Alteration of the renin-angiotensin system in caerulein induced acute pancreatitis in the mouse

A comprehensive guide to the pharmacologic regulation of angiotensin converting enzyme 2 (ACE2), the SARS-CoV-2 entry receptor

The recent emergence of coronavirus disease-2019 (COVID-19) as a global pandemic has prompted scientists to address an urgent need for defining mechanisms of disease pathology and treatment. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent for COVID-19, employs angiotensin converting enzyme 2 (ACE2) as its primary target for cell surface attachment and likely entry into the host cell. Thus, understanding factors that may regulate the expression and function of ACE2 in the healthy and diseased body is critical for clinical intervention. Over 66% of all adults in the United States are currently using a prescription drug and while earlier findings have focused on possible upregulation of ACE2 expression through the use of renin angiotensin system (RAS) inhibitors, mounting evidence suggests that various other widely administered drugs used in the treatment of hypertension, heart failure, diabetes mellitus, hyperlipidemias, coagulation disorders, and pulmonary disease may also present a varied risk for COVID-19. Specifically, we summarize mechanisms on how heparin, statins, steroids and phytochemicals, besides their established therapeutic effects, may also interfere with SARS-CoV-2 viral entry into cells. We also describe evidence on the effect of several vitamins, phytochemicals, and naturally occurring compounds on ACE2 expression and activity in various tissues and disease models. This comprehensive review aims to provide a timely compendium on the potential impact of commonly prescribed drugs and pharmacologically active compounds on COVID-19 pathology and risk through regulation of ACE2 and RAS signaling.

Pancreatic Blood Flow with Special Emphasis on Blood Perfusion of the Islets of Langerhans

The pancreatic islets are more richly vascularized than the exocrine pancreas, and possess a 5- to 10-fold higher basal and stimulated blood flow, which is separately regulated. This is reflected in the vascular anatomy of the pancreas where islets have separate arterioles. There is also an insulo-acinar portal system, where numerous venules connect each islet to the acinar capillaries. Both islets and acini possess strong metabolic regulation of their blood perfusion. Of particular importance, especially in the islets, is adenosine and ATP/ADP. Basal and stimulated blood flow is modified by local endothelial mediators, the nervous system as well as gastrointestinal hormones. Normally the responses to the nervous system, especially the parasympathetic and sympathetic nerves, are fairly similar in endocrine and exocrine parts. The islets seem to be more sensitive to the effects of endothelial mediators, especially nitric oxide, which is a permissive factor to maintain the high basal islet blood flow. The gastrointestinal hormones with pancreatic effects mainly influence the exocrine pancreatic blood flow, whereas islets are less affected. A notable exception is incretin hormones and adipokines, which preferentially affect islet vasculature. Islet hormones can influence both exocrine and endocrine blood vessels, and these complex effects are discussed. Secondary changes in pancreatic and islet blood flow occur during several conditions. To what extent changes in blood perfusion may affect the pathogenesis of pancreatic diseases is discussed. Both type 2 diabetes mellitus and acute pancreatitis are conditions where we think there is evidence that blood flow may contribute to disease manifestations. © 2019 American Physiological Society. Compr Physiol 9:799-837, 2019.

Anti-inflammatory and Antioxidant Effects of Captopril Compared to Methylprednisolone in L-Arginine-Induced Acute Pancreatitis

BACKGROUND

Acute pancreatitis (AP) is an inflammatory disease mediated by damage in acinar cells and pancreatic inflammation with infiltration of leukocytes. The pancreatic renin-angiotensin system may play an important role in the pathogenesis of AP.

AIM

The present study aimed to investigate the possible protective role of captopril (CAP), an angiotensin-converting enzyme inhibitor, in attenuating L-arginine-induced AP rat model and to elucidate the underlying molecular mechanisms.

METHODS

Forty-eight adult male Wister rats were divided into four equal groups: control group (vehicle, orally for 10 days), AP group (3 g/kg L-arginine, single i.p.) on 10th day of the experiment, CAP group (50 mg/kg captopril, orally, once daily), and MP group (30 mg/kg methylprednisolone, orally, once daily). CAP and MP were administered for 10 days prior to L-arginine injection. Rats were sacrificed 24 h after arginine injection. Inflammatory biomarkers; tumor necrosis factor alpha (TNF-α) concentration, myeloperoxidase (MPO) activity, and inducible nitric oxide synthase (iNOS) gene expression were determined in pancreas. Oxidative stress biomarkers; pancreatic nitric oxide (NO) and reduced glutathione (GSH) concentrations were measured. Moreover, serum α-amylase and lipase activities were measured and histopathological studies of the pancreas were done.

RESULTS

CAP group showed a significant reduction in pancreatic TNF-α concentration, MPO activity, NO concentration, and downregulation of iNOS gene expression compared to AP group. CAP group also showed a significant increase in GSH concentration with amelioration of histological changes of AP as well as MP group.

CONCLUSION

Captopril treatment showed a protective and comparable effect with MP treatment in AP rat model.

Effect of high dose lactulose on intra-abdominal hypertension and intestinal mucosal barrier function in patients with moderate acute pancreatitis

AIM

To investigate the effect of high dose lactulose on intra-abdominal hypertension and intestinal mucosal barrier function in patients with moderate acute pancreatitis.

METHODS

Ninety patients with moderate acute pancreatitis admitted to Taishun County People's Hospital from February 2015 to February 2017 were included and randomly divided into an observation group and a control group, with 45 cases in each group. On the basis of conventional symptomatic treatment, both groups were treated with somatostatin and esomeprazole, and the observation group was additionally treated with high dose lactulose. Hospitalization time, time to abdominal pain relief, time to intestinal function recovery, intra-abdominal hypertension, intestinal mucosal barrier function, and therapeutic effect were compared between the two groups.

RESULTS

Hospitalization time, time to abdominal pain relief, and time to intestinal function recovery were significantly shorter in the observation group than in the control group (P < 0.05). Intra-abdominal hypertension, endotoxin, D-lactic acid, diamine oxidase, and urinary amylase levels in the observation group after treatment were lower than those in the control group (P < 0.05). The total effective rate in the observation group (95.11%) was higher than that in the control group (80.00%; P < 0.05).

CONCLUSION

The combination of high dose lactulose with somatostatin and esomeprazole can reduce intra-abdominal hypertension and endotoxin, D-lactic acid, diamine oxidase, and urinary amylase levels and enhance intestinal mucosal barrier function in patients with moderate acute pancreatitis.

Association between ACE2/ACE balance and pneumocyte apoptosis in a porcine model of acute pulmonary thromboembolism with cardiac arrest

Acute pulmonary embolism (APE) is frequently reported in patients with cardiac arrest (CA) in emergency care. Pneumocyte apoptosis is commonly observed in the lungs following an APE. An important pathological mechanism evoking apoptosis during a lipopolysaccharide-induced acute lung injury is the angiotensin-converting enzyme 2 (ACE2)/ACE imbalance. The present study uses a porcine model to examine the anti-apoptotic effects of captopril on APE-CA and the return of spontaneous circulation (ROSC). Pigs were randomly assigned into four groups: Control, APE-CA, ROSC-saline, and ROSC-captopril. Surviving pigs were euthanized at 6 h and lungs were isolated for analysis using several biochemical assays. Compared with the control group, the ACE2/ACE ratio was lower in the APE-CA and ROSC pigs. In addition, APE-CA pigs had higher Bcl-2-associated X protein (Bax) and cleaved caspase-3 levels, and lower B-cell lymphoma-2 (Bcl-2) level compared to control pigs. Captopril treatment reduced lung apoptosis, as demonstrated by lower TUNEL-positive cells, higher Bcl-2, and lower cleaved caspase-3 protein levels in the lung. Notably, the ACE2/ACE ratio was positively correlated with Bcl-2 protein levels and Bcl-2/Bax ratio. In conclusion, captopril has a protective effect against lung apoptosis following ROSC and that maintaining the balance of the ACE2/ACE axis is important for inhibiting pulmonary apoptosis during APE.

Angiotensin‑(1‑7) attenuates caerulein‑induced pancreatic acinar cell apoptosis

Extensive apoptosis of pancreatic acinar cells frequently occurs in acute pancreatitis (AP), and has been identified to be closely associated with the decrease of pancreatic parenchymal cells and pancreatic damage. The present study aimed to investigate the possible effect of angiotensin (Ang)‑(1‑7) on caerulein (CAE)‑induced pancreatic acinar cell apoptosis. Mouse pancreatic acinar cancer cells (MPC‑83) were divided into 4 groups: Control group; CAE group; CAE + Ang‑(1‑7) group; and CAE + Ang‑(1‑7) antagonist (A779) group. The control group consisted of normal MPC‑83 cells without special treatment. The CAE group was stimulated with 10 nmol/l CAE and harvested at 2, 6, 12, 24 and 48 h. For the CAE + Ang‑(1‑7) group and CAE + A779 group, the CAE‑induced pancreatic acinar cells were mock pretreated or pretreated with different concentrations of Ang‑(1‑7) or A779 (10‑7, 10‑6 or 10‑5 mol/l) for 30 min. Caspase‑3 is a critical executioner of apoptosis, as it is either partly or completely responsible for the proteolytic cleavage of numerous key proteins including the nuclear enzyme poly (ADP‑ribose) polymerase. Activation of caspase‑3 requires proteolytic processing of its inactive zymogen into activated p17 and p12 fragments. Thus, the present study investigated the apoptotic markers, including cleaved caspase‑3, B‑cell lymphoma 2 (Bcl‑2), Bcl‑2‑like protein 4 (Bax) and renin‑angiotensin system (RAS) pathway related proteins (ACE2 and Mas receptor). The results demonstrated that the cleaved caspase‑3 levels were increased in the CAE group (P<0.05), peaking at 24 h, and declined when incubated with Ang‑(1‑7). Following treatment with Ang‑(1‑7), levels of the anti‑apoptotic protein Bcl‑2 rose dramatically in a dose‑dependent manner. The ratio of the pro‑apoptotic protein Bax to the anti‑apoptotic protein Bcl‑2 dropped notably, which demonstrated a tendency towards curbing apoptosis. In addition, the cleaved caspase‑3 levels, and the ratio of Bax to Bcl‑2 in the CAE + A779 group presented a significant rise compared with the CAE group. It was concluded that Ang‑(1‑7) may possess an inhibitory effect on CAE‑induced pancreatic acinar cell apoptosis and that appropriate interventions in RAS may attenuate pancreatic injury during AP.