Angiotensin-converting enzyme gene DD genotype neither increases susceptibility to acute pancreatitis nor influences disease severity

The effect of renin angiotensin system genetic variants in acute pancreatitis

OBJECTIVES

We sought association of genetic variants in the renin-angiotensin system (RAS) and vitamin D system with acute pancreatitis (AP) development and severity.

BACKGROUND

The endocrine RAS is involved in circulatory homeostasis through the pressor action of angiotensin II at its AT1 receptor. However, local RAS regulate growth and inflammation in diverse cells and tissues, and their activity may be suppressed by vitamin D. Intrapancreatic angiotensin II generation has been implicated in the development of AP.

METHODS

Five hundred forty-four white patients with AP from 3 countries (United Kingdom, 22; Germany, 136; and The Netherlands 386) and 8487 control subjects (United Kingdom 7833, The Netherlands 717) were genotyped for 8 polymorphisms of the RAS/vitamin D systems, chosen on the basis of likely functionality.

RESULTS

The angiotensin-converting enzyme I (rather than D) allele was significantly associated with alcohol-related AP when all cohorts were combined (P = 0.03). The renin rs5707 G (rather than A) allele was associated with AP (P = 0.002), infected necrosis (P = 0.025) and mortality (P = 0.046).

CONCLUSIONS

The association of 2 RAS polymorphisms with AP suggests the need for further detailed analysis of the role of RAS/vitamin D in the genesis or severity of AP, particularly given the ready potential for pharmacological manipulation of this system using existing marketed agents. However, further replication studies will be required before any such association is considered robust, particularly given the significant heterogeneity of AP causation and clinical course.

Association between angiotensin-converting enzyme gene insertion/deletion polymorphism and pancreatitis risk: A meta-analysis

OBJECTIVE

Many studies have focused on the relationship between the angiotensin-converting enzyme gene (ACE) insertion/deletion (I/D) polymorphism and pancreatitis risk, but the results remain inconsistent. Thus, a meta-analysis was carried out to derive a more precise estimation of the association between ACE I/D polymorphism and pancreatitis risk.

METHODS

Relevant publications were searched in several widely used databases and seven studies from six eligible articles were included in the meta-analysis. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the association between ACE I/D polymorphism and pancreatitis risk.

RESULTS

Significant associations between ACE I/D polymorphism and pancreatitis risk were observed in both overall meta-analysis for DI versus II (OR=0.80, 95% CI=0.67-0.96) and DD + DI versus II (OR=0.83, 95% CI=0.70-0.98), and acute pancreatitis subgroup for DI versus II (OR=0.65, 95% CI=0.44-0.95). However, no significant pancreatitis risk variation was detected for all genetic models in the subgroup meta-analysis based on ethnicity.

CONCLUSIONS

According to the results of our meta-analysis, the ACE I/D polymorphism probably associates with pancreatitis risk, especially acute pancreatitis risk, with the I allele acting as a risk factor.

The Renin-angiotensin system and reactive oxygen species: implications in pancreatitis

SIGNIFICANCE

The renin-angiotensin system (RAS) is a circulating hormonal system involved in the regulation of blood pressure and circulating fluid electrolytes. Recent findings have revealed that locally generated angiotensin (Ang) II plays a pivotal role in normal physiology as well as pathophysiology in various tissues and organs, including the pancreas. This review article summarizes current progress that has been made in elucidating the putative roles of Ang II in both acute and chronic pancreatitis.

RECENT ADVANCES

A convergence of evidence suggests that the underlying mechanism may involve reactive oxygen species (ROS)-generating systems, such as nicotinamide adenine dinucleotide phosphate oxidase, and subsequent elevation of proinflammatory and profibrogenic gene expression as well as protein activity. More importantly, Ang II-induced ROS interacts with other ROS-generating systems to positively feed-forward the ROS-induced signaling.

CRITICAL ISSUES AND FUTURE DIRECTIONS

Advances in basic research indicate that RAS blockers may provide potential therapeutic role for the management of pancreatic inflammation and, more importantly, pancreatitis-associated complications. Genetic alterations resulting from a malfunction in the epigenetic control of pancreatic RAS could be a causative factor in the development of pancreatitis.

Review article: pancreatic renin-angiotensin systems in health and disease

BACKGROUND

In addition to the circulating (endocrine) renin-angiotensin system (RAS), local renin-angiotensin systems are now known to exist in diverse cells and tissues. Amongst these, pancreatic renin-angiotensin systems have recently been identified and may play roles in the physiological regulation of pancreatic function, as well as being implicated in the pathogenesis of pancreatic diseases including diabetes, pancreatitis and pancreatic cancer.

AIM

To review and summarise current knowledge of pancreatic renin-angiotensin systems.

METHODS

We performed an extensive PubMed, Medline and online review of all relevant literature.

RESULTS

Pancreatic RAS appear to play various roles in the regulation of pancreatic physiology and pathophysiology. Ang II may play a role in the development of pancreatic ductal adenocarcinoma, via stimulation of angiogenesis and prevention of chemotherapy toxicity, as well as in the initiation and propagation of acute pancreatitis (AP); whereas, RAS antagonism is capable of preventing new-onset diabetes and improving glycaemic control in diabetic patients. Current evidence for the roles of pancreatic RAS is largely based upon cell and animal models, whilst definitive evidence from human studies remains lacking.

CONCLUSIONS

The therapeutic potential for RAS antagonism, using cheap and widely available agents, and may be untapped and such roles are worthy of active investigation in diverse pancreatic disease states.

Implications of the angiotensin converting enzyme gene insertion/deletion polymorphism in health and disease: a snapshot review

This review considers the 250+ papers concerning the association of the angiotensin converting enzyme (ACE) gene insertion/deletion polymorphism (rs1799752) and various disease conditions published in 2009. The deletion allele occurs in approximately 55% of the population and is associated with increased activity of the ACE enzyme. It might be predicted that the D allele, therefore, might be associated with pathologies involving increased activity of the renin-angiotensin system. The D allele was seen to be associated with an increased risk of hypertension, pre-eclampsia, heart failure, cerebral infarct, diabetic nephropathy, encephalopathy, asthma, severe hypoglycaemia in diabetes, gastric cancer (in Caucasians) and poor prognosis following kidney transplant. On the positive side, the D allele appears to offer protection against schizophrenia and chronic periodontitis and confers greater up-per-body strength in old age. The I allele, meanwhile, offers improved endurance/athletic performance and aerobic capacity as determined by lung function tests, although it does increase the risk of oral squamous cell carcinoma and obstructive sleep apnoea in hypertensives.

Angiotensin-Converting Enzyme Genotype and Acute Pancreatitis in Turkey

The renin-angiotensin system (RAS) has been implicated in the pathogenesis of acute and chronic pancreatitis. Angiotensin-converting enzyme (ACE) is the key enzyme which activates RAS. The ACE intron 16 insertion/ deletion (I/D) polymorphism is associated with ACE activity and is considered to be a risk factor for several inflammatory processes. We investigated this polymorphism in 68 patients with acute pancreatitis (AP) and 157 healthy Turkish control subjects. Patients were evaluated with ultrasonography, abdominal tomography and laboratory markers and grouped by status for diabetes mellitus (DM), hypertension (HT), and both these diseases and by etiology. Genotyping of the I/D polymorphism was performed by polymerase chain reaction (PCR). The DD genotype was more prevalent in healthy controls, however, genotype II was significantly more frequent in AP patients (p <0.05). In severe AP patients, the genotype II frequency was significantly higher than in controls (p <0.05). Acute pancreatitis patients with both DM and HT had lower frequencies of genotype DD and of the D allele, and higher frequencies of genotype II and of the I allele than patients with either DM or HT (p <0.05).

Cholangitis of Pancreatitis? Does the Angiotensin-Converting Enzyme Genotype Favor Either?

Acute cholangitis and pancreatitis are serious complications of gallstones, with considerable morbidity and mortality. Angiotensin-converting enzyme (ACE) is an exopeptidase that is important in regulating blood pressure, metabolizing bradykinin and in maintaining an inflammatory response. To determine whether the ACE genotype determines occurrence of cholangitis or pancreatitis we examined ACE I/D genotypes in 31 patients who had cholangitis, 44 patients with biliary pancreatitis and 157 healthy individuals. The patients had been hospitalized at the Department and Intensive Care Faculty of Medicine, Ege University, Izmir, Turkey. The patients were recalled 4 years later and their prognosis was evaluated. The ACE II genotype was found at a higher frequency in the cholangitis and biliary pancreatitis patients when compared with the healthy subjects (p <0.05). There was no significant difference between cholangitis and biliary pancreatitis cases regarding the genotype and allele distribution (p >0.05). Recurrence of infection occurred more frequently in the patients with the DD genotype, although it was not significant according to the first assessment (p >0.05). The ACE gene polymorphism did not seem to favor development of either cholangitis or pancreatitis.