Serum IGF-I Levels Correlate to Improvement of Functional Outcome after Ischemic Stroke

Abstract

GH has positive cognitive effects when given to GH-IGF-I-deficient patients. GH and IGF-I exert both neuroprotective and regenerative effects on experimental stroke. We investigated whether the endogenous serum IGF-I (s-IGF-I) levels correlated with recovery of functional independence in patients who had suffered an ischemic stroke. The s-IGF-I levels were measured in 407 patients (260 males, 147 females) with mean age of 55 (range, 18-69) yr and 40 randomly selected matched controls who were previously included in the Sahlgrenska Academy Study on Ischemic Stroke. Serum samples were collected on two occasions: acutely at 1-10 d (median, 4 d) after stroke and 3 months after the stroke. Recovery after ischemic stroke was evaluated using the modified Rankin scale 3 and 24 months after the stroke, and the Scandinavian Stroke Scale was used for assessments during the acute stage and 3 months after the stroke. The s-IGF-I levels were higher in the acute stage than after 3 months and compared with the controls (P < 0.001 and P < 0.01, respectively), and the s-IGF-I levels were progressively lower in the elderly patients. The levels of s-IGF-I in the acute phase and after 3 months both positively correlated with improvement in the modified Rankin scale scores between 3 and 24 months (P = 0.001; r = 0.174, and P < 0.001; r = 0.24, respectively). A high s-IGF-I during the rehabilitation phase of stroke correlates to better recovery of long-term function.