The pancreas is responsible for supply and control of
multiple hormones. Not just the all-important insulin but its partner in crime
glucagon, as well as somatostatin and pancreatic polypeptide. On top of all
this the pancreas produces many enzymes that help the body digest food: lipase,
amylase, trypsinogen, chymotrypsinogen, elastase and carboxypeptidase. An
impressive list for such an underestimated organ.
Of course all this makes living without a pancreas quite a
challenge.
We have tried our best to replicate all the functions that
nature perfected long ago but our attempts at being a pseudopancreas appear
amateurish when compared to such an impressive organ.
The biochemists have given us the enzymes and drugs to help
Finlay survive, modern medical technology has given us insulin pumps to finely
tune our glucose control and the surgeons have aided us with 24-hour feeding
access through a feeding tube. But it is one of the pancreases lesser-known
functions that has left us struggling recently.
One of Finlay’s issues is his size. He is small. At 4 years
old we can get him in 2 year old pants if we pull the elastic waistband really
tight. Unfortunately fattening him up has not been easy. He grew reasonably
well in the first couple of years but he has hardly put on any weight in the
last year. And the problem seems to be an inability to digest and absorb his
food. We can give him all the food and nutritional drink supplements we can
shove in him. We can feed him through a tube when he’s asleep and we can give
him lots of enzymes to replace the ones he can’t produce. But all this isn’t
helping him grow. And it’s a clever little property of the pancreas that is to
blame.
When food exits the stomach it is very acidic due to the
gastric acid in the stomach. This creates a problem as the enzymes released by
the pancreas to digest the food are destroyed by strong acid. So the pancreas
releases bicarbonate (the same as baking soda) along with the enzymes to
neutralise the acidic food and allow the enzymes to work.
So for our attempts at being a pseudopancreas we feed him
some enzymes in tiny spheres that have a special coating that protects the
enzymes through the acid stomach but which dissolve, releasing the enzymes,
once they are in the less acidic duodenum. Unfortunately because he has no
pancreas he has no bicarbonate released into his gut so the duodenum stays
acidic. That means the little spheres carry on through the gut until eventually
the environment is suitable for the coating to dissolve but by then most of the
benefit has been lost and not enough food gets digested.
So what is the answer? With the rarity of Finlay’s condition
there are no treatment guidelines, no established protocols backed by years of
research and experience. We work on a combination of educated guesswork and….
well, complete guesswork. One strategy is to look at conditions with similar
problems. In this case cystic fibrosis is a good model for what Finlay is
dealing with. In CF the secretions from the pancreas can become blocked as the
organs get covered in the thick gunk that typifies the disease. For many CF
patients, reducing the stomach acid works well to reduce the acid environment
in the duodenum and let the enzymes work.
So we have started a course of a proton pump inhibitor, a
class of drug that reduces the amount of acid the stomach produces. Hopefully
that will help reduce the acidity of the whole digestive tract and get more
food being digested and absorbed.
Time will tell if this helps him put weight on but if it
does it will be one more small victory in our efforts to replicate this amazing
organ.
