trying to identify more sensitive and specific prognostic signs of the severity of attacks of pancreatitis; one study suggests that computer-based neural networks may be an alternative to biochemical markers and clinical scoring systems. The systemic severity of episodes of pancreatitis seems to be related to a multitude of proinflammatory cytokines and chemokines acting at sites distant from the pancreas. Selective blockade of some of these peptides (eg, endothelin-1 and platelet-activating factor) has decreased mortality and distant organ damage in animal models and may deserve clinical evaluation. Gene therapy may be more efficient than pharmacologic therapy in increasing anti-inflammatory cytokine (interleukin-10) levels. Clinical studies have further underlined the usefulness of prophylactic antibiotics in severe acute pancreatitis. Radiologic and endoscopic techniques may be alternatives to surgery for certain complications of pancreatitis (eg, infected necrosis and pseudocysts) in particular subsets of patients.