Polymorphisms in the Surfactant Protein A Gene Are Associated with the Susceptibility to Recurrent Urinary Tract Infection in Chinese Women

Abstract

Recurrent urinary tract infection (r-UTI) remains one of the common infections affecting adult female. Almost 27% of women developed a recurrent UTI within the 6 months (Foxman 1990) and nearly 50% of women developed a recurrence within the first year following the initial infection (Mabeck 1972). Clinical studies showed that only a fraction of r-UTI patients had obvious functional, anatomic and behavioral risk factors, which were considered to be strongly associated with an increased risk of r-UTI. Recently, genetic studies have reported the associations of polymorphisms within innate immune molecules such as Toll-like receptor 2 and 4 (TLR2 and TLR4) with r

Surfactant Protein D Inhibits Adherence of Uropathogenic Escherichia coli to the Bladder Epithelial Cells and the Bacterium-induced Cytotoxicity

“…Previous studies have shown that SP-D expression is increased in the mouse reproductive tract (31) and rat prostate (32) infected with Chlamydia and E. coli, respectively. A recent report showed that the urine SP-D levels were decreased in patients with recurrent urinary tract infection compared with healthy individuals (29). Taken together with the results obtained from this study and previous studies (29,31,32), the endogenous lectin SP-D possesses potential functions to protect against the bacterial infection.…”

“…A recent report showed that the urine SP-D levels were decreased in patients with recurrent urinary tract infection compared with healthy individuals (29). Taken together with the results obtained from this study and previous studies (29,31,32), the endogenous lectin SP-D possesses potential functions to protect against the bacterial infection. We investigated the protective role of SP-D in adherence of UPEC to the bladder urothelium, which is the first critical step for establishing UPEC infection, and examined the mechanisms of SP-D-dependent defense against UPEC infection.…”

“…This study (see Fig. 1H) and a previous study (29) indicate the presence of SP-D protein in human urine. The results from immunochemistry and immunoblot analysis are consistent with the idea that SP-D is expressed in the bladder.…”

“…Urine-SP-D protein is detected by enzyme-linked immunosorbent assay (ELISA) in urine (29). We determined whether SP-D was present in human urine by Western blot analysis using anti-SP-D polyclonal antibody.…”

Non-Pulmonary Immune Functions of Surfactant Proteins A and D

“…SP-D may also play a protective role against tubulointerstitial fibrosis (the common pathway to end-stage renal disease), as overexpressing SP-D in human kidney proximal tubular cells inhibits the expression of monocyte chemoattractant protein-1, a protein that when upregulated leads to disease progression [40] . In a study involving Chinese women, it was found that individuals carrying an Ala19Val polymorphism in SP-A1 or a Lys223Gln polymorphism in SP-A2 show increased susceptibility to recurring urinary tract infections [41] further emphasising that SPs seem to have important roles in preventing infection of the urinary tract.…”