Insulin-like growth factor-I decreases serum lipoprotein (a) during long-term treatment of patients with Laron syndrome.
An increased circulating level of lipoprotein(a) [Lp(a)] is a well-recognized risk factor for coronary artery disease. While much remains to be understood about its regulation and physiological functions, we explored the effect of recombinant insulin-like growth factor-I (IGF-I) administration on circulating Lp(a) levels in 10 Laron syndrome (LS) patients (five children and five adults) with inherited IGF-I deficiency. There was no relationship between pretreatment or posttreatment Lp(a) levels and age and sex of the patients. With IGF-I treatment for 6 to 12 months, there was a significant reduction in Lp(a) (65.7% +/- 15.5%, P < .0001) from the pretreatment level of 76 +/- 45 mg/L to the posttreatment level of 29 +/- 26 mg/L. This decrease was dosage-dependent on the IGF-I administered (r = .685, F = 0.708, P = .029) and correlated more strongly with the dosage ratio of the end to the beginning of treatment (r = .78, F = 12.23, P = .008). The higher the IGF-I dose and the higher the dose ratio, the greater the Lp(a) decrease and the lower the Lp(a) at the end of treatment. In conclusion, we observed a dose-dependent relationship between IGF-I administration and Lp(a) reduction in patients with LS. Further studies are needed to elucidate the mechanism of the effect, but our findings suggest a possible metabolic link between these two and shed more light on the regulation of apolipoprotein(a) [apo(a)] expression. It could also open an avenue for additional therapeutic usage of IGF-I.
Laron
Z
Z
Endocrinology and Diabetes Research Unit, Schneider Children's Hospital, Petal Tikva, Israel.
Wang
X L
XL
Klinger
B
B
Silbergeld
A
A
Wilcken
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DE
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007223:Infant; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000627:therapeutic use*; D017270:Lipoprotein(a) / Q000097:blood*; D008297:Male; D011986:Receptors, Somatotropin / Q000097:blood / Q000172:deficiency*; D013577:Syndrome; D013997:Time Factors
D017270:Lipoprotein(a); D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I