Protective Effects of PACAP in Peripheral Organs.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide widely distributed in the nervous system, where it exerts strong neuroprotective effects. PACAP is also expressed in peripheral organs but its peripheral protective effects have not been summarized so far. Therefore, the aim of the present paper is to review the existing literature regarding the cytoprotective effects of PACAP in non-neuronal cell types, peripheral tissues, and organs. Among others, PACAP has widespread expression in the digestive system, where it shows protective effects in various intestinal pathologies, such as duodenal ulcer, small bowel ischemia, and intestinal inflammation. PACAP is present in both the exocrine and endocrine pancreas as well as liver where it reduces inflammation and steatosis by interfering with hepatic pathology related to obesity. It is found in several exocrine glands and also in urinary organs, where, with its protective effects being mainly published regarding renal pathologies, PACAP is protective in numerous conditions. PACAP displays anti-inflammatory effects in upper and lower airways of the respiratory system. In the skin, it is involved in the development of inflammatory pathology such as psoriasis and also has anti-allergic effects in a model of contact dermatitis. In the non-neuronal part of the visual system, PACAP showed protective effects in pathological conditions of the cornea and retinal pigment epithelial cells. The positive role of PACAP has been demonstrated on the formation and healing processes of cartilage and bone where it also prevents osteoarthritis and rheumatoid arthritis development. The protective role of PACAP was also demonstrated in the cardiovascular system in different pathological processes including hyperglycaemia-induced endothelial dysfunction and age-related vascular changes. In the heart, PACAP protects against ischemia, oxidative stress, and cardiomyopathies. PACAP is also involved in the protection against the development of pre-senile systemic amyloidosis, which is presented in various peripheral organs in PACAP-deficient mice. The studies summarized here provide strong evidence for the cytoprotective effects of the peptide. The survival-promoting effects of PACAP depend on a number of factors which are also shortly discussed in the present review.

Negotiating the complexities of exocrine and endocrine dysfunction in chronic pancreatitis.

Chronic pancreatitis is a chronic inflammatory disease of the pancreas characterised by irreversible morphological change and typically causing pain and/or permanent loss of function. This progressive, irreversible disease results in destruction of healthy pancreatic tissue and the development of fibrous scar tissue. Gradual loss of exocrine and endocrine function follows, along with clinical manifestations such as steatorrhoea, abdominal pain and diabetes. Nutrition in chronic pancreatitis has been described as a problem area and, until recently, there was little research on the topic. It is often asserted that >90 % of the pancreas must be damaged before exocrine insufficiency occurs; however, an exploration of the original studies from the 1970s found that the data do not support this assertion. The management of steatorrhoea with pancreatic enzyme replacement therapy is the mainstay of nutritional management, and early identification and treatment is a key. The presence of steatorrhoea, coupled with poor dietary intake (due to intractable abdominal pain, gastrointestinal side effects and often alcoholism) renders the chronic pancreatitis patients at considerable risk for undernutrition, muscle depletion and fat-soluble vitamin deficiency. Premature osteoporosis/osteopenia afflicts two-thirds of patients as a consequence of poor dietary intake of calcium and vitamin D, low physical activity, low sunlight exposure, heavy smoking, as well as chronic low-grade inflammation. Bone metabolism studies show increased bone formation as well as bone resorption in chronic pancreatitis, indicating that bone turnover is abnormally high. Loss of the pancreatic islet cells occurs later in the disease process as the endocrine cells are diffusely distributed throughout the pancreatic parenchyma. Patients may develop type 3c (pancreatogenic) diabetes, which is complicated by concurrent decreased glucagon secretion, and hence an increased risk of hypoglycaemia. Diabetes control is further complicated by poor diet, malabsorption and (for some) alcoholism, and therefore those with type 3c diabetes have clinical characteristics and therapeutic goals that are different from that of type 1 and type 2 diabetes patients. This review describes emerging research and clinical guidelines for nutrition in chronic pancreatitis.

Association of Anticentromere Antibodies With More Severe Exocrine Glandular Dysfunction in Sjögren's Syndrome: Analysis of the Sjögren's International Collaborative Clinical Alliance Cohort.

OBJECTIVE: Anticentromere antibodies (ACAs) define a subset of primary Sjögren's syndrome (SS) with a unique phenotype, including features of limited cutaneous systemic sclerosis and a lower frequency of anti-SSA/SSB antibodies. We sought to determine whether ACAs are associated with more severe exocrine glandular dysfunction in a large cohort of primary SS subjects. METHODS: We performed a cross-sectional analysis of 1,361 subjects with primary SS from the Sjögren's International Collaborative Clinical Alliance Registry, stratified by the presence or absence of ACAs. ACAs were assayed by immunofluorescence staining on HEp-2 cells. RESULTS: ACAs were present in 82 of the 1,361 SS subjects (6%) and were associated with older age, female sex, and lower frequencies of anti-SSA/SSB, rheumatoid factor, and hyperglobulinemia. Among ACA-positive versus ACA-negative subjects, there was a higher frequency of a focus score ≥2 (71% versus 53%; P = 0.002), a higher median focus score (2.8 versus 2.5; P = 0.0440), and greater exocrine gland dysfunction: Schirmer's test value: median 4 versus 5 mm/5 minutes; P = 0.0003, and unstimulated whole saliva (UWS) flow rate: median 0.08 versus 0.37 ml/5 minutes; P < 0.0001. ACA-positive subjects had an increased risk of UWS <0.1 ml/minute (odds ratio [OR] 12.24 [95% confidence interval (95% CI) 4.91-41.02]) and Schirmer's test value <5 mm/5 minutes (OR 2.52 [95% CI 1.50-4.36]) after correcting for age, sex, anti-SSA/SSB, and focus score. Labial gland fibrosis was not different between the 2 groups. CONCLUSION: In a large international registry of SS, ACA had an independent association with more severe exocrine glandular dysfunction. This dysfunction was associated with more pronounced labial salivary glandular inflammation but not fibrosis.

Biallelic PDX1 (insulin promoter factor 1) mutations causing neonatal diabetes without exocrine pancreatic insufficiency.

AIMS: Recessive PDX1 (IPF1) mutations are a rare cause of pancreatic agenesis, with three cases reported worldwide. A recent report described two cousins with a homozygous hypomorphic PDX1 mutation causing permanent neonatal diabetes with subclinical exocrine insufficiency. The aim of our study was to investigate the possibility of hypomorphic PDX1 mutations in a large cohort of patients with permanent neonatal diabetes and no reported pancreatic hypoplasia or exocrine insufficiency. METHODS: PDX1 was sequenced in 103 probands with isolated permanent neonatal diabetes in whom ABCC8, KCNJ11 and INS mutations had been excluded. RESULTS: Sequencing analysis identified biallelic PDX1 mutations in three of the 103 probands with permanent neonatal diabetes (2.9%). One proband and his affected brother were compound heterozygotes for a frameshift and a novel missense mutation (p.A34fsX191; c.98dupC and p.P87L; c.260C>T). The other two probands were homozygous for novel PDX1 missense mutations (p.A152G; c.455C>G and p.R176Q; c.527G>A). Both mutations affect highly conserved residues located within the homeobox domain. None of the four cases showed any evidence of exocrine pancreatic insufficiency, either clinically, or, where data were available, biochemically. In addition a heterozygous nonsense mutation (p.C18X; c.54C>A) was identified in a fourth case. CONCLUSIONS: This study demonstrates that recessive PDX1 mutations are a rare but important cause of isolated permanent neonatal diabetes in patients without pancreatic hypoplasia/agenesis. Inclusion of the PDX1 gene in mutation screening for permanent neonatal diabetes is recommended as a genetic diagnosis reveals the mode of inheritance, allows accurate estimation of recurrence risks and confirms the requirement for insulin treatment.

Neuroimmune interactions in Sjögren's syndrome: relationship of exocrine gland dysfunction with autoantibodies to muscarinic acetylcholine receptor-3 and mental health status parameters.

OBJECTIVES: Antimuscarinic acetylcholine receptor-3 (m3AChR) autoantibodies have been described in primary Sjögren's syndrome (pSS). The aim of this study was to compare various methods for their detection and to assess the contributions of anti-m3AChR and other immunological and psychosocial factors to the pathomechanism of secondary SS (sSS). METHODS: Sixty-five rheumatoid arthritis (RA) patients, 103 systemic lupus erythematosus (SLE) patients, 76 pSS patients and 50 controls were compared. Three immunodominant epitopes of m3AChR were synthesized and used in ELISA. Two extracellular epitopes were also prepared in fusion with glutathione-S-transferase and one in conjugation with bovine serum albumin. Mental health status was assessed with the 36-item Short-Form Health Survey and Functional Assessment of Chronic Illness Therapy fatigue scale. Correlations were evaluated between glandular function and anti-m3AChR positivities and specificities, features of SLE and RA, and mental health parameters. RESULTS: Fourteen RA and 27 SLE patients had sSS. The autoantibody levels to all epitopes of m3AChR were significantly higher in pSS and SLE patients than in the controls. The fusion protein forms discriminated RA from pSS and SLE; furthermore, the YNIP fusion protein also distinguished pSS from SLE. The prevalence and the mean levels of all autoantibodies did not differ statistically between sicca and non-sicca SLE or RA patients. Glandular dysfunction correlated with higher age in SLE and RA and an impaired health-related quality of life in SLE. CONCLUSIONS: The second and third extracellular loops of m3AChR are antigenic in pSS. Immunoassays with antigens as fusion peptides demonstrate the best performance. Sicca SLE patients have worse mental health status. Anti-m3AChR antibodies represent a peculiar example of neuroimmune interactions.

GATA6 mutations cause a broad phenotypic spectrum of diabetes from pancreatic agenesis to adult-onset diabetes without exocrine insufficiency.

We recently reported de novo GATA6 mutations as the most common cause of pancreatic agenesis, accounting for 15 of 27 (56%) patients with insulin-treated neonatal diabetes and exocrine pancreatic insufficiency requiring enzyme replacement therapy. We investigated the role of GATA6 mutations in 171 subjects with neonatal diabetes of unknown genetic etiology from a cohort of 795 patients with neonatal diabetes. Mutations in known genes had been confirmed in 624 patients (including 15 GATA6 mutations). Sequencing of the remaining 171 patients identified nine new case subjects (24 of 795, 3%). Pancreatic agenesis was present in 21 case subjects (six new); two patients had permanent neonatal diabetes with no enzyme supplementation and one had transient neonatal diabetes. Four parents with heterozygous GATA6 mutations were diagnosed with diabetes outside the neonatal period (12-46 years). Subclinical exocrine insufficiency was demonstrated by low fecal elastase in three of four diabetic patients who did not receive enzyme supplementation. One parent with a mosaic mutation was not diabetic but had a heart malformation. Extrapancreatic features were observed in all 24 probands and three parents, with congenital heart defects most frequent (83%). Heterozygous GATA6 mutations cause a wide spectrum of diabetes manifestations, ranging from pancreatic agenesis to adult-onset diabetes with subclinical or no exocrine insufficiency.

Inducible tertiary lymphoid structures, autoimmunity, and exocrine dysfunction in a novel model of salivary gland inflammation in C57BL/6 mice.

Salivary glands in patients with Sjögren's syndrome (SS) develop ectopic lymphoid structures (ELS) characterized by B/T cell compartmentalization, the formation of high endothelial venules, follicular dendritic cell networks, functional B cell activation with expression of activation-induced cytidine deaminase, as well as local differentiation of autoreactive plasma cells. The mechanisms that trigger ELS formation, autoimmunity, and exocrine dysfunction in SS are largely unknown. In this article, we present a novel model of inducible ectopic lymphoid tissue formation, breach of humoral self-tolerance, and salivary hypofunction after delivery of a replication-deficient adenovirus-5 in submandibular glands of C57BL/6 mice through retrograde excretory duct cannulation. In this model, inflammation rapidly and consistently evolves from diffuse infiltration toward the development of SS-like periductal lymphoid aggregates within 2 wk from AdV delivery. These infiltrates progressively acquire ELS features and support functional GL7(+)/activation-induced cytidine deaminase(+) germinal centers. Formation of ELS is preceded by ectopic expression of lymphoid chemokines CXCL13, CCL19, and lymphotoxin-ß, and is associated with development of anti-nuclear Abs in up to 75% of mice. Finally, reduction in salivary flow was observed over 3 wk post-AdV infection, consistent with exocrine gland dysfunction as a consequence of the inflammatory response. This novel model has the potential to unravel the cellular and molecular mechanisms that regulate ELS formation and their role in exocrine dysfunction and autoimmunity in SS.

Endometrial secretions: creating a stimulatory microenvironment within the human early placenta and implications for the aetiopathogenesis of preeclampsia.

Endometrial glands represent an important source of nutrients for the conceptus during the first trimester. Their secretions are enriched with carbohydrates, and glycogen accumulates within the syncytiotrophoblast of the placenta. It has been assumed that fetal and placental metabolism follow adult pathways, although it is now appreciated that early development occurs in a low-oxygen environment. In past decades, a novel family of putative insulin mediators, inositol phosphoglycans (IPGs), was discovered. These molecules act as allosteric activators and/or inhibitors of enzymes and transduction proteins involved in the control of cell signalling and metabolic pathways, and determine the specificity of responses after activation of the insulin receptor. One member, IPG P-type, activates pyruvate dehydrogenase phosphatase (PDH-Pase), glycogen synthase phosphatase, and glycerol-3-phosphate acyltransferase. Activation of key phosphatases play a major role in the regulation of glucose disposal by oxidative metabolism via PDH, and the non-oxidative storage by glycogen synthesis, both pathways classically known to be regulated by insulin. High concentrations of IPG P-type in amniotic fluid suggest a role in the regulation of carbohydrate metabolism in the fetal-placental unit. Glycogen accumulation in the syncytiotrophoblast also occurs in preeclamptic pregnancies, and is consistently associated with higher placental levels of IPG P-type. Here, we explore the relationship between nutrients provided by the endometrial glands during early pregnancy, IPG P-type and fetal metabolic requirements. We also discuss whether a disconnect between the placental/fetal metabolic state and oxygen tension could lead to a preeclamptic-type syndrome via leakage of Warburg/IPG mediators into the maternal circulation.

Tratamiento de fondo del síndrome seco. ¿Qué puede aportar el reumatólogo? / Etiologic treatment of sicca syndrome. What can the rheumatologist offer?

En el síndrome de Sjögren primario (SSP) no se ha descrito hasta el momento una terapia eficaz para las manifestaciones glandulares a pesar del desarrollo de múltiples agentes orales y biológicos en los últimos años. Varios fármacos empleados como tratamiento de fondo en otras enfermedades se han probado empíricamente y, reconocida la hiperactividad de la célula B en el SSP, también los moduladores de estas se han ensayado en esta enfermedad. En este artículo se revisan los datos existentes sobre el uso de tratamientos modificadores de la enfermedad exclusivamente en el síndrome seco, encontrando que los ensayos publicados con fármacos antirreumáticos orales han mostrado resultados contradictorios y desalentadores, mientras que algunos tratamientos biológicos han resultado esperanzadores. Los problemas encontrados se centran sobre todo en la falta de una correcta y homogénea metodología en los diseños de los ensayos (AU)

No effective treatment has been documented for the glandular primary Sjögren syndrome (PSS) despite the development of oral and biologic agents that have significant activity against other autoimmune disorders. Some disease-modifying agents have been empirically evaluated for the treatment of PSS. Targeting B cells also seems very promising in SSP because of the B-cell hyperactivity recognized in this desease. This article reviews existing data on the use of disease-modifying therapy for glandular of SSP. To date, published studies and trials of oral DMARDs for the treatment of SSP have shown disappointing results. B-cell modulation is clearly a promising therapy for PSS. Many challenges in trial design and execution are evident from the studies reviewed (AU)

Transgenic animals may help resolve a sticky situation in cystic fibrosis.

Cystic fibrosis (CF) is caused by defects in the CFTR, a cAMP-activated Cl- channel of epithelia. The resulting reduction in epithelial fluid transport creates abnormally viscous secretions from airway mucous glands that may be a major factor in CF pathology. Mouse airways have few mucous glands, and the mouse model of CF exhibits no significant airway disease. Pigs and ferrets, however, have approximately the same number of airway mucous glands as humans. In this issue of the JCI, three independent research groups conclude that changes in airway mucous gland function in CFTR-deficient animals of these species resemble the changes seen in human CF. It is expected, therefore, that these animals will develop lung disease similar to human CF and prove to be valuable models on which to test potential therapies.

Hyposecretion of fluid from tracheal submucosal glands of CFTR-deficient pigs.

Cystic fibrosis (CF) results from mutations that disrupt CF transmembrane conductance regulator (CFTR), an anion channel found mainly in apical membranes of epithelial cells. CF leads to chronic infection of the airways with normally innocuous bacteria and fungi. Hypotheses to explain the pathophysiology of CF airways have been difficult to test because mouse models of CF do not develop human-like airway disease. The recent production of pigs lacking CFTR and pigs expressing the most common CF-causing CFTR mutant, DeltaF508, provide another model that might help clarify the pathophysiology of CF airway disease. Here, we studied individual submucosal glands from 1-day-old piglets in situ in explanted tracheas, using optical methods to monitor mucus secretion rates from multiple glands in parallel. Secretion rates from control piglets (WT and CFTR+/-) and piglets with CF-like disease (CFTR-/- and CFTR-/DeltaF508) were measured under 5 conditions: unstimulated (to determine basal secretion), stimulated with forskolin, stimulated with carbachol, stimulated with substance P, and, as a test for synergy, stimulated with forskolin and a low concentration of carbachol. Glands from piglets with CF-like disease responded qualitatively to all agonists like glands from human patients with CF, producing virtually no fluid in response to stimulation with forskolin and substantially less in response to all other agonists except carbachol. These data are a step toward determining whether gland secretory defects contribute to CF airway disease.

Pathogenetic mechanisms in the initiation and perpetuation of Sjögren's syndrome.

Sjögren's syndrome (SS), a chronic autoimmune disorder, particularly compromises the function of exocrine glands. The involvement of these glands is characterized by focal, mononuclear cell infiltrates that surround the ducts and replace the secretory units. The pathogenetic mechanisms of this autoimmune exocrinopathy have not been fully elucidated. Immunologically-activated or apoptotic glandular epithelial cells that expose autoantigens in genetically predisposed individuals might drive autoimmune-mediated tissue injury. Alterations in several immune mediators, such as upregulation of type I interferon-regulated genes, abnormal expression of B-cell-activating factor and activation of the interleukin-23-type 17 T-helper cell pathway, have been reported. Extension of the pathological process that affects the exocrine glands into periepithelial and extraepithelial tissue can cause a considerable percentage of patients to exhibit systemic findings that involve the lungs, liver or kidneys. These manifestations develop as a result of lymphocytic invasion or an immune-complex-mediated process, or both, and present as skin vasculitis coupled with peripheral neuropathy or glomerulonephritis (or both). Patients with systemic extraepithelial manifestations display low serum levels of the complement component C4 and mixed type II cryoglobulins, and show an increased risk of developing non-Hodgkin lymphoma, thereby reflecting an overall worse prognosis with higher mortality rates than those without extraepithelial manifestations.

[Impairment of humoral regulation of exocrine pancreatic function in chronic pancreatitis].

AIM: To elicit the role of cholecistokinin (CCK), biogenic amines, bile acids (BA) in development of functional pancreatic insufficiency (PI) in chronic pancreatitis (CP). MATERIAL AND METHODS: Blood concentrations of CCK, serotonin and acetylcholin, fecal concentration of elastase (E-1), BA spectrum in the blood and duodenal content were studied in 46 CP patients (20 patients with alcoholic pancreatitis--AP and 26 patients with biliary pancreatitis--BP) and 15 healthy controls. RESULTS: In AP patients E-1 fell to 78.4 +/- 6.3 mcg/g (severe exocrine PI), while in BP patients E-1 was 170.0 +/- 28.9 mcg/g. CCK in AP and BP decreased to 0.33 +/- 0.03 and 0.45 +/- 0.03 ng/ml, respectively (control--1.60 +/- 0.02 ng/ml, respectively, p < 0.05). AP and BP patients had a rise in the absolute concentration and percentage of the total fraction of the taurodioxicholanic acids to 10.2 +/- 1.6 and 15.0 +/- 2.3%, respectively, (control 9.5 +/- 1.2%) in duodenal bile. The concentration of glycocholic acid fell to 24.1 +/- 1.6 and 23.7 +/- 3.7%, respectively, (control--36.4 +/- 2.4%, p < 0.05). AP patients had more significant decrease of taurocholic acid--to 4.5 +/- 0.7% (control--9.2 +/- 0.7%, p < 0.05). In the peripheral blood of AP patients there was an elevated basal level of serotonin and acetylcholine in the presence of low cholinesterase activity. After meal, acetylcholine concentration lowered in high secretion of serotonin. CONCLUSION: Depending on severity of destructive changes in the pancreas, AP and BP patients had different degree of exocrine insufficiency which may be secondary to the absence of acetylcholine rise in the blood after meal. Alterations in the composition of the conjugates of cholic and taurodioxicholanic BA lead to alterations of CCK blood concentration and, therefore, to changes in exocrine pancreatic secretion. Imbalance between serotonin and acetylcholine levels after meal evidences for defects in conventional regulatory interrelations. Decreased threshold of nociceptors activation in simultaneous enhancement of afferent nociceptive flows may entail pain syndrome in CP.

Autoimmune diseases and Sjogren's syndrome: an autoimmune exocrinopathy.

Autoimmune diseases include a diverse group of over 80 conditions. Sjögren's syndrome is the second most common autoimmune rheumatic disease, with an estimated prevalence in the United States of 2-4 million persons. There are prominent and consistent oral and dental findings in Sjögren's syndrome related to the autoimmune-mediated loss of normal salivary function. Additionally, nonoral clinical manifestations of Sjögren's syndrome include: dry eyes (with specific ocular surface changes termed keratoconjunctivitis sicca); other xeroses, such as dryness of the nose, throat, skin, and vagina; peripheral (and less frequently central) neuropathies; myalgias and arthralgias; thyroid disorders (particularly autoimmune thyroiditis); pulmonary disorders; renal disorders; and lymphoma. There is a significant (20- to 40-fold) increase in the incidence of malignant lymphoma, particularly in primary Sjögren's syndrome. Establishing the diagnosis of Sjögren's syndrome has been difficult in the light of its nonspecific symptoms (dry eyes and mouth), disagreement on diagnostic criteria, and a lack of both sensitive and specific laboratory markers. Many serum and salivary biomarkers for Sjögren's syndrome have been proposed although, to date, none has proven to be sufficiently specific for diagnostic purposes or has been well correlated with disease activity measures. Investigators have recently begun to apply modern genomic and proteomic approaches to identify candidate biomarkers in Sjögren's syndrome. The results of these investigations promise to provide a wealth of information on candidate biomarkers and possible etiopathological mechanisms underlying this disorder. Further, this information will improve clinical outcomes by fostering the design of new rational therapeutics and assisting in the monitoring of clinical disease.

Submucosal gland dysfunction as a primary defect in cystic fibrosis.

It has been proposed that defective submucosal gland function in CF airways is a major determinant of CF airway disease. We tested the hypothesis that submucosal gland function is defective early in CF subjects with minimal clinical disease. Functional assays of gland fluid secretion rate and viscosity were performed on freshly obtained nasal biopsies from 6 CF subjects and 5 non-CF controls (age range 2-22 years). Secretions from individual submucosal glands were visualized by light/fluorescence microscopy after orienting and immobilizing biopsy specimens in a custom chamber. The viscosity of freshly secreted gland fluid after pilocarpine, measured by fluorescence recovery after photobleaching of microinjected FITC-dextran, was 4.9 +/- 0.2- vs. 2.2 +/- 0.2-fold greater than water viscosity in CF vs. non-CF specimens, respectively (SE, P<10(-4)). Gland fluid secretion rate in CF specimens, measured by video imaging (4.5+/-0.5 nL/min/gland, n=6), was 2.7-fold reduced compared to non-CF specimens (n=3, P<0.05). Quantitative histology revealed similar size and morphology of submucosal glands in CF and non-CF specimens. Our results suggest that defective airway submucosal gland function is an early, primary defect in CF. Therapies directed at normalizing gland fluid secretion early in CF may thus reduce lung disease.

Exocrine specific expression of Connexin32 is dependent on the basic helix-loop-helix transcription factor Mist1.

Gap junctions are intercellular channels that provide direct passage of small molecules between adjacent cells. In pancreatic acini, the connexin26 (Cx26) and connexin32 (Cx32) proteins form functional channels that coordinate the secretion of digestive enzymes. Although the function of Cx26/Cx32 gap junctions are well characterized, the regulatory circuits that control the spatial and temporal expression patterns of these connexin genes are not known. In an effort to identify the molecular pathways that regulate connexin gene expression, we examined Cx26 and Cx32 gene activities in mice lacking the basic helix-loop-helix transcription factor Mist1 (Mist1KO). Mist1, Cx26 and Cx32 are co-expressed in most exocrine cell types, and acinar cells from Mist1KO mice exhibit a highly disorganized cellular architecture and an altered pattern of expression for several genes involved in regulated exocytosis. Analysis of Mist1KO mice revealed a dramatic decrease in both connexin proteins, albeit through different molecular mechanisms. Cx32 gene transcription was greatly reduced in all Mist1KO exocrine cells, while Cx26 gene expression remained unaffected. However, in the absence of Cx32 protein, Cx26 did not participate in gap junction formation, leading to a complete lack of intercellular communication among Mist1KO acinar cells. Additional studies testing Mist1 gene constructs in pancreatic exocrine cells confirmed that Mist1 transcriptionally regulates expression of the Cx32 gene. We conclude that Mist1 functions as a positive regulator of Cx32 gene expression and, in its absence, acinar cell gap junctions and intercellular communication pathways become disrupted.

The effect of perfusion with UW solution on the skeletal muscle and vascular endothelial exocrine function in rat hindlimbs.

BACKGROUND: The effect of University of Wisconsin (UW) solution perfusion for extremity preservation is still unknown although it is widely used. The purpose of this study is to examine the effect of UW solution perfusion on skeletal muscle preservation in a rat model. MATERIALS AND METHODS: Rat hindlimbs were amputated and either preserved with UW solution perfusion (UW perfusion group) or given no perfusion (no-perfusion group) for 5 h at 25 degrees C. They were then transplanted to other isogeneic rats. ATP in the muscle and serum creatine phosphokinase were measured after 24 h of reperfusion. The vascular endothelial function of the femoral artery rings was measured before and after 24 h of reperfusion in the presence or absence of indomethacin (cyclooxygenase inhibitor) and L-NMMA (nitric oxide synthase inhibitor). TEA (calcium-activated potassium channel inhibitor) was also used to verify the vasodilator function. Reperfusion blood flow was monitored during the first 2 h of reperfusion. RESULTS: ATP in the UW perfusion group was significantly decreased after 24 h of reperfusion, while that in the no-perfusion group recovered. Reperfusion blood flow in the UW solution perfusion group was significantly lower than that in the no-perfusion group. Acetylcholine-induced relaxation in the UW perfusion group was significantly reduced before and after 24 h of reperfusion compared to that in the no-perfusion group and was mostly diminished by indomethacin and L-NMMA administration. CONCLUSIONS: Skeletal muscle injury is augmented by UW solution perfusion, probably due to deterioration of the vascular endothelial function resulting in blood supply diminution.

Conservative treatment of chronic pancreatitis.

Chronic pancreatitis has been difficult to treat because the origin, pathophysiologic mechanisms and causes of unrelenting pain are so poorly understood. Furthermore, the pharmacologic agents often employed in other diseases with pain appear to be ineffective in many cases. The conservative management of chronic pancreatitis aims at (1) limiting progression and complications of the disease; (2) replacing lost exocrine and endocrine function; and (3) pain control. Thus, life style changes such as cessation of alcohol consumption and tobacco smoking, trials of pancreatic enzymes, treatment of duct obstruction and pseudocysts, and surgical therapies are currently employed. The good news is that the understanding of the underlying pathophysiological mechanisms is now advancing rapidly, and hopefully patient-specific and highly effective therapies will become available in the near future.