Assay for the Pancreatic Polypeptide: an Help for Clinical Practice Guidelines in Classification of the Diabetes

All diabetes are the result of endrocrine deficiency. The endocrine deficiency may be absolute, as in type 1 diabetes, considered as an elective and exclusive attack of pancreatic Beta cell, or it could be relative, as un type 2 diabetes.

More rarely, diabetes fit into a broader context of pancreatic failure, with diffuse involvement of the exocrine and endocrine function, suggesting an impairment of the whole endocrine secretion of the pancreas, affecting the entire islet of Langerhans, such as in type 3c diabetes, whose prototypes are total pancreatectomy, chronic alcoholic pancreatitis, cystic fibrosis.

The diagnostic of type 3c diabetes is not always obvious, with several clinical presentations, without biological specific disease tag. Moreover, it also appears that the common form of diabetes, type 1 and type 2, may be associated with an exocrine function deficit and with a decrease of the pancreatic volume correlated with exocrine function abnormalities, and a decrease of insulin secretion capacity. The consequences of a spread of the disease beyond the Beta cells remain uncertain, but they could be linked, as in type 3c diabetes, with severe form of hypoglycaemia, due to glucagon deficiency, or nutritional deficiency due to the exocrine deficiency.

The pancreatic polypeptide belongs to the neuropeptide Y family, it is produced by the endocrine pancreatic F cells, located in the hook and the head of the pancreas. Food intake stimulates its secretion. The role of the pancreatic polypeptide in human is uncertain.

Investigators propose to study the pancreatic polypeptide in type 1 and type 3c diabetes before and after a mixed meal in order to study the other endocrine functions of the islet of Langerhans, to evaluate the possibility, or not, of a more diffuse pancreatic involvement in type 1 diabetes, considered as an elective pathology of the pancreatic Beta cell.

Inclusion criteria

• Patients aged 18 years or older
• Patients with type 1 diabetes with anti-GAD and / or IA2 and / or Znt8 positive antibodies, or characteristic clinical history, with and without exocrine deficiency (*)
• Patients with chronic alcoholic pancreatitis or cystic fibrosis origin (type 3c diabetes), complicated with diabetes defined by HbA1c> 6.5% or treated with oral anti-diabetic and / or insulin
• Patients who have given informed and written consent to participate in research
• Patients affiliated to a social security scheme (*): The exocrine deficiency is defined by an assay of fecal elastase:
• without deficit of exocrine function = fecal elastase = /> 100 μg / g
• with deficit of exocrine function = fecal elastase <100 μg / g

Exclusion criteria

• Pregnancy
• Severe renal impairment (eDFG <45 mL / min / 1.73 m²)