Macrophage activation in type 1 diabetic patients with catheter obstruction during peritoneal insulin delivery with an implantable pump.
OBJECTIVE
The purpose of this study was to evaluate the activation of macrophages in type 1 diabetic patients during peritoneal insulin delivery with an implantable pump against two types of insulin: that which was collected from the pump reservoir and that which came straight fromn the bottle (i.e., vial insltlin). Macrophage activation was studied in patients with and without cathcter obstruction and compared with activation in healthy subjects.


METHODS
Human insulin (21 PH, 400 U/ml; Hoescht) was collected from the pump reservoir (Minimed) of diabetic patients with (n = 3) or without (n = 7) catheter obstruction, as assessed by histological examination of the catheter tip. Monocytes were obtained from venous blood samples from both kinds of diabetic patients and from healthy subjects (n = 5) and were differentiated into monocyte-derived macrophages in culture. Their chemotaxis and tumor necrosis factor-alpha (TNF-alpha) release were studied with respect to both types of insulin, as previously stated. Formyl-methionyl-leucyl-phenylalanine (fMLP) and lipopolysaccharide (LPS) were used as controls.


RESULTS
Neither insulin recovered from the pump reservoir nor vial insulin proved chemotactic to macrophages from either healthy subjects or those diabetic patients with and without catheter obstruction. The migration toward fMLP of macrophages from patients presenting a catheter obstruction was significantly higher than that observed with macrophages from either diabetic patients without obstruction or healthy subjects, the chemotactic index (mean +/- SD) was 3.81 +/- 0.36 vs. 2.30 +/- 0.89 and 2.60 +/- 0.80, respectively (P < 0.05). LPS significantly stimulated the TNF-alpha secretion of macrophages from diabetic subjects with a catheter obstruction, whereas both native and reservoir-recovered insulin had no effect on this release (144.83 +/- 67.25 vs. 5.15 +/- 2.93 and 5.27 +/- 2.43 pg/ml, P < 0.001).


CONCLUSIONS
The human insulin used in implantable pumps, regardless of how long it had remained in the pump reservoir, did not induce macrophage activation in diabetic patients treated through intraperitoneal insulin delivery. In some of these diabetic patients, catheter obstruction could be explained by their high capacity of macrophage chemotaxis.
Kessler
L
L
Department of Endocrinology-Diabetology, University Hospital, Strasbourg, France. laurence.kessler@medecine.u-strasbg.fr
Tritschler
S
S
Bohbot
A
A
Sigrist
S
S
Karsten
V
V
Boivin
S
S
Dufour
P
P
Belcourt
A
A
Pinget
M
M
D000328:Adult; D002404:Catheterization / Q000295:instrumentation; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects; D003470:Culture Media; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D015918:Infusion Pumps, Implantable / Q000009:adverse effects*; D007328:Insulin / Q000494:pharmacology; D007332:Insulin Infusion Systems / Q000009:adverse effects*; D008262:Macrophage Activation; D008297:Male; D008875:Middle Aged; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D003470:Culture Media; D007328:Insulin; D014409:Tumor Necrosis Factor-alpha; D009240:N-Formylmethionine Leucyl-Phenylalanine