Knockdown of the Shwachman-Diamond syndrome gene, SBDS, induces galectin-1 expression and impairs cell growth

Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by exocrine pancreatic insufficiency and bone marrow failure. The depletion of SBDS protein by RNA interference has been shown to cause inhibition of cell proliferation in several cell lines. However, the precise mechanism by which the loss of SBDS leads to inhibition of cell growth remains unknown. To evaluate the impaired growth of SBDS-knockdown cells, we analyzed Epstein-Barr virus-transformed lymphoblast cells (LCLs) derived from two patients with SDS (c. 183_184TA > CT and c. 258 + 2 T > C). After 3 days of culture, the growth of LCL-SDS cell lines was considerably less than that of control donor cells. By annealing control primer-based GeneFishing PCR screening, we found that galectin-1 (Gal-1) mRNA expression was elevated in LCL-SDS cells. Western blot analysis showed that the level of Gal-1 protein expression was also increased in LCL-SDS cells as well as in SBDS-knockdown 32Dcl3 murine myeloid cells. We confirmed that recombinant Gal-1 inhibited the proliferation of both LCL-control and LCL-SDS cells and induced apoptosis (as determined by annexin V-positive staining). These results suggest that the overexpression of Gal-1 contributes to abnormal cell growth in SBDS-deficient cells.

M phase-specific interaction between SBDS and RNF2 at the mitotic spindles regulates mitotic progression

Shwachman-Diamond syndrome (SDS) is an autosomal recessive inherited disorder caused by biallelic mutations in the Shwachman-Bodian-Diamond syndrome (SBDS) gene. SBDS protein is involved in ribosome biogenesis; therefore SDS is classified as a ribosomopathy. SBDS is localized at mitotic spindles and stabilizes microtubules. Previously, we showed that SBDS interacts with ring finger protein 2 (RNF2) and is degraded through RNF2-dependent ubiquitination. In this study, we investigated when and where SBDS interacts with RNF2 and the effects of the interaction on cells. We found that SBDS co-localized with RNF2 on centrosomal microtubules in the mitotic phase (M phase), whereas SBDS and RNF2 localized to the nucleolus and nucleoplasm in the interphase, respectively. The microtubule-binding assay revealed that SBDS interacted directly with microtubules and RNF2 interacted with SBDS bound to microtubules. In addition, SBDS was ubiquitinated and degraded by RNF2 during the M phase. Moreover, RNF2 overexpression accelerated mitotic progression. These findings suggest that SBDS delays mitotic progression, and RNF2 releases cells from suppression through the ubiquitination and subsequent degradation of SBDS. The interaction between SBDS and RNF2 at mitotic spindles might be involved in mitotic progression as a novel regulatory cascade.

Shwachman-Diamond syndromes: clinical, genetic, and biochemical insights from the rare variants

Shwachman-Diamond syndrome is a rare inherited bone marrow failure syndrome characterized by neutropenia, exocrine pancreatic insufficiency, and skeletal abnormalities. In 10-30% of cases, transformation to a myeloid neoplasm occurs. Approximately 90% of patients have biallelic pathogenic variants in the SBDS gene located on human chromosome 7q11. Over the past several years, pathogenic variants in three other genes have been identified to cause similar phenotypes; these are DNAJC21, EFL1, and SRP54. Clinical manifestations involve multiple organ systems and those classically associated with the Shwachman-Diamond syndrome (bone, blood, and pancreas). Neurocognitive, dermatologic, and retinal changes may also be found. There are specific gene-phenotype differences. To date, SBDS, DNAJC21, and SRP54 variants have been associated with myeloid neoplasia. Common to SBDS, EFL1, DNAJC21, and SRP54 is their involvement in ribosome biogenesis or early protein synthesis. These four genes constitute a common biochemical pathway conserved from yeast to humans that involve early stages of protein synthesis and demonstrate the importance of this synthetic pathway in myelopoiesis.

Effect of Pancrelipase Therapy on Exocrine Pancreatic Insufficiency Symptoms and Coefficient of Fat Absorption Associated With Chronic Pancreatitis

OBJECTIVE

The aim of this study was to evaluate whether improvement in coefficient of fat absorption (CFA) with pancreatic enzyme replacement therapy correlates with clinical symptoms in patients with chronic pancreatitis with moderate to severe exocrine pancreatic insufficiency.

METHODS

Data were pooled from 2 randomized double-blind trials of the effects of 1 week of pancrelipase (n = 59) versus placebo (n = 57) on CFA and stool frequency, stool consistency, abdominal pain, and flatulence; 1 trial included a 51-week open-label pancrelipase treatment period (n = 34).

RESULTS

Compared with placebo, significantly more patients receiving pancrelipase reported decreased stool frequency at week 1 (72% vs 38%; P < 0.001). Although 30% of patients receiving pancrelipase and 20% receiving placebo reported improved stool consistency, changes in stool consistency, abdominal pain, and flatulence were not different between groups. Mean CFA absolute change from baseline was significantly greater with pancrelipase versus placebo (24.7% vs 6.4%; P < 0.001). Improvements in stool consistency and frequency correlated with CFA improvement. Symptom improvements persisted or further improved through 52 weeks of treatment.

CONCLUSIONS

Pancrelipase significantly improved exocrine pancreatic insufficiency maldigestive symptoms. Improvements in objective stool symptoms with pancreatic enzyme replacement therapy correlated with CFA improvement at 1 week.

Improved residual fat malabsorption and growth in children with cystic fibrosis treated with a novel oral structured lipid supplement: A randomized controlled trial

Background

In the primary analysis of a 12-month double-blind randomized active placebo-controlled trial, treatment of children with cystic fibrosis (CF) and pancreatic insufficiency (PI) with a readily absorbable structured lipid (Encala™, Envara Health, Wayne, PA) was safe, well-tolerated and improved dietary fat absorption (stool coefficient of fat absorption [CFA]), growth, and plasma fatty acids (FA).

Objective

To determine if the Encala™ treatment effect varied by severity of baseline fat malabsorption.

Methods

Subjects (n = 66, 10.5±3.0 yrs, 39% female) with baseline CFA who completed a three-month treatment with Encala™ or a calorie and macronutrient-matched placebo were included in this subgroup analysis. Subjects were categorized by median baseline CFA: low CFA (<88%) and high CFA (≥88%). At baseline and 3-month evaluations, CFA (72-hour stool, weighed food record) and height (HAZ), weight (WAZ) and BMI (BMIZ) Z-scores were calculated. Fasting plasma fatty acid (FA) concentrations were also measured.

Results

Subjects in the low CFA subgroup had significantly improved CFA (+7.5±7.2%, mean 86.3±6.7, p = 0.002), and reduced stool fat loss (-5.7±7.2 g/24 hours) following three months of Encala^TM treatment. These subjects also had increased plasma linoleic acid (+20%), α-linolenic acid (+56%), and total FA (+20%) (p≤0.005 for all) concentrations and improvements in HAZ (0.06±0.08), WAZ (0.17±0.16), and BMIZ (0.20±0.25) (p≤0.002 for all). CFA and FA were unchanged with placebo in the low CFA group, with some WAZ increases (0.14±0.24, p = 0.02). High CFA subjects (both placebo and Encala™ groups) had improvements in WAZ and some FA.

Conclusions

Subjects with CF, PI and more severe fat malabsorption experienced greater improvements in CFA, FA and growth after three months of Encala™ treatment. Encala™ was safe, well-tolerated and efficacious in patients with CF and PI with residual fat malabsorption and improved dietary energy absorption, weight gain and FA status in this at-risk group.

Lung disease and vitamin D levels in cystic fibrosis infants and preschoolers

INTRODUCTION

Vitamin D acts on the immune system and lung response. Patients with cystic fibrosis (CF) may be deficient in this vitamin. The aims of the study were to evaluate vitamin D levels and severity of lung disease in infants and preschoolers diagnosed with CF, and to compare them to a group of children without pancreatic insufficiency (PI).

METHODS

Patients with CF up to 4 years old were included, and compared to an age-matched group of children without diagnosis of CF. CF group had medical records and High Resolution Thorax Computed Tomography (HRCCT) evaluated in order to verify the severity of lung disease. Information on demographic data, sun exposure habits, supplemental vitamin D therapy, and on the season at the time of vitamin D sampling were collected for both groups.

RESULTS

This study included 45 patients in the CF group and 102 in the non-CF group, with no differences in age (P = 0.327) between them. There was no association between vitamin D levels and markers of lung disease in the CF group. The non-CF group had lower daily sun exposure (P = 0.034), and lower supplementation than the CF group (P < 0.001). Supplementation and seasonality were the determinant variables for vitamin D levels, which were lower for non-supplemented children and for assessments during fall/winter.

CONCLUSION

There was no association between lung disease severity and vitamin D levels in CF group. Supplementation and seasonality were associated to higher vitamin levels.

Zinc deficiency in patients with chronic pancreatitis

BACKGROUND

Zinc is a key element in numerous proteins and plays an important role in essential cell functions such as defense against free radicals and DNA damage repair. Chronic pancreatitis (CP) is a chronic inflammation with progressive fibrosis of pancreas ultimately resulting in pancreatic exocrine insufficiency (PEI), which is associated with malnutrition. Studies analyzing zinc levels in patients with CP are sparse and lead to conflicting results.

AIM

To investigate serum zinc levels in patients with CP of various etiologies.

METHODS

Between October 2015 and March 2018, patients with a diagnosis of CP were identified and recruited from the Pancreatic Outpatient Clinic at the Karolinska University Hospital in Stockholm, Sweden. Demographic, clinical and laboratory data were analyzed. Etiology of CP was determined according to the M-ANNHEIM classification system into the following etiological subcategories: alcohol consumption, nicotine consumption, hereditary factors, efferent pancreatic duct factors and immunological factors. Pancreatic exocrine function was defined as normal (fecal elastase 1 > 200 μg/g), mildly reduced (100-200 μg/g) and severely reduced (fecal elastase 1 < 100 μg/g).

RESULTS

A total of 150 patients were included in the analysis. Zinc deficiency (< 11 μmol/L) was present in 39 (26.0%) of patients: 22 females and 17 males. In the group of patients with zinc deficiency, 76.7% of patients had an exocrine pancreatic insufficiency (FE-1 < 200 μg/g). Older age was significantly associated with low zinc levels. Following a univariate analysis, patients aged 60-69 and patients ≥ 70 years of age had a significantly higher prevalence of zinc deficiencies compared to patients < 40 years of age [OR: 3.8, 95%CI (1.08-13.4); P = 0.04]; [OR 6.26, 95%CI (1.94-20.2), P > 0.002]. Smoking and number of pack-years were additionally associated with low zinc levels. The risk of zinc deficiency in current smokers and smokers with ≥ 20 pack-years was approximately three times higher compared to those who had never smoked. Gender, body mass index, etiology of CP, presence of diabetes mellitus, levels of glycated hemoglobin (HbA1c), bone mineral density, alcohol intake and presence of PEI were not associated with low zinc levels.

CONCLUSION

Zinc deficiency is common in patients with CP and is significantly associated with age ≥ 60, smoking and the number of pack-years, but not with PEI.

Nutritional support and therapy in pancreatic surgery: A position paper of the International Study Group on Pancreatic Surgery (ISGPS)

BACKGROUND

The optimal nutritional therapy in the field of pancreatic surgery is still debated.

METHODS

An international panel of recognized pancreatic surgeons and pancreatologists decided that the topic of nutritional support was of importance in pancreatic surgery. Thus, they reviewed the best contemporary literature and worked to develop a position paper to provide evidence supporting the integration of appropriate nutritional support into the overall management of patients undergoing pancreatic resection. Strength of recommendation and quality of evidence were based on the approach of the grading of recommendations assessment, development and evaluation Working Group.

RESULTS

The measurement of nutritional status should be part of routine preoperative assessment because malnutrition is a recognized risk factor for surgery-related complications. In addition to patient's weight loss and body mass index, measurement of sarcopenia and sarcopenic obesity should be considered in the preoperative evaluation because they are strong predictors of poor short-term and long-term outcomes. The available data do not show any definitive nutritional advantages for one specific type of gastrointestinal reconstruction technique after pancreatoduodenectomy over the others. Postoperative early resumption of oral intake is safe and should be encouraged within enhanced recovery protocols, but in the case of severe postoperative complications or poor tolerance of oral food after the operation, supplementary artificial nutrition should be started at once. At present, there is not enough evidence to show the benefit of avoiding oral intake in clinically stable patients who are complicated by a clinically irrelevant postoperative pancreatic fistula (a so-called biochemical leak), while special caution should be given to feeding patients with clinically relevant postoperative pancreatic fistula orally. When an artificial nutritional support is needed, enteral nutrition is preferred whenever possible over parenteral nutrition. After the operation, regardless of the type of pancreatic resection or technique of reconstruction, patients should be monitored carefully to assess for the presence of endocrine and exocrine pancreatic insufficiency. Although fecal elastase-1 is the most readily available clinical test for detection of pancreatic exocrine insufficiency, its sensitivity and specificity are low. Pancreatic enzyme replacement therapy should be initiated routinely after pancreatoduodenectomy and in patients with locally advanced disease and continued for at least 6 months after surgery, because untreated pancreatic exocrine insufficiency may result in severe nutritional derangement.

CONCLUSION

The importance of this position paper is the consensus reached on the topic. Concentrating on nutritional support and therapy is of utmost value in pancreatic surgery for both short- and long-term outcomes.

Impact of the treatment of pancreatic exocrine insufficiency on survival of patients with unresectable pancreatic cancer: a retrospective analysis

BACKGROUND

Malnutrition and weight loss are commonly observed in patients with pancreatic cancer and contribute to poor survival. Pancreatic exocrine insufficiency (PEI), which can be caused by ductal obstruction by a tumor, causes maldigestion and malabsorption of nutrients, thus contributing to malnutrition in these patients. In this study, we evaluated the effects of pancreatic enzyme replacement therapy (PERT) on survival in patients with unresectable pancreatic cancer.

METHODS

A retrospective analysis was conducted on a database of patients with unresectable, pathologically confirmed pancreatic cancer. All patients were evaluated for palliative chemotherapy and received the optimal palliative care. Patients were divided into two groups: Group 1 received standard therapy; Group 2 underwent additional evaluation of the pancreatic function and therapy with PERT, if needed. Survival (median and 95% confidence interval [CI]) was analyzed using Kaplan-Meier and Cox regression; groups were compared using the log-rank test.

RESULTS

Overall, 160 patients with unresectable pancreatic cancer were included in the analysis (mean age: 70.5 years [range 28-100]; gender: 57.5% male; tumor stage: 78.7% Stage IV). Eighty-six patients (53.75%) were in Group 1 and 74 (46.25%) were in Group 2. Age, gender, tumor size, location and stage, weight loss, and serum CA 19-9 were similar between groups. Ninety-three (58.1%) patients received palliative chemotherapy; 46.5% in Group 1 and 71.6% in Group 2 (P < 0.001). Forty-nine (66.2%) patients in Group 2 and none in Group 1 received PERT. Survival in Group 2 (189 days, 95% CI 167.0-211.0 days) was significantly longer than in Group 1 (95.0 days, 95% CI 75.4-114.6 days) (HR 2.117, 95% CI 1.493-3.002; P < 0.001). Chemotherapy and PERT were significantly and independently associated with longer survival in a model controlled by age and tumor stage. In patients with significant weight loss at diagnosis (> 10% bodyweight within 6 months), PERT was associated with longer survival (HR 2.52, 95% CI 1.55-4.11; P < 0.001).

CONCLUSIONS

In patients with unresectable pancreatic cancer, PERT in patients with PEI was associated with longer survival compared with those not receiving PERT, especially in those experiencing significant weight loss. This finding should guide future prospective clinical trials of similar interventions.

Secretin-stimulated ultrasound estimation of pancreatic secretion in cystic fibrosis validated by magnetic resonance imaging

OBJECTIVES

Secretin-stimulated magnetic resonance imaging (s-MRI) is the best validated radiological modality assessing pancreatic secretion. The purpose of this study was to compare volume output measures from secretin-stimulated transabdominal ultrasonography (s-US) to s-MRI for the diagnosis of exocrine pancreatic failure in cystic fibrosis (CF).

METHODS

We performed transabdominal ultrasonography and MRI before and at timed intervals during 15 minutes after secretin stimulation in 21 CF patients and 13 healthy controls. To clearly identify the subjects with reduced exocrine pancreatic function, we classified CF patients as pancreas-sufficient or -insufficient by secretin-stimulated endoscopic short test and faecal elastase.

RESULTS

Pancreas-insufficient CF patients had reduced pancreatic secretions compared to pancreas-sufficient subjects based on both imaging modalities (p < 0.001). Volume output estimates assessed by s-US correlated to that of s-MRI (r = 0.56-0.62; p < 0.001). Both s-US (AUC: 0.88) and s-MRI (AUC: 0.99) demonstrated good diagnostic accuracy for exocrine pancreatic failure.

CONCLUSIONS

Pancreatic volume-output estimated by s-US corresponds well to exocrine pancreatic function in CF patients and yields comparable results to that of s-MRI. s-US provides a simple and feasible tool in the assessment of pancreatic secretion.

KEY POINTS

• Cystic fibrosis patients with affected pancreas have reduced pancreatic secretions. • Secretin-stimulated sonography is a simple and feasible method to assess pancreatic output. • Secretin-simulated MRI is a more precise method to assess pancreatic secretions. • The sonographic and MRI methods yielded comparable pancreatic secretory output estimates.

Cutis laxa, exocrine pancreatic insufficiency and altered cellular metabolomics as additional symptoms in a new patient with ATP6AP1-CDG

Congenital disorders of glycosylation (CDG) are genetic defects in the glycoconjugate biosynthesis. >100 types of CDG are known, most of them cause multi-organ diseases. Here we describe a boy whose leading symptoms comprise cutis laxa, pancreatic insufficiency and hepatosplenomegaly. Whole exome sequencing identified the novel hemizygous mutation c.542T>G (p.L181R) in the X-linked ATP6AP1, an accessory protein of the mammalian vacuolar H⁺-ATPase, which led to a general N-glycosylation deficiency. Studies of serum N-glycans revealed reduction of complex sialylated and appearance of truncated diantennary structures. Proliferation of the patient's fibroblasts was significantly reduced and doubling time prolonged. Additionally, there were alterations in the fibroblasts' amino acid levels and the acylcarnitine composition. Especially, short-chain species were reduced, whereas several medium- to long-chain acylcarnitines (C14-OH to C18) were elevated. Investigation of the main lipid classes revealed that total cholesterol was significantly enriched in the patient's fibroblasts at the expense of phophatidylcholine and phosphatidylethanolamine. Within the minor lipid species, hexosylceramide was reduced, while its immediate precursor ceramide was increased. Since catalase activity and ACOX3 expression in peroxisomes were reduced, we assume an ATP6AP1-dependent impact on the β-oxidation of fatty acids. These results help to understand the complex clinical characteristics of this new patient.

Molecular basis of the human ribosomopathy Shwachman-Diamond syndrome

Mutations that target the ubiquitous process of ribosome assembly paradoxically cause diverse tissue-specific disorders (ribosomopathies) that are often associated with an increased risk of cancer. Ribosomes are the essential macromolecular machines that read the genetic code in all cells in all kingdoms of life. Following pre-assembly in the nucleus, precursors of the large 60S and small 40S ribosomal subunits are exported to the cytoplasm where the final steps in maturation are completed. Here, I review the recent insights into the conserved mechanisms of ribosome assembly that have come from functional characterisation of the genes mutated in human ribosomopathies. In particular, recent advances in cryo-electron microscopy, coupled with genetic, biochemical and prior structural data, have revealed that the SBDS protein that is deficient in the inherited leukaemia predisposition disorder Shwachman-Diamond syndrome couples the final step in cytoplasmic 60S ribosomal subunit maturation to a quality control assessment of the structural and functional integrity of the nascent particle. Thus, study of this fascinating disorder is providing remarkable insights into how the large ribosomal subunit is functionally activated in the cytoplasm to enter the actively translating pool of ribosomes.

Reduced β-Cell Secretory Capacity in Pancreatic-Insufficient, but Not Pancreatic-Sufficient, Cystic Fibrosis Despite Normal Glucose Tolerance

Patients with pancreatic-insufficient cystic fibrosis (PI-CF) are at increased risk for developing diabetes. We determined β-cell secretory capacity and insulin secretory rates from glucose-potentiated arginine and mixed-meal tolerance tests (MMTTs), respectively, in pancreatic-sufficient cystic fibrosis (PS-CF), PI-CF, and normal control subjects, all with normal glucose tolerance, in order to identify early pathophysiologic defects. Acute islet cell secretory responses were determined under fasting, 230 mg/dL, and 340 mg/dL hyperglycemia clamp conditions. PI-CF subjects had lower acute insulin, C-peptide, and glucagon responses compared with PS-CF and normal control subjects, indicating reduced β-cell secretory capacity and α-cell function. Fasting proinsulin-to-C-peptide and proinsulin secretory ratios during glucose potentiation were higher in PI-CF, suggesting impaired proinsulin processing. In the first 30 min of the MMTT, insulin secretion was lower in PI-CF compared with PS-CF and normal control subjects, and glucagon-like peptide 1 and gastric inhibitory polypeptide were lower compared with PS-CF, and after 180 min, glucose was higher in PI-CF compared with normal control subjects. These findings indicate that despite "normal" glucose tolerance, adolescents and adults with PI-CF have impairments in functional islet mass and associated early-phase insulin secretion, which with decreased incretin responses likely leads to the early development of postprandial hyperglycemia in CF.

Evaluation of energy metabolism and calcium homeostasis in cells affected by Shwachman-Diamond syndrome

Isomorphic mutation of the SBDS gene causes Shwachman-Diamond syndrome (SDS). SDS is a rare genetic bone marrow failure and cancer predisposition syndrome. SDS cells have ribosome biogenesis and their protein synthesis altered, which are two high-energy consuming cellular processes. The reported changes in reactive oxygen species production, endoplasmic reticulum stress response and reduced mitochondrial functionality suggest an energy production defect in SDS cells. In our work, we have demonstrated that SDS cells display a Complex IV activity impairment, which causes an oxidative phosphorylation metabolism defect, with a consequent decrease in ATP production. These data were confirmed by an increased glycolytic rate, which compensated for the energetic stress. Moreover, the signalling pathways involved in glycolysis activation also appeared more activated; i.e. we reported AMP-activated protein kinase hyper-phosphorylation. Notably, we also observed an increase in a mammalian target of rapamycin phosphorylation and high intracellular calcium concentration levels ([Ca(2+)]i), which probably represent new biochemical equilibrium modulation in SDS cells. Finally, the SDS cell response to leucine (Leu) was investigated, suggesting its possible use as a therapeutic adjuvant to be tested in clinical trials.

Comparison of 72-hour fecal fat quantification and the 13C-mixed triglyceride breath test in assessing pancreatic exocrine sufficiency in children with chronic pancreatitis

INTRODUCTION

Chronic pancreatitis (CP) in children is still a rare, although increasingly recognized entity. Over the duration of the disease several complications can be observed, two of which are major ones: endo- and exocrine insufficiency. In the medical care of children with CP it is crucial to diagnose the decreased endo- and exocrine function of the pancreas, in order to preserve patients from malnutrition and the failure to thrive. The aim of the study was to compare the usefulness of two indirect methods of assessing the pancreas exocrine function in children with CP.

MATERIAL AND METHODS

Ninety one patients with CP were enrolled in the study (41 boys, 50 girls, aged 2-17.8 years). Only Patients who had had both the 72-hour fecal fat quantification and the 13C-mixed triglyceride breath test (13C -MTBT) performed were selected. We compared the results of both tests for sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) in detecting exocrine pancreatic insufficiency.

RESULTS

Out of 91 patients, 12 were diagnosed with exocrine pancreatic insufficiency (EPI). The sensitivity of the fecal fat quantification was 50%, the specificity for the test was 100%. PPV and NPV were 100% and 93%, respectively. 13C-MTBT had the sensitivity of 42% and the specificity of 99%. PPV and NPV for the breath test were of 83% and 92%, respectively. No statistically significant discrepancy between the values obtained was found.

CONCLUSIONS

Although the 72-hour fecal fat quantification remains the gold standard in detecting EPI, both of the methods that had been investigated were shown to be comparable regarding sensitivity, specificity, PPV and NPV in assessing pancreas exocrine sufficiency in children with CP. Due to the easier execution of the breath test, both for the patient and for medical personnel, its importance may increase.

Eukaryotic translation initiation factor 6 is a novel regulator of reactive oxygen species-dependent megakaryocyte maturation

BACKGROUND

Ribosomopathies constitute a class of inherited disorders characterized by defects in ribosome biogenesis and function. Classically, bone marrow (BM) failure is a clinical symptom shared between these syndromes, including Shwachman-Bodian-Diamond syndrome (SBDS). Eukaryotic translation initiation factor 6 (eIF6) is a critical translation factor that rescues the quasilethal effect of the loss of the SBDS protein.

OBJECTIVES

To determine whether eIF6 activity is necessary for BM development.

METHODS

We used eIF6(+/-) mice and primary BM megakaryocytes to investigate the involvement of eIF6 in the regulation of hematopoiesis.

RESULTS

We provide evidence that reduced eIF6 expression negatively impacts on megakaryopoiesis. We show that inhibition of eIF6 leads to a reduction in cell size and mean ploidy level of megakaryocytes and a delay in megakaryocyte maturation by blocking the G1 /S transition. Consistent with this phenotype, only few megakaryocyte-forming proplatelets were found in eIF6(+/-) cells. We also discovered that, in eIF6(+/-) cells, the steady-state abundance of mitochondrial respiratory chain complex I-encoding mRNAs is decreased, resulting in decreased reactive oxygen species (ROS) production. Intriguingly, connectivity map analysis showed that eIF6-mediated changes overlap with specific translational inhibitors. eIF6 is a translation factor acting downstream of insulin/phorbol 12-myristate 13-acetate (PMA) stimulation. PMA treatment significantly restored eIF6(+/-) megakaryocyte maturation, indicating that activation of eIF6 is essential for the rescue of the phenotype.

CONCLUSIONS

Taken together, our results show a role for eIF6-driven translation in megakaryocyte development, and unveil the novel connection between translational control and ROS production in this cell subset.

[COMPARATIVE EVALUATION OF THE EFFECTIVENESS OF THE USE OF 13C-LABELED MIXED TRIGLYCERIDE AND 13C-STARCH BREATH TESTS IN PATIENTS WITH CHRONIC PANCREATITIS AFTER CHOLECYSTECTOMY]

The results of a comprehensive study of 96 patients after cholecystectomy are provided. The higher sensitivity and informativeness of the 13C-labeled mixed triglyceride breath .test compared with 13C-starch breath test for determining functional pancreatic insufficiency in patients after cholecystectomy in early stages of its formation was set.

In Vivo Senescence in the Sbds-Deficient Murine Pancreas: Cell-Type Specific Consequences of Translation Insufficiency

Genetic models of ribosome dysfunction show selective organ failure, highlighting a gap in our understanding of cell-type specific responses to translation insufficiency. Translation defects underlie a growing list of inherited and acquired cancer-predisposition syndromes referred to as ribosomopathies. We sought to identify molecular mechanisms underlying organ failure in a recessive ribosomopathy, with particular emphasis on the pancreas, an organ with a high and reiterative requirement for protein synthesis. Biallelic loss of function mutations in SBDS are associated with the ribosomopathy Shwachman-Diamond syndrome, which is typified by pancreatic dysfunction, bone marrow failure, skeletal abnormalities and neurological phenotypes. Targeted disruption of Sbds in the murine pancreas resulted in p53 stabilization early in the postnatal period, specifically in acinar cells. Decreased Myc expression was observed and atrophy of the adult SDS pancreas could be explained by the senescence of acinar cells, characterized by induction of Tgfβ, p15^Ink4b and components of the senescence-associated secretory program. This is the first report of senescence, a tumour suppression mechanism, in association with SDS or in response to a ribosomopathy. Genetic ablation of p53 largely resolved digestive enzyme synthesis and acinar compartment hypoplasia, but resulted in decreased cell size, a hallmark of decreased translation capacity. Moreover, p53 ablation resulted in expression of acinar dedifferentiation markers and extensive apoptosis. Our findings indicate a protective role for p53 and senescence in response to Sbds ablation in the pancreas. In contrast to the pancreas, the Tgfβ molecular signature was not detected in fetal bone marrow, liver or brain of mouse models with constitutive Sbds ablation. Nevertheless, as observed with the adult pancreas phenotype, disease phenotypes of embryonic tissues, including marked neuronal cell death due to apoptosis, were determined to be p53-dependent. Our findings therefore point to cell/tissue-specific responses to p53-activation that include distinction between apoptosis and senescence pathways, in the context of translation disruption.

Growth of all living things relies on protein synthesis. Failure of components of the complex protein synthesis machinery underlies a growing list of inherited and acquired multi—organ syndromes referred to as ribosomopathies. While ribosomes, the critical working components of the protein synthesis machinery, are required in all cell types to translate the genetic code, only certain organs manifest clinical symptoms in ribosomopathies, indicating specific cell-type features of protein synthesis control. Further, many of these diseases result in cancer despite an inherent deficit in growth. Here we report a range of consequences of protein synthesis insufficiency with loss of a broadly expressed ribosome factor, leading to growth impairment and cell cycle arrest at different stages. Apparent induction of p53-dependent cell death and arrest pathways included apoptosis in the fetal brain and senescence in the mature exocrine pancreas. The senescence, considered a tumour suppression mechanism, was accompanied by the expression of biomarkers associated with early stages of malignant transformation. These findings inform how cancer may initiate when growth is compromised and provide new insights into cell-type specific consequences of protein synthesis insufficiency.

Pharmacological challenges in chronic pancreatitis

Drug absorption in patients with chronic pancreatitis might be affected by the pathophysiology of the disease. The exocrine pancreatic insufficiency is associated with changes in gastrointestinal intraluminal pH, motility disorder, bacterial overgrowth and changed pancreatic gland secretion. Together these factors can result in malabsorption and may also affect the efficacy of pharmacological intervention. The lifestyle of chronic pancreatitis patients may also contribute to gastrointestinal changes. Many patients limit their food intake because of the pain caused by eating and in some cases food intake is more or less substituted with alcohol, tobacco and coffee. Alcohol and drug interaction are known to influence the pharmacokinetics by altering either drug absorption or by affecting liver metabolism. Since patients suffering from chronic pancreatitis experience severe pain, opioids are often prescribed as pain treatment. Opioids have intrinsic effects on gastrointestinal motility and hence can modify the absorption of other drugs taken at the same time. Furthermore, the increased fluid absorption caused by opioids will decrease water available for drug dissolution and may hereby affect absorption of the drug. As stated above many factors can influence drug absorption and metabolism in patients with chronic pancreatitis. The factors may not have clinical relevance, but may explain inter-individual variations in responses to a given drug, in patients with chronic pancreatitis.

Late vitamin K deficiency bleeding leading to a diagnosis of cystic fibrosis: a case report

Vitamin K deficiency bleeding (VKDB) in infants still occurs despite worldwide use of prophylaxis. Clinical manifestations can be dramatic with over 50% of patients presenting with intracranial haemorrhage and a mortality rate of 20% in late vitamin K deficiency bleeding. Special attention should be given to infants with a high risk profile (preterm, breast feeding, cholestasis, malabsorption). A tentative diagnosis can be made observing quick normalisation of some easy-to-perform haemostatic parameters (PT, aPTT) after administration of vitamin K. Nowadays, VKDB can still be the first clinical sign of diseases causing malabsorption of fat-soluble vitamins. In this case report, VKDB led to the diagnosis of cystic fibrosis, the most common fatal autosomal recessive disease among Caucasian people.

Suppressed glucose metabolism in acinar cells might contribute to the development of exocrine pancreatic insufficiency in streptozotocin-induced diabetic mice

High prevalence of exocrine pancreatic insufficiency has been observed in diabetic patients. However, the underlying mechanisms are not well known. Reduced cytosolic Ca(2+) signals in pancreatic acinar cells may contribute to lower digestive enzyme secretion. It is well known that adenosine triphosphate (ATP) regulates cytosolic Ca(2+) signals in acinar cells; however, little is known as to whether diabetes impairs glucose metabolism that produces ATP in acinar cells. Streptozotocin (STZ)-induced diabetic C57BL/6 mouse model was used. Four weeks after being diabetic, pancreatic acinar cells were isolated; and amylase secretion and contents, glucose utilization and oxidation, the activities of several key enzymes for glucose metabolism, and ATP and nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH) contents were determined. Compared with controls, diabetic mice had lower body weight. Cholecystokinin-8- and acetylcholine-stimulated amylase secretion was significantly impaired, and total amylase activity in acinar cells of STZ-diabetic mice was markedly reduced. Glucose utilization and oxidation were suppressed; measured enzyme activities for glucose metabolism and the ATP and NADPH contents were significantly reduced. These data indicate that glucose metabolism and ATP and NADPH productions are very important for maintaining acinar cell normal function. Reduction of ATP (reduces cytosolic Ca(2+) signals) and NADPH (reduces cell capability for antioxidative stress) productions may contribute to the development of exocrine pancreatic insufficiency in STZ-diabetic mice.

Efficacy and safety of Creon 24,000 in subjects with exocrine pancreatic insufficiency due to cystic fibrosis

BACKGROUND

Pancreatic enzyme replacement therapy is critical for adequate nutrition in cystic fibrosis (CF) patients with exocrine pancreatic insufficiency (EPI).

METHODS

This was a double-blind, randomised, placebo-controlled, two-period crossover study assessing efficacy and safety of Creon 24,000-unit capsules in CF subjects > or =12 years with EPI. Patients were randomised to one of two 5-day sequences, Creon/placebo or placebo/Creon (target dose, 4000 lipase units/g fat). Primary outcome was the coefficient of fat absorption (CFA); secondary outcomes were coefficient of nitrogen absorption (CNA), symptoms, and safety.

RESULTS

Thirty-two subjects were randomised. Mean CFA and CNA were significantly greater with Creon than placebo (CFA, 88.6% vs. 49.6%; CNA, 85.1% vs. 49.9%; p<0.001 for both). Symptoms were improved and fewer treatment-emergent adverse events were reported with Creon than placebo. One patient discontinued for weight loss unrelated to study drug.

CONCLUSIONS

This study demonstrated Creon was effective in treating EPI due to CF and was safe and well tolerated.

Growth is dependent on the exocrine pancreas function in young weaners but not in growing-finishing pigs

A correlation between the exocrine pancreatic function and growth has been previously demonstrated in growing pigs but the data are inconsistent. This was investigated by studying the growth performance of pigs with exocrine pancreatic insufficiency (EPI) at different ages and maintained under similar conditions. Twelve 7 week old (10.5+/-1.3 kg) weaners, and twelve 16 week old (43+/-5 kg) growing-finishing pigs were used in the experiments, and 6 pigs from each group were operated and pancreatic duct-ligated. Starting at 3-5 weeks after the operation, when EPI had developed, weekly recordings of feed consumption and growth were done before, during and after feed supplementation with porcine pancreatin (Creon 10000). In weaner pigs, EPI caused growth arrest while it did not affect the growth of older pigs, as compared to respective un-operated groups of pigs. The daily feed consumption (DFC) was lower in the weaner EPI pigs while it was similar in the growing-finishing EPI-pigs, as compared to un-operated pigs. Feed supplementation with Creon improved the DFC and growth in both the EPI and un-operated pigs. In conclusion, the results showed the importance of the exocrine pancreatic function for growth in weaner pigs, while in older animals it played a minor role in growth. Feed supplementation with pancreatin increased the appetite and ensured an improved feed conversion.

Determinants of Exocrine Pancreatic Function as Measured by Fecal Elastase-1 Concentrations (FEC) in Patients with Diabetes mellitus

OBJECTIVE

Recently it has been shown that there is not only endocrine insufficiency in diabetic patients, but a frequent co-morbidity of both, the endocrine and exocrine pancreas. The present study was performed to further analyse the determinants of exocrine pancreatic function in patients with diabetes mellitus.

METHODS

The records of 1992 patients with diabetes mellitus who had been treated in our hospital during a 2-year period were re-evaluated. Defined parameters were documented in standardized data sheets. Records were further checked for the results of imaging procedures of the pancreas. In 307 patients FEC had been performed and documented. Only these patients were included in further evaluation.

RESULTS

FEC was inversely correlated with diabetes duration and HbA1c-levels but not with age. C-peptide levels correlated positively with FEC. BMI and FEC were also significantly correlated. There was no correlation between diabetes therapy and exocrine pancreatic function as there was no correlation with any concomitant medication. The presence of diabetes-associated antibodies was not related to FEC. According to the documented data 38 were classified as type-1 diabetes (12.4%), 167 as type-2 (54.4%), and 88 patients met the diagnostic criteria of type-3 (28.7%). Fourteen patients could not be classified because of lacking information (4.6%).

CONCLUSIONS

Exocrine insufficiency might be explained as a complication of diabetes mellitus. However, it is more likely that type-3 diabetes is much more frequent than previously believed. Consequently the evaluation of exocrine function and morphology should be included into the clinical workup of any diabetic patient at least at the time of manifestation.

[Clinical features of different variants of excretory pancreatic insufficiency]

AIM

To analyse course of excretory pancreatic insufficiency (EPI) of pancreatic and not origin as well as factors associated with its development.

MATERIAL AND METHODS

A total of 139 patients with chronic pancreatitis or malabsorption were examined. The pancreatic function was assessed by the results of elastase test - concentration of pancreatic elastase 1 in the feces. EPI was detected in 57 patients (fecal pancreatic elastase 1 under 200 mcg/g); 38 patients had chronic pancreatitis and absolute EPI, 19 patients had relative EPI (the elastase was low, pancreatic pathology was absent, but other gastroenterological diseases were present--enteropathy, Crohn's disease, previous surgery).

RESULTS

Pancreatic insufficiency in patients with pancreatitis was 36.5%. It was associated with the disease duration. Diarrheal and asthenic syndromes, normal or low lipase levels in the serum were found. Patients with relative insufficiency were significantly younger, had shorter disease duration, more frequent diarrhea, were thinner. Correction of diarrheal syndrome was more successful in patients with absolute insufficiency. Pancreatic elastase concentration in the feces persisted for a year in patients with absolute EPI and normalized in patients with enteropathies after etiotropic and pathogenetic therapy.

A case of fulminant type 1 diabetes mellitus with exocrine pancreatic insufficiency and enhanced glucagon response to meal ingestion

Non-specific aggression to endocrine alpha and beta cells as well as exocrine pancreas has been suggested in fulminant type 1 diabetes (FT1DM), while its effect on glucagon secretion and exocrine function is unknown. Here, we report a FT1DM case with exocrine pancreatic insufficiency and enhanced glucagon response to meal ingestion.

MRI findings in Shwachman diamond syndrome

Shwachman Diamond Syndrome (SDS) is a rare congenital disorder characterized by pancreatic insufficiency, bone marrow dysfunction, and skeletal changes. Because of the heterogeneous clinical presentation and the limits of laboratory tests that assess pancreatic insufficiency, the diagnosis of SDS can be challenging. Pancreatic lipomatosis, a typical feature of this syndrome, is also difficult to assess by direct tissue sampling. In these circumstances, magnetic resonance imaging (MRI) provides a readily available, noninvasive tool to evaluate the pancreatic fat content. We report a case of a 12-month-old male in which abdominal MRI was used to confirm the clinical diagnosis of SDS.

Fecal calprotectin and elastase 1 determinations in patients with pancreatic diseases: a possible link between pancreatic insufficiency and intestinal inflammation

BACKGROUND

Fecal calprotectin determination has been demonstrated to be useful in diagnosing various inflammatory diseases of the gastrointestinal tract; however, data available for patients with pancreatic diseases are scarce. Our aim was to assess fecal calprotectin in order to evaluate the presence of intestinal inflammation in patients with pancreatic disease.

METHODS

Eligible patients with suspected pancreatic illness were enrolled, and in all of them fecal calprotectin and elastase-1, as well as serum amylase and lipase activities, were assayed using commercially available kits.

RESULTS

A total of 90 subjects (47 men, 43 women, mean age 58.6 +/- 14.9 years) were enrolled: 20 (22.2%) had chronic pancreatitis; 15 (16.7%) had pancreatic cancer; six (6.7%) had chronic nonpathological pancreatic hyperenzymemia; 16 (17.8%) had nonpancreatic diseases; and 23 (25.6%) had no detectable diseases. Diarrhea was present in 19 patients (21.1%). In univariate analyses, the presence of diarrhea and low fecal elastase-1 concentrations were significantly associated (P = 0.019 and P = 0.002, respectively) with abnormally high fecal calprotectin concentration, and the multivariate analysis demonstrated that low fecal elastase-1 concentration was the only variable independently associated with a high fecal calprotectin concentration.

CONCLUSIONS

Pancreatic insufficiency may cause intestinal inflammation, probably because of a modification of the intestinal ecology.

Airway nitric oxide in patients with cystic fibrosis is associated with pancreatic function, Pseudomonas infection, and polyunsaturated fatty acids

BACKGROUND

Airway nitric oxide (NO) is low or normal in cystic fibrosis (CF) patients. This may affect bacterial status since NO has antimicrobial properties. Arachidonic acid (AA), which is increased in the serum and airways of CF patients, has been shown to reduce NO levels. The aim of this study was to investigate whether airway NO level correlates with genotype and pancreatic function, and whether low airway NO level is associated with bacterial infection and increased serum AA level in CF patients.

METHOD

Nasal NO (nNO) and exhaled NO (eNO) were measured according to the European Respiratory Society/American Thoracic Society standard in 59 CF patients aged 7 to 55 years, 80% of whom were pancreatic insufficient (PI) and 51% were chronically infected with Pseudomonas aeruginosa.

RESULTS

PI CF patients had significantly lower nNO levels than pancreatic-sufficient (PS) patients. Airway NO level did not correlate with lung function or inflammatory parameters. PI patients chronically infected with P aeruginosa had significantly lower nNO levels than noninfected PI patients. nNO level correlated inversely with the AA/docosahexaenoic acid ratio, and eNO with the essential fatty acid (FA) deficiency index, which is the ratio between mead acid and AA.

CONCLUSIONS

CF patients with PI, which is associated with more severe genotypes, had lower airway NO levels than patients with PS. Low NO level was correlated to chronic P aeruginosa infection, and an association was found between airway NO level and the abnormal serum phospholipid FA pattern.

Resting energy expenditure in females with cystic fibrosis: Is it affected by puberty?

OBJECTIVE

The aims of this study were to determine the effect of puberty and the menstrual cycle on resting energy expenditure (REE) in females with cystic fibrosis (CF).

DESIGN

Cross-sectional study. All participants had measurements of REE, anthropometry and pubertal staging. The measurements in the postmenarche group were carried out both in the follicular and luteal phases of their menstrual cycle.

SETTING

CF outpatient clinic at the Children's Hospital at Westmead.

SUBJECTS

Fifty-six females with CF and pancreatic insufficiency (13 postmenarche) were recruited from the hospital clinic and 63 controls (21 postmenarche) were recruited through families and friends of hospital staff.

RESULTS

Females with CF had a higher REE than controls (111.6+/-12.8% of predicted from controls P<0.001). There was a significant effect of menarche on REE with a decrease in the postmenarche -470 kJ/24 h compared with premenarche after adjustment for fat-free mass, fat mass and group (control or CF). There was no difference in REE between the follicular and luteal phases for either CF or controls.

CONCLUSIONS

Females with CF had raised REE that appeared to be independent of menarche. This study implies all females with CF and pancreatic insufficiency may need more intensive dietary management, owing to raised REE, to maintain growth and nutritional status, and possibly improve survival.

Evaluation of formulas for calculating total energy requirements of preadolescent children with cystic fibrosis

BACKGROUND

To support age-appropriate growth and to prevent and treat malnutrition in children with cystic fibrosis (CF), energy requirements for those children are often set above the requirements for healthy children. Care providers use one of several empirically derived formulas to calculate energy requirements, yet the validity of these formulas has seldom been tested.

OBJECTIVE

We evaluated 6 proposed formulas for calculating energy requirements in children with CF against a total energy requirement for children with CF (TER-CF) derived from measured total energy expenditure, fecal fat energy loss, and the theoretic energy required for age-appropriate tissue accretion.

DESIGN

Subjects were children aged 6-8 y who had CF and pancreatic insufficiency. Calculated TERs from each formula were evaluated against TER-CF by using summary statistics, regression analysis, and residual plots.

RESULTS

Subjects (n = 53) had suboptimal nutrition and growth status and mild-to-moderate lung disease. The formula that most closely (within 2%) approximated TER-CF was the estimated energy requirement (EER) formula at the active level (EERact). Regression analysis of TER-CF onto calculated TER from each formula yielded the best indexes of model fit for the EERact formula; residual plots of the EERact formula were tightly and normally distributed around zero.

CONCLUSIONS

The EERact formula should be used to establish TER-CF in children in this age group who have mild-to-moderate CF. Changes in weight, height, and other indicators of nutritional status must be monitored to modify TER-CF as needed to support individual patient care goals.

Remission of digestive insufficiency by islet transplantation to the pancreas

Pancreatic digestive insufficiency is a common problem in both Type 1 and Type 2 diabetes and remains a serious consequence of diabetes in developing countries. The problem is not corrected by supportive therapies including exogenous insulin injections. It is our hypothesis that digestive insufficiency may be corrected or diminished by the transplantation of islets to the pancreas, thereby supplying islet hormones directly to acinar tissue analogous to the normal pancreas. Diabetic rats received 1000 syngeneic islets and dogs received 7600 autologous islets per kilogram as a transplant to the pancreas. Blood glucose and amylase concentrations were normalized in islet recipients in contrast with controls receiving no islets or islets transplanted to the renal capsule. These results suggest that diabetic digestive insufficiency may be corrected by intrapancreatic islet transplantation.

Safety and preliminary clinical activity of a novel pancreatic enzyme preparation in pancreatic insufficient cystic fibrosis patients

OBJECTIVES

Currently available pancreatic enzyme products are crude porcine products with few data available regarding their efficacy, safety, and manufacture. We conducted a phase 1 study of a novel pancreatic enzyme product, TheraCLEC-Total (TCT), a proprietary formulation of microbial-derived lipase, protease, and amylase, to determine its safety and preliminary efficacy in cystic fibrosis.

METHODS

We conducted an open-label, dose-ranging study in 23 subjects diagnosed with pancreatic insufficiency with cystic fibrosis. The subjects received TCT containing lipase dose of 100, 500, 1000, 2500, or 5000 USP U/kg per meal with each meal or snack for 3 days. The clinical and laboratory parameters and adverse events (AEs) were monitored.

RESULTS

There were no serious AEs. Most AEs were mild, although gastrointestinal complaints were common. TCT increased the coefficient of fat and nitrogen absorption in all groups except in the low-dose group. At the other dosing levels, the mean coefficient of fat and nitrogen absorption increases were 19.1% +/- 24.9% and 17.8% +/- 13.6%, respectively, whereas the mean stool weight decreased by 517 +/- 362 g.

CONCLUSIONS

TCT was well tolerated in this short-term exposure study. The preliminary efficacy data demonstrate lipase and protease activity with little difference seen with lipase doses greater than 500 USP U/kg per meal. These data support a larger randomized phase 2 trial.

Pancreaticojejunal anastomosis is preferable to pancreaticogastrostomy after pancreaticoduodenectomy for longterm outcomes of pancreatic exocrine function

BACKGROUND

The aim of this study was to evaluate pancreatic exocrine and endocrine function after pancreaticoduodenectomy.

STUDY DESIGN

Pancreatic exocrine function was evaluated by a questionnaire and medical examination of stools after discontinuing pancreatic enzyme supplements for at least 10 days. Severe steatorrhea was defined as frequent, nauseating, yellow, and pasty stools, fecal output >200 g/d for more than 3 days. Endocrine function was evaluated by blood glucose level. Association between severe steatorrhea and age, indication, histologic obstructive pancreatitis, pancreaticojejunal anastomosis (PJA), pancreaticogastric anastomosis (PGA), and morbidity was studied.

RESULTS

Fifty-two patients underwent pancreaticoduodenectomy, complication rate was 33%. PJA was performed in 41 patients (79%) and PGA in 11 patients (21%). At a median followup of 75 months (24 to 156 months), 65% of the patients received pancreatic enzyme supplements. Severe steatorrhea was observed in 22 patients (42%). Incidence of postoperative diabetes was 14.6%. Patient age (more than 60 years), postoperative complication, and obstructive pancreatitis were not associated with postoperative severe steatorrhea. In cases of nonhistologic obstructive pancreatitis, PGA was more frequently associated with severe steatorrhea than PJA (70% versus 21.7%, p < 0.025). No factor significantly influenced incidence of postoperative diabetes.

CONCLUSIONS

After pancreaticoduodenectomy, 42% of patients presented with severe steatorrhea. PJA allows better pancreatic exocrine function preservation than PGA and should be recommended.

Comparison of inulin and lactulose as reference standards in the breath hydrogen test assessment of carbohydrate malabsorption in patients with chronic pancreatic exocrine insufficiency

Although often used as a reference standard in the breath hydrogen test (BHT), lactulose fermentation produces more hydrogen, compared to starch, and may therefore not be ideal. This study compares inulin with lactulose as reference standard in the study of carbohydrate malabsorption. Seventeen patients with malabsorption due to chronic pancreatitis and 15 normal controls were studied. Following overnight fasts, BHTs were performed after ingesting 10 g lactulose, 10 g inulin, and 200 g (16 g highly resistant starch) maize meal. Lactulose fermentation produced significantly more hydrogen than inulin in patients with malabsorption (97 +/- 20 vs 45 +/- 22 ppm x hr; P < 0.05) and controls (43 +/- 18 vs 21 +/- 10 ppm x hr; P < 0.05). Patients produced more hydrogen than controls with both standards (lactulose, 97 +/- 20 vs 43 +/- 18 ppm x hr, P < 0.05; inulin 45 +/- 22 vs 21 +/- 10 ppm x hrs; P < 0.05), suggesting adaptation of the colonic flora. Calculated CHO malabsorption was 2.5 +/- 0.8 vs 5.2 +/- 3.8 g with lactulose and 5.2 +/- 3.1 vs 11.2 +/- 9.6 g with inulin as standards in controls and patients, respectively (P < 0.05). Lactulose produces more breath hydrogen than inulin. Calculation of CHO malabsorption using these standards is therefore not comparable.

Does the pancreas really produce much more lipase than required for fat digestion?

Thirty years ago, it was reported that a linear relationship does not exist between the amounts of human pancreatic lipase secreted in chronic pancreatitis and the degree of steatorrhea, which was considered to appear only after more than 90% of the pancreatic secretory capacity had been lost. From these observations, it was generally thought that the lipolytic potential of the pancreas is much higher than required. In recent years, however, it has been noted that: 1) the level of inhibition of digestive lipases and gastrointestinal lipolysis by the lipase inhibitor orlistat were almost linearly correlated with the amount of excreted fat; 2) in minipigs with experimentally-induced pancreatic exocrine insufficiency, the amounts of enteric-coated pancreatic extracts needed for restoring fat digestion to normal levels were estimated to be much higher than those usually administered; 3) human pancreatic lipase specific activity on meal triglycerides is 3 orders of magnitude lower than the very high specific activity usually measured under experimental in vitro conditions which are far from physiological conditions; 4) in patients with reduced human pancreatic lipase secretion, gastric lipase plays a significant role in fat digestion. This last observation might explain the absence of a linear relationship between human pancreatic lipase secretion in chronic pancreatitis and steatorrhea. From the low specific activity displayed by human pancreatic lipase on meal triglycerides, one can better understand why more lipase than expected is needed, why fat digestion lasts for more than a few minutes and, finally, why there is not such an excess secretory capacity for lipase as had been previously thought.

Comparing the urinary pancreolauryl ratio and faecal elastase-1 as indicators of pancreatic insufficiency in clinical practice

BACKGROUND

The urine pancreolauryl ratio (uPLR) and, more recently, the faecal pancreatic elastase-1, are widely used for the noninvasive diagnosis of exocrine pancreatic insufficiency. Both tests have previously been validated against 'gold standard' tests of pancreatic function, but their use in a clinical setting has never been directly compared.

METHODS

We performed a comparative study of the pancreolauryl ratio (PLR) and the faecal elastase-1 (FE-1) test in patients with a clinical suspicion for pancreatic insufficiency. The results were compared with the clinical response to pancreatic enzyme supplementation using pre-defined criteria.

RESULTS

Forty-five patients were enrolled in the study and 33 were given a trial of pancreatic enzyme supplementation. Twenty-four out of these 33 showed a positive clinical response to enzyme supplements. Of the 24 responders, 19 had positive FE-1 (<200 microg/g faeces), but only 12 had a positive uPLR (<20). There was a significant correlation between the FE-1 result and clinical response to enzyme supplements (p = 0.01), but not between the PLR and clinical response (p = 0.15).

CONCLUSIONS

FE-1 is a simpler test for the patient to perform and more accurately predicts the response to pancreatic enzyme supplementation in patients with chronic, unexplained diarrhoea with a clinical suspicion of pancreatic insufficiency than the PLR. This makes the FE-1 of greater use in clinical practice than the PLR.

Fecal elastase: pancreatic status verification and influence on nutritional status in children with cystic fibrosis

OBJECTIVES

To evaluate fecal elastase 1 (FE) levels in young children with cystic fibrosis and pancreatic insufficiency and to explore the relationship between FE and growth, nutrition, pulmonary status and fat absorption over a 24-month period.

METHODS

FE, indicating pancreatic lipase activity, was assessed in children (6.0 to 8.9 years of age) with cystic fibrosis and pancreatic insufficiency. FE >15 microg/g stool was defined as residual pancreatic activity, suggesting some pancreatic function, and FE </=15 microg/g stool was defined as no pancreatic activity, suggesting pancreatic insufficiency. Seven-day weighed food records were collected and coefficient of fat absorption was calculated using dietary records and 72-hour stool collection. Height adjusted for mid-parental height, weight, body mass index, upper arm muscle area and upper arm fat area were measured and Z scores were calculated. Forced expiratory volume in 1 second was the measure of pulmonary function.

RESULTS

Ten children (12%) had residual pancreatic activity (range, 17 to 667 microg/g stool) and 75 had no pancreatic activity. Children with no pancreatic activity had significantly lower coefficients of fat absorption than did those with residual pancreatic activity (81% +/- 14% versus 94% +/- 3%; P = 0.009) and significantly lower adjusted height Z score (-0.8 +/- 1.0 versus -0.1 +/- 1.3; P = 0.03). Children with residual pancreatic activity had significantly greater improvement in weight for age Z scores, upper arm muscle area Z scores, and upper arm fat area Z scores than children with no pancreatic activity (P </= 0.01). Children with no pancreatic activity were significantly (P = 0.007) more likely to have the DeltaF508/DeltaF508 genotype than were those with residual pancreatic activity (61% versus 11%).

CONCLUSIONS

These data suggest that a substantial number (12% in this sample) of children with cystic fibrosis have a misclassified pancreatic status. Children with residual FE had greater fat absorption and improved growth and nutritional status over 24 months. FE assessment should be used to verify pancreatic status in patients with cystic fibrosis.

Digestibility rates of major and trace elements in pancreatic duct-ligated pigs

Ligation of pancreatic duct in pigs leads to a severe maldigestion of calcium and magnesium. Substitution of missing enzymes results in a 'normalization' of the digestibility rates of these elements. In comparison to controls the pre-caecal phosphorus digestibility decreased, but the total digestibility rates increased, after ligation of the pancreatic duct. Furthermore, the total amount of absorbed phosphorus was significantly higher in pancreatic duct ligated pigs. Further studies have to be carried out to investigate, whether phosphorus in exocrine pancreatic insufficiency is excreted with urine, as in this study the observed Ca:P-ratio in blood was in a physiological range. Without a forced renal excretion of phosphorus, consequences and risks (e.g. secondary hyperparathyroidism) of the regulation have to be considered. Regarding the elements sodium, potassium and chloride, an increased faecal excretion could be observed in pancreatic duct ligated pigs. As a substitution with enzyme products led to digestibility rates similar to those in controls, no losses of electrolytes have to be feared. Even though pancreatic juice seems to have influences on the digestibility of investigated trace elements (copper, zinc, iron and manganese), it did not lead to severe imbalances in the corresponding mineral metabolism.

Duodenal acidity may increase the risk of pancreatic cancer in the course of chronic pancreatitis: an etiopathogenetic hypothesis

Chronic pancreatitis patients have an increased risk of developing pancreatic cancer. The cause of this increase has yet to be fully explained but smoking and inflammation may play an important role. To these, we must now add a new potential risk factor, namely duodenal acidity. Patients with chronic pancreatitis very often present pancreatic exocrine insufficiency combined with a persistently low duodenal pH in the postprandial period. The duodenal mucosa in chronic pancreas patients with pancreatic insufficiency has a normal concentration of s-cells and, therefore, the production of secretin is preserved. Pancreatic ductal cells are largely responsible for the amount of bicarbonate and water secretion in response to secretin stimulation. When gastric acid in the duodenum is not well-balanced by alkaline pancreatic secretions, it may induce a prolonged secretin stimulus which interacts with the pancreatic ductal cells resulting in an increased rate of ductular cell activity and turnover. N-Nitroso compounds from tobacco, identified in human pancreatic juice and known to be important carcinogens, may then act on these active cells, thereby increasing the risk of cancer. Duodenal acidity is probably of particular concern in patients who have undergone a duodenum-preserving pancreatic head resection, since, in this anatomic situation, pancreatic juice transits directly via the jejunal loop, bypassing the duodenum. Patients undergoing a Whipple procedure or side-to-side pancreaticojejunostomy are probably less critically affected because secretions transit, at least in part, via the papilla. If the duodenal acidity hypothesis proves correct, then, in addition to stopping smoking, reduction of duodenal acid load in patients with pancreatic insufficiency may help decrease the risk of pancreatic cancer.

Mechanism of exocrine pancreatic insufficiency in streptozotocin-induced diabetes mellitus in rat: effect of cholecystokinin-octapeptide

This study investigated the effects of cholecystokinin-octapeptide (CCK-8) on pancreatic juice flow and its contents, and on cytosolic calcium (Ca2+) and magnesium (Mg2+) levels in streptozotocin (STZ)-induced diabetic rats compared to healthy age-matched controls. Animals were rendered diabetic by a single injection of STZ (60 mg kg(-1), I.P.). Age-matched control rats obtained an equivalent volume of citrate buffer. Seven weeks later, animals were either anaesthetised (1 g kg(-1) urethane; IP) for the measurement of pancreatic juice flow or humanely killed and the pancreas isolated for the measurements of cytosolic Ca2+ and Mg2+ levels. Non-fasting blood glucose levels in control and diabetic rats were 92.40 +/- 2.42 mg dl(-1) (n = 44) and >500 mg dl(-1) (n = 27), respectively. Resting (basal) pancreatic juice flow in control and diabetic anaesthetised rats was 0.56 +/- 0.05 ul min(-1) (n = 10) and 1.28 +/- 0.16 ul min(-1) (n = 8). CCK-8 infusion resulted in a significant (p < 0.05) increase in pancreatic juice flow in control animals compared to a much larger increase in diabetic rats. In contrast, CCK-8 evoked significant (p < 0.05) increases in protein output and amylase secretion in control rats compared to much reduced responses in diabetic animals. Basal [Ca2+]i in control and diabetic fura-2-loaded acinar cells was 109.40 +/- 15.41 nM (n = 15) and 130.62 +/- 17.66 nM (n = 8), respectively. CCK-8 (10(-8)M) induced a peak response of 436.55 +/- 36.54 nM (n = 15) and 409.31 +/- 34.64 nM (n = 8) in control and diabetic cells, respectively. Basal [Mg2+]i in control and diabetic magfura-2-loaded acinar cells was 0.96 +/- 0.06 nM (n = 18) and 0.86 +/- 0.04 nM (n = 10). In the presence of CCK-8 (10(-8)) [Mg2+]i in control and diabetic cells was 0.80 +/- 0.05 nM (n = 18) and 0.60 +/- 0.02 nM (n = 10), respectively. The results indicate that diabetes-induced pancreatic insufficiency may be associated with derangements in cellular Ca2+ and Mg2+ homeostasis.

Effects of exchange of dietary medium chain triglycerides for long-chain triglycerides on serum biochemical variables and subjectively assessed well-being of dogs with exocrine pancreatic insufficiency

OBJECTIVE

To test the hypothesis that exchange of medium-chain triglycerides (MCTs) for long-chain triglycerides (LCTs) in the diet of dogs with well-managed exocrine pancreatic insufficiency (EPI) changes serum biochemical variables and to subjectively assess the well-being of dogs with EPI in response to experimental diets.

ANIMALS

21 dogs with EPI and 6 healthy control dogs.

PROCEDURE

The effects of 3 diets containing 0%, 16%, or 35% of the total fat content as MCTs were examined in a randomized controlled double-blind crossover trial. The 3 diets were fed for 12 weeks each. Dietary effects were evaluated by both subjective and objective variables.

RESULTS

Analysis of subjective data revealed no significant difference in appetite, attitude, drinking behavior, volume of feces, defecation frequency, color of feces, consistency of feces, flatulence, or borborygmus among dogs fed the 3 experimental diets. A high MCT content in the diet was associated with significantly higher serum vitamin E, cholesterol, triglyceride, retinyl stearate, retinyl palmitate, and total vitamin A concentrations in dogs with EPI and significantly higher serum vitamin E concentrations in control dogs, compared with low MCT content. High MCT content in the diet was also associated with significantly lower concentrations of serum linoleic acid (C18:2[n-6]) in dogs with EPI and in control dogs, compared with low MCT content.

CONCLUSIONS AND CLINICAL RELEVANCE

A high MCT content in the diet leads to increases in serum concentrations of cholesterol and certain fat-soluble vitamins. However, no effect was found on the subjective well-being of the dogs as evaluated by their owners.

Exocrine pancreatic function after alcoholic or biliary acute pancreatitis

OBJECTIVES

There have been various studies of exocrine pancreatic function after acute pancreatitis, but few have examined the relationship between this function and the etiology of the pancreatitis. The aim of this work was to study pancreatic function in patients who had had acute alcoholic or acute biliary pancreatitis.

METHODS

Seventy-five patients who had had a single attack of acute pancreatitis were studied. The etiology was alcohol in 36 and cholelithiasis in 39. Pancreatic function was studied between 4 and 18 months after pancreatitis by duodenal intubation in 18 patients (8 alcohol, 10 lithiasis) and by the amino acid consumption test (AACT) in the remaining 57 (28 alcohol, 29 lithiasis). For those who underwent AACT, the test was repeated 1 year after the first examination.

RESULTS

Among the 36 patients with alcoholic pancreatitis, most had impaired pancreatic function at both duodenal intubation (8/8, 100%) and at AACT (22/28, 78.6%); at the second test, the AACT remained pathological (18/23, 82.1%). Of the 39 patients with biliary pancreatitis, only 4 of the 10 (40%) who underwent duodenal intubation and only 5 of the 29 (17.2%) who performed AACT had pancreatic insufficiency; at the second test, only 4 of the 26 (15.4%) who repeated the AACT were pathological. The differences in the frequency and degree of pancreatic insufficiency between patients with alcoholic and those with biliary pancreatitis were statistically significant.

CONCLUSIONS

The results show that after alcoholic acute pancreatitis, the pancreatic insufficiency was significantly more frequent and more severe than after biliary pancreatitis. These findings together with the fact that the insufficiency was also more persistent suggest that acute alcoholic pancreatitis may occur in a pancreas that already has chronic lesions.

The enzyme levels in blood are not affected by oral administration of a pancreatic enzyme preparation (Creon 10,000) in pancreas-insufficient pigs

After oral intake, small amounts of intact protein may be absorbed into the blood circulation. The current study investigated whether orally administered pancreatic enzymes were absorbed from the intestine. The study included 28 pigs; 3 control pigs with intact pancreatic function and 25 pigs that were made exocrine pancreas insufficient by duct ligation (20 pigs) or total pancreatectomy (5 pigs). The pigs received a pancreatic enzyme preparation (0, 2, 4, or 8 g of Creon 10,000) together with the feed. The blood plasma was analyzed for pancreatic lipase activity with a [3H]-triolein substrate assay, while (pro)colipase and cationic trypsin(ogen) levels were measured with enzyme-linked immunosorbent assay (ELISA). Administration of Creon (0-8 g) caused no significant changes in plasma (pro)colipase or cationic trypsin(ogen) levels. Lipase activity peaks in plasma samples were found, but they did not correspond to the administration of Creon. The potential source of these plasma lipase activity peaks is discussed. The results showed no absorption into blood of pancreatic enzymes after oral administration (0, 2, 4, or 8 g of Creon mixed with 100 g of feed) to pancreas-insufficient pigs.

Rescue of defective pancreatic secretion in cystic-fibrosis cells by suppression of a novel isoform of phospholipase C

BACKGROUND

Cystic fibrosis is caused by mutations in the gene encoding an ion-transport protein, the cystic-fibrosis transmembrane conductance regulator (CFTR). Defective secretion of anions is the primary cause of many of the clinical manifestations of cystic fibrosis, including pancreatic insufficiency. We aimed to identify a molecular mechanism from which a new method to circumvent defective pancreatic secretion could be derived.

METHODS

Multiple-human-tissue RT-PCR and semiquantitative RT-PCR analyses were used to examine gene expression. An antisense technique was used in conjunction with radioimmunoassay, Fura-2 spectrofluorometry, immunohistochemistry, and the short-circuit current technique (Ussing chamber) for elucidation of gene function and its application in rescuing defective pancreatic secretion.

FINDINGS

We cloned a newly identified gene, NYD-SP27, which has structural similarity to an isoform of phospholipase C. NYD-SP27 was expressed endogenously in human pancreatic-duct cells and upregulated in cystic fibrosis. Suppression of NYD-SP27, by transfection of its antisense into human cystic-fibrosis pancreatic-duct cells, resulted in augmentation of phospholipase-C-coupled calcium-ion release and protein kinase C activity, improvement in the amount of mutated CFTR reaching the plasma membrane, and restoration of cAMP-activated pancreatic anion secretion.

INTERPRETATION

NYD-SP27 exerts an inhibitory effect on phospholipase-C-coupled processes that depend on calcium ions and protein kinase C, including CFTR trafficking and function. Its upregulation in pancreatic-duct cells may reveal a previously unsuspected defect in cystic fibrosis contributing to pancreatic insufficiency, and thus represents a new target for pharmacological intervention in cystic fibrosis.

[Clinical surveillance of patients with chronic recurrent pancreatitis]

Clinical surveillance of patients affected by chronic relapsing pancreatitis is not a particularly difficult task. In fact, a number of precise landmarks is available such as recurrence of pain and nutritional conditions, possibly enriched by biochemical (specially serum pancreatic enzymes) and imaging data (US, CT, MR), which also may be periodically scheduled. Despite the opinion of some experts, the best timing for the periodical checks should probably be decided on an individual basis. A suitable surveillance program may also be useful to favour the patient compliance and to implement any therapeutic measures.