GH and IGF-I deficiency are associated with reduced loss of fat mass after laparoscopic-adjustable silicone gastric banding.
BACKGROUND
GH secretion is reduced in obese subjects and increases after body weight loss. It is still unclear if changes in the GH/IGF-I axis after laparoscopic-adjustable silicone gastric banding (LASGB) are associated with changes of body composition.


OBJECTIVE
To analyse the relationships between changes in the GH/IGF-I axis and those of body weight and composition before and after LASGB.


METHODS
Observational, prospective.


METHODS
University 'Federico II' of Naples (Italy).


METHODS
Seventy-two severely obese females (BMI: 44.9 +/- 4.68; mean age: 33.1 +/- 11.34 years) were studied.


METHODS
GH peak after GHRH plus arginine test, IGF-I, IGFBP-3 and ALS levels, fat mass (FM) and free fat mass (FFM) (by Bioelectrical Impedance Analysis) at baseline and 6 months after LASGB. The change in percentage of individual variables was calculated as well as that of excess of body weight loss (EBWL%). The FM%, FFM% and EBWL% were correlated with peak GH and IGF-I levels changes.


RESULTS
At baseline, GH deficiency (GHD) (GH peak = 4.1 microg/l) was found in 22 patients (31%), 16 of them also had IGF-I deficiency (< -2SDS). IGF-I levels were inversely correlated with waist circumference (r = -0.72, P < 0.001) and FM% (r = -0.75, P < 0.001). Post-LASGB the patients were classified as follows: group (1) GH and IGF-I sufficient (n = 44; 61.1%); group (2) GH and IGF-I deficient (n = 14; 19.4%) and group (3) GH sufficient and IGF-I deficient (n = 14; 19.4%). The percentage changes of EWBL (P < 0.05, P = 0.051, respectively) and FM (P < 0.001, P < 0.01, respectively) were lower in groups (2) and (3) than in group (1). At the stepwise linear regression analysis, postoperative IGF-I levels were the strongest determinant of percent changes of FM (P < 0.0001), of FFM (P = 0.009) and of EBWL (P < 0.0001).


CONCLUSIONS
IGF-I levels is the most sensitive to unfavourable changes in body composition 6 months after LASGB making investigation of the somatotropic axis useful in the evaluation of bariatric surgery outcomes.
Di Somma
Carolina
C
Department of Molecular and Clinical Endocrinology and Oncology, Division of Endocrinology, University Federico II of Naples, Naples, Italy. cdisomma@unina.it
Angrisani
Luigi
L
Rota
Francesca
F
Savanelli
Maria Cristina
MC
Cascella
Teresa
T
Belfiore
Annamaria
A
Orio
Francesco
F
Lombardi
Gaetano
G
Colao
Annamaria
A
Savastano
Silvia
S
D000273:Adipose Tissue / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D001823:Body Composition / Q000502:physiology; D005260:Female; D015391:Gastroplasty / Q000379:methods*; D006130:Growth Disorders / Q000097:blood / Q000473:pathology / Q000503:physiopathology*; D019382:Human Growth Hormone / Q000097:blood / Q000172:deficiency*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000172:deficiency*; D010535:Laparoscopy / Q000379:methods; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D011379:Prognosis; D012826:Silicone Elastomers / Q000627:therapeutic use; D015431:Weight Loss / Q000502:physiology*; D055815:Young Adult
D012826:Silicone Elastomers; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I