Immunoreactive calmodulin in cystic fibrosis kidneys

[Renal diseases in cystic fibrosis]

Patients with cystic fibrosis (CF) show a continuing improvement in their life expectancy thanks to advances in knowledge of this disorder, allowing better multidisciplinary routine monitoring and earlier therapeutic interventions. Likewise, more than of 40% of these patients are adults and CF is no more only a pediatric disease. Due to their higher life expectancy, CF patients present new and unusual complications that were not recorded before. Among them, some renal disorders have to be added to the CF-related renal diseases. They are due to frequent and prolonged exposure to various potentially nephrotoxic factors that need to be taken into account early enough in order to avoid renal failure : essentially risk factors for kidney stones formation, bacterial infections with their associated immune complexes diseases, nephrotoxic effects of antibiotics, diabetes mellitus. Because we observed a case of IgA glomerulonephritis in a 35-year-old patient with cystic fibrosis, we have searched about all these renal consequences due to this affection and here report them.

The association of nephrolithiasis with cystic fibrosis

BACKGROUND

There is a growing body of evidence regarding the association between cystic fibrosis (CF) and nephrolithiasis and the role that Oxalobacter formigenes may have in that association.

METHODS

We performed a MEDLINE search of "cystic fibrosis and nephrolithiasis" and "Oxalobacter formigenes." Epidemiological and experimental evidence and possible mechanisms explaining the association were critically reviewed.

RESULTS

Of patients with CF, 3.0% to 6.3% are affected with nephrolithiasis, a percentage greater than that of age-matched controls without CF, in whom the rate is 1% to 2%. Studies have suggested possible mechanisms for the association, including hyperuricosuria, hyperoxaluria, primary defects in calcium handling caused by mutation of the CF transmembrane regulator (CFTR), hypocitraturia, and lack of colonization with O formigenes, an enteric oxalate-degrading bacterium. The absence of colonization could be related to frequent courses of antibiotics.

CONCLUSION

Although the incidence of stones in patients with CF may be increased compared with controls without CF, many possible mechanisms are implicated. The relative contributions of these mechanisms remain uncertain. Future directions may include specific identification of lithogenic risks and therapy aimed at stone prevention in this population.