Researchers investigated point mutations in two transporters of vitamin B1, a regulator of glucose metabolism, into the cells of type 1 diabetes patients and found that two specific mutations were associated with reduced rates of the retinal and kidney disease, or a combination of those diseases. These results might explain why some type 1 diabetes patients are less susceptible to disease complications related to damaged capillaries.
The research paper, “Variation in SLC19A3 and Protection from Microvascular Damage in Type 1 Diabetes,” was published in diabetes, the journal of the American Diabetes Association.
Retinopathy, or diabetic retinal disease, and nephropathy, or diabetic kidney disease, are among the most significant complications resulting from diabetes. Both involve microvascular (capillary) damage, whose main risk factor is high blood sugar. However, researchers have observed that the risk for such complications is not fully explained by diabetes duration or exposure to high glucose, which suggests that genetic factors might play a role in their pathogenesis.
The researchers investigated the genetic variants of transporters of vitamin B1 (thiamine), as it has been previously shown that vitamin B1 regulates intracellular glucose metabolism, and its presence inside cells can prevent damage caused by high blood glucose, reducing the patient’s susceptibility to related diseases. They tested, in a research database with extensive data on type 1 diabetes patients, several single-nucleotide polymorphisms (SNPs) in two vitamin B1 transporters (SLC19A2/3) for association with retinopathy, nephropathy, or a combination of the two. Results showed that two specific point mutations in the SLC19A3 were associated with reduced incidence of retinopathy and the combination of retinopathy and nephropathy. The variant’s protective effect remained significant even after other common risk factors were taken into account. This protective effect was also confirmed by analysis of North American patient data.
Iiro Toppila, one of the study’s researchers, said in a press release, “Based on these results, it seems that the SLC19A3 gene has a role in the development of diabetic nephropathy and diabetic retinopathy. The results also help explain why some patients with type 1 diabetes are more likely to develop complications than others. However, further research is needed into the biological effects of point mutations.”