Fibronectin and Complement Secretion By Monocytes and Peritoneal Macrophages In Vitro From Patients Undergoing Continuous Ambulatory Peritoneal Dialysis

Abstract

We investigated the role of the opsonic glycoprotein fibronectin in the host defense of the peritoneum in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Fibronectin concentration in peritoneal dialysate from high infection rate CAPD patients (greater than 1.50 episodes peritonitis per year) was significantly less than from low infection rate CAPD patients (less than 0.55 episodes peritonitis per year). In vitro secretion of fibronectin by cultured peritoneal macrophages from patients with high infection rate was less than from low infection rate patients (P less than 0.05) and controls (P less than 0.01). In vitro secretion of the second component of complement, however, was similar in both high and low infection rate patients. Plasma fibronectin concentration and in vitro fibronectin secretion by cultured peripheral blood monocytes was not different between high infection rate patients and low infection rate patients, but was less than normals. Decreased fibronectin secretion by peritoneal macrophages is associated with a higher incidence of peritonitis among CAPD patients.

Fibronectin during CAPD-Related Peritonitis: No Indications for Intraperitoneal Production

“…This can possibly be attributed to the use of differ ent assays. The dialysate fibronectin concen trations we measured after recovery from the infection were similar to those reported in peritoneal effluent of uninfected CAPD pa tients by other groups [3,13,14], Serum fibronectin levels remained stable during peritonitis and were not different from values measured after recovery. This is in contradiction to a study by Giacchino et al, that reported lower plasma levels during peri toneal inflammation [16].…”

“…The serum fibro nectin concentrations we measured were slightly lower than the levels of 300-400 mg/1 reported for healthy individuals in the litera ture [7,8]. Other groups have also reported significantly lower serum fibronectin levels for uremic patients, treated with either hemo dialysis or peritoneal dialysis, compared to normal controls [3,19].…”

“…Fibronectin is a high molecular weight gly coprotein (440 kD) that can be synthesized in vitro by a variety of cells including macro phages, fibroblasts and endothelial cells [1][2][3]. served in nephrotic syndrome patients, whereas decreased plasma levels have been reported after major surgery, trauma and in patients with disseminated intravascular co agulation [7][8][9].In these latter patients, low plasma levels were associated with a poor prognosis.…”

“…Soluble fibronectin acts as an op sonin, involved in the clearance of particulate debris and microorganisms [4,10,11], The insoluble form of fibronectin promotes adhe sion of cells to collagen [4], With respect to these functions fibronectin could also be of potential interest during treatment with con tinuous ambulatory peritoneal dialysis (CAPD). Fibronectin is present on peritoneal mesothelial cells [12], and production of this glycoprotein has been demonstrated in vitro for peritoneal macrophages isolated from CAPD patients [3]. In addition, several au thors have measured fibronectin in peritoneal effluent from stable patients treated with CAPD [3,13,14].…”

“…Fibronectin is present on peritoneal mesothelial cells [12], and production of this glycoprotein has been demonstrated in vitro for peritoneal macrophages isolated from CAPD patients [3]. In addition, several au thors have measured fibronectin in peritoneal effluent from stable patients treated with CAPD [3,13,14]. However, it is still unclear whether fibronectin present in peritoneal ef fluent is synthesized locally within the perito neal cavity, as suggested by some authors [15], or derived from the circulation by transperitoneal transport, as proposed by others [13,14], Furthermore, both increased and de creased peritoneal fibronectin levels have been reported during peritoneal inflamma tion [15,16],…”