Acute and chronic pancreatitis in patients with inborn errors of metabolism

Hyperhomocysteinemia in acute hepatic porphyria (AHP) and implications for treatment with givosiran

INTRODUCTION

Homocysteine is a sulfur-containing amino acid formed in the intermediary metabolism of methionine. Amino acid metabolism and heme biosynthesis pathways are complexly intertwined. Plasma homocysteine elevation, hyperhomocysteinemia (HHcy), has been reported in patients with acute hepatic porphyria (AHP), a family of rare genetic disorders caused by defects in hepatic heme biosynthesis.

AREAS COVERED

This article summarizes published case series in which givosiran, a subcutaneously administered small interfering RNA approved for AHP treatment, appeared to exacerbate dysregulated homocysteine metabolism in patients with AHP. A comprehensive exploratory analysis of ENVISION trial data demonstrated that on a population level, givosiran increased homocysteine but with wide interpatient variations, and there is no proof of correlations between HHcy and changes in efficacy or safety of givosiran.

EXPERT OPINION

The strong correlation and co-increase of homocysteine and methionine suggest that HHcy associated with givosiran is likely attributable to the impaired trans-sulfuration pathway catalyzed by cystathionine β-synthase, which uses vitamin B6 as a cofactor. Data-based consensus supports monitoring total plasma homocysteine and vitamin B6, B12, and folate levels before and during givosiran treatment; supplementing with pyridoxine/vitamin B6 in patients with homocysteine levels >100 μmol/L; and involving patients with homocysteine levels >30 μmol/L in decisions to supplement.

Severe homocysteinemia in two givosiran-treated porphyria patients: is free heme deficiency the culprit?

Givosiran is a novel approach to treat patients with acute intermittent porphyrias (AIP) by silencing of ∂-ALA-synthase 1, the first enzyme of heme biosynthesis in the liver. We included two patients in the Envision study who responded clinically well to this treatment. However, in both patients, therapy had to be discontinued because of severe adverse effects: One patient (A) developed local injection reactions which continued to spread all over her body with increasing number of injections and eventually caused a severe systemic allergic reaction. Patient B was hospitalized because of a fulminant pancreatitis. Searching for possible causes, we also measured the patients plasma homocysteine (Hcy) levels in fluoride-containing collection tubes: by LC-MS/MS unexpectedly, plasma Hcy levels were 100 and 200 in patient A and between 100 and 400 μmol/l in patient B. Searching for germline mutations in 10 genes that are relevant for homocysteine metabolism only revealed hetero- and homozygous polymorphisms in the MTHFR gene. Alternatively, an acquired inhibition of cystathionine-beta-synthase which is important for homocysteine metabolism could explain the plasma homocysteine increase. This enzyme is heme-dependent: when we gave heme arginate to our patients, Hcy levels rapidly dropped. Hence, we conclude that inhibition of ∂-ALA-synthase 1 by givosiran causes a drop of free heme in the hepatocyte and therefore the excessive increase of plasma homocysteine. Hyperhomocysteinemia may contribute to the adverse effects seen in givosiran-treated patients which may be due to protein-N-homocysteinylation.

Pancreatic involvement in patients with inborn errors of metabolism

Background

Repeated inflammation of the pancreas can cause pancreatitis or diabetes. It is well recognized that the organic acidemias may be complicated by pancreatitis but less recognized are other metabolic disorders in which pancreatitis can occur. This study shows that long-term follow-up of patients with various metabolic disorders in Korea revealed several with episodes of isolated pancreatitis or diabetes concomitantly with pancreatitis.

Results and discussion

In this study, two patients with methylmalonic aciduria (MMA), two with propionic acidemia (PPA), one with fatty acid oxidation disorder (FAOD), and one with hyperornithinemia, gyrate atrophy, and juvenile onset diabetes mellitus (DM) were clinically followed for up to 10 – 21 years. Two Korean siblings with MMA showed recurrent pancreatitis from the age of 15 and 19, respectively. The frequency of admission due to pancreatitis was up to 11 times. One patient with MMA developed diabetes mellitus at the age of 20. The other patient with MMA developed recurrent pancreatitis at 4 years and diabetes at 8 years of age. One of the patients with PPA presented with diabetic ketoacidosis. The other PPA patient died of cardiac arrest at age 10. The patient with FAOD presented with pancreatitis at 10 years and died at the age of 15 years due to cardiac arrest. A 35-year-old woman with hyperornithinemia/gyrate atrophy was diagnosed with juvenile onset diabetes at the age of 7 years. No pancreatitis occurred during the follow-up period.

Conclusions

We conclude that various metabolic disorders can trigger acute or chronic pancreatitis. Proper and prompt multidisciplinary management of metabolic derangement is crucial for preventing pancreatic damage. Further clinical and investigational studies are required to elucidate the pathogenesis of pancreatitis and diabetes mellitus in patients with inborn errors in metabolism.

Nutrition and Inflammatory Biomarkers in Chronic Pancreatitis Patients

BACKGROUND

Chronic pancreatitis (CP) patients frequently experience malabsorption and maldigestion, leading to micronutrient and macronutrient deficiencies. Comorbid diabetes and lifestyle habits, such as alcohol consumption, may impact nutrition status.

METHODS

We compared micronutrient antioxidant, bone metabolism, serum protein, and inflammatory marker levels in 301 CP patients and 266 controls with no known pancreatic disease. We analyzed serum prealbumin and retinol binding protein; vitamins A, D, E, and B12; osteocalcin; tumor necrosis factor-α; and C-reactive protein (CRP). We also evaluated biomarkers among subsets of patients, examining factors including time since diagnosis, body mass index, alcohol as primary etiology, diabetes mellitus, vitamin supplementation, and pancreatic enzyme replacement.

RESULTS

After correcting for multiple comparisons, CP patients had significantly lower levels than controls of the following: vitamin A (40.9 vs 45.4 μg/dL) and vitamin E (α-tocopherol [8.7 vs 10.3 mg/L] and γ-tocopherol [1.8 vs 2.2 mg/L]), as well as osteocalcin (7.9 vs 10 ng/mL) and serum prealbumin (23 vs 27 mg/dL). Both patients and controls who took vitamin supplements had higher serum levels of vitamins than those not taking supplements. Compared with controls, in controlled analyses, CP patients had significantly lower levels of vitamins A, D, and E (both α-tocopherol and γ-tocopherol). CP patients also had significantly lower levels of osteocalcin, serum prealbumin, and retinol binding protein, and higher CRP.

CONCLUSIONS

CP patients demonstrated lower levels of selected nutrition and bone metabolism biomarkers than controls. Diabetes and alcohol did not impact biomarkers. Vitamin supplements and pancreatic enzyme replacement therapy improved nutrition biomarkers in CP patients.

The impact of lipoprotein lipase deficiency on health-related quality of life: a detailed, structured, qualitative study

Background

Lipoprotein lipase deficiency (LPLD) is an autosomal recessive inherited disorder caused by loss-of-function mutations in genes involved in the lipoprotein lipase pathway. It is characterised by chylomicronaemia, severe hypertriglyceridaemia and an increased risk of recurrent pancreatitis that often requires hospitalisation. This research aimed to improve our understanding of the debilitating impact that LPLD has on the daily lives of patients and their families.

Methods

The research comprised a 2-h interview with the patient and, where possible, a 1-h interview with a family member; a 1-week pre- and post-interview task (written and/or video diary); and a 30–45-min follow-up telephone interview. Feelings and thoughts at each stage of the disease journey were captured on a 0–10 rating scale, while the impact of disease on overall health status was measured via the EuroQoL 5 domains, 3 levels (EQ-5D-3L) questionnaire (descriptive and visual analogue scale).

Results

Of four patients identified, three (two female, one male) were recruited to participate in the study; the male patient did not complete the pre-interview task or consent to a family member interview. Demographics and medical history differed among patients in terms of age at symptom onset, their journey to LPLD diagnosis, treatments, the number of attacks of pancreatitis and lengths of hospitalisations. Health-related quality of life, assessed by the EQ-5D-3L, was poor during acute attacks of pancreatitis but was minimally impacted by their condition at interview. Patients described feeling apprehensive, frightened, anxious, depressed or frustrated during and after hospitalisations; spouses of the two female patients also reported being worried or afraid. LPLD affected many aspects of daily living, including diet; socialising and building relationships; state of mind (fear of another attack of pancreatitis or lack of disease control); college and working life (through absenteeism and consequent financial implications); and being reliant on family and friends for support.

Conclusions

The interviews of the three patients with LPLD highlighted several concerns and emphasised the need for improved education, support, dietary advice and appropriate disease management. Additional support services would ease the fear and uncertainty surrounding attacks of pancreatitis, and would allow for improved treatment during hospitalisations.

Electronic supplementary material

The online version of this article (10.1186/s13023-017-0706-1) contains supplementary material, which is available to authorized users.

Mechanism of mitochondrial permeability transition pore induction and damage in the pancreas: inhibition prevents acute pancreatitis by protecting production of ATP

OBJECTIVE

Acute pancreatitis is caused by toxins that induce acinar cell calcium overload, zymogen activation, cytokine release and cell death, yet is without specific drug therapy. Mitochondrial dysfunction has been implicated but the mechanism not established.

DESIGN

We investigated the mechanism of induction and consequences of the mitochondrial permeability transition pore (MPTP) in the pancreas using cell biological methods including confocal microscopy, patch clamp technology and multiple clinically representative disease models. Effects of genetic and pharmacological inhibition of the MPTP were examined in isolated murine and human pancreatic acinar cells, and in hyperstimulation, bile acid, alcoholic and choline-deficient, ethionine-supplemented acute pancreatitis.

RESULTS

MPTP opening was mediated by toxin-induced inositol trisphosphate and ryanodine receptor calcium channel release, and resulted in diminished ATP production, leading to impaired calcium clearance, defective autophagy, zymogen activation, cytokine production, phosphoglycerate mutase 5 activation and necrosis, which was prevented by intracellular ATP supplementation. When MPTP opening was inhibited genetically or pharmacologically, all biochemical, immunological and histopathological responses of acute pancreatitis in all four models were reduced or abolished.

CONCLUSIONS

This work demonstrates the mechanism and consequences of MPTP opening to be fundamental to multiple forms of acute pancreatitis and validates the MPTP as a drug target for this disease.

Acute pancreatitis with rapid clinical improvement in a child with isovaleric acidemia

Isovaleric acidemia is a rare branched-chain organic acidemia. The authors describe a 3.5-year-old girl with isovaleric acidemia and acute abdominal pain associated with bilious emesis. Elevated serum amylase and abdominal ultrasonography demonstrating an enlarged and edematous pancreas, along with the presence of peripancreatic exudates, confirmed the presence of acute pancreatitis. The patient recovered quickly with intravenous hydration, pancreatic rest, and administration of intravenous L-carnitine. Pancreatitis should be ruled out in the context of vomiting in any patient with isovaleric acidemia. Conversely, branched-chain organic acidemias should be included in the differential diagnosis of any child with pancreatitis of unknown origin.

Genetic aspects of pancreatitis

Acute pancreatitis and chronic pancreatitis are complex inflammatory disorders of the pancreas with unpredictable severity, complications, and clinical courses. Growing evidence for genetic risk and modifying factors, plus strong evidence that only a minority of patients with these disorders are heavy alcohol drinkers, has revolutionized our concept of these diseases. Once considered a self-inflicted injury, pancreatitis is now recognized as a complex inflammatory condition like inflammatory bowel disease. Genetic linkage and candidate gene studies have identified six pancreas-targeting factors that are associated with changes in susceptibility to acute and/or chronic pancreatitis, including cationic trypsinogen (PRSS1), anionic trypsinogen (PRSS2), serine protease inhibitor Kazal 1 (SPINK1), cystic fibrosis transmembrane conductance regulator (CFTR), chymotrypsinogen C (CTRC) and calcium-sensing receptor (CASR). Patients with mutations in these genes are at increased risk of pancreatitis caused by a variety of stresses including hyperlipidemia and hypercalcemia. Multiple studies are reporting new polymorphisms, as well as complex gene x gene and gene x environmental interactions.

Reversible leukoencephalopathy with acute neurological deterioration and permanent residua in classical homocystinuria: A case report

We report a 24-year-old patient with underlying classical homocystinuria who developed acute neurological deterioration apparently induced by malnutrition secondary to poor compliance with treatment and pancreatitis. Neurological examination revealed stupor, tremor of the upper extremities, spasticity, and Babinski responses of the bilateral lower extremities. The biochemical profile, including marked hypermethioninaemia, hyperhomocysteinaemia, and decreased cystine in plasma, is consistent with cystathionine β-synthase deficiency. Brain MRI showed reversible diffuse white-matter changes without evidence of thrombosis. The clinical features and neuroimaging including diffusion-weighted MRI suggest a demyelinating process similar to other inborn errors of the transsulfuration pathway such as methylenetetrahydrofolate reductase deficiency, disorders affecting methylcobalamin metabolism (cobalamin C, D, E, and G disorders), and methionine adenosyltransferase deficiency. She was left with residual spastic paraparesis despite normal follow-up MRI. Our observation suggests that reversible demyelination is another neurological manifestation of classical homocystinuria; however, the pathophysiology is unknown.

Recent insights into the cellular mechanisms of acute pancreatitis

In acute pancreatitis, initiating cellular events causing acinar cell injury includes co-localization of zymogens with lysosomal hydrolases, leading to premature enzyme activation and pathological exocytosis of zymogens into the interstitial space. This is followed by processes that accentuate cell injury; triggering acute inflammatory mediators, intensifying oxidative stress, compromising the microcirculation and activating a neurogenic feedback. Such localized events then progress to a systemic inflammatory response leading to multiorgan dysfunction syndrome with resulting high morbidity and mortality. The present review discusses some of the most recent insights into each of these cellular processes postulated to cause or propagate the process of acute pancreatitis, and also the role of alcohol and genetics.