Objectives: To measure indices of copper status in adult men with cystic fibrosis (CF). A previous study in children showed changes in copper homeostasis compared to controls. This study was designed to investigate whether this observation persisted into adulthood.
Methods: This was a case-control age-matched study using seven men with CF and six healthy men. Blood samples were drawn into metal free tubes and fractionated into plasma, polymorphonuclear cells, mononuclear cells and erythrocytes. Cell fractions were assayed for copper and CuZn-superoxide dismutase; plasma was assayed for ceruloplasmin.
Results: The men with cystic fibrosis had significantly greater plasma copper and ceruloplasmin activity, yet had significantly lower copper-zinc superoxide dismutase activity in mononuclear and polymorphonuclear cells. Furthermore, the mononuclear cells of the cystic fibrosis subjects had about 45% percent less copper-zinc superoxide dismutase protein. Cellular copper levels were not statistically different between the two groups. A significant correlation was found between lung function and copper-zinc superoxide dismutase activity in the polymorphonuclear cells. Iron status was normal.
Conclusions: The results indicate that individuals with cystic fibrosis have altered copper distribution compared to control individuals. Some aspects are characteristic of an inflammatory response; however, other measures suggest that copper homeostasis may be abnormal. It is not known whether the deviation in copper homeostasis in these individuals is a result of poor copper absorption, inadequate dietary intake, a result of their chronic inflammation or a direct effect due to the defect in ion transport caused by the disease. However, this research suggests that the severity of the disease and the activity of a copper dependent enzyme may be related. Further work will be necessary to determine the cause of the abnormal copper homeostasis and whether correcting it has any bearing on the course of the disease.