Leptin modulates the inflammatory response in acute pancreatitis

Impact of Hepatic Steatosis, Psoas Muscle Mass, and Density on Outcomes in Patients with Moderately Severe and Severe Acute Pancreatitis: A Serial Computed Tomography-Based Retrospective Study

Background and Objective There is limited literature on the association of fatty liver and muscle mass with outcomes of acute pancreatitis (AP) in Indian patients. We aim to investigate the impact of these parameters on clinical outcomes in AP patients based on serial computed tomography (CT) scans.

Materials and Methods Consecutive patients of AP who had a baseline CT scan within 2 weeks of pain onset and a follow-up CT scan within 2 months of initial CT scan were included. Fatty liver, spleen to liver attenuation difference (AD), psoas muscle area (PMA), and psoas muscle attenuation (PMAt) were assessed on baseline and follow-up portal venous CT scans. Their association with the length of hospitalization, intensive care unit (ICU) admission, length of ICU stay, surgery, and mortality were assessed using univariate and multivariate analysis.

Results One hundred and ninety-eight patients (143 [72.2%] males, mean age 37.9 [ ± 12.4] years) were included. The mean interval between the two CT scans was 30 days (± 13.5 days). Twenty-four (12.1%) patients had fatty liver at baseline CT and 58 (29.3%) patients had fatty liver on follow-up CT (p < 0.001). The mean AD at the baseline scan was –10.2 (± 12.3) Hounsfield units (HU) and on follow up was –18.8 (± 21.7) HU (p < 0.001). PMA in baseline CT was 13.9 (± 5.5) mm2 and on follow-up was 11.2 (± 4.6) mm2 (p < 0.001). PMAt on baseline CT was 49.2 (± 8.2) HU and on follow-up was 47.1 (± 12.1) HU (p < 0.001). In multivariate analysis, the PMA and PMAt were significantly associated with the clinical outcomes. There was no association of fatty liver with clinical outcomes. The parameter with the highest area under the curve for predicting clinical outcomes was PMAt at follow-up CT.

Conclusion Psoas muscle-based assessment is associated with clinical outcomes in patients with AP.

Assessment of Acute Pancreatitis Severity and Prognosis with CT-Measured Body Composition

Objective

The aim of this study was to investigate the possible association of muscle and adipose parameters with the severity and prognosis of patients hospitalized with acute pancreatitis (AP).

Methods

A total of 392 hospitalized patients and 309 controls were enrolled in the study analysis from April 1, 2016, to February 1, 2021. The computed tomography scans of each population were evaluated for muscle and adipose parameters. The effects of parameters on developing moderately severe acute pancreatitis (MSAP) or severe acute pancreatitis (SAP) were evaluated using univariate and multivariate logistic regression analyses. Associations with disease recurrence and death were analyzed through Cox regression analysis.

Results

The AP patients had higher levels of visceral adipose tissue (144.25 vs 97.81 cm², p < 0.001) and subcutaneous adipose tissue (135 vs 120 cm², p < 0.001) but lower levels of adipose tissue attenuation (visceral and subcutaneous) and skeletal muscle attenuation (SMA) than the controls (p < 0.05, respectively). Visceral adipose tissue (VAT) and SMA differed significantly with p-values of 0.014 and 0.003 in the different severity groups of AP. In multivariate analysis, VAT and SMA were associated with MSAP or SAP, with odds ratios of 1.003 and 0.973, respectively (95% CI 1.000-1.006, p = 0.041; 95% CI 0.953-0.993, p = 0.010). Cox regression analysis showed that low SMA was strongly associated with an increased mortality in MSAP and SAP patients (HR 10.500, 95% CI 1.344-82.025, p = 0.025). Regression analysis also showed an association of VAT loss of more than 17% with reduced 1-year recurrence of acute pancreatitis (HR 0.427, 95% CI 0.189-0.967, p = 0.041).

Conclusion

VAT and SMA were influential factors for the severity and prognosis of patients with AP. Patients should proper diet and exercise after discharge to reduce VAT and strengthen muscle function to improve prognosis.

Role of Leptin in the Digestive System

Leptin is a pluripotent peptide hormone produced mainly by adipocytes, as well as by other tissues such as the stomach. Leptin primarily acts on the central nervous system, particularly the hypothalamus, where this hormone regulates energy homeostasis and neuroendocrine function. Owing to this, disruption of leptin signaling has been linked with numerous pathological conditions. Recent studies have also highlighted the diverse roles of leptin in the digestive system including immune regulation, cell proliferation, tissue healing, and glucose metabolism. Of note, leptin acts differently under physiological and pathological conditions. Here, we review the current knowledge on the functions of leptin and its downstream signaling in the gastrointestinal tract and accessory digestive organs, with an emphasis on its physiological and pathological implications. We also discuss the current therapeutic uses of recombinant leptin, as well as its limitations.

The role of immune dysfunction in obesity-associated cancer risk, progression, and metastasis

Obesity has been linked to an increased risk of and a worse prognosis for several types of cancer. A number of interrelated mediators contribute to obesity's pro-tumor effects, including chronic adipose inflammation and other perturbations of immune cell development and function. Here, we review studies examining the impact of obesity-induced immune dysfunction on cancer risk and progression. While the role of adipose tissue inflammation in obesity-associated cancer risk has been well characterized, the effects of obesity on immune cell infiltration and activity within the tumor microenvironment are not well studied. In this review, we aim to highlight the impact of both adipose-mediated inflammatory signaling and intratumoral immunosuppressive signaling in obesity-induced cancer risk, progression, and metastasis.

Early Enteral Nutrition Prevent Acute Pancreatitis From Deteriorating in Obese Patients

GOALS

The aim of this study was to determine a potential strategy to prevent acute pancreatitis (AP) from deteriorating in obese patients.

BACKGROUND

Nutritional support plays a critical role in the treatment of AP. Early enteral nutrition (EEN) is considered to be able to protect mucosa of AP patients and alleviate inflammatory reactions. Obesity worsen AP prognosis. However, little is known about the effects of EEN in obese patients.

STUDY

Prospective randomized control trial. Subjects with moderately severe AP or severe AP were divided into the visceral fat obesity (VFO) group and the non-VFO group by obesity index VFO. The patients received "delayed" enteral nutrition (started enteral nutrition feeding after the first 48 hours after admission to the hospital: group A: patients of non-VFO, n=108; group B: VFO patients, n=88) or EEN (in the VFO subgroup, group C: n=91).Occurrence of complication, clinical outcomes, plasma levels of cytokines, and intestine gut barrier index were measured at different timepoints after admission.

RESULTS

VFO was a risk factor for aggravating of AP. EEN prevented the VFO patients from developing pancreatic necrotic infection, the mechanism of which might be related with inhibiting excessive inflammatory reactions, adjusting the imbalance of inflammatory response, and alleviating ischemia of intestine mucosa.

CONCLUSIONS

The potential strategy, EEN, was able to prevent AP from deteriorating in obese patients.

Leptin and Immunological Profile in Obesity and Its Associated Diseases in Dogs

Growing scientific evidence has unveiled increased incidences of obesity in domestic animals and its influence on a plethora of associated disorders. Leptin, an adipokine regulating body fat mass, represents a key molecule in obesity, able to modulate immune responses and foster chronic inflammatory response in peripheral tissues. High levels of cytokines and inflammatory markers suggest an association between inflammatory state and obesity in dogs, highlighting the parallelism with humans. Canine obesity is a relevant disease always accompanied with several health conditions such as inflammation, immune-dysregulation, insulin resistance, pancreatitis, orthopaedic disorders, cardiovascular disease, and neoplasia. However, leptin involvement in many disease processes in veterinary medicine is poorly understood. Moreover, hyperleptinemia as well as leptin resistance occur with cardiac dysfunction as a consequence of altered cardiac mitochondrial metabolism in obese dogs. Similarly, leptin dysregulation seems to be involved in the pancreatitis pathophysiology. This review aims to examine literature concerning leptin and immunological status in obese dogs, in particular for the aspects related to obesity-associated diseases.

Obesity Aggravates Acute Pancreatitis via Damaging Intestinal Mucosal Barrier and Changing Microbiota Composition in Rats

Obesity may aggravate acute pancreatitis (AP) through damaging the intestinal mucosal barrier (IMB). The underlying mechanism remains unclear. This study was aimed to provide further data to clarify the mechanism. 48 rats were divided into 4 groups: 1) normal control (NC), chow-fed rats with sham operation, 2) no-obese rats with AP (NAP), chow-fed rats with taurocholate infusion, 3) obese control (OC), high-fat diet (HFD)-fed rats with sham operation, and 4) obese rats with AP (OAP), HFD-fed rats with taurocholate infusion. Pancreatic pathologic score (11.39 ± 1.76 vs. 14.11 ± 1.05, p = 0.005), intestinal permeability to FD4 (0.91 ± 0.25 μg/ml vs. 7.06 ± 3.67 μg/ml, p < 0.001), serum leptin (10.25 ± 5.59 ng/ml vs. 79.73 ± 38.44 ng/ml, p < 0.001) and ileal apoptosis (2.05 ± 0.73% vs. 4.53 ± 2.28%, p = 0.006) were significantly higher in OAP than in NAP group. The intestinal bacterial richness (Chao 1 and OTUs) was significantly lower in OAP than in NAP rats. The higher abundance of Proteobacteria and reduced proportions of intestinal Actinobacteria, Allobaculum and Barnesiella were detected in OAP group. Obesity may result in decreased intestinal leptin/ObR-b binding, distinct phylogenetic clusters of ileal bacterial communities, increased intestinal inflammatory injury and the insufficient intestinal epithelial cells proliferation during AP attack. Pancreatic injury was aggravated due to obesity associated dysfunction of IMB.

Emergence of Leptin in Infection and Immunity: Scope and Challenges in Vaccines Formulation

Deficiency of leptin (ob/ob) and/or desensitization of leptin signaling (db/db) and elevated expression of suppressor of cytokine signaling-3 (SOCS3) reported in obesity are also reported in a variety of pathologies including hypertriglyceridemia, insulin resistance, and malnutrition as the risk factors in host defense system. Viral infections cause the elevated SOCS3 expression, which inhibits leptin signaling. It results in immunosuppression by T-regulatory cells (Tregs). The host immunity becomes incompetent to manage pathogens' attack and invasion, which results in the accelerated infections and diminished vaccine-specific antibody response. Leptin was successfully used as mucosal vaccine adjuvant against Rhodococcus equi. Leptin induced the antibody response to Helicobacter pylori vaccination in mice. An integral leptin signaling in mucosal gut epithelial cells offered resistance against Clostridium difficile and Entameoba histolytica infections. We present in this review, the intervention of leptin in lethal diseases caused by microbial infections and propose the possible scope and challenges of leptin as an adjuvant tool in the development of effective vaccines.

Associations between circulating levels of adipocytokines and abdominal adiposity in patients after acute pancreatitis

Adipocytokines are strongly associated with abdominal adiposity during the course of acute pancreatitis (AP). This study investigated associations between a panel of adipocytokines and abdominal adiposity in AP patients after hospital discharge, as well as the effect of several covariates. Fasting venous blood samples were collected to measure adiponectin, interleukin 6, leptin, monocyte chemoattractant protein 1, tumour necrosis factor α (TNFα), resistin, and retinol-binding protein 4. Waist circumference (WC), waist-hip ratio, and waist-height ratio (WheightR) were used as measures of abdominal adiposity. Generalised linear models were built, adjusting for age, sex, ethnicity, diabetes status, aetiology, duration since admission for AP, recurrence, and severity of AP. A total of 93 patients were studied, on average at 22 months after AP. Interleukin 6, TNFα, and leptin were significantly associated with WC in both the unadjusted and all the three adjusted models. Also, they were significantly associated with WheightR in both the unadjusted and the three adjusted models. Other studied adipocytokines did not show a consistent association or were not significantly associated with the abdominal adiposity indices. The results suggest that excess abdominal adiposity favours pro-inflammatory milieu in AP patients after hospital discharge, independent of diabetes and effect of other covariates.

Increased Leptin and Leptin Receptor Expression in Dogs With Gallbladder Mucocele

BACKGROUND

Leptin and its receptor play a role in several disease processes such as pancreatitis and heart disease. However, their association with gallbladder mucocele (GBM) in dogs has not been reported.

HYPOTHESIS/OBJECTIVES

To evaluate differences in the expression of leptin and leptin receptor between dogs with and without GBM.

ANIMALS

Twenty-five healthy dogs, including 9 laboratory beagle dogs, and 22 client-owned dogs with GBM.

METHODS

Serum leptin concentration was determined in blood samples of all dogs by ELISA. Canine gallbladder samples were collected from 9 dogs with GBM that underwent surgery for therapeutic purposes and from 9 healthy laboratory beagle dogs as a normal control group. Samples were analyzed for leptin and leptin receptor mRNA by real-time polymerase chain reaction.

RESULTS

Serum leptin concentration was significantly higher in dogs with GBM than in healthy dogs (medians of 7.03 and 2.18 ng/mL, respectively; P < .001). Patients with GBM that had undergone surgery had significantly higher serum leptin concentrations than those that had not (medians of 12.2 and 4.09 ng/mL, respectively; P = .001). However, no difference in serum leptin concentration was found between dogs with GBM with or without endocrinopathies. The mRNA expression levels of leptin and its receptor were significantly increased in the gallbladder tissues of dogs with GBM.

CONCLUSIONS AND CLINICAL IMPORTANCE

Dysregulation of leptin might be involved in the pathophysiology of GBM, and leptin concentrations might be associated with GBM severity.

The clinical value of adipokines in predicting the severity and outcome of acute pancreatitis

Background

Recent data shows that patients with severe acute pancreatic might benefit from early intensive therapy, enteral nutrition and timely transfer to specialized centers. The early prophylactic use of antibiotics in AP remains controversial. The role and need for new markers in stratification of acute pancreatitis is also uncertain. This study aims to evaluate the prognostic usefulness of adipokines in prediction of the severity and outcome of acute pancreatitis (AP).

Methods

Prospective study was conducted in four clinical centers. The diagnosis and severity assessment of AP was established according to the revised 2012 Atlanta classification. Adipokines, IL-6 and CRP levels were measured at admission and on 3rd day of hospital stay and compared with the control group. The predictive accuracy of each marker was measured by area under the receiver operating curve.

Results

Forty healthy controls and 102 patients were enrolled in to the study. Twenty seven (26.5 %) patients had mild, 55 (53.9 %) - moderate and 20 (19.6 %) - severe AP. Only resistin (cut-off value 13.7 ng/ml) and IL-6 (cut-off value 473.4 pg/ml) were reliable early markers of SAP. IL-6 with cut-off value of 157.0 pg/ml was a predictor of necrosis. The peripancreatic necrosis volume of 112.5 ml was a marker of SAP and 433.0 ml cut-off value could be used to predict the need of interventions.

Conclusions

The prognostic value of adipokines in AP is limited. Only admission resistin levels could serve as an early predictor for SAP.

The Lithuanian Regional Ethics Committee approved the study protocol (permission No. L-12-02/1/2/3/4) and all the patients and the control group provided written informed consent.

Resistin: New serum marker for predicting severity of acute pancreatitis

OBJECTIVE

To assess the effectiveness of resistin in predicting the severity of acute pancreatitis.

METHODS

Patients with acute pancreatitis who presented at the Gastroenterology Clinic, Erzurum Education and Research Hospital, Turkey were enrolled in this prospective study. White blood cell (WBC), C-reactive protein (CRP) and resistin levels were measured on admission and at 24 h, day 3 and day 7 following admission, along with other blood parameters. Patients were divided into two groups: mild acute pancreatitis and moderate/severe acute pancreatitis.

RESULTS

Of 59 patients with acute pancreatitis (mild, n = 37; moderate/severe, n = 22), significant between-group differences were found in terms of resistin and CRP levels. Receiver operating curve analysis showed that resistin levels were better for predicting severe cases of acute pancreatitis than CRP or WBC levels on day 3 (area under the curve [AUC], 0.88 versus 0.81 and 0.63, respectively). Resistin levels on day 3 were better than CRP levels for predicting necrosis development (AUC, 0.70 versus 0.69, respectively).

CONCLUSIONS

Resistin may represent a new, effective indicator to predict the severity of acute pancreatitis and presence of necrosis in patients with acute pancreatitis.

The effect of enteral nutrition on adipokines in patients with acute pancreatitis

The mechanism behind the beneficial effects of enteral nutrition (EN) for patients with acute pancreatitis (AP) is largely unknown. Adipokines, as mediators of metabolism and inflammation, may be a possible mechanism. The study aimed to investigate the effect of EN on adipokines early in the course of AP. Patients with AP were randomised to EN or nil-by-mouth (NBM). Blood samples were taken on the first 4 d of admission and adipokine concentrations for adiponectin, leptin, omentin, resistin and visfatin were determined by ELISA assays. A linear mixed model analysis was run to determine differences in adipokine concentrations between the two study groups. A total of thirty-two patients were included in the study. Omentin concentrations were significantly higher in patients who received EN compared with NBM across the first 4 d of admission (mean difference: 11·6 (95 % CI 1·0, 22·3) ng/ml; P = 0·033). Leptin concentrations were significantly higher in patients who received EN compared with NBM after adjusting for age, sex and BMI (mean difference: 2·3 (95 % CI 0·1, 4·5) ng/ml; P = 0·037). No significant difference in adiponectin, resistin or visfatin concentrations were observed between the two study groups. EN significantly increases omentin and leptin concentrations in AP. Future research should be directed towards understanding whether these adipokines are responsible for the therapeutic benefits of EN.

Hormonal protection in acute pancreatitis by ghrelin, leptin and melatonin

Acute pancreatitis is a nonbacterial disease of the pancreas. The severe form of this ailment is characterized by high mortality. Whether acute pancreatitis develops as the severe type or resolves depends on the intensity of the inflammatory process which is counteracted by the recruitment of innate defense mechanisms. It has been shown that the hormones ghrelin, leptin and melatonin are able to modulate the immune function of the organism and to protect the pancreas against inflammatory damage. Experimental studies have demonstrated that the application of these substances prior to the induction of acute pancreatitis significantly attenuated the intensity of the inflammation and reduced pancreatic tissue damage. The pancreatic protective mechanisms of the above hormones have been related to the mobilization of non-specific immune defense, to the inhibition of nuclear factor kappa B and modulation of cytokine production, to the stimulation of heat shock proteins and changes of apoptotic processes in the acinar cells, as well as to the activation of antioxidant system of the pancreatic tissue. The protective effect of ghrelin seems to be indirect and perhaps dependent on the release of growth hormone and insulin-like growth factor 1. Leptin and ghrelin, but not melatonin, employ sensory nerves in their beneficial action on acute pancreatitis. It is very likely that ghrelin, leptin and melatonin could be implicated in the natural protection of the pancreatic gland against inflammatory damage because the blood levels of these substances increase in the initial phase of pancreatic inflammation. The above hormones could be a part of the innate resistance system which might remove noxious factors and could suppress or attenuate the inflammatory process in the pancreas.

The potential role of BMI, plasma leptin, nesfatin-1 and ghrelin levels in the early detection of pancreatic necrosis and severe acute pancreatitis: a prospective cohort study

BACKGROUND

Early prediction of disease severity in acute pancreatitis (AP) is crucial. The aim of this study was to investigate the body-mass index (BMI), plasma leptin, nesfatin-1 and ghrelin levels as potential markers predicting peripancreatic necrosis and severity in acute pancreatitis.

METHODS

In the study period, 97 consecutive patients with AP were prospectively analysed. Severe AP was defined according to the Atlanta Criteria. BMI was also calculated. To measure plasma Leptin, Nesfatin-1 and Ghrelin concentrations, the blood samples were obtained from patients within 24 hours of admission.

RESULTS

Out of 97 patients, 92(70 females, 22 males) were considered eligible for analysis. Of the 92 patients, 30 patients (32.6%) were assessed as severe pancreatitis. BMI and leptin levels were significantly higher in patients with severe pancreatitis. The pooled sensitivity and specificity of BMI as a predictor for the development of pancreatic necrosis were 0.90(95%CI = 0.56-0.99) and 0.70(95%CI = 0.58-0.79), respectively; with an overall area under curve value of 0.78.The pooled sensitivity and specificity of leptin levels as a predictor for development of pancreatic necrosis were 1(95%CI = 0.69-1) and 0.73(95%CI = 0.62-0.82),respectively; with an overall area under curve value of 0.82.Nesfatin-1 and ghrelin levels showed no significant difference in patients with mild pancreatitis (6.97 ± 0.84 ng/ml and 2.3(1.0-9.9);respectively) and severe pancreatitis (6.74 ± 0.65 ng/ml and 2.0(1.9-9.9); respectively) (p = 0.1923 and 0.8531;respectively).

CONCLUSION

BMI and plasma leptin levels both were correlated with the severity of pancreatitis. Leptin levels showed better area under the curve, sensitivity and specificity values compared to BMI in prediction of pancreatic necrosis.Nesfatin-1 and ghrelin levels were not found to be predictors of the severity of disease.

Serum adipokine concentrations in dogs with acute pancreatitis

Background

Limited information is available about the role of adipokines in the development and progression of acute pancreatitis (AP) in dogs.

Objectives

To determine whether the circulating concentrations of adipokines differed between healthy dogs and dogs with AP, and whether the circulating concentrations differed between AP survivors and AP nonsurvivors.

Animals

Twenty‐eight healthy dogs and 25 client‐owned dogs with AP.

Methods

Prospective observational cohort study of 25 client‐owned dogs with newly diagnosed AP and 28 otherwise healthy dogs with similar body condition scores. The serum concentrations of leptin, adiponectin, resistin, visfatin, interleukin (IL)‐1β, IL‐6, IL‐10, IL‐18, and tumor necrosis factor (TNF)‐α were measured.

Results

The serum concentrations of leptin (P = .0021), resistin (P = .0010), visfatin (P < .0001), IL‐1β (P < .0001), IL‐6 (P = .0002), IL‐10 (P < .0001), and IL‐18 (P < .0001) were significantly higher in dogs with AP than healthy dogs, whereas the adiponectin concentration (P = .0011) was significantly lower. There were significant differences in the serum concentrations of leptin (P = .028) and adiponectin (P = .046) in survivors and nonsurvivors. After the disappearance of clinical signs, the concentrations of resistin (P = .037) and IL‐1β (P = .027) decreased significantly, whereas the serum concentrations of leptin (P > .999), adiponectin (P = .11), visfatin (P = .83), IL‐6 (P = .82), IL‐10 (P = .82), IL‐18 (P = .56), and TNF‐α (P = .94) did not differ significantly.

Conclusion and Clinical Importance

This study showed that dysregulation of adipokines might be involved in the pathogenesis of AP. In addition, leptin and adiponectin are likely to be associated with mortality rate in AP.

Cytoprotective effect of 1-nitro-2-phenylethane in mice pancreatic acinar cells subjected to taurocholate: putative role of guanylyl cyclase-derived 8-nitro-cyclic-GMP

The nitroderivative 1-nitro-2-phenylethane (NPE) was recently described as a compound possessing heme-dependent soluble guanylyl cyclase (sGC) stimulating properties in vascular smooth muscle cells. In this study, we tested such pharmacological property of NPE in mice pancreatic acinar cells subjected to the bile salt taurocholate, a type of pathological stimulus that simulates pancreatitis. Here, isolated acinar cells were treated with NPE in order to assess the role of sGC on the detrimental effects induced by taurocholate. NPE reduced taurocholate-elicited Ca(2+) overload, production of reactive oxygen species (ROS), apoptosis, necrosis, and exerted a protective effect against mitochondrial membrane potential (ΔΨm) dissipation. These NPE-induced effects were abolished by pretreatment with ODQ and KT 5823, and after the blockade of nitric oxide (NO) synthase with l-NAME, inhibitors of key components of the sGC pathway. Contrarily to cGMP that alone increased ΔΨm collapse and cell damage, the cytoprotective effect of NPE on ΔΨm and cell necrosis was almost reproduced by 8-nitro-cGMP, a second messenger generated by sGC under oxidative stress conditions. In conclusion, putative sGC stimulation with NPE reveals its cytoprotective profile on pancreatic cells subjected to taurocholate. Moreover, ROS and NO conjunctly appear to drive sGC activity in pancreatic acinar cells to implement an adaptive mechanism in response to oxidative and Ca(2+) stress through 8-nitro-cGMPsynthesis.

Leptin: molecular mechanisms, systemic pro-inflammatory effects, and clinical implications

Leptin, the adipokine produced mainly by the white adipose tissue, plays important roles not only in the regulation of food intake, but also in controlling immunity and inflammation. It has been widely demonstrated that the absence of leptin leads to immune defects in animal and human models, ultimately increasing mortality. Leptin also regulates inflammation by means of actions on its receptor, that is widely spread across different immune cell populations. The molecular mechanisms by which leptin determines its biological actions have also been recently elucidated, and three intracellular pathways have been implicated in leptin actions: JAK-STAT, PI3K, and ERK 1/2. These pathways are closely regulated by intracellular proteins that decrease leptin biological activity. In this review, we discuss the molecular mechanisms by which leptin regulates immunity and inflammation, and associate those mechanisms with chronic inflammatory disorders.

Value of adipokines in predicting the severity of acute pancreatitis: Comprehensive review

AIM: To analyze the prognostic value of adipokines in predicting the course, complications and fatal outcome of acute pancreatitis (AP).

METHODS: We performed the search of PubMed database and the systemic analysis of the literature for both experimental and human studies on prognostic value of adipokines in AP for period 2002-2012. Only the papers that described the use of adipokines for prediction of severity and/or complications of AP were selected for further analysis. Each article had to contain information about the levels of measured adipokines, diagnosis and verification of AP, to specify presence of pancreatic necrosis, organ dysfunction and/or mortality rates. From the very beginning, study was carried out adhering to the PRISMA checklist and flowchart for systemic reviews. To assess quality of all included human studies, the Quality Assessment of Diagnostic Accuracy Studies tool was used. Because of the high heterogeneity between the studies, it was decided to refrain from the statistical processing or meta-analysis of the available data.

RESULTS: Nine human and three experimental studies were included into review. In experimental studies significant differences between leptin concentrations at 24 and 48 h in control, acute edematous and acute necrotizing pancreatitis groups were found (P = 0.027 and P < 0.001). In human studies significant differences between leptin and resitin concentrations in control and acute pancreatitis groups were found. 1-3 d serum adiponectin threshold of 4.5 μg/mL correctly classified the severity of 81% of patients with AP. This threshold yielded a sensitivity of 70%, specificity 85%, positive predictive value 64%, negative predictive value88% (area under curve 0.75). Resistin and visfatin concentrations differ significantly between mild and severe acute pancreatitis groups, they correlate with severity of disease, need for interventions and outcome. Both adipokines are good markers for parapancreatic necrosis and the cut-off values of 11.9 ng/mL and 1.8 ng/mL respectively predict the high ranges of radiological scores. However, the review revealed that all nine human studies with adipokines are very different in terms of methodology and objectives, so it is difficult to generalize their results. It seems that concentrations of the leptin and resistin increases significantly in patients with acute pancreatitis compared with controls. Serum levels of adiponectin, visfatin and especially resitin (positive correlation with Acute Physiology and Chronic Health Evaluation II, Ranson and C-reactive protein) are significantly different in mild acute pancreatitis and severe acute pancreatitis patients, so, they can serve as a markers for the disease severity prediction. Resistin and visfatin can also be used for pancreatic and parapancreatic necrosis prediction, interventions needs and possible, outcome.

CONCLUSION: High levels of adipokines could allow for prediction of a severe disease course and outcome even in small pancreatic lesions on computed tomography scans.

Adipokine levels in the course of mild biliary pancreatitis

OBJECTIVES

Obesity markedly increases the risk of severe acute pancreatitis (AP). Several adipokines have been ascribed a role as a predictor of clinical severity in AP. Therefore, the aim of this study was to investigate a possible relationship between leptin and adiponectin and mild biliary AP.

METHODS

We included 24 consecutive patients with mild biliary AP and 24 consecutive healthy age- and sex-matched controls. Clinical severity was classified by the Ranson score. ELISA was used to assess leptin and adiponectin levels on admission and in remission. Complete blood cell counts and other laboratory tests were also performed at baseline and in remission.

RESULTS

Leptin, adiponectin, insulin and HOMA-IR measurements showed no difference in pancreatitis patients both on admission and in remission compared to the control group. No difference was found in leptin, insulin or HOMA-IR levels in the course of pancreatitis. However, adiponectin levels were higher in remission compared to admission.

CONCLUSIONS

Increased adiponectin levels in remission may be an indication of improvement in this condition. Further studies are needed to determine whether adiponectin provides protection from AP.

Progression of pancreatitis prior to diabetes onset in WBN/Kob-Lepr(fa) rats

We established the WBN/Kob-Lepr(fa) rat as a new congenic strain for the fa allele of the leptin receptor gene (Lepr). Homozygous (fa/fa) WBN/Kob-Lepr(fa) rats provide a model of non-insulin-dependent diabetes, although its onset is secondary to pancreatitis. In the present study, we compared histopathological observations of pancreatitis in each genotype of this rat, to examine its suitability as a model of pancreatitis. The histopathological findings of the pancreatitis revealed intense changes dependent on age, such as hemorrhage or hemosiderin deposition. The pancreatitis in homozygous (fa/fa) WBN/Kob-Lepr(fa) rats were more severe than those of WBN/Kob rats.

The influence of dietary restriction on the development of diabetes and pancreatitis in female WBN/Kob-fatty rats

Original WBN/Kob male rats commonly develop chronic pancreatitis by the age of 3 months, while diabetes mellitus occurs at 9 months. In contrast, female rats of this strain do not show pancreatitis or diabetes. The WBN/Kob-fatty rat is a homozygous (fa/fa) congenic strain for the fa allele of the leptin receptor gene (Lepr). In WBN/Kob-fatty rats, both females and males provide a model of non-insulin-dependent diabetes with obesity. The leptin receptor fatty gene (Lepr(fa)) induces obesity and hyperphagia. In the present study, we examined the effect of dietary restriction on pancreatitis and diabetes in female WBN/Kob-fatty rats. Five female fatty rats comprised a restricted feeding group with paired-feeding from 3 to 13 weeks of age, and five female lean rats comprised a control group with paired-feeding. At 13 weeks of age, two of the five female fatty rats of the control group developed diabetes mellitus, while no female fatty rats of the restricted feeding group developed diabetes mellitus. At this stage, pathological changes of the pancreas were observed in female fatty rats. All female fatty rats showed severe interlobular, intra-lobular and intra-islet fibrosis. In female fatty rats of the restricted feeding group, pathological changes of the pancreas were milder those of the free-feeding fatty group. Although dietary restriction could not completely prevent pancreatitis in female fatty rats, the development of diabetes was inhibited by its reduction of the severity of pancreatitis.

Human bone marrow-derived clonal mesenchymal stem cells inhibit inflammation and reduce acute pancreatitis in rats

BACKGROUND & AIMS

Acute pancreatitis (AP) has a high mortality rate; repetitive AP induces chronic AP and pancreatic adenocarcinoma. Mesenchymal stem cells (MSCs) have immunoregulatory effects and reduce inflammation. We developed a protocol to isolate human bone marrow-derived clonal MSCs (hcMSCs) from bone marrow aspirate and investigated the effects of these cells in rat models of mild and severe AP.

METHODS

Mild AP was induced in Sprague-Dawley rats by 3 intraperitoneal injections of cerulein (100 μg/kg), given at 2-hour intervals; severe AP was induced by intraparenchymal injection of 3% sodium taurocholate solution. hcMSCs were labeled with CM-1,1'-dioctadecyl-3,3,3'-tetramethylindo-carbocyanine perchloride and administered to rats through the tail vein.

RESULTS

hcMSCs underwent self-renewal and had multipotent differentiation capacities and immunoregulatory functions. Greater numbers of infused hcMSCs were detected in pancreas of rats with mild and severe AP than of control rats. Infused hcMSCs reduced acinar-cell degeneration, pancreatic edema, and inflammatory cell infiltration in each model of pancreatitis. The hcMSCs reduced expression of inflammation mediators and cytokines in rats with mild and severe AP. hcMSCs suppressed the mixed lymphocyte reaction and increased expression of Foxp3(+) (a marker of regulatory T cells) in cultured rat lymph node cells. Rats with mild or severe AP that were given infusions of hcMSCs had reduced numbers of CD3(+) T cells and increased expression of Foxp3(+) in pancreas tissues.

CONCLUSIONS

hcMSCs reduced inflammation and damage to pancreatic tissue in a rat model of AP; they reduced levels of cytokines and induced numbers of Foxp3(+) regulatory T cells. hcMSCs might be developed as a cell therapy for pancreatitis.

Admission resistin levels predict peripancreatic necrosis and clinical severity in acute pancreatitis

OBJECTIVES

Peripancreatic necrosis determines clinical severity in acute pancreatitis. Early markers predicting peripancreatic necrosis and clinical severity are lacking. Because adipocytes of peripancreatic adipose tissue secret highly active adipocytokines, the aim of the study was to investigate whether adipocytokines are able to serve as early markers predicting peripancreatic necrosis and clinical severity.

METHODS

A total of 50 patients (20 women, 30 men) with acute pancreatitis were included in this noninterventional, prospective, and monocentric cohort study on diagnostic accuracy. Clinical severity was classified by the Ranson score and the APACHE (Acute Physiology And Chronic Health Evaluation) II score. Pancreatic and peripancreatic necrosis were quantified by using the computed tomography-based Balthazar score, the Schroeder score, and the pancreatic necrosis score. Adiponectin, leptin, and resistin were measured at admission and daily for at least 10 days by enzyme-linked immunosorbent assay.

RESULTS

In contrast to admission C-reactive protein values, admission resistin values were significantly correlated with clinical severity and even with clinical end points such as death and need for interventions. Admission resistin levels were significantly elevated in patients with higher pancreatic and extrapancreatic necrosis scores. It was shown by receiver-operator characteristics that admission resistin concentration provides a positive predictive value of 89% in predicting the extent of peripancreatic necrosis (area under the curve, 0.8; P=0.002; sensitivity, 80%; specificity, 70%) by using a cutoff value of 11.9 ng/ml.

CONCLUSIONS

Admission resistin concentration serves as an early predictive marker of peripancreatic necrosis and clinical severity in acute pancreatitis. Resistin may have potential for clinical use as a new and diagnostic serum marker.

A murine model of obesity implicates the adipokine milieu in the pathogenesis of severe acute pancreatitis

Obesity is clearly an independent risk factor for increased severity of acute pancreatitis (AP), although the mechanisms underlying this association are unknown. Adipokines (including leptin and adiponectin) are pleiotropic molecules produced by adipocytes that are important regulators of the inflammatory response. We hypothesized that the altered adipokine milieu observed in obesity contributes to the increased severity of pancreatitis. Lean (C57BL/6J), obese leptin-deficient (LepOb), and obese hyperleptinemic (LepDb) mice were subjected to AP by six hourly intraperitoneal injections of cerulein (50 microg/kg). Severity of AP was assessed by histology and by measuring pancreatic concentration of the proinflammatory cytokines IL-1beta and IL-6, the chemokine MCP-1, and the marker of neutrophil activation MPO. Both congenitally obese strains of mice developed significantly more severe AP than wild-type lean animals. Severity of AP was not solely related to adipose tissue volume: LepOb mice were heaviest; however, LepDb mice developed the most severe AP both histologically and biochemically. Circulating adiponectin concentrations inversely mirrored the severity of pancreatitis. These data demonstrate that congenitally obese mice develop more severe AP than lean animals when challenged by cerulein hyperstimulation and suggest that alteration of the adipokine milieu exacerbates the severity of AP in obesity.

Interleukin-18, together with interleukin-12, induces severe acute pancreatitis in obese but not in nonobese leptin-deficient mice

Obesity is associated with increased severity of acute pancreatitis (AP). The cytokines IL-18 and IL-12 are elevated in patients with AP, and IL-18 levels are high in obesity. We aimed to develop a pathologically relevant model to study obesity-associated severe AP. Lean WT and obese leptin-deficient ob/ob mice received two injections of IL-12 plus IL-18. Survival, pancreatic inflammation, and biochemical markers of AP were measured. Dosing with IL-12 plus IL-18 induced 100% lethality in ob/ob mice; no lethality was observed in WT mice. Disruption of pancreatic exocrine tissue and acinar cell death as well as serum amylase and lipase levels were significantly higher in ob/ob than in WT mice. Edematous AP developed in WT mice, whereas obese ob/ob mice developed necrotizing AP. Adipose tissue necrosis and saponification were present in cytokine-injected ob/ob but not in WT mice. Severe hypocalcemia and elevated acute-phase response developed in ob/ob mice. The cytokine combination induced high levels of regenerating protein 1 and pancreatitis-associated protein expression in the pancreas of WT but not of ob/ob mice. To differentiate the contribution of obesity to that of leptin deficiency, mice received short- and long-term leptin replacement therapy. Short-term leptin reconstitution in the absence of major weight loss did not protect ob/ob mice, whereas leptin deficiency in the absence of obesity resulted in a significant reduction in the severity of the pancreatitis. In conclusion, we developed a pathologically relevant model of AP in which obesity per se is associated with increased severity.

Serum adiponectin and leptin concentrations in patients with chronic pancreatitis of alcoholic and nonalcoholic origin

OBJECTIVE

The aim of this study was to assess serum adiponectin and leptin concentrations in patients with chronic pancreatitis of alcoholic and nonalcoholic origin.

METHODS

Forty-four male patients with chronic pancreatitis of alcoholic origin and 10 patients of nonalcoholic origin as well 16 healthy subjects were examined. Fasting blood samples were collected. Serum adiponectin, leptin, and insulin concentrations were determined by radioimmunoassay methods.

RESULTS

Patients with chronic pancreatitis had lower body mass index values compared with those of control. Nonetheless, there were no differences in serum adiponectin concentration between pancreatitis patients and healthy controls. Pancreatitis patients had lower serum leptin and insulin concentrations than healthy subjects. No difference in serum leptin and insulin concentrations between patients with chronic pancreatitis of alcoholic and nonalcoholic origin was observed. The serum adiponectin/leptin concentration ratio was higher in chronic pancreatitis patients than in control subjects.

CONCLUSIONS

Chronic pancreatitis in humans (a) is associated with the decrease in serum leptin and insulin concentrations, (b) does not affect serum adiponectin concentration but increases serum adiponectin/leptin concentration ratio, and (c) alters the interrelationship between serum adiponectin and insulin concentrations. Moreover, these results suggest that changes in serum leptin and insulin concentrations are independent on the etiology of chronic pancreatitis.

Leptin and its correlation with exocrine and endocrine pancreatic function in idiopathic chronic pancreatitis: implications for pathophysiology

OBJECTIVES

Leptin alters pancreatic exocrine and beta-cell secretion in animal studies. We hypothesized that leptin might be important in the pathogenesis of idiopathic chronic pancreatitis (ICP) and/or the development of diabetes in ICP.

METHODS

Fifty patients with ICP (25 with diabetes, 25 without diabetes) and 25 healthy controls were included in a prospective, case-control study. Fasting plasma leptin concentration was measured by enzyme-linked immunosorbent assay. Exocrine and endocrine pancreatic functions were assessed by fecal chymotrypsin and serum C-peptide, respectively. Anthropometric parameters and body fat mass (FM) were measured.

RESULTS

Patients with ICP (mean age, 30 years; 33 men) had significantly lower body mass index (19.5 +/- 2.6 kg/m2) and FM (10.6 +/- 4.2 kg) as compared with controls (body mass index, 21.7 +/- 4.1 kg/m2; FM, 19.0 +/- 16.6 kg; P < 0.01). Fecal chymotrypsin (median, 5.2 [range, 0.3-42.6] U/kg) and C-peptide (median, 1.7 [range, 0.2-9.5] ng/mL) were significantly lower in patients than in controls (12.9 [range, 2.5-33.0] U/kg and 3.5 [range, 0.3-10.3] ng/mL; P < 0.01). Plasma leptin concentration was slightly lower but statistically insignificant in patients with ICP (median, 4.0 [range, 2.0-62.5] ng/mL) as compared with controls (median, 5.0 [range, 2.0-63.0] ng/mL). Patients with and those without diabetes were also comparable with regard to their leptin concentration, pancreatic functions, and anthropometric parameters.

CONCLUSIONS

Leptin does not seem to have a pathophysiological role in either ICP or the development of diabetes in ICP.

Leptin treatment ameliorates acute lung injury in rats with cerulein-induced acute pancreatitis

AIM: To determine the effect of exogenous leptin on acute lung injury (ALI) in cerulein-induced acute pancreatitis (AP).

METHODS: Forty-eight rats were randomly divided into 3 groups. AP was induced by intraperitoneal (i.p.) injection of cerulein (50 μg/kg) four times, at 1 h intervals. The rats received a single i.p. injection of 10 μg/kg leptin (leptin group) or 2 mL saline (AP group) after cerulein injections. In the sham group, animals were given a single i.p. injection of 2 mL saline. Experimental samples were collected for biochemical and histological evaluations at 24 h and 48 h after the induction of AP or saline administration. Blood samples were obtained for the determination of amylase, lipase, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, macrophage inflammatory peptide (MIP)-2 and soluble intercellular adhesion molecule (sICAM)-1 levels, while pancreatic and lung tissues were removed for myeloperoxidase (MPO) activity, nitric oxide (NOx) level, CD40 expression and histological evaluation.

RESULTS: Cerulein injection caused severe AP, confirmed by an increase in serum amylase and lipase levels, histopathological findings of severe AP, and pancreatic MPO activity, compared to the values obtained in the sham group. In the leptin group, serum levels of MIP-2, sICMA-1, TNF-α, and IL-1β, pancreatic MPO activity, CD40 expression in pancreas and lung tissues, and NOx level in the lung tissue were lower compared to those in the AP group. Histologically, pancreatic and lung damage was less severe following leptin administration.

CONCLUSION: Exogenous leptin attenuates inflamma-tory changes, and reduces pro-inflammatory cytokines, nitric oxide levels, and CD40 expression in cerulein-induced AP and may be protective in AP associated ALI.

Decreased serum leptin concentration in patients with chronic pancreatitis

OBJECTIVE

Previously reported data suggest that serum leptin concentration changes in some acute and chronic inflammatory diseases. The aim of the present study was to assess serum leptin concentration in patients with chronic pancreatitis.

METHODS

Forty-four male patients with chronic pancreatitis and 16 healthy (male) subjects were examined. Fasting blood samples were collected from patients and healthy controls. Serum leptin and insulin concentrations were determined by radioimmunoassay method.

RESULTS

Significantly lower serum leptin concentration in patients with chronic pancreatitis than in healthy subjects was found. No significant difference in serum leptin concentration between patients without and with exacerbation of chronic pancreatitis on admission was observed. Moreover, patients with chronic pancreatitis had (a) lower serum insulin concentration, (b) higher serum glucose concentration, and (c) lower body mass index than healthy subjects.

CONCLUSION

The results presented in this article indicate that chronic pancreatitis in humans is associated with the decrease in serum leptin concentration. One can suppose that the decrease in serum insulin concentration, maldigestion, and fat loss all contribute to the decrease of serum leptin concentration in chronic pancreatitis.

Role of ghrelin and leptin in predicting the severity of acute pancreatitis

Ghrelin and leptin are the hormones that influence endocrine and exocrine functions of the pancreas and regulate feeding behaviors and energy metabolism. The aim of this study was to investigate the levels of ghrelin and leptin in pancreatitis of different severities and the relation of these hormones with blood glucose level and proinflammatory cytokines. The study was performed on 90 Wistar Albino rats. Three experimental groups composed of 30 rats were established: control group, 0.9% NaCl solution was injected intraperitoneally (i.p); acute edematous pancreatitis (AEP) group, 1 microg/100 g cerulein was injected i.p. five times, at 1-hr intervals; and acute necrotizing pancreatitis (ANP) group, 500 mg/100 g L-arginine was injected i.p. Ten animals in each group were sacrificed under anesthesia 12, 24 and 48 hr after the last injection. After blood withdrawal, the pancreas was totally excised. The levels of blood sugar, lipase, serum tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), ghrelin, and leptin were investigated and histopathologic examination was performed. Following pancreatitis induction, serum ghrelin levels increased at 24 hr and reached the peak level at 48 hr. Its level in the AEP group was higher than in the ANP group. Serum leptin levels in the AEP and ANP groups increased after 12 hr and stayed at high levels until 48 hr compared with the control group. Similarly to ghrelin and leptin, blood glucose levels increased in both pancreatitis groups, but the increase was more prominent in the ANP group, with levels >200 mg/ml at 48 hr. The levels of TNF-alpha and IL-1beta in the AEP and ANP groups reached the peak level at 24 hr and then decreased to a level close to that of the control group at 48 hr. We conclude that serum leptin and ghrelin levels increase in the first 48 hr of AEP and ANP. As the serum ghrelin levels in ANP are higher than in AEP, it can be used as a marker to show the severity of pancreatitis. While TNF-alpha and IL-1beta can be used as a prognostic factor in the first 24 hr, ghrelin and leptin can be used subsequently.

Potential of adipocytokines in predicting peripancreatic necrosis and severity in acute pancreatitis: pilot study

BACKGROUND AND AIM

Severe acute pancreatitis is characterized by lipase-induced peripancreatic fat cell necrosis. Because adipocytes secret several highly active molecules, the aim of the present study was to investigate the hypothesis that adipocytokines could serve as potential markers predicting peripancreatic necrosis and severity in acute pancreatitis.

METHODS

A total of 23 patients (11 females, 12 males) with acute pancreatitis were included and a computed tomography (CT) examination was available in 20 patients. Balthazar score, Schröder score, pancreatic necrosis score, Ranson score and APACHE II score were calculated, correlated with biochemical parameters and analyzed using receiver-operator characteristics (ROC) analysis. Adipocytokine serum levels were measured daily by enzyme-linked immunosorbent assay (ELISA) over 10 days after admission.

RESULTS

Resistin and leptin were significantly elevated in patients with severe pancreatitis and were correlated with a radiological scoring system for extrapancreatic necrosis. Whereas resistin correlated positively with clinical scoring systems, time until discharge and the need for interventions, leptin was correlated positively with C-reactive protein (CRP) levels. Resistin levels measured on the day of admittance had a positive predictive value of 93.3% (cut-off: >6.95 ng/mL) in predicting a Schröder score >3.

CONCLUSION

Resistin, and to a lesser extent leptin, but not adiponectin levels are novel potential markers for extrapancreatic necrosis and severity of acute pancreatitis and should therefore be tested in larger cohorts of patients.

Role of adipose tissue as an inflammatory organ in human diseases

Reviews on the inflammatory role of adipose tissue outside the field of metabolism are rare. There is increasing evidence provided by numerous basic research studies from nearly all internal medicine subspecializations that adipocytes and adipocytokines are involved in primary inflammatory processes and diseases. Therefore, it is the aim of the present review to discuss and to summarize the current knowledge on the inflammatory role of adipocytokines and special types of regional adipocytes such as retroorbital, synovial, visceral, subdermal, peritoneal, and bone marrow adipocytes in internal medicine diseases. Future clinical and therapeutic implications are discussed.

Is leptin related to systemic inflammatory response in acute pancreatitis?

AIM: To evaluate the relationship between leptin and systemic inflammation in acute pancreatitis.

METHODS: Consecutive patients with acute pancreatitis were included. Body mass index and serum samples were obtained at admission. Leptin, TNF-α, IL-6, -8 and -10 levels were determined by ELISA. Severity was defined according to Atlanta criteria.

RESULTS: Fifty-two (29 females) patients were studied. Overall body mass index was similar between mild and severe cases, although women with severe pancreatitis had lower body mass index (P = 0.04) and men showed higher body mass index (P = 0.05). No difference was found in leptin levels regarding the severity of pancreatitis, but higher levels tended to appear in male patients with increased body mass index and severe pancreatitis (P = 0.1). A multivariate analysis showed no association between leptin levels and severity. The strongest cytokine associated with severity was IL-6. Correlations of leptin with another cytokines only showed a trend for IL-8 (P = 0.058).

CONCLUSION: High body mass index was associated with severity only in males, which may be related to android fat distribution. Serum leptin seems not to play a role on the systemic inflammatory response in acute pancreatitis and its association with severe outcome in males might represent a marker of increased adiposity.

Free radicals and the pancreatic acinar cells: role in physiology and pathology

Reactive oxygen and nitrogen species (ROS and RNS) play an important role in signal transduction and cell injury processes. Nitric oxide synthase (NOS)-the key enzyme producing nitric oxide (NO)-is found in neuronal structures, vascular endothelium and, possibly, in acinar and ductal epithelial cells in the pancreas. NO is known to regulate cell homeostasis, and its effects on the acinar cells are reviewed here. ROS are implicated in the early events within the acinar cells, leading to the development of acute pancreatitis. The available data on ROS/RNS involvement in the apoptotic and necrotic death of pancreatic acinar cells will be discussed.

Leptin and adiponectin levels in acute pancreatitis

OBJECTIVES

Obesity is a risk factor for a severe form of acute pancreatitis (AP). Because the underlying mechanisms are poorly known, we studied relationship between the severity of AP and plasma levels of leptin and adiponectin, 2 adipokines regulating the course of systemic inflammation.

METHODS

The study comprises 12 patients with severe AP and 12 control patients with mild AP matched by age (+/-10 years), body mass index (+/-3 kg/m), sex, and etiology of AP. Quantikine Human Adiponectin and Quantikine Human Leptin Immunoassays (R&D Systems, Minneapolis, Minn) were used to measure the adipokine levels in the patients' plasma on admission and during the hospital stay.

RESULTS

Median leptin concentrations on admission were 6.1 ng/mL (range, 1.6-72.9 ng/mL) in the severe AP group and 9.0 ng/mL (range, 2.5-36.3 ng/mL) in the mild AP group (P > 0.05). In severe AP, the value at days 2 to 4 (7.7 ng/mL; range, 1.6-13.9 ng/mL) did not differ from respective on-admission value (P > 0.05). In mild AP, the value at days 2 to 4 (3.8 ng/mL; range, 1.6-12.9 ng/mL) was lower than the respective on-admission value (P = 0.005). Adiponectin concentrations on admission were 5642 ng/mL (range, 1201-19,400 ng/mL) for severe AP and 6314 ng/mL (range, 1980-24,340 ng/mL) for mild AP (P > 0.05). Maximum variation of adiponectin level (the highest value minus the lowest value) was greater in severe AP than in mild AP (P = 0.001).

CONCLUSIONS

In patients matched by age, sex, body mass index, and etiology, the on-admission plasma levels of adiponectin and leptin do not correlate with disease severity, suggesting that the adipokines do not affect the course of AP.

Pioglitazone, a specific ligand of peroxisome proliferator-activated receptor-gamma, protects pancreas against acute cerulein-induced pancreatitis

AIM: To determine the effect of pioglitazone, a specific peroxisome proliferator-activated receptor-γ (PPARγ) ligand, on the development of acute pancreatitis (AP) and on the expression of heat shock protein 70 (HSP70) in the pancreas.

METHODS: AP was induced in rats by subcutaneous infusion of cerulein for 5 h. Pancreatic blood flow was measured by laser Doppler flowmetry. Plasma lipase activity, interleukin-1β (IL-1β) and IL-10 were determined. Pancreatic weight and histology were evaluated and pancreatic DNA synthesis and blood flow as well as pancreatic mRNA for IL-1β and HSP70 were assessed in rats treated with pioglitazone alone or in combination with cerulein.

RESULTS: Pioglitazone administered (10-100 mg/kg i.g.) 30 min before cerulein, attenuated dose-dependently the pancreatic tissue damage in cerulein-induced pancreatitis (CIP) as demonstrated by the improvement of pancreatic histology, reduction in plasma lipase activity, plasma concentration of pro-inflammatory IL-1β and its gene expression in the pancreas and attenuation of the pancreatitis-evoked fall in pancreatic blood flow. CIP increased pancreatic HSP70 mRNA and protein expression in the pancreas and this effect was enhanced by pioglitazone treatment.

CONCLUSION: Pioglitazone attenuates CIP and the beneficial effect of this pioglitazone is multifactorial probably due to its anti-inflammatory activities, to the suppression of IL-1β and to the overexpression of HSP70. PPARγ ligands could represent a new therapeutic option in the treatment of AP.

Plasma leptin levels in rats with pancreatitis

Diagnosis of pancreatitis is based on the determination of serum amylase and lipase levels. However, recent identification of specific leptin receptors in the pancreas suggests that this peptide may also play some roles in the modulation of pancreatic function. The objective of the present study was to investigate the relationship between serum leptin levels and pancreatitis. Thirty male Wistar rats were divided into 3 groups: the control group, acute pancreatitis group and chronic pancreatitis group. Pancreatitis was induced by injection of ethyl alcohol into the common biliary duct. A sham laparotomy was performed in the control group. Control and acute pancreatitis groups were sacrificed 24 hours later, and chronic pancreatitis group was sacrificed on postoperative day 7. Blood was taken by cardiac puncture for the determination of plasma leptin levels, and the pancreatic tissue was excised for histopathologic confirmation of pancreatitis. Plasma leptin rose significantly from the median of 0.78 +/- 0.12 ng/ml in the control group to 1.92 +/- 0.10 ng/ml and 1.86 +/- 0.13 ng/ml in acute and chronic pancreatitis groups, respectively (p < 0.001, for both). There was no significant difference in the plasma leptin levels between the acute pancreatitis group and the chronic pancreatitis group (p > 0.05). These findings confirm that leptin has a role in pancreas inflammation, and the inflamed tissue can be the source of local production of leptin.

Role of leptin as an immunomodulator of blood mononuclear cells: mechanisms of action

Leptin is a an adipocyte-secreted hormone that regulates weight centrally. However, the leptin receptor is expressed not only in the central nervous system, but also in peripheral tissues, such as haematopoietic and immune systems. Therefore, the physiological role of leptin should not be limited to the regulation of food intake and energy expenditure. Moreover, the leptin receptor bears homology to members of the class I cytokine family, and recent data have demonstrated that leptin is able to modulate the immune response. Thus, the leptin receptor is expressed in human peripheral blood mononuclear cells, mediating the leptin effect on proliferation and activation. In vitro activation and HIV infection in vivo induce the expression of the long isoform of the leptin receptor in mononuclear cells. Also, leptin stimulates the production of proinflammatory cytokines from cultured monocytes and enhances the production of Th1 type cytokines from stimulated lymphocytes. Moreover, leptin has a trophic effect on monocytes, preventing apoptosis induced by serum deprivation. Leptin stimulation activates JAK-STAT, IRS-1-PI3K and MAPK signalling pathways. Leptin also stimulates Tyr-phosphorylation of the RNA-binding protein Sam68 mediating the dissociation from RNA. In this way, leptin signalling could modulate RNA metabolism. These signal transduction pathways provide possible mechanisms whereby leptin may modulate activation of peripheral blood mononuclear cells. Therefore, these data support the hypothesis regarding leptin as a proinflammatory cytokine with a possible role as a link between the nutritional status and the immune response. Moreover, these immunoregulatory functions of leptin could have some relevance in the pathophysiology of obesity.