Localized bioelectrical conduction block from radiofrequency gastric ablation persists after healing: safety and feasibility in a recovery model.

Gastric ablation has demonstrated potential to induce conduction blocks and correct abnormal electrical activity (i.e., ectopic slow-wave propagation) in acute, intraoperative in vivo studies. This study aimed to evaluate the safety and feasibility of gastric ablation to modulate slow-wave conduction after 2 wk of healing. Chronic in vivo experiments were performed in weaner pigs (n = 6). Animals were randomly divided into two groups: sham-ablation (n = 3, control group; no power delivery, room temperature, 5 s/point) and radiofrequency (RF) ablation (n = 3; temperature-control mode, 65°C, 5 s/point). In the initial surgery, high-resolution serosal electrical mapping (16 × 16 electrodes; 6 × 6 cm) was performed to define the baseline slow-wave activation profile. Ablation (sham/RF) was then performed in the mid-corpus, in a line around the circumferential axis of the stomach, followed by acute postablation mapping. All animals recovered from the procedure, with no sign of perforation or other complications. Two weeks later, intraoperative high-resolution mapping was repeated. High-resolution mapping showed that ablation successfully induced sustained conduction blocks in all cases in the RF-ablation group at both the acute and 2 wk time points, whereas all sham-controls had no conduction block. Histological and immunohistochemical evaluation showed that after 2 wk of healing, the lesions were in the inflammation and early proliferation phase, and interstitial cells of Cajal (ICC) were depleted and/or deformed within the ablation lesions. This safety and feasibility study demonstrates that gastric ablation can safely and effectively induce a sustained localized conduction block in the stomach without disrupting the surrounding slow-wave conduction capability.NEW & NOTEWORTHY Ablation has recently emerged as a tool for modulating gastric electrical activation and may hold interventional potential for disorders of gastric function. However, previous studies have been limited to the acute intraoperative setting. This study now presents the safety of gastric ablation after postsurgical recovery and healing. Localized electrical conduction blocks created by ablation remained after 2 wk of healing, and no perforation or other complications were observed over the postsurgical period.

Chronic Pancreatitis Is Characterized by Elevated Circulating Periostin Levels Related to Intra-Pancreatic Fat Deposition.

BACKGROUND: Periostin is a matricellular protein that induces fibrillogenesis and activates cell migration. It is overexpressed in common fibrotic diseases and is also associated with abdominal adiposity/ectopic fat phenotypes. The study aimed to investigate circulating levels of periostin in health and after an attack of pancreatitis, as well as their associations with abdominal adiposity/ectopic fat phenotypes. METHODS: Blood samples were obtained from healthy controls, as well as definite chronic pancreatitis (CP) and acute pancreatitis (AP) individuals during follow-up visits. Fat depositions in the pancreas, liver, skeletal muscle, as well as visceral and subcutaneous fat volumes, were quantified with the use of magnetic resonance imaging. A series of multivariable analyses were conducted, accounting for possible confounders. RESULTS: A total of 121 individuals were included. Periostin levels were significantly higher in the CP group compared with the other groups in both unadjusted (F = 3.211, P = 0.044) and all adjusted models (F = 4.165, P = 0.019 in the most adjusted model). Intra-pancreatic fat deposition (but not the other fat phenotypes) was significantly associated with periostin concentration in the CP group (ß = 49.63, P = 0.034) and explained most of its variance (32.0%). CONCLUSIONS: Individuals with CP, but not healthy individuals or those after clinical resolution of AP, are characterized by elevated circulating levels of periostin that are positively associated with intra-pancreatic fat deposition.

Implications of Tobacco Smoking and Alcohol Consumption on Ectopic Fat Deposition in Individuals After Pancreatitis.

OBJECTIVES: Tobacco smoking and alcohol consumption are established risk factors for pancreatitis. This study investigated the associations between tobacco smoking/alcohol consumption in people after an attack of pancreatitis and intrapancreatic fat deposition (IPFD), intrahepatic fat deposition (IHFD), and skeletal muscle (SMFD) fat deposition. METHODS: In this cross-sectional study, magnetic resonance imaging was used to quantify IPFD, IHFD, and SMFD by 2 independent raters. A validated questionnaire was used to determine tobacco smoking and alcohol consumption. RESULTS: A total of 119 individuals after an attack of pancreatitis were included. Average tobacco smoking contributed most to variance in IPFD (R = 6.5%) and least to variance in SMFD (R = 0.4%). Average alcohol consumption contributed most to variance in variance in IPFD (R = 2.8%) and least to IHFD (R = 1.1%). Packs/day contributed more than years of smoking to variance in IPFD (R = 4.9 and 0.2%, correspondingly), whereas years of drinking contributed more than average daily alcohol consumption (R = 3.9 and 3.2%, correspondingly). CONCLUSIONS: Tobacco smoking and alcohol consumption contributed more to variance in IPFD than IHFD and SMFD. Smoking contributed more than drinking to variance in IPFD. The daily amount of tobacco smoked appeared to be more important than years of smoking for IPFD.

Reduced Skeletal Muscle Volume and Increased Skeletal Muscle Fat Deposition Characterize Diabetes in Individuals after Pancreatitis: A Magnetic Resonance Imaging Study.

BACKGROUND: Skeletal muscle has been implicated in the pathogenesis of type 2 diabetes but it has never been investigated in diabetes after pancreatitis. The aim was to investigate the relationship between psoas muscle volume (PMV) and diabetes in individuals after pancreatitis, as well as its associations with ectopic fat phenotypes and insulin traits. METHODS: Individuals after an attack of pancreatitis and healthy individuals were studied in a cross-sectional fashion. All participants underwent magnetic resonance imaging, based on which PMV, skeletal muscle fat deposition (SMFD), as well as liver and intra-pancreatic fat depositions were derived. Fasting and postprandial blood samples were collected to calculate indices of insulin sensitivity and secretion. Linear regression analyses were conducted, adjusting for possible confounders (age, sex, body composition, comorbidities, use of insulin, and others). RESULTS: A total of 153 participants were studied. PMV was significantly decreased in the diabetes group compared with healthy controls (ß = -30.0, p =.034 in the most adjusted model). SMFD was significantly inversely associated with PMV (ß = -3.1, p < 0.001 in the most adjusted model). The Matsuda index of insulin sensitivity was significantly directly associated with PMV (ß = 1.6, p = 0.010 in the most adjusted model). CONCLUSIONS: Diabetes in individuals after pancreatitis is characterized by reduced PMV. Reduced PMV is associated with increased SMFD and decreased insulin sensitivity in individuals after pancreatitis.

Associations Between Cannabis Use, Abdominal Fat Phenotypes and Insulin Traits.

BACKGROUND: General obesity has been linked to dysregulation of the endocannabinoid system in humans. However, there is a lack of studies on the relationship between cannabis use and specific abdominal fat phenotypes. The aim was to investigate the associations between cannabis use and magnetic resonance imaging-derived fat phenotypes, as well as indices of insulin sensitivity and insulin secretion. METHODS: In this cross-sectional study, magnetic resonance imaging was used to quantify subcutaneous fat volume (SFV), visceral fat volume (VFV), intra-hepatic fat deposition (IHFD), intra-pancreatic fat deposition (IPFD) and skeletal muscle fat deposition (SMFD) by two independent observers. Insulin sensitivity was determined based on HOMA-IS, Raynaud index and Matsuda index, whereas insulin secretion was determined based on HOMA-ß, insulinogenic index 30' and insulinogenic index 60'. A validated questionnaire was used to ascertain participants' cannabis use. Linear regression models were constructed, adjusting for demographics, glycated hemoglobin, physical activity, tobacco smoking and alcohol consumption. RESULTS: A total of 120 individuals were included. Cannabis use explained 9.2% of variance in IHFD, 4.4% in SMFD, 3.4% in VFV, 0.4% in SFV and 0.2% in IPFD. Regular cannabis users had significantly greater IHFD compared with never users, in both the unadjusted (P = 0.002) and all adjusted (P = 0.002; P = 0.008) analyses. The other fat phenotypes did not differ significantly between either regular or non-regular users compared with never users. Regular cannabis users had significantly greater insulin secretion (as defined by the insulinogenic index 60') compared with never users, in both the unadjusted (P = 0.049) and all adjusted (P = 0.003; P = 0.004) analyses. Cannabis use explained 20.3% of variance in the insulinogenic index 60', but was not significantly associated with the other indices of insulin secretion. There were no significant differences in indices of insulin sensitivity in either regular or non-regular cannabis users compared with never users. CONCLUSION: Regular cannabis use may be a risk factor for non-alcoholic fatty liver disease (but not IPFD) and may alter the neuromodulation of insulin secretion. Further investigations are now warranted to elucidate the mechanisms underlying these associations.

Psoas muscle size as a magnetic resonance imaging biomarker of progression of pancreatitis.

OBJECTIVE: Pancreatitis often represents a continuous inflammatory process, from the first episode of acute pancreatitis (FAP) to recurrent acute pancreatitis (RAP) to chronic pancreatitis (CP). Psoas muscle size is a validated surrogate for global skeletal mass, changes in which are associated with inflammation. The objective was to investigate psoas muscle size in individuals following FAP, RAP, and CP, as well as its associations with pro-inflammatory cytokines. METHODS: Individuals following pancreatitis and healthy individuals were recruited. All participants underwent magnetic resonance imaging, from which psoas muscle volume was derived independently by two raters in a blinded fashion. Circulating levels of four major cytokines (interleukin-6, tumour necrosis factor-α, C-C motif chemokine ligand 2, and leptin) were measured. Five linear regression additive models were built to adjust for possible confounders (age, sex, body composition, physical activity, tobacco smoking, alcohol consumption, comorbidities, and endocrine and exocrine pancreatic functions). RESULTS: A total of 145 participants were enrolled. A significant downward trend in psoas muscle volume was observed between healthy controls and individuals following FAP, RAP, and CP in all adjusted models (p = 0.047, 0.005, 0.004, and < 0.001). Leptin was significantly associated with psoas muscle volume in all models (ß = - 0.16, p = 0.030 in the most adjusted model). The other studied cytokines were not significantly associated with psoas muscle volume. CONCLUSIONS: Psoas muscle size is significantly reduced along the continuum from FAP to RAP to CP. Leptin appears to be one of the factors implicated in this. Further studies are warranted to investigate the relationship between skeletal muscle and inflammation of the pancreas. KEY POINTS: • First acute pancreatitis, recurrent acute pancreatitis, and chronic pancreatitis were associated with progressively reduced psoas muscle size. • The findings were independent of age, sex, body fat composition, physical activity, tobacco smoking, alcohol consumption, comorbidities, and exocrine and endocrine functions of the pancreas. • The mechanism underlying the observed findings may involve hyperleptinaemia.