A new combination therapy in severe acute pancreatitis--hyperbaric oxygen plus 3-aminobenzamide: an experimental study

Alteration of gut microbiota in acute pancreatitis and associated therapeutic strategies

Gut microbiome is considered as a crucial regulator of human health. Alteration of gut microbiome has been reported in acute pancreatitis (AP) and probably contributes to the severity of disease. Explore the precise role of gut microbiome in the pathogenesis of AP could offer new strategies to improve the clinical outcomes of AP. This review summarizes the role of gut microbiome in AP, lists possible mechanisms associated with it and offers an overview of current treatments based on gut microbiome.

Effects of the Poly(ADP-Ribose) Polymerase Inhibitor Olaparib in Cerulein-Induced Pancreatitis

OBJECTIVE

Activation of the constitutive nuclear and mitochondrial enzyme poly (ADP-ribose) polymerase (PARP) has been implicated in the pathogenesis of cell dysfunction, inflammation, and organ failure in various forms of critical illness. The objective of our study was to evaluate the efficacy and safety of the clinically approved PARP inhibitor olaparib in an experimental model of pancreatitis in vivo and in a pancreatic cell line subjected to oxidative stress in vitro. The preclinical studies were complemented with analysis of clinical samples to detect PARP activation in pancreatitis.

METHODS

Mice were subjected to cerulein-induced pancreatitis; circulating mediators and circulating organ injury markers; pancreatic myeloperoxidase and malondialdehyde levels were measured and histology of the pancreas was assessed. In human pancreatic duct epithelial cells (HPDE) subjected to oxidative stress, PARP activation was measured by PAR Western blotting and cell viability and DNA integrity were quantified. In clinical samples, PARP activation was assessed by PAR (the enzymatic product of PARP) immunohistochemistry.

RESULTS

In male mice subjected to pancreatitis, olaparib (3 mg/kg i.p.) improved pancreatic function: it reduced pancreatic myeloperoxidase and malondialdehyde levels, attenuated the plasma amylase levels, and improved the histological picture of the pancreas. It also attenuated the plasma levels of pro-inflammatory mediators (TNF-α, IL-1β, IL-2, IL-4, IL-6, IL-12, IP-10, KC) but not MCP-1, RANTES, or the anti-inflammatory cytokine IL-10. Finally, it prevented the slight, but significant increase in plasma blood urea nitrogen level, suggesting improved renal function. The protective effect of olaparib was also confirmed in female mice. In HPDE cells subjected to oxidative stress olaparib (1 μM) inhibited PARP activity, protected against the loss of cell viability, and prevented the loss of cellular NAD levels. Olaparib, at 1μM to 30 μM did not have any adverse effects on DNA integrity. In human pancreatic samples from patients who died of pancreatitis, increased accumulation of PAR was demonstrated.

CONCLUSION

Olaparib improves organ function and tempers the hyperinflammatory response in pancreatitis. It also protects against pancreatic cell injury in vitro without adversely affecting DNA integrity. Repurposing and eventual clinical introduction of this clinically approved PARP inhibitor may be warranted for the experimental therapy of pancreatitis.

Hyperbaric Oxygen Ameliorated Acute Pancreatitis in Rats via the Mitochondrial Pathway

BACKGROUND

Acute pancreatitis (AP) is a common disease of the digestive system. The mechanism of hyperbaric oxygen (HBO) therapy for AP is not completely clear.

AIMS

This study investigated the effects of HBO in AP and whether it acts through the mitochondria-mediated apoptosis pathway.

METHODS

Eighty male Sprague-Dawley rats were randomly assigned to four groups: control (8 rats), sham (24 rats), AP (24 rats), or AP + HBO (24 rats). AP was induced by ligating the pancreatic duct. The AP + HBO group was given HBO therapy starting at 6 h postinduction. Eight rats in each group were killed on days 1, 2, and 3 postinduction to assess pancreatic injury, mitochondrial membrane potential, ATP level, and expression levels of BAX, Bcl-2, caspase-3, caspase-9, and PARP in pancreatic tissue and blood levels of amylase, lipase, and pro-inflammatory cytokines.

RESULTS

HBO therapy alleviated the severity of AP and decreased histopathological scores and levels of serum amylase, lipase, and pro-inflammatory cytokines. Compared to AP induction alone, HBO therapy increased expression of the apoptotic protein BAX, caspase-3, caspase-9, and PARP and ATP levels in tissues and decreased antiapoptotic protein Bcl-2 expression levels and the mitochondrial membrane potential on the first day; the results on the second day were partly consistent with those on the first day, while there was no obvious difference on the third day.

CONCLUSIONS

HBO therapy could induce caspase-dependent apoptosis in AP rats to alleviate pancreatitis, which was possibly triggered by mitochondrial apoptosis pathway regulation of Bcl-2 family members.

Hyperbaric Oxygen Therapy Dampens Inflammatory Cytokine Production and Does Not Worsen the Cardiac Function and Oxidative State of Diabetic Rats

Hyperbaric oxygen therapy (HBOT) is frequently used after soft tissue injuries and in diabetic patients with ulcerated wounds; however, its ability to increase oxidative stress casts doubts. Diabetes (DM) in male Wistar rats (N = 20) weighing 300 g were induced by a single dose of streptozotocin. Ten diabetics (DMHBOT) and 10 controls (CHBOT) underwent a one-hour long hyperbaric oxygen treatment protocol (2.5 bar) 12 times after the 3rd week of diabetes. Ten animals remained untreated. Eight weeks after diabetes induction, we measured the 24-hour blood glucose profile and cardiovascular function (sonocardiography and the relaxation ability of aortae). Malonyl-dialdehyde (MDA) and cytokine levels were measured in blood plasma. Poly(ADP-ribose) polymerase (PARP) activity was estimated in cardiac and aortic tissue. HBOT did not alter most of the cardiovascular parameters. PARylation in cardiac and aortic tissues, plasma MDA levels were elevated in diabetic rats. HBOT prevented the increase of MDA in diabetic animals. In addition, levels of the pro-inflammatory cytokine-induced neutrophil chemoattractant-1 (CINC-1) the levels of anti-inflammatory tissue inhibitor of metalloproteases-1 were not altered in diabetes or in hyperoxia. Our results suggest that HBOT does not increase long-term oxidative stress, and, similar to training, the TBARS products, nitrotyrosine formation and poly(ADP-ribosyl)ation may be eased as a result of hyperoxia.