title: Reduced capillary hydraulic conductivity in skeletal muscle and skin in Type I diabetes: a possible cause for reduced transcapillary fluid absorption during hypovolaemia.
abstract: OBJECTIVE
  Patients with Type I (insulin-dependent) diabetes mellitus have a reduced transcapillary fluid absorption from skeletal muscle and skin and thus defective plasma volume regulation during hypovolaemia. Our aim was to find whether a defective capillary filtration coefficient or impaired transcapillary driving force are aetiologic factors for this reduction.
  
  
  METHODS
  We investigated 11 diabetic patients (diabetes duration 6.9 +/- 1.1 years, age 26 +/- 1 years), without complications and 12 control subjects (26 +/- 1 years). Their capillary filtration coefficient was measured in the upper arm using a volumetric technique at rest and during lower body negative pressure (LBNP). We calculated the driving force for transcapillary fluid transfer.
  
  
  RESULTS
  The increase in heart rate and the decrease in systolic blood pressure during lower body negative pressure were similar in diabetic and control subjects. The resting capillary filtration coefficient was decreased in the diabetic subjects, 0.033 +/- 0.003 vs 0.051 +/- 0.007 ml x 100 ml(-1) x min(-1) x mmHg(-1) (p < 0.05). During lower body negative pressure, the capillary filtration coefficient increased 35 % in both groups compared with resting capillary filtration coefficient and was still decreased in diabetes; 0.046 +/- 0.004 compared with 0.069 +/- 0.006 ml x 100ml(-1) x min(-1) x mmHg(-1) (p < 0.01). The established driving force during lower body negative pressure was 1.37 +/- 0.11 vs 1.30 +/- 0.15 mmHg (NS) in diabetic and control subjects, respectively.
  
  
  CONCLUSIONS
  Our study indicates that a reduced capillary filtration coefficient rather than defective regulation of transcapillary driving force, is the reason for the reduced transcapillary fluid absorption during hypovolaemic circulatory stress found in Type I diabetic patients.
authors.affiliation: Department of Endocrinology, Lund University, Malmö University Hospital, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Olsen
authors.forename: T
authors.initials: T
authors.lastname: Länne
mesh_terms: D000328:Adult; D001794:Blood Pressure; D002196:Capillaries / Q000502:physiology / Q000503:physiopathology*; D002199:Capillary Permeability / Q000502:physiology*; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D004562:Electrocardiography; D006339:Heart Rate; D006801:Humans; D020896:Hypovolemia / Q000503:physiopathology*; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply*; D010991:Plethysmography; D012016:Reference Values; D012867:Skin / Q000098:blood supply*