Alterations of lipoprotein subfractions in GH-deficient adults.

GH-unsubstituted patients had lower apolipoprotein A1 compared to controls and higher apolipoprotein B100 compared to GH-substituted patients.

• GHU patients demonstrated lower apolipoprotein A1 compared to controls (p=0.02)
• GHU patients showed higher apolipoprotein B100 compared to GHS patients (p=0.02)
• Standard lipid parameters, apoM, and apoL1 levels were not different between the groups
• Study included 11 GH-substituted patients, 9 GH-unsubstituted patients, and 37 controls

Both GH-unsubstituted and GH-substituted patients showed higher sphingosine 1-phosphate (S1P) levels compared to controls.

• GHU patients showed higher S1P compared to controls (p=0.04)
• GHS patients showed higher S1P compared to controls (p=0.01)
• S1P was determined by ELISA
• ApoL1, apoM, and S1P were among the novel biomarkers measured in addition to lipoprotein subfractions

Both GH-unsubstituted and GH-substituted patients showed higher percentages of intermediate-density lipoprotein (IDL) compared to controls.

• GHU patients had higher percentage of IDL compared to controls (p=0.03)
• GHS patients had higher percentage of IDL compared to controls (p=0.01)
• Lipoprotein subfractions were separated using the Lipoprint system
• Mean LDL size was lower in GHU compared to GHS patients (p=0.04)

Intermediate HDL percentage was lower in both GH-unsubstituted and GH-substituted patients compared to controls, while small HDL percentage was higher in GH-unsubstituted patients.

• Percentage of intermediate HDL was lower in GHU compared to controls (p<0.001)
• Percentage of intermediate HDL was lower in GHS compared to controls (p<0.01)
• GHU demonstrated higher percentage of small HDL than controls (p<0.001)
• These HDL subfraction differences were not reflected in standard lipid parameters

Log10IGF-1 correlated positively with large and intermediate HDL subfractions and negatively with small HDL subfraction across all subjects.

• Log10IGF-1 correlated positively with percentage of large HDL (r=0.27; p=0.04)
• Log10IGF-1 correlated positively with percentage of intermediate HDL (r=0.38; p<0.01)
• Log10IGF-1 correlated negatively with percentage of small HDL (r=-0.46; p<0.01)
• Log10IGF-1 was the best predictor of small HDL in overall subjects (standardized β=-0.46; p<0.001)

In the GH-withdrawal study, GH discontinuation increased HDL-6 amount and GH reinstitution increased IDL percentage.

• The amount of HDL-6 increased with GH-withdrawal (p=0.03)
• The percentage of IDL increased with reinstitution of GH-replacement (p=0.05)
• GH-replacement was discontinued for 2 months in the 11 GHS patients
• Measurements were performed before GH-discontinuation, at the end of the 2-month GH-withdrawal, and 1 month after reinstituting GH-replacement
• No changes in standard lipid parameters were observed during the withdrawal study