Scientists Are Creating Vaccines For Type 1 Diabetes
According to the Centers for Disease Control and Prevention, approximately 1.6 million Americans have type 1 diabetes. Every year, these numbers get worse. Globally, the number of individuals living with type 1 diabetes seems to be increasing by around 3-4% annually.
Since it’s mostly seen in children, teens, and young adults, the disease was previously known as juvenile diabetes. However, middle-aged adults and older people can be diagnosed with it, too.
Unfortunately, there’s no cure. The main treatment options include a low-carb and low-sugar diet accompanied by daily insulin injections. Although insulin pumps have started to replace insulin injections, many diabetes patients lack access to this more advanced medical technology and need to take insulin injections every day for the rest of their lives. There sure are other options, but they come with serious risks and lifelong consequences. Pancreas transplants, for example, are restricted to only the most unmanageable cases because of health risks, and patients who get them are generally required to take anti-rejection medication for the rest of their lives.
While type 2 diabetes can be prevented by maintaining a healthy lifestyle and a healthy weight, there's nothing you can do to avoid type 1 diabetes. This is why scientists from all around the world are working on different types of vaccines, which could reverse the condition and finally offer a viable cure.
What is diabetes?
Diabetes is a metabolic disorder that causes high blood sugar levels because the body develops insulin resistance (a condition in which the cells do not respond to insulin) or because the pancreas doesn’t produce enough insulin to absorb glucose. Type 1 diabetes, however, is an autoimmune disease in which the immune system attacks and destroys insulin-producing cells in the pancreas, causing sugar to build up in the bloodstream.
In patients diagnosed with this condition, the cells that synthesize insulin in the pancreas are attacked by cells in the immune system. This causes low insulin secretion, and it results in an inability to process glucose, which then accumulates in the bloodstream. It is not known what triggers the autoimmune response in the first place, but it may involve genetic factors or exposure to viruses and other environmental conditions.
This ultimately gives way to a wide range of short-term and long-term complications, many of which are life-threatening. These include blindness, cardiovascular issues, nerve damage leading to amputation, kidney failure, and inevitably death. In fact, both Type 1 and Type 2 diabetes are actually some of the main causes of lower-limb amputation and adult blindness.
Vaccine Strategies For Type 1 Diabetes
- Antigen-Specific Vaccines
As mentioned, type 1 diabetes occurs when certain white blood cells fail to recognize the insulin-producing beta cells as a normal part of the pancreas.
These white blood cells, called T cells, mistake the cells as intruders that are invading the pancreas and attack them, leading to a decline in the production of insulin.
Conventional vaccines boost immune responses against foreign antigens by exposing the immune system to them in a controlled way. Contrarily, in type 1 diabetes vaccination, the goal is to inhibit the incorrect immune response against beta cells. This is called inverse vaccination.
Because reducing the number or the function of T cells would affect the entire immune system, scientists have been studying antigen-specific vaccines. These would work only on diabetes autoantigens to stimulate immune tolerance.
- Single Peptide Vaccines
These vaccines are based on specific pancreatic substances. Insulin-based vaccines failed in humans, but scientists discovered that some compounds, called peptides, which help the body fight bacteria and promote wound healing, can induce anti-inflammatory responses. This is important because type 1 diabetes starts with insulitis, an inflammation of the pancreatic Islets of Langerhans, caused by white blood cells attacking the islets' insulin-producing beta cells.
The most promising peptide is DiaPep277, a stable 24 amino-acid peptide that activates anti-inflammatory and regulatory white blood cells. This peptide can diminish the immune response that leads to the destruction of beta cells and regulate that immune response to preserve beta cells. This vaccine is on phase III trial.
- Altered Peptide Ligand Vaccines
APL vaccines are based on peptide fragments modified with amino acid substitutions that bind to MHC molecules.
MHC is short for Major Histocompatibility Complex. It’s a group of genes that trigger the detection of pathogens and the immune system’s response against them. APL vaccines manipulate this process to induce specific white blood cell responses to prevent them from attacking pancreatic beta cells.
Insulin-based peptides are candidates to act as altered peptide ligands in this kind of vaccine as they can delay type 1 diabetes, research has shown.
- Adjuvant Stimulated Diabetes Vaccines
To overcome the limitations of single peptide vaccines, scientists decided to add ingredients to make them stronger.
This is the case with antigen-specific immunotherapy Dyamid, created by Swedish biotech company Diamyd Medical. It is based on the protein GAD65, an endogenous antigen involved in the pathology of autoimmune diabetes.
In clinical trials, this treatment demonstrated an enhanced, more selective immune response that helped protect beta cells and insulin production.
Dyamid is currently in large-scale phase III clinical trials.
- TB Vaccine, Repurpose
Researchers from Massachusetts General Hospital have found that Bacillus Calmette-Guérin (BCG) vaccine, created in 1921 to prevent tuberculosis, is also able to normalize blood sugar levels through the regulatory T-cell gene Foxp3, which is usually altered in type 1 diabetes.
By restoring normal gene expression in key immune cells, the vaccine can reduce beta cells destruction, and even increase blood sugar consumption to attain more balanced glucose levels.
Currently, Massachusetts General Hospital wants to start a pediatric trial but is awaiting approval from the FDA.
As you can tell, there are several options in different stages of development that may end up being effective treatments against type 1 diabetes. We'll have to wait to see if they're going to prevent the illness or even go as far as to cure it. Either way, it's great news for type 1 diabetics or people at risk of having the disease.
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