Isaac Samuel

Roux-en-Y gastric bypass ameliorates polycystic ovary syndrome and dramatically improves conception rates: a 9-year analysis

BACKGROUND Polycystic ovary syndrome (PCOS) is a common cause of infertility, especially in the morbidly obese. We evaluated the long-term effects of Roux-en-Y gastric bypass on PCOS and infertility. METHODS A total of 566 morbidly obese women underwent Roux-en-Y gastric bypass from 2000 to 2009. A total of 31 patients (5.5%) had a history of PCOS. Of the 31 patients, 6 were postmenopausal and 5 lost to follow-up and were excluded. Telephone interviews were conducted with the 20 eligible patients. RESULTS The mean age and body mass index was 32 ± 5.8 years (range 22-42) and 52.8 ± 9.08 kg/m(2) (range 37-76) before surgery. All 20 patients had ≥ 2 of 3 diagnostic criteria for PCOS, including clinical or biochemical evidence of hyperandrogenism, anovulation, or polycystic ovaries. Of these, 85% had oligomenorrhea, 70% had hirsutism, and 45% had type 2 diabetes mellitus with medication. Before surgery, 8 patients conceived with or without hormonal treatment, 2 did not desire pregnancy, and 10 did not conceive. The mean follow-up was 46.7 months. After surgical weight loss, menstruation was corrected in 82%, hirsutism had resolved in 29%, and 77.8% of those with diabetes had complete remission. Of the 10 patients who did not conceive before surgery, 4 no longer desired pregnancy, and the remaining 6 patients had become pregnant within 3 years of surgery-5 without any hormonal treatment and 1 with in utero insemination. CONCLUSION Surgical weight loss after Roux-en-Y gastric bypass achieves excellent amelioration of PCOS manifestations and the postoperative conception rate in infertile PCOS subjects desiring pregnancy was 100%.

The novel cytokine interleukin-33 activates acinar cell proinflammatory pathways and induces acute pancreatic inflammation in mice.

Background Acute pancreatitis is potentially fatal but treatment options are limited as disease pathogenesis is poorly understood. IL-33, a novel IL-1 cytokine family member, plays a role in various inflammatory conditions but its role in acute pancreatitis is not well understood. Specifically, whether pancreatic acinar cells produce IL-33 when stressed or respond to IL-33 stimulation, and whether IL-33 exacerbates acute pancreatic inflammation is unknown. Methods/Results In duct ligation-induced acute pancreatitis in mice and rats, we found that (a) IL-33 concentration was increased in the pancreas; (b) mast cells, which secrete and also respond to IL-33, showed degranulation in the pancreas and lung; (c) plasma histamine and pancreatic substance P concentrations were increased; and (d) pancreatic and pulmonary proinflammatory cytokine concentrations were increased. In isolated mouse pancreatic acinar cells, TNF-α stimulation increased IL-33 release while IL-33 stimulation increased proinflammatory cytokine release, both involving the ERK MAP kinase pathway; the flavonoid luteolin inhibited IL-33-stimulated IL-6 and CCL2/MCP-1 release. In mice without duct ligation, exogenous IL-33 administration induced pancreatic inflammation without mast cell degranulation or jejunal inflammation; pancreatic changes included multifocal edema and perivascular infiltration by neutrophils and some macrophages. ERK MAP kinase (but not p38 or JNK) and NF-kB subunit p65 were activated in the pancreas of mice receiving exogenous IL-33, and acinar cells isolated from the pancreas of these mice showed increased spontaneous cytokine release (IL-6, CXCL2/MIP-2α). Also, IL-33 activated ERK in human pancreatic tissue. Significance As exogenous IL-33 does not induce jejunal inflammation in the same mice in which it induces pancreatic inflammation, we have discovered a potential role for an IL-33/acinar cell axis in the recruitment of neutrophils and macrophages and the exacerbation of acute pancreatic inflammation. Conclusion IL-33 is induced in acute pancreatitis, activates acinar cell proinflammatory pathways and exacerbates acute pancreatic inflammation.

In Vitro Evidence for Role of ERK, p38, and JNK in Exocrine Pancreatic Cytokine Production

Elucidation of mechanisms of acinar cell cytokine production is essential for a better understanding of acute pancreatitis pathogenesis. We hypothesize that the stress kinases ERK, p38, and JNK play an important role in acinar cell cytokine production. Rat pancreatic fragments were incubated with 100 nM concentration of the cholecystokinin analog caerulein or 100 nM caerulein and specific ERK inhibitor (100 µM PD98059), specific p38 inhibitor (10 µM SB203580), or specific JNK inhibitor (20 µM SP600125). After 3 hours of caerulein treatment, pancreatic fragments were homogenized and assayed for total and phosphorylated ERK, p38, and JNK, and for tumor necrosis factor-α or interleukin-1β concentrations (ELISA). Pancreatic fragments stimulated with caerulein showed activation of ERK, p38, and JNK and increased cytokine concentrations (ANOVA, P<0.05). Specific stress kinase inhibitors significantly attenuated caerulein-induced activation of the corresponding stress kinase and cytokine production; however, the effect of the JNK inhibitor was comparatively less convincing. Increased activation of ERK, p38, and JNK in pancreatic fragments was not associated with significant increases in total ERK, total p38, or total JNK concentrations. The stress kinases ERK and p38 play an important role in caerulein-stimulated exocrine pancreatic overproduction of cytokines. The role of JNK needs further evaluation in this experimental model.

Bile-Pancreatic Juice Exclusion Increases p38MAPK Activation and TNF-α Production in Ligation-Induced Acute Pancreatitis in Rats

Acute pancreatitis is associated with stress kinase activation and cytokine production. We hypothesize that bile-pancreatic juice exclusion activates p38MAPK and induces TNF-α production in ligation-induced acute pancreatitis. We compared rats with 1–3 h of duct ligation, duct ligation with duodenal bile-pancreatic juice replacement from a donor rat, and sham operation. Pancreatic homogenates were analyzed as follows: (a) Immunoblots using phospho-specific p38MAPK antibody showed increased p38MAPK activation after ligation that was inhibited by bile-pancreatic juice replacement. (b) Immune-complex kinase assay using ATF-2 as substrate showed increased p38MAPK activation after ligation that was subdued by bile-pancreatic juice replacement. (c) ELISA showed increased pancreatic TNF-α production after ligation that was significantly ameliorated by bile-pancreatic juice replacement. Conclusion: Bile-pancreatic juice exclusion from gut increases p38MAPK activation and TNF-α production in this experimental model. Our findings support our central hypothesis that bile-pancreatic juice exclusion exacerbates cell stress and acute inflammation in ligation-induced acute pancreatitis.

Bile and pancreatic juice exclusion activates acinar stress kinases and exacerbates gallstone pancreatitis

HYPOTHESIS Bile and pancreatic juice exclusion from gut activates acinar stress kinases and exacerbates gallstone pancreatitis as evidenced by the ameliorating effects of replacement therapy in an experimental model of duct ligation-induced acute pancreatitis. In the early stages of gallstone pancreatitis, bile-pancreatic juice cannot enter the gut. Enteral exclusion worsens pancreatitis by causing feedback hyperstimulation of the exocrine pancreas that activates acinar cell stress kinases. Investigations using a unique surgical model, the Donor Rat Model, showed that duodenal replacement of bile-pancreatic juice in rats with duct ligation attenuates pancreatic stress kinase activation, reduces pancreatic cytokine production, and ameliorates pancreatic morphologic changes. These findings suggest that exclusion-induced acinar hyperstimulation, in the presence of duct obstruction, exacerbates acute pancreatitis via stress kinase activation. Although acinar hyperstimulation has often been implicated in the pathogenesis of acute pancreatitis, the lack of supporting evidence remains a conspicuous void. The proposed hypothesis draws on fresh evidence to present a new paradigm that reexamines the role of exocrine pancreatic hyperstimulation in gallstone pancreatitis pathogenesis.

Bile-Pancreatic Juice Exclusion Promotes Akt/NF-κB Activation and Chemokine Production in Ligation-Induced Acute Pancreatitis

Using a unique surgical model (the donor rat model), we showed previously that duodenal replacement of bile-pancreatic juice, obtained fresh from a donor rat, ameliorates ligation-induced acute pancreatitis. We hypothesize that bile-pancreatic juice exclusion from gut exacerbates Akt/nuclear factor-kB (NF-kB) pathway activation and induces chemokine production in ligation-induced acute pancreatitis. We compared rats with bile-pancreatic duct ligation to those with duodenal bile-pancreatic juice replacement fresh from a donor rat beginning immediately before duct ligation. Sham control rats had ducts dissected but not ligated. Rats were killed 1 or 3 hours after operation (n=7/group). Akt activation (immunoblotting, immune-complex kinase assay, and ELISA), inhibitory protein I-kB (I-kB) activation (immunoblotting), and production of chemokines MCP-1 and RANTES (ELISA) were measured in pancreatic homogenates. NF-kB was quantitated in nuclear fractions using electrophoretic mobility shift assay. Duct ligation produced significant increases in pancreatic Akt, IkB, and NF-kB activation and production of MCP-1 and RANTES. Activation of the Akt/NF-kB pathway and increased MCP-1 and RANTES production in response to duct ligation were significantly reduced by bile-pancreatic juice replacement (ANOVA, P<0.05). Bile-pancreatic juice exclusion stimulates Akt/NF-kB pathway activation and increases chemokine production in ligation-induced acute pancreatitis.

Mechanism of Acute Pancreatitis Exacerbation by Enteral Bile-Pancreatic Juice Exclusion

Using an original model, the donor rat model, we previously showed that bile-pancreatic juice exclusion from gut exacerbates ligation-induced acute pancreatitis. Here, we examine the mechanism by which bile-pancreatic juice exclusion from gut exacerbates acute pancreatitis. In the first part of the study we test the hypothesis that Na taurocholate and trypsin are components of bile-pancreatic juice that exacerbate acute pancreatitis when excluded. Our experiments show that combined replacement of Na taurocholate and trypsin ameliorates acute pancreatitis. In the second part of the study we test the hypothesis that bile-pancreatic juice exclusion from gut exacerbates acute pancreatitis via combined CCK-A and cholinergic receptor pathways. Our experiments show that combined CCK-A and cholinergic receptor blockade significantly ameliorates acute pancreatitis while blockade of either receptor alone does not. We conclude that bile-pancreatic juice exclusion-induced exacerbation of ligation-induced acute pancreatitis involves a neurohormonal duodenal response to exclusion of trypsin and Na taurocholate resulting in acinar cell hyperstimulation via combined CCK-A and cholinergic receptor-mediated pathways.

SWELL1 is a regulator of adipocyte size, insulin signalling and glucose homeostasis

Adipocytes undergo considerable volumetric expansion in the setting of obesity. It has been proposed that such marked increases in adipocyte size may be sensed via adipocyte-autonomous mechanisms to mediate size-dependent intracellular signalling. Here, we show that SWELL1 (LRRC8a), a member of the Leucine-Rich Repeat Containing protein family, is an essential component of a volume-sensitive ion channel (VRAC) in adipocytes. We find that SWELL1-mediated VRAC is augmented in hypertrophic murine and human adipocytes in the setting of obesity. SWELL1 regulates adipocyte insulin–PI3K–AKT2–GLUT4 signalling, glucose uptake and lipid content via SWELL1 C-terminal leucine-rich repeat domain interactions with GRB2/Cav1. Silencing GRB2 in SWELL1 KO adipocytes rescues insulin-pAKT2 signalling. In vivo, shRNA-mediated SWELL1 knockdown and adipose-targeted SWELL1 knockout reduce adiposity and adipocyte size in obese mice while impairing systemic glycaemia and insulin sensitivity. These studies identify SWELL1 as a cell-autonomous sensor of adipocyte size that regulates adipocyte growth, insulin sensitivity and glucose tolerance.

Dominant Negative p38 Mitogen-Activated Protein Kinase Expression Inhibits NF-κB Activation in AR42J Cells

Background: The role of the p38 mitogen-activated protein (MAP) kinase in acute pancreatitis pathogenesis is controversial. We hypothesize that p38 plays a role in regulating NF-ĸB activation in exocrine pancreatic cells. Methods: AR42J cells incorporating an NF-ĸB-responsive luciferase reporter, with and without adenoviral transduction of DNp38, were stimulated with cholecystokinin (CCK) or tumor necrosis factor-α (TNF-α) prior to measuring NF-ĸB activation. Results: CCK- or TNF-α-stimulated NF-ĸB-dependent gene transcription (luciferase assay) was substantially subdued by DNp38 expression. These findings were confirmed by electrophoretic mobility shift assay. Nuclear translocation of the p65 NF-ĸB subunit following agonist stimulation was evident (supershift). Characterization studies showed excellent adenoviral infection efficiency and cell viability in our AR42J cell model. Agonist-stimulated dose- and time-dependent p38 activation, with inhibition by DNp38 expression, was also confirmed. Conclusion: The p38 MAP kinase regulates NF-ĸB pathway activation in exocrine pancreatic cells, and thus potentially plays a role in the mechanism of acute pancreatitis pathogenesis.

CCK-A receptor induction and P38MAPK and NF-κB activation in acute pancreatitis

Bile-pancreatic duct ligation in rats excludes bile-pancreatic juice from the gut and induces acute pancreatitis. Bile-pancreatic juice exclusion from the gut results in increased plasma cholecystokinin (CCK) levels. CCK-A receptor-mediated exocrine pancreatic hyperstimulation is implicated in disease pathogenesis. In the present study, we show for the first time a progressive rise in CCK-A receptor protein expression in ligation-induced acute pancreatitis in rats. As CCK-A receptor induction could amplify CCK-mediated acinar hyperstimulation and exacerbate acinar cell stress with activation of the p38MAPK stress kinase pathway, we studied CCK-A receptor protein expression and p38MAPK activation in duct ligation-induced acute pancreatitis in rats. Compared to sham-operated controls, acute pancreatitis induced by bile-pancreatic duct ligation associates with a temporal increase in pancreatic CCK-A receptor protein expression, p38MAPK expression and activation, and NF-ĸB activation. These findings may have significance in the mechanism of disease pathogenesis in this experimental model.