Corticosteroids correct aberrant CFTR localization in the duct and regenerate acinar cells in autoimmune pancreatitis

Inflammation increases cells expressing ZSCAN4 and progenitor cell markers in the adult pancreas

We have recently identified the zinc finger and SCAN domain containing 4 (Zscan4), which is transiently expressed and regulates telomere elongation and genome stability in mouse embryonic stem (ES) cells. The aim of this study was to examine the expression of ZSCAN4 in the adult pancreas and elucidate the role of ZSCAN4 in tissue inflammation and subsequent regeneration. The expression of ZSCAN4 and other progenitor or differentiated cell markers in the human pancreas was immunohistochemically examined. Pancreas sections of alcoholic or autoimmune pancreatitis patients before and under maintenance corticosteroid treatment were used in this study. In the adult human pancreas a small number of ZSCAN4-positive (ZSCAN4⁺) cells are present among cells located in the islets of Langerhans, acini, ducts, and oval-shaped cells. These cells not only express differentiated cell markers for each compartment of the pancreas but also express other tissue stem/progenitor cell markers. Furthermore, the number of ZSCAN4⁺ cells dramatically increased in patients with chronic pancreatitis, especially in the pancreatic tissues of autoimmune pancreatitis actively regenerating under corticosteroid treatment. Interestingly, a number of ZSCAN4⁺ cells in the pancreas of autoimmune pancreatitis returned to the basal level after 1 yr of maintenance corticosteroid treatment. In conclusion, coexpression of progenitor cell markers and differentiated cell markers with ZSCAN4 in each compartment of the pancreas may indicate the presence of facultative progenitors for both exocrine and endocrine cells in the adult pancreas.

Cerulein-induced chronic pancreatitis does not require intra-acinar activation of trypsinogen in mice

BACKGROUND & AIMS

Premature activation of trypsinogen activation can cause pancreatic injury and has been associated with chronic pancreatitis (CP). Mice that lack intra-acinar activation of trypsinogen, such as trypsinogen-7-null (T(-/-)) and cathepsin B-null (CB(-/-)) mice, have been used to study trypsin-independent processes of CP development. We compared histologic features and inflammatory responses of pancreatic tissues from these mice with those from wild-type mice after the development of CP.

METHODS

CP was induced in wild-type, T(-/-), and CB(-/-) mice by twice-weekly induction of acute pancreatitis for 10 weeks; acute pancreatitis was induced by hourly intraperitoneal injections of cerulein (50 μg/kg × 6). Pancreatic samples were collected and evaluated by histologic and immunohistochemical analyses. Normal human pancreas samples, obtained from the islet transplant program at the University of Minnesota, were used as controls and CP samples were obtained from surgical resections.

RESULTS

Compared with pancreatic tissues from wild-type mice, those from T(-/-) and CB(-/-) mice had similar levels of atrophy, histomorphologic features of CP, and chronic inflammation. All samples had comparable intra-acinar activation of nuclear factor (NF)-κB, a transcription factor that regulates the inflammatory response, immediately after injection of cerulein. Pancreatic tissue samples from patients with CP had increased activation of NF-κB (based on nuclear translocation of p65 in acinar cells) compared with controls.

CONCLUSIONS

Induction of CP in mice by cerulein injection does not require intra-acinar activation of trypsinogen. Pancreatic acinar cells of patients with CP have increased levels of NF-κB activation compared with controls; regulation of the inflammatory response by this transcription factor might be involved in the pathogenesis of CP.

Autoimmune pancreatitis: current concepts

Autoimmune pancreatitis (AIP) is a distinct type of chronic pancreatitis with unique clinical, pathological, serological, and imaging features. AIP usually presents with obstructive jaundice. Imaging studies often reveal enlargement of the pancreas with a pancreatic mass and strictures of the main pancreatic duct. Two subtypes of AIP have recently been identified. Type I AIP is more prevalent in elderly Asian males and is characterized by lymphoplasmacytic sclerosing pancreatitis, obliterative phlebitis, and infiltration of large numbers of IgG4-positive plasma cells. Type II AIP is more prevalent in Caucasians and is characterized by granulocyte epithelial lesions. Most patients with type I AIP have a significantly elevated serum IgG4 concentration, which is an important feature for diagnosis and for differentiating between AIP and other conditions such as pancreatic cancer. Extrapancreatic complications are common, such as sclerosing cholangitis, sclerosing sialadenitis, retroperitoneal fibrosis in type I AIP, and ulcerative colitis in type II AIP. A rapid response to glucocorticoids treatment is suggestive of AIP, but the relapse rate is high, warranting the use of immunosuppressant treatment. B-cell depletion with rituximab may be a promising therapy. The prognosis of AIP is generally benign if treated promptly, and spontaneous remission occurs in a proportion of patients.

Molecular mechanisms of pancreatic stone formation in chronic pancreatitis

Chronic pancreatitis (CP) is a progressive inflammatory disease in which the pancreatic secretory parenchyma is destroyed and replaced by fibrosis. The presence of intraductal pancreatic stone(s) is important for the diagnosis of CP; however, the precise molecular mechanisms of pancreatic stone formation in CP were left largely unknown. Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel expressed in the apical plasma membrane of pancreatic duct cells and plays a central role in [Formula: see text] secretion. In previous studies, we have found that CFTR is largely mislocalized to the cytoplasm of pancreatic duct cells in all forms of CP and corticosteroids normalizes the localization of CFTR to the proper apical membrane at least in autoimmune pancreatitis. From these observations, we could conclude that the mislocalization of CFTR is a cause of protein plug formation in CP, subsequently resulting in pancreatic stone formation. Considering our observation that the mislocalization of CFTR also occurs in alcoholic or idiopathic CP, it is very likely that these pathological conditions can also be treated by corticosteroids, thereby preventing pancreatic stone formation in these patients. Further studies are definitely required to clarify these fundamental issues.

CFTR-mediated Cl(-) transport in the acinar and duct cells of rabbit lacrimal gland

PURPOSE

We investigated the role that the cystic fibrosis transmembrane conductance regulator (CFTR) may play in Cl(-) transport in the acinar and ductal epithelial cells of rabbit lacrimal gland (LG).

METHODS

Primary cultured LG acinar cells were processed for whole-cell patch-clamp electrophysiological recording of Cl(-) currents by using perfusion media with high and low [Cl(-)], 10 µM forskolin and 100 µM 3-isobutyl-1-methylxanthine (IBMX), the non-specific Cl(-) channel blocker 4,4'-disothiocyanostilbene-2, 2' sulphonic acid (DIDS; 100 µM) and CFTRinh-172 (10 µM), a specific blocker for CFTR. Ex vivo live cell imaging of [Cl(-)] changes in duct cells was performed on freshly dissected LG duct with a multiphoton confocal laser scanning microscope using a Cl(-) sensitive fluorescence dye, N-[ethoxycarbonylmethyl]-6-methoxy-quinolinium bromide.

RESULTS

Whole-cell patch-clamp studies demonstrated the presence of Cl(-) current in isolated acinar cells and revealed that this Cl(-) current was mediated by CFTR channel. Live cell imaging also showed the presence of CFTR-mediated Cl(-) transport across the plasma membrane of duct cells.

CONCLUSIONS

Our previous data showed the presence of CFTR in all acinar and duct cells within the rabbit LG, with expression most prominent in the apical membranes of duct cells. The present study demonstrates that CFTR is actively involved in Cl(-) transport in both acinar cells and epithelial cells from duct segments, suggesting that CFTR may play a significant role in LG secretion.

CFTR polymorphisms of healthy individuals in two Chinese cities--Changchun and Nanjing

BACKGROUND AND AIM

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes a chloride channel, cause cystic fibrosis. In order to investigate the polymorphic backgrounds of CFTR genes of healthy populations in different Chinese cities (Changchun and Nanjing), we analyzed 119 blood samples (Changchun 64, Nanjing 55) of randomly selected healthy individuals for poly T, TG-repeats and M470V polymorphisms. We analyzed the differences of CFTR polymorphic distributions between the two Chinese cities from the south and the north. Methods Genomic DNA was extracted from whole blood. DNA fragments of CFTR gene were amplified by polymerase chain reaction (PCR). Poly-T and TG repeats were directly sequenced by auto sequencer (ABI 310). M470V was detected by a HphI restriction enzyme.

RESULTS

The T7 allele was the most common haplotype in Changchun (0.938) and Nanjing (0.927) populations. The T5 allele was present in only 7 Changchun and 3 Nanjing subjects. The TG11 and TG12 alleles were dominant haplotypes in Changchun (TG11 0.500, TG12 0.453) and Nanjing (TG11 0.345, TG12 0.609). The frequency of the V470 allele was 0.633 in Changchun, which was higher than that in Nanjing (0.500) (p < 0.05). There were three major haplotypes: T7-TG11-V470, T7-TG12-M470 and T7-TG12-V470. The T7-TG11-V470 was the most common haplotype in Changchun (0.514), while T7-TG12-M470 was the most common haplotype in Nanjing (0.500).

CONCLUSION

Though Changchun and Nanjing are in the same country, their polymorphic backgrounds of CFTR gene are very different. Most of the two populations have genotypes that cause lower CFTR function.

Risk factors for pancreatic stone formation in autoimmune pancreatitis over a long-term course

BACKGROUND

Autoimmune pancreatitis (AIP) has the potential to progress to a chronic state that forms pancreatic stones. The aim of this study was to clarify the risk factors underlying pancreatic stone formation in AIP.

METHODS

Sixty-nine patients with AIP who had been followed for at least 3 years were enrolled for evaluation of clinical and laboratory factors as well as computed tomography and endoscopic retrograde cholangiopancreatography findings.

RESULTS

During the course of this study, increased or de novo stone formation was seen in 28 patients, who were defined as the stone-forming group. No stones were observed in 32 patients, who were defined as the non-stone-forming group. Nine patients who had stones at diagnosis but showed no change during the course of this study were excluded from our cohort. Univariate analysis revealed no significant differences in clinical or laboratory factors associated with AIP-specific inflammation between the two groups. However, pancreatic head swelling (P = 0.006) and narrowing of both Wirsung's and Santorini's ducts in the pancreatic head region (P = 0.010) were significantly more frequent in the stone-forming group. Furthermore, multivariate analysis identified Wirsung and Santorini duct narrowing at diagnosis as a significant independent risk factor for pancreatic stone formation (OR 4.4, P = 0.019).

CONCLUSIONS

A primary risk factor for pancreatic stone formation in AIP was narrowing of both Wirsung's and Santorini's ducts, which most presumably led to pancreatic juice stasis and stone development.

Commensal Flora, is it an Unwelcomed Companion as a Triggering Factor of Autoimmune Pancreatitis?

The etiopathogenesis of many autoimmune disorders has not been identified. The aim of this paper is to focus on the involvement of bacterial exposure, as an environmental factor, in the pathogenesis of autoimmune pancreatitis (AIP), which is broadly categorized as autoimmune disorders involving pancreatic lesions. Avirulent and/or commensal bacteria, which may have an important role(s) as initiating/progressing factors in the pathogenesis of autoimmune disorder AIP, will be emphasized.

Molecular mechanism of pancreatic and salivary gland fluid and HCO3 secretion

Fluid and HCO(3)(-) secretion is a vital function of all epithelia and is required for the survival of the tissue. Aberrant fluid and HCO(3)(-) secretion is associated with many epithelial diseases, such as cystic fibrosis, pancreatitis, Sjögren's syndrome, and other epithelial inflammatory and autoimmune diseases. Significant progress has been made over the last 20 years in our understanding of epithelial fluid and HCO(3)(-) secretion, in particular by secretory glands. Fluid and HCO(3)(-) secretion by secretory glands is a two-step process. Acinar cells secrete isotonic fluid in which the major salt is NaCl. Subsequently, the duct modifies the volume and electrolyte composition of the fluid to absorb the Cl(-) and secrete HCO(3)(-). The relative volume secreted by acinar and duct cells and modification of electrolyte composition of the secreted fluids varies among secretory glands to meet their physiological functions. In the pancreas, acinar cells secrete a small amount of NaCl-rich fluid, while the duct absorbs the Cl(-) and secretes HCO(3)(-) and the bulk of the fluid in the pancreatic juice. Fluid secretion appears to be driven by active HCO(3)(-) secretion. In the salivary glands, acinar cells secrete the bulk of the fluid in the saliva that is driven by active Cl(-) secretion and contains high concentrations of Na(+) and Cl(-). The salivary glands duct absorbs both the Na(+) and Cl(-) and secretes K(+) and HCO(3)(-). In this review, we focus on the molecular mechanism of fluid and HCO(3)(-) secretion by the pancreas and salivary glands, to highlight the similarities of the fundamental mechanisms of acinar and duct cell functions, and to point out the differences to meet gland-specific secretions.

Three cases of bronchial asthma preceding IgG4-related autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis is characterized by diffuse swelling of the pancreas and a high serum immunoglobulin (Ig) G4 concentration. Histopathologically, dense infiltration of lymphocytes and IgG4-positive plasma cells with fibrosis are seen in the pancreas. Although allergic diseases complicating autoimmune pancreatitis have been reported, the clinical features of bronchial asthma complicated by autoimmune pancreatitis remain unclear.

CASE SUMMARY

We report three cases of bronchial asthma preceding the onset of type 1 autoimmune pancreatitis by 3 months to 30 years. All three cases were males with high serum IgG, IgG4, and IgE concentrations. The radioallergosorbent tests were positive for common allergens such as mites and house dust. One case had a pulmonary manifestation that proved to be an inflammatory pseudotumor of the lung with an accumulation of IgG4-positive plasma cells. The asthma symptom was ameliorated by oral prednisolone therapy for autoimmune pancreatitis, and when the corticosteroid doses were reduced, asthma became worse in all three cases.

DISCUSSION

It is possible that atopy and increased Th2 cell activity are related to a higher coincidence of IgG4-related diseases such as type 1 autoimmune pancreatitis. Because the present cases are few in number, further studies are necessary.

Type 1 autoimmune pancreatitis

Before the concept of autoimmune pancreatitis (AIP) was established, this form of pancreatitis had been recognized as lymphoplasmacytic sclerosing pancreatitis or non-alcoholic duct destructive chronic pancreatitis based on unique histological features. With the discovery in 2001 that serum IgG4 concentrations are specifically elevated in AIP patients, this emerging entity has been more widely accepted. Classical cases of AIP are now called type 1 as another distinct subtype (type 2 AIP) has been identified. Type 1 AIP, which accounts for 2% of chronic pancreatitis cases, predominantly affects adult males. Patients usually present with obstructive jaundice due to enlargement of the pancreatic head or thickening of the lower bile duct wall. Pancreatic cancer is the leading differential diagnosis for which serological, imaging, and histological examinations need to be considered. Serologically, an elevated level of IgG4 is the most sensitive and specific finding. Imaging features include irregular narrowing of the pancreatic duct, diffuse or focal enlargement of the pancreas, a peri-pancreatic capsule-like rim, and enhancement at the late phase of contrast-enhanced images. Biopsy or surgical specimens show diffuse lymphoplasmacytic infiltration containing many IgG4⁺ plasma cells, storiform fibrosis, and obliterative phlebitis. A dramatic response to steroid therapy is another characteristic, and serological or radiological effects are normally identified within the first 2 or 3 weeks. Type 1 AIP is estimated as a pancreatic manifestation of systemic IgG4-related disease based on the fact that synchronous or metachronous lesions can develop in multiple organs (e.g. bile duct, salivary/lacrimal glands, retroperitoneum, artery, lung, and kidney) and those lesions are histologically identical irrespective of the organ of origin. Several potential autoantigens have been identified so far. A Th2-dominant immune reaction and the activation of regulatory T-cells are assumed to be involved in the underlying immune reaction. IgG4 antibodies have two unique biological functions, Fab-arm exchange and a rheumatoid factor-like activity, both of which may play immune-defensive roles. However, the exact role of IgG4 in this disease still remains to be clarified. It seems important to recognize this unique entity given that the disease is treatable with steroids.

Chronic pancreatitis

PURPOSE OF REVIEW

We review important new clinical observations in chronic pancreatitis made in the past year.

RECENT FINDINGS

Tropical pancreatitis associates with SPINK1 and/or CFTR gene mutations in approximately 50% of patients, similar to the frequency in idiopathic chronic pancreatitis. Corticosteroids increase secretin-stimulated pancreatic bicarbonate concentrations in autoimmune pancreatitis (AIP) by restoring mislocalized CFTR protein to the apical ductal membrane. Most patients with asymptomatic hyperenzymemia have pancreatic lesions of unclear significance or no pancreatic lesions. Common pitfalls in the use of diagnostic tests for exocrine pancreatic insufficiency (EPI) confound interpretation of findings in irritable bowel syndrome and severe renal insufficiency. Further study is needed to improve the accuracy of endoscopic ultrasonography (EUS) to diagnose chronic pancreatitis. Celiac plexus block provides short-term pain relief in a subset of patients.

SUMMARY

Results of this year's investigations further elucidated the genetic associations of tropical pancreatitis, a reversible mislocalization of ductal CFTR in AIP, the association of asymptomatic pancreatic hyperenzymemia with pancreatic disorders, limitations of diagnostic tests for EPI, diagnosis of chronic pancreatitis by EUS and endoscopic pancreatic function testing and treatment of pain.

Determinants of coupled transport and uncoupled current by the electrogenic SLC26 transporters

Members of the SLC26 family of anion transporters mediate the transport of diverse molecules ranging from halides to carboxylic acids and can function as coupled transporters or as channels. A unique feature of the two members of the family, Slc26a3 and Slc26a6, is that they can function as both obligate coupled and mediate an uncoupled current, in a channel-like mode, depending on the transported anion. To identify potential features that control the two modes of transport, we performed in silico modeling of Slc26a6, which suggested that the closest potential fold similarity of the Slc26a6 transmembrane domains is to the CLC transporters, despite their minimal sequence identity. Examining the predicted Slc26a6 fold identified a highly conserved glutamate (Glu⁻; Slc26a6(E357)) with the predicted spatial orientation similar to that of the CLC-ec1 E148, which determines coupled or uncoupled transport by CLC-ec1. This raised the question of whether the conserved Glu⁻ in Slc26a6(E357) and Slc26a3(E367) have a role in the unique transport modes by these transporters. Reversing the Glu⁻ charge in Slc26a3 and Slc26a6 resulted in the inhibition of all modes of transport. However, most notably, neutralizing the charge in Slc26a6(E357A) eliminated all forms of coupled transport without affecting the uncoupled current. The Slc26a3(E367A) mutation markedly reduced the coupled transport and converted the stoichiometry of the residual exchange from 2Cl⁻/1HCO₃⁻ to 1Cl⁻/1HCO₃⁻, while completely sparing the current. These findings suggest the possibility that similar structural motif may determine multiple functional modes of these transporters.

Effects of CFTR gene silencing by siRNA or the luminal application of a CFTR activator on fluid secretion from guinea-pig pancreatic duct cells

AIMS

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP regulated chloride channel expressed in the apical plasma membrane of pancreatic duct cells where it plays an important role in fluid secretion. The purpose of this study was to elucidate the role of the CFTR chloride channel on ion and fluid secretion from the guinea-pig pancreas by manipulating the expression of CFTR by RNA interference or by luminal application of a CFTR selective activator, MPB91, in isolated cultured pancreatic ducts.

MATERIALS AND METHODS

Using cDNA isolated from the guinea-pig small intestine, fragments of the CFTR gene were generated by polymerase chain reaction and directly sequenced. Two different RNA duplexes for small interference RNA (siRNA) were designed from the sequence obtained. Fluid secretion from the isolated guinea-pig pancreatic ducts was measured using video-microscopy. The amount of CFTR chloride channel or AQP1 water channel expressed in pancreatic ducts was examined by immunoblotting with antibodies against CFTR or AQP1, respectively.

RESULTS

Guinea-pig CFTR consists of 1481 amino acid residues. An additional glutamine residue was found to be inserted between amino acid residues 403 and 404 of human CFTR. Forskolin-stimulated fluid secretion from intact pancreatic ducts was significantly higher in the presence of MPB91 compared to fluid secretion in the absence of MPB91. Both basal and forskolin-stimulated fluid secretion in pancreatic ducts transfected with CFTR specific siRNAs were reduced by ∼50% compared to fluid secretion from ducts transfected with scrambled negative control dsRNAs. The amount of CFTR and AQP1 proteins was reduced to 34% and 45% of control, respectively.

CONCLUSIONS

The activity of the CFTR chloride channel or the amount of CFTR protein expressed determines the rate of fluid secretion from the isolated guinea-pig pancreatic ducts.

Pancreas divisum

We review important new clinical observations in pancreas divisum (PD) made since 2007. PD is common and has the same prevalence in the general population and idiopathic pancreatitis (IP). Up to 53% of patients with PD and IP have underlying idiopathic chronic pancreatitis (CP), and in rigorous prospective clinical follow-up and/or natural history studies, many with idiopathic recurrent acute pancreatitis (IRAP) have idiopathic CP. According to retrospective studies, PD does not modify the natural course of nonalcoholic or alcoholic CP. CFTR and/or SPINK1 gene mutations associate with IP (idiopathic CP and IRAP) independently of the presence of PD. More than one third of patients with pancreatitis or presumed pancreaticobiliary pain respond to placebo. Authors of uncontrolled studies report a significant symptomatic response to surgery and endotherapy in patients with IP and PD, but the response remains unproven and is largely limited to those with IRAP and not idiopathic CP or chronic pain.

Characteristics of pancreatic diabetes in patients with autoimmune pancreatitis

OBJECTIVE

Although patients with autoimmune pancreatitis (AIP) tend to have concurrent diverse disorders, very few studies have focused on diabetes mellitus (DM) coexisting with AIP.

METHODS

In total 102 AIP patients with DM were divided into three groups. Those with DM before the onset of AIP were labeled group A (n=35), those who developed DM and AIP simultaneously were labeled group B (n=58) and those who developed DM after steroid therapy for AIP were labeled group C (n=9). The characteristics of DM among the three groups were evaluated.

RESULTS

No significant differences were noted in the age of DM onset among the three groups. However, the mean duration of DM was significantly longer in group A (8.7 years) than in groups B and C. AIP developed 6.8 years after DM onset in group A, whereas it developed 1.8 years after steroid therapy in group C. Group A had the highest rate (25.7%) of family members with a history of AIP. Levels of serum albumin, total cholesterol and triglyceride were significantly lower in group A. No correlations were found between glycated hemoglobin and benzoyl-tyrosyl para-aminobenzoic acid. Hypoglycemia was observed in 20% of patients under insulin therapy. Most of them were habitual drinkers and received no pancreatic enzymes. Group A showed a high prevalence of retinopathy, nephropathy and macrovascular disorders than group B.

CONCLUSION

Aspects of AIP-associated pancreatic diabetes were clarified. AIP-associated DM must be controlled by a full assessment of the pancreatic endocrine and exocrine function.

Current concept of endoscopic ultrasound-guided fine needle aspiration for pancreatic cancer

Endoscopic ultrasound (EUS) provides detailed, high-resolution images of the pancreas. However, whether a lesion is malignant or benign cannot be diagnosed solely from its imaging features on EUS. The introduction of EUS-guided fine needle aspiration (EUS-FNA) offers the possibility to obtain a cytological or histological diagnosis of pancreatic lesions with a high sensitivity and specificity. Although the clinical utility of EUS-FNA for pancreatic diseases is widely accepted, the indication for preoperative tissue diagnosis of pancreatic lesions suspected to be malignant is still controversial. This review highlights the diagnostic potential of EUS-FNA, as well as its current indications and contraindications, complications, and techniques.

Chronic pancreatitis

Chronic pancreatitis is a progressive fibroinflammatory disease that exists in large-duct (often with intraductal calculi) or small-duct form. In many patients this disease results from a complex mix of environmental (eg, alcohol, cigarettes, and occupational chemicals) and genetic factors (eg, mutation in a trypsin-controlling gene or the cystic fibrosis transmembrane conductance regulator); a few patients have hereditary or autoimmune disease. Pain in the form of recurrent attacks of pancreatitis (representing paralysis of apical exocytosis in acinar cells) or constant and disabling pain is usually the main symptom. Management of the pain is mainly empirical, involving potent analgesics, duct drainage by endoscopic or surgical means, and partial or total pancreatectomy. However, steroids rapidly reduce symptoms in patients with autoimmune pancreatitis, and micronutrient therapy to correct electrophilic stress is emerging as a promising treatment in the other patients. Steatorrhoea, diabetes, local complications, and psychosocial issues associated with the disease are additional therapeutic challenges.

The acinar-ductal tango in the pathogenesis of acute pancreatitis

There is an unacceptably high mortality in acute pancreatitis, which is due to the lack of specific treatments for the disease. A major reason stated to account for the inability to develop effective treatments is that there are multiple pathobiologic pathways activated in the acinar cell mediating pancreatitis making it difficult to choose molecular targets for therapeutic strategies. However, this reasoning limits opportunities for therapeutic development because it does include another important participant in pancreatitis - the pancreatic duct cells. The most recent advance in pancreatitis research is that depletion of both glycolytic and oxidative ATP synthesis is a common event in both acinar and ductal cells. Although ATP has a very short half-life in the blood and is hydrolysed to ADP, there is clear evidence that encapsulating ATP into liposomes can effectively drive ATP into the cells which can be effective in protecting them from necrosis. In this review, we will examine the effects of different insults associated with pancreatitis on both the acinar and ductal components of the exocrine pancreas pointing out the role of the ductal epithelial responses in both attenuating and increasing the severity of pancreatitis. In addition, we propose that exogenous ATP administration may restore ductal and acinar function providing therapeutic benefit.

Treatment approaches to IgG4-related systemic disease

PURPOSE OF REVIEW

IgG4-related systemic disease (IgG4-RSD) is a systemic fibroinflammatory condition that can affect any organ system. Prompt recognition and management of this disease process are necessary to prevent sclerosis and permanent organ damage. Here, we review the advances in treatment approaches to IgG4-RSD.

RECENT FINDINGS

Most information regarding treatment is derived from retrospective case series of patients with autoimmune pancreatitis (AIP), and follow-up periods have generally been short. A variety of IgG4-RSD presentations respond rapidly to glucocorticoid treatment. Glucocorticoids have become a standard therapy for AIP, but the indications requiring treatment as well as the appropriate starting dose and duration of therapy remain controversial. The importance of maintenance of glucocorticoids following remission induction is debatable. As our knowledge grows regarding other organ manifestations of IgG4-RSD with longer follow-ups, the necessity of steroid-sparing agents to manage frequent relapses becomes clear.

SUMMARY

The natural history and long-term prognosis of IgG4-RSD are not well understood. Large prospective studies and randomized controlled trials of patients with wide spectrum manifestations of IgG4-RSD are required to support better approaches to treatment.

IRBIT governs epithelial secretion in mice by antagonizing the WNK/SPAK kinase pathway

Fluid and HCO(3)(-) secretion are fundamental functions of epithelia and determine bodily fluid volume and ionic composition, among other things. Secretion of ductal fluid and HCO(3)(-) in secretory glands is fueled by Na(+)/HCO(3)(-) cotransport mediated by basolateral solute carrier family 4 member 4 (NBCe1-B) and by Cl(-)/HCO(3)(-) exchange mediated by luminal solute carrier family 26, member 6 (Slc26a6) and CFTR. However, the mechanisms governing ductal secretion are not known. Here, we have shown that pancreatic ductal secretion in mice is suppressed by silencing of the NBCe1-B/CFTR activator inositol-1,4,5-trisphosphate (IP(3)) receptor-binding protein released with IP(3) (IRBIT) and by inhibition of protein phosphatase 1 (PP1). In contrast, silencing the with-no-lysine (WNK) kinases and Ste20-related proline/alanine-rich kinase (SPAK) increased secretion. Molecular analysis revealed that the WNK kinases acted as scaffolds to recruit SPAK, which phosphorylated CFTR and NBCe1-B, reducing their cell surface expression. IRBIT opposed the effects of WNKs and SPAK by recruiting PP1 to the complex to dephosphorylate CFTR and NBCe1-B, restoring their cell surface expression, in addition to stimulating their activities. Silencing of SPAK and IRBIT in the same ducts rescued ductal secretion due to silencing of IRBIT alone. These findings stress the pivotal role of IRBIT in epithelial fluid and HCO(3)(-) secretion and provide a molecular mechanism by which IRBIT coordinates these processes. They also have implications for WNK/SPAK kinase-regulated processes involved in systemic fluid homeostasis, hypertension, and cystic fibrosis.

Diagnosis and treatment of autoimmune pancreatitis

PURPOSE OF REVIEW

To summarize the existing knowledge of autoimmune pancreatitis (AIP) and to review the progress made in the diagnosis and treatment of AIP in the past year.

RECENT FINDINGS

The term 'AIP' appears to encompass at least two distinct subtypes, type 1 and type 2. Type 1 AIP is the pancreatic manifestation of a systemic fibroinflammatory disease called immunoglobulin G4-associated systemic disease. Type 2 AIP affects younger patients, does not have a gender predilection and is associated with normal serum immunoglobulin G4 levels. Existing criteria are geared toward diagnosis of type 1; type 2 AIP can be definitively diagnosed only on pancreatic histology. Both subtypes respond to corticosteroid therapy. However, there are no standardized protocols for initial treatment or management and prevention of relapses in AIP. A novel antibody for AIP has recently been identified and its performance needs validation from other centers. Newly published strategies for differentiating AIP from pancreatic cancer are available.

SUMMARY

AIP is a rare disease whose recognition and understanding are evolving. Much needs to be elucidated with regard to its cause, pathogenesis, treatment of relapse and long-term outcomes. A multidisciplinary team, familiar with the disease, is critical in making the correct diagnosis.