Duvvuru Nageshwar Reddy

Mutations in the pancreatic secretory trypsin inhibitor gene (PSTI/SPINK1) rather than the cationic trypsinogen gene (PRSS1) are significantly associated with tropical calcific pancreatitis

Pancreatitis is a global health care problem with varied aetiologies. Alcoholism is responsible in the majority of patients while other causes, such as heredity, gallstones, hyperlipidaemia, hypercalcaemia, and idiopathic pancreatitis, are relatively rare.1,2 The causal factor in 20-30% of such cases is still not known and they fall into the category of idiopathic chronic pancreatitis (ICP).1,2 Although the exact pathogenesis is not clear, autodigestion secondary to aberrant intraductal activation of zymogens by trypsin is a primary common event. A genetic basis was reported in 1996 by familial linkage analysis3–5 and confirmed by detection of missense mutations, namely R122H and N29I, in the cationic trypsinogen gene ( PRSS1 ) in hereditary pancreatitis (HP) patients.6,7 HP is a relatively rare autosomal dominant disorder where typical acute attacks in childhood and frequent progression to chronic pancreatitis are seen to occur in two or more subjects or generations. Subsequent studies from other parts of the world have also reported the two common mutations8,9 and other mutations in the PRSS1 gene in both HP and ICP patients.8,10,11 However, only about 60% cases of HP and less than 20% with a diagnosis of ICP have a mutated PRSS1 gene, suggesting the presence of other candidate genes. Pancreatic secretory trypsin inhibitor (PSTI/SPINK1) is a potent protease inhibitor and thought to be a major protective mechanism preventing inappropriate activation of pancreatic digestive enzyme cascade by inhibiting up to 20% of potential trypsin activity.12 The human SPINK1 gene on chromosome 5 is approximately 7.5 kb long with four exons and codes for a product of 79 amino acids including a signal peptide of 23 amino acids.13 Since the inhibitor molecule provides the first line of defence against prematurely activated trypsinogen within the pancreas, it has recently …

Absence of PRSS1 mutations and association of SPINK1 trypsin inhibitor mutations in hereditary and non-hereditary chronic pancreatitis

Background and aims: Mutations in the cationic trypsinogen (protease, serine, 1 (trypsin 1); PRSS1) gene are causally associated with recurrent acute and chronic pancreatitis. We investigated whether mutations in the PRSS1 gene are associated with hereditary and non-hereditary pancreatitis. As a modifier role has been proposed for trypsin inhibitor (serine protease inhibitor, Kazal type I; SPINK1) mutations, the role of SPINK1 mutations in these patients was also analysed. Subjects and methods: The coding regions of PRSS1 and SPINK1 genes were sequenced in 290 controls and 198 patients, of whom 120 were diagnosed as idiopathic (ICP), 41 as alcoholic (ACP), and 37 as hereditary pancreatitis (HP). Twenty four unaffected relatives of HP probands were also analysed and genotype-phenotype correlations and statistical analyses were performed. Results: No mutations in the PRSS1 gene were detected in any of the patients, including HP patients, while the N34S mutation was observed in the SPINK1 gene in the majority of HP patients (73%). Similarly, 26.8% of ACP (11 of 41) and 32.5% (39 of 120) of ICP patients also had SPINK1 mutations. The N34S mutation was observed in both homozygous and heterozygous conditions. In comparison, only 2.76% of the control population had the N34S allele (p<0.001). The P55S mutation was observed in one ICP and one ACP patient, and in three normal individuals. Genotype-phenotype correlations did not suggest any significant difference in the age of onset, severity of disease, or pancreatic endocrine insufficiency in patients with or without mutated SPINK1 and irrespective of the allelic status of N34S SPINK1. Conclusions: Irrespective of the aetiology, mutations in the PRSS1 gene are not associated with chronic pancreatitis, including HP. In contrast, the N34S mutation in the SPINK1 gene shows a significant correlation in these patients. A comparable phenotype in terms of age of onset, diabetes mellitus, and other phenotypic features in patients with or without SPINK1 mutations and N34S homozygotes and heterozygotes suggests that there may still be involvement of other genetic or environmental factors.

Clinical trial: a randomized trial comparing fluoroscopy guided percutaneous technique vs. endoscopic ultrasound guided technique of coeliac plexus block for treatment of pain in chronic pancreatitis

Background  Coeliac plexus block (CPB) is a management option for pain control in chronic pancreatitis. CPB is conventionally performed by percutaneous technique with fluoroscopic guidance (PCFG). Endoscopic ultrasound (EUS) is increasingly used for CPB as it offers a better visualization of the plexus. There are limited data comparing the two modalities.

Association of cathepsin B gene polymorphisms with tropical calcific pancreatitis

Background and aims: Tropical calcific pancreatitis (TCP) is a type of chronic pancreatitis unique to countries in the tropics. Mutations in pancreatic secretory trypsin inhibitor (SPINK1) rather than cationic trypsinogen (PRSS1) explain the disease in only 50% of TCP patients. As cathepsin B (CTSB) is known to activate cationic trypsinogen, we attempted to understand the role of CTSB mutations in TCP. Evidence of epistatic interaction was investigated with the previously associated N34S SPINK1 allele, a variant considered to be a modifier rather than a true susceptibility allele. Subjects and methods: We sequenced the coding region of CTSB gene in 51 TCP patients and 25 controls and further genotyped 89 patients and 130 controls from the same cohort for Leu26Val, C595T, T663C, and Ser53Gly polymorphisms. The positive findings observed in the earlier cohort were re-examined in an ethnically matched replication cohort comprising 166 patients and 175 controls. Appropriate statistical analyses were performed and Bonferroni correction for multiple testing was applied. Results: We found a statistically significant association of the Val26 allele at Leu26Val polymorphism with an odds ratio (OR) of 2.15 (95% confidence interval (CI) 1.60–2.90 (p = 0.009)), after Bonferroni correction (corrected p value = 0.025). This significant association of Leu26Val with TCP was replicated in another cohort (OR 2.10 (95% CI 1.56–2.84); p = 0.013). Val26 allele also showed significantly higher frequency in N34S positive and N34S negative patients than in controls (p = 0.019 and 0.013, respectively). We also found significant differences in the mutant allele frequencies at Ser53Gly and C595T single nucleotide polymorphisms between N34S positive patients and controls (p = 0.008 and 0.001, respectively). Although haplotype analysis did not complement the results of allelic association, it did uncover a unique haplotype protective for TCP (p = 0.0035). Conclusion: Our study suggests for the first time that CTSB polymorphisms are associated with TCP. As PRSS1 mutations are absent in TCP and the N34S SPINK1 mutation is proposed to play a modifier role, these variants may be critical as a trigger for cationic trypsinogen activation.

Feasibility and efficiency of a new 22G core needle: a prospective comparison study.

BACKGROUND AND STUDY AIMS Histological examination of core tissue samples may have advantages over cytology in endoscopic ultrasound (EUS)-guided sampling. We aimed to evaluate the feasibility and efficiency of a new 22G core biopsy needle. PATIENTS AND METHODS Consecutive patients with a pancreatic mass lesion or peri-intestinal lymphadenopathy sequentially underwent fine needle biopsy with both a newly developed 22G core needle (the FNB needle) and a standard 22G fine needle aspiration (FNA) needle, in randomized order. RESULTS In 144 patients, mean age 48 years (± standard deviation [SD] 14; range 18 - 82), with 145 lesions (mean lesion size 39 ± 15 mm, range 15 - 99), EUS-guided sampling was technically feasible with both needles in all patients. Mean number of passes to obtain sufficient tissue was 1.2 ± 0.5 with the core needle vs. 2.5 ± 0.9 with the standard needle (P < 0.001). FNB specimens were adequate for evaluation in 125 (86.2 %) vs. 127 (87.6 %) with FNA (P = 0.72). Among 139 patients available for follow-up, FNB provided a correct diagnosis in 110 (79.1 %) and FNA in 112 (80.6 %) (P = 0.73). Sensitivity, specificity, positive and negative predictive values, and accuracy for diagnosis of malignancy were 90 %, 100 %, 100 %, 93 %, 96 % for FNB and 77 %, 100 %, 100 %, 85 %, 92 % for FNA, respectively (P > 0.05). CONCLUSION FNB with the new 22G core needle was technically feasible, efficient and comparable to FNA with a standard needle. The core needle required fewer passes to provide an adequate sample, offering potentially shorter procedure time.

Comprehensive screening of chymotrypsin C ( CTRC ) gene in tropical calcific pancreatitis identifies novel variants

Objective In a previous study, the authors have shown that rather than variants in trypsinogen gene(s), mutations in pancreatic secretory trypsin inhibitor (encoded by SPINK1) and cathepsin B (CTSB) are associated with tropical calcific pancreatitis (TCP). Recently, chymotrypsin C (CTRC) variants that diminish its activity or secretion were found to predict susceptibility to chronic pancreatitis (CP). The authors analysed CTRC variants in a large, ethnically matched case-control TCP cohort. Design The authors sequenced all eight exons and flanking regions in CTRC in 584 CP patients (497 TCP, 87 idiopathic CP) and 598 normal subjects and analysed the significance of association using χ2 test. The authors also investigated interaction of CTRC variants with p.N34S SPINK1 and p.L26V CTSB mutations. Results The authors identified 14 variants in CTRC, of which non-synonymous variants were detected in 71/584 CP patients (12.2%) and 22/598 controls (3.7%; OR 3.62, 95% CI 2.21 to 5.93; p=6.2×10−8). Rather than the commonly reported p.K247_R254del variant in Caucasians, p.V235I was the most common mutation in Indian CP patients (28/575 (4.9%); OR 7.60, 95% CI 2.52 to 25.71; p=1.01×10−5). Another pathogenic variant, p.A73T was identified in 3.1% (18/584) patients compared with 0.3% (2/598) in controls (OR=9.48, 95% CI 2.19 to 41.03, p=2.5×10−4). The authors also observed significant association for the synonymous variant c.180C>T (p.(=)) with CP (OR 2.71, 95% CI 1.79 to 4.12, p=5.3×10−7). Two novel nonsense mutations, p.G242AfsX9 and p.W113X were also identified exclusively in CP patients. No interaction between CTRC variants and p.N34S SPINK1 or p.L26V CTSB mutations was observed. Conclusion This study on a large cohort of TCP patients provides evidence of allelic heterogeneity and confirms that CTRC variants play a significant role in its pathogenesis.

Mutations in anionic trypsinogen gene are not associated with tropical calcific pancreatitis

Pancreatitis is considered to be an autodigestive disease due to premature activation of trypsinogen inside the pancreas. Its genetic basis has recently been established with the identification of causal mutations in cationic trypsinogen gene ( PRSS1 ) in patients with hereditary1 and non-hereditary pancreatitis.2 Mutations in other genes such as SPINK1 (encoding pancreatic secretory trypsin inhibitor)3 and cystic fibrosis transmembrane conductance regulator ( CFTR )4,5 genes have also been associated with the disease. Tropical calcific pancreatitis is a type of idiopathic pancreatitis, reported particularly in the tropics. Recently, we and others demonstrated absence of PRSS1 mutations but significant prevalence of the N34S mutation …

Electrical stimulation therapy of the lower oesophageal sphincter for refractory gastro-oesophageal reflux disease - interim results of an international multicentre trial.

A previous single‐centre study showed that lower oesophageal sphincter electrical stimulation therapy (LES‐EST) in gastro‐oesophageal reflux disease (GERD) patients improves reflux symptoms and decreases oesophageal acid exposure.

Lack of significant association of an insertion/deletion polymorphism in the angiotensin converting enzyme (ACE) gene with tropical calcific pancreatitis

BackgroundThe genetic basis of tropical calcific pancreatitis (TCP) is different and is explained by mutations in the pancreatic secretory trypsin inhibitor (SPINK1) gene. However, mutated SPINK1 does not account for the disease in all the patients, neither does it explain the phenotypic heterogeneity between TCP and fibro-calculous pancreatic diabetes (FCPD). Recent studies suggest a crucial role for pancreatic renin-angiotensin system during chronic hypoxia in acute pancreatitis and for angiotensin converting enzyme (ACE) inhibitors in reducing pancreatic fibrosis in experimental models. We investigated the association of ACE gene insertion/deletion (I/D) polymorphism in TCP patients using a case-control approach. Since SPINK1 mutations are proposed a modifier role, we also investigated its interaction with the ACE gene variant.MethodsWe analyzed the I/D polymorphism in the ACE gene (g.11417_11704del287) in 171 subjects comprising 91 TCP and 80 FCPD patients and compared the allelic and genotypic frequency in them with 99 healthy ethnically matched control subjects.ResultsWe found 46% and 21% of TCP patients, 56% and 19.6% of FCPD patients and 54.5% and 19.2% of the healthy controls carrying the I/D and D/D genotypes respectively (P>0.05). No significant difference in the clinical picture was observed between patients with and without the del allele at the ACE in/del polymorphism in both categories. No association was observed with the presence or absence of N34S SPINK1 mutation in these patients.ConclusionWe conclude that the ACE insertion/deletion variant does not show any significant association with the pathogenesis, fibrosis and progression of tropical calcific pancreatitis and the fibro-calculous pancreatic diabetes.

Endoscopic ultrasound guided fine-needle aspiration of lymph nodes and solid masses: factors influencing the cellularity and adequacy of the aspirate.

Goals: To study the factors that influence the cellularity and adequacy of endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA). Background: An on-site cytopathology service is preferred during EUS-guided FNA. However, this is not always available. Factors that influence the aspirate cellularity and adequacy have not been well defined in the absence of on-site cytopathology. Study: EUS-guided FNA procedures without an on-site cytopathologist from a single center were retrospectively studied. FNA of solid masses and lymph nodes (LN) were included. The FNA cellularity, hemorrhagic content, and endoscopists’ assessment of adequacy were analyzed. Results: A total of 166 patients from January 2009 to October 2010 were included. A total of 520 FNA passes were performed. Of the 166 lesions, 70 (42.2%) were solid masses and 96 (57.8%) were LNs. A 22-G needle was used in 72.3% and 25 G in 27.7% of the patients. The median (range) number of FNA passes was 3 (1 to 7) for LNs and 3 (1 to 5) for solid masses. With this, the endoscopists had an accuracy of 92.2% (153/166) for obtaining an adequate aspirate. Of the 166 samples, 4 (2.4%) were acellular, 20 (12.0%) sparsely cellular, 52 (31.4%) moderately cellular, and 90 (54.2%) highly cellular. The 25-G needle had significantly more adequate aspirates than the 22-G needle for solid masses (P=0.011). Also, increasing passes correlated with higher cellularity (P=0.002) and an adequate aspirate (P=0.021). No correlation was found for LN FNA. Lesion size did not influence the cellularity or adequacy (P>0.05). The degree of hemorrhage was not influenced by the needle gauge, number of passes, or lesion size. The diagnostic yield was not affected by hemorrhage in the sample (P>0.05). Conclusions: EUS-guided FNA obtains a high proportion of adequate aspirates for LNs and solid masses, even without an on-site cytopathologist. Small proportions of inadequate samples still occur. For solid masses, a 25-G needle with at least 3 passes is more likely to provide an adequate aspirate than a 22-G needle and fewer passes. Hemorrhage did not affect the cytopathology’s ability to make a diagnosis.