Zsolt Balla

Interacting effects of capsaicin and anandamide on intracellular calcium in sensory neurones.

Capsaicin (100 nM to 1 μM) and anandamide (200 nM to 10 μM) caused a transient increase in fluorescence of fura-2 loaded cultured small trigeminal neurones of rats measured with a ratiometric technique. The percentage of cells responding to capsaicin at 100 nM, 330 nM and 1 μM was 47.4%, 45.3%, and 70.4%, respectively. Averaged peak value of fluorescense ratio (R) at 340 and 380 nm excitation was slightly dose dependent. Peaks of anandamide-induced transients were R = 0.2 at 200 nM and 0.16 at 10 μM. Near 40% of capsaicin-sensitive cells responded also to anandamide. Anandamide (200 nM) inhibited the capsaicin-induced calcium influx. The results suggest that anandamide increases intracellular calcium and inhibits capsaicin-evoked calcium transients.

Modeling long-term diabetes and related complications in rats.

INTRODUCTION Accurate preclinical modeling of diabetic complications such as retinopathy, nephropathy and neuropathy is crucial to enable the development of novel preventative therapies. The aims of this study were to establish a model of long-term diabetes with sustained medium scale hyperglycemia and characterize the pathological changes detectable after 4months, with particular respect to dependence on the degree of hyperglycemia. METHODS Streptozotocin-induced diabetic CFY rats were subjected to four different insulin substitution protocols to achieve different levels of glycemic control (Diabetic 1-4 groups). Eyes were investigated by ophthalmoscopy, kidney function by urine analysis, and neuropathy by functional tests. Retinal and renal morphological evaluations were performed by histology, immuno-histochemistry and electron microscopy. RESULTS Rats of the Diabetic 3 group showed massive hyperglycemia-dependent anterior segment neovascularization, enhanced total retinal score and retinal apoptotic cell number, degeneration of dopaminergic amacrine cells, increased glomerular PAS-positivity, altered excreted total protein/creatinine ratio and cold allodynia, parallel with medium scale hyperglycemia (blood glucose level between 22 and 25mmol/L) and satisfying state of health. DISCUSSION We established a treatment protocol in rats enabling complex investigation of diabetic retinopathy, nephropathy and neuropathy on a long-term period. Clearly hyperglycemic dependent parameters of these complications serve as good outcome measures for preclinical trials. Our results provide a useful basis for designing studies for testing preventative treatments as well as other translational medical research in this field.

Ductal Mucus Obstruction and Reduced Fluid Secretion Are Early Defects in Chronic Pancreatitis

Objective: Defective mucus production in the pancreas may be an important factor in the initiation and progression of chronic pancreatitis (CP), therefore we aimed to (i) investigate the qualitative and quantitative changes of mucus both in human CP and in an experimental pancreatitis model and (ii) to correlate the mucus phenotype with epithelial ion transport function. Design: Utilizing human tissue samples and a murine model of cerulein induced CP we measured pancreatic ductal mucus content by morphometric analysis and the relative expression of different mucins in health and disease. Pancreatic fluid secretion in CP model was measured in vivo by magnetic resonance cholangiopancreatography (MRCP) and in vitro on cultured pancreatic ducts. Time-changes of ductal secretory function were correlated to those of the mucin production. Results: We demonstrate increased mucus content in the small pancreatic ducts in CP. Secretory mucins MUC6 and MUC5B were upregulated in human, Muc6 in mouse CP. In vivo and in vitro fluid secretion was decreased in cerulein-induced CP. Analysis of time-course changes showed that impaired ductal ion transport is paralleled by increased Muc6 expression. Conclusion: Mucus accumulation in the small ducts is a combined effect of mucus hypersecretion and epithelial fluid secretion defect, which may lead to ductal obstruction. These results suggest that imbalance of mucus homeostasis may have an important role in the early-phase development of CP, which may have novel diagnostic and therapeutic implications.

Bidirectional Relationship Between Reduced Blood pH and Acute Pancreatitis: A Translational Study of Their Noxious Combination

Acute pancreatitis (AP) is often accompanied by alterations in the acid-base balance, but how blood pH influences the outcome of AP is largely unknown. We studied the association between blood pH and the outcome of AP with meta-analysis of clinical trials, and aimed to discover the causative relationship between blood pH and AP in animal models. PubMed, EMBASE, and Cochrane Controlled Trials Registry databases were searched from inception to January 2017. Human studies reporting systemic pH status and outcomes (mortality rate, severity scores, and length of hospital stay) of patient groups with AP were included in the analyses. We developed a new mouse model of chronic metabolic acidosis (MA) and induced mild or severe AP in the mice. Besides laboratory blood testing, the extent of pancreatic edema, necrosis, and leukocyte infiltration were assessed in tissue sections of the mice. Thirteen studies reported sufficient data in patient groups with AP (n = 2,311). Meta-analysis revealed markedly higher mortality, elevated severity scores, and longer hospital stay in AP patients with lower blood pH or base excess (P < 0.001 for all studied outcomes). Meta-regression analysis showed significant negative correlation between blood pH and mortality in severe AP. In our mouse model, pre-existing MA deteriorated the pancreatic damage in mild and severe AP and, vice versa, severe AP further decreased the blood pH of mice with MA. In conclusion, MA worsens the outcome of AP, while severe AP augments the decrease of blood pH. The discovery of this vicious metabolic cycle opens up new therapeutic possibilities in AP.