﻿Glucose is one of the preferred fuels for our cells;
But controlling the glucose levels in our bodies requires tight regulation.
After a meal, our bodies begin the elaborate process of breaking down
the food into its constituent nutrients, like sugars and proteins and other things
which are mostly absorbed in the small intestine into the bloodstream.
Once the glucose is in the bloodstream, some of it gets sent to the liver for storage,
and the rest is sent to fuel the body's power-hungry cells.
But there’s another step before cells can accept the payload.
As the amount of glucose in the blood reaches a certain level, this is detected by a group
of cells in the pancreas called beta cells, which cluster together in structures called islets.
These beta cells release a hormone called insulin which acts like a key, binding to
cells and unlocking their glucose channels. This allows glucose to move across their cell
walls, causing blood sugar levels to go back down again.
As such, insulin is vital for regulating how much sugar is in our blood at any one time….
Unfortunately, this fine-tuned regulation of blood sugar levels can go wrong,
such as in type 1 and type 2 diabetes.
Type 1 diabetes is an autoimmune disease where the pancreatic beta cells are
mistakenly destroyed by the immune system, meaning insulin production drops.
This removes the normal sugar surveillance and response system from the pancreatic islets and
with very little insulin being secreted, the blood sugar levels spiral out of control.
The pathophysiology of Type 2 diabetes is very different, but can be just as harmful.
In this instance, the pancreas’ beta cells function perfectly well at first,
secreting insulin in response to increased blood sugar levels.
But the target cells themselves don’t respond to that insulin so the blood,
again, becomes saturated with sugars. This is known as insulin resistance.
In addition, some people have genetic mutations that mean they are more at risk of beta cell
failure and insulin resistance.
In type 2 diabetes, the beta cells often
overcompensate for the sugar-saturated blood by producing too much insulin; however, over time,
beta cells become dysfunctional and cannot produce enough insulin for the body's needs'
In both diseases, over time the high levels of blood glucose, a situation termed ‘hyperglycemia’,
damage nerves and blood vessels, which increases the risk of blindness, kidney
failure, heart attack, and stroke.
Unfortunately there is currently no cure for either disease, but the complications of hyperglycemia can be managed.
People with Type 1 diabetes need to replace the function of their beta cells,
by monitoring their blood sugar levels and injecting insulin when needed.
Nowadays, this can be achieved automatically with an insulin pump,
and technologies are advancing that make blood glucose monitoring easier.
Type 2 diabetes can often be avoided altogether if spotted early enough…
People with high blood sugar levels, but not yet in the type 2 diabetes range,
are termed 'prediabetic', and with changes to diet and exercise, the progression to type 2
diabetes can often be halted.
Individuals who do go on to develop type 2 diabetes are typically treated with a drug called metformin, which needs to be
taken with or after every meal.
Despite these strategies to manage diabetes, there is a strong research effort to find cheaper, simpler, more effective treatments.
An active area of research for Type 1 diabetes is ‘immunotherapies’ which are aimed at getting
in early to stop the immune system’s attack on the pancreas’ beta cells.
Pancreas or islet transplants can also be performed,
and work is under way to generate beta-cells from stem cells for transplantation
A group of newer therapies for type 2 diabetes are designed to mimic a class
of hormones called incretins, which are normally produced in the gut after
a meal and stimulate insulin secretion before blood sugar levels start to rise.
This is known as the incretin effect, which is diminished in patients with type 2 diabetes.
Drugs that mimic incretins reboot the incretin effect.
These drugs improve weight loss by reducing appetite,
and also improve cardiovascular outcomes.
Several drugs are in clinical trials that mimic multiple incretin hormones at once, following promising results in animal models.
As new therapies for diabetes are realised , there is a growing understanding that patients
respond differently to different therapies.
And efforts to utilise precision medicine will hopefully improve the prediction, prevention and treatment of diabetes for individual patients.