Individuals with type 1 diabetes who take blood pressure medication, verapamil, require less insulin on a daily basis. The corresponding study was published in Nature.
Type 1 diabetes is an autoimmune disease that leads to the loss of pancreatic beta cells, which produce the body’s insulin. To counteract this process, type 1 diabetic patients need to take insulin either via injections or a pump. The is currently no oral treatment for the condition.
A study from 2014 found that verapamil can reverse diabetes in animals. A clincial trial carried out in 2018 found that regular oral administration of verapamil enabled type 1 diabetic patients to produce higher levels of insulin, meaning they needed to inject less to regulate their blood sugar levels.
The present study is a continuation of this 2018 research. For the study, the researchers examined changes in circulating proteins in response to verapamil treatment in patient blood samples. They found verapamil altered quantities of 53 proteins, including proteins linked to immunomodulation and autoimmunity of type 1 diabetes.
The researchers also found that levels of chromogranin A (CHGA) in diabetic participants were reduced following treatment with verapamil when compared to those who did not undergo the treatment. The researchers note that CHGA serves as an autoantigen in type 1 diabetes and provokes immune T cells involved in the autoimmune disease.
The researchers also found that after one year of treatment with verpamil, diabetic patients had similar CHGA levels as nondiabetic patients. In the second year of verapamil treatment, CHGA levels continued to drop; however, the researchers found that verapamil treatment may need to continue longer than a year as CHGA levels rose in patients who discontinued verpamil during year 2 of the study.
Further tests found that verapamil can reverse the effects of type 1 diabetes on various immune cells, including circulating proinflammatory cytokines and T helper cell subsets.
From RNA sequencing of pancreatic cells, the researchers then found that verapamil promotes anti-oxidative, anti-cell death, and immunomodulatory gene expression. These changes, say the researchers, may explain some of the improvements in pancreatic function with continued verapamil use.
The researchers caution that their findings need to be verified by larger clinical trials before any conclusions can be reached.
"In humans with Type 1 diabetes, even a small amount of preserved endogenous insulin production -- as opposed to higher exogenous insulin requirements -- has been shown to be associated with improved outcomes and could help improve quality of life and lower the high costs associated with insulin use," said Anath Shalev, M.D., director of the Comprehensive Diabetes Center at the University of Alabama at Birmingham.
"The fact that these beneficial verapamil effects seemed to persist for two years, whereas discontinuation of verapamil led to disease progression, provides some additional support for its potential usefulness for long-term treatment,” she added.