How Pancreas insuffiency in Cystic Fibrosis plays an important role in weight management
The pancreas lies behind the stomach and the beginning of the small intestine and plays an important role in the digestive process.
The pancreas has 2 main functions:
- Exocrine secretion of pancreatic juice (containing digestive enzymes) and sodium bicarbonate to neutralize stomach acid.
- Endocrine secretion of primarily insulin.
1. Exocrine function affected by cystic fibrosis
The pancreas consists mainly of exocrine cells which produce digestive enzymes and secretes them via specific ducts into the small intestines as a reaction to the hormone “Cholecystokinin”. This hormone is triggered when food enters the duodenum. The produced enzymes are: amylase, lipase, protease and trypsin, and serve to break down respectively starch, fat and protein for absorption in the body.
Cystic fibrosis problem
In CF, the pancreatic ducts are obstructed with typically thick mucus, preventing enzymes and sodium bicarbonate from reaching the duodenum. The food passes through the intestines without proper digestion and absorption.
With no proper treatment, patients would suffer continuous malabsorption, leading to the following gastrointestinal problems:
- Steatorrhea: heavy, foul smelling stools,
- Swelling of the abdomen caused by larger stools,
- Abdominal bloating, and
- Abdominal pain
Malabsorption ultimately leads to poor growth and weight loss. Treatment consists in taking pancreatic enzyme replacement pills. These enzyme replacement pills help in the digestion of mainly fat and protein. The therapy helps patients absorb most of the nutrients the body needs for normal weight gain or for regaining weight. The therapy is easy, as patients just need to take some pills during meals.
In normal people, the pancreas stores inactive forms of enzymes and activates them only when leaving the organ. For a reason that is still unknown, in CF the enzymes are prematurely activated. This activation can start to digest the pancreas leading to inflammation which is called pancreatitis.
2. Endocrine function also altered by cystic fibrosis
The pancreas also functions as an endocrine gland thanks to the islets of Langerhans. These islets are found throughout the organ and a healthy person has roughly 1 million of them. Three main cell types can be found in the islets, differentiated by their secretions:
- Alpha cells secrete glucagon, a hormone that converts liver glycogen into glucose (sugar) when blood glucose level is low,
- Beta cells emit insulin which enables glucose absorption from blood into the muscles and the liver in the form of glycogen,
- Delta cells secrete somatostatin a hormone which slows down insulin and glucagon secretion.
The islets are in direct contact with blood vessels through a network of capillaries enabling them to release the hormones directly into the blood stream (endocrine).
Distorted insulin production in cystic fibrosis causes diabetes
Although the exocrine function is the most dominant in CF, insulin production can also be altered. This problem usually starts between the ages of 18 and 21, although it can start at any time. The gluey mucus causes fibrosis (scarring) to the islet cells of Langerhans, damaging to the beta or insulin producing cells. The result is diabetes.
The only possible treatment at the moment for cystic fibrosis related diabetes is insulin therapy.
Disclaimer: This website provides general information about cystic fibrosis and in no means should be taken as a medical or health advice. Please consult your doctor before acting on any of its information.