Lower immunity and recurring infections are common in type 1 and type 2 diabetes. Research has shown that the immune system of people with diabetes has lower levels of the antimicrobial peptide psoriasin, which compromises the urinary bladder’s cell barrier, increasing the risk of urinary tract infection. The study is published in Nature Communications.
One effect of diabetes is that it compromises the innate immune system, leaving many people with increased susceptibility to regular infections, such as urinary tract infections (UTI)s caused by E. coli bacteria. In people with diabetes, these are more likely to lead to general blood poisoning, sepsis, originating in the urinary tract.
An endogenous antibiotic
Karolinska Institutet researchers investigated whether glucose levels in people with diabetes (type 1, type 2, or prediabetes) are linked with psoriasin, an endogenous antibiotic which is a part of the innate immune system.
Using samples of urine, bladder cells and blood serum from patients, the researchers analysed levels of psoriasin and other peptides necessary for ensuring that the bladder mucosa remains intact and protects against infection. The findings were then verified in mice and urinary bladder cells with and without infection.
“We found that high glucose concentrations reduce the levels of the antimicrobial peptide psoriasin, while insulin has no effect,” said Professor Annelie Brauner, who led the study. “People with diabetes have lower levels of psoriasin, which weakens the cells’ protective barrier function and increases the risk of bladder infection.”
Oestrogen therapy reduced bacterial population
Professor Brauner’s research group has previously shown that oestrogen restores the protective function of bladder cells in humans and mice and thereby help to regulate the immune response to a UTI. The researchers therefore tested how oestrogen treatment affects infected cells exposed to high glucose concentrations. They found that the treatment boosted levels of psoriasin and reduced bacterial populations, indicating that the treatment may have an effect also among patients with diabetes.
“We now plan to probe deeper into the underlying mechanisms of infections in individuals with diabetes,” said lead author Soumitra Mohanty. “The ultimate goal is to reduce the risk of infection in this growing patient group.”
Source: Karolinska Institutet
