4 replies to this topic

[liorrh]

there is sort of a villainiffication of IGF-I due to its apparent role in tumors etc, but I beg the differ.

here is one example

: Neurobiol Aging. 2005 Dec 6; [Epub ahead of print] Related Articles, Links 

Plasma IGF-I levels and cognitive performance in older women.

Okereke O, Kang JH, Ma J, Hankinson SE, Pollak MN, Grodstein F.

Division of Aging, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, 3rd floor, 181 Longwood Avenue, Boston, MA 02115, USA; Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, 3rd floor, 181 Longwood Avenue, Boston, MA 02115, USA.

BACKGROUND: Emerging biologic and epidemiologic evidence suggests benefits of insulin-like growth factor-I (IGF-I) in cognitive aging. OBJECTIVE: To examine the relation of circulating IGF-I to cognition. METHODS: We measured plasma IGF-I and IGF-binding protein-3 (IGFBP-3) in 590 women aged 60-68 years. An average 10 years later, we administered telephone-based tests of general cognition (Telephone Interview of Cognitive Status [TICS]), verbal memory, category fluency, and attention. We estimated multivariable-adjusted mean differences in performance across levels of IGF-I/IGFBP-3 molar ratio. RESULTS: On the TICS, each standard deviation (S.D.) increase in molar ratio was significantly associated with better performance: multivariable-adjusted mean difference=0.2 units, 95% confidence interval (0.0,0.4), p=0.05. This effect estimate for each S.D. increase in molar ratio was cognitively equivalent to the mean difference we observed on the TICS between women 1 year apart in age. On a global score combining all tests, there was also a trend of better performance with each S.D. increase in molar ratio (p=0.07). IGF-I levels were not associated with performance in verbal memory. CONCLUSIONS: Higher IGF-I levels may be associated with better general cognition.

PMID: 16337715

[liorrh]

IGF inversly correlated to arthrosclerotic risk factors.

J Endocrinol Invest. 2005 May;28(5):440-8. Related Articles, Links 


Circulating insulin-like growth factor-I levels are correlated with the atherosclerotic profile in healthy subjects independently of age.

Colao A, Spiezia S, Di Somma C, Pivonello R, Marzullo P, Rota F, Musella T, Auriemma RS, De Martino MC, Lombardi G.

Department of Molecular and Clinical Endocrinology and Oncology, "Federico II" University, Naples, Italy. colao@unina.it

To investigate the relationships between the GH-IGF-I axis and the atherosclerotic profile, we designed this open, observational, prospective study. Peak GH after GHRH+arginine (ARG) test, serum IGF-I and IGF binding protein-3 (IGFBP-3), lipid profile, homeostasis model assessment (HOMA) index and intima-media thickness (IMT) at common carotid arteries were measured in 174 healthy individuals (92 women, 82 men, aged 18-80 yr). Exclusion criteria for this study were: 1) body mass index (BMI) > or = 30 kg/m2; 2) personal history of cardiovascular diseases; 3) previous or current treatments of diabetes or hypertension; 4) previous corticosteroids treatment for longer than 2 weeks or estrogens for longer than 3 months; 5) smoking of more than 15 cigarettes/day and alcohol abuse. Subjects were divided according to age in decade groups from < 20 to > 70 yr. BMI increased with age, as did systolic and diastolic blood pressures, although they remained in the normal range. The GH peak after GHRH+ARG test was significantly higher in the subjects aged < 20 yr than in all the other groups (p < 0.01), but was similar in the remaining groups. An inverse correlation was found between the IGF-I z-score and total/HDL-cholesterol ratio (p = 0.02) and mean IMT (p = 0.0009); IGFBP-3 z-score and mean IMT (p = 0.043); IGF: IGFBP-3 molar ratio and total/HDL-cholesterol ratio (p < 0.0001) and mean IMT (p < 0.0001). Atherosclerotic plaques were found in 7 out of 12 subjects (53.8%) with a z-IGF-I score from < or = -2 to -1, in 4 out of 63 (6.3%) with a z-IGF-I score from -0.99 to 0.1 out of 66 (1.5%) with a z-IGF-I score from 0.1 to 1 and none of the 33 subjects with an IGF-I z-score >1 (p = 0.006). At multi-step regression analysis, age was the best predictor of HDL-cholesterol levels and mean IMT, IGF-I level was the best predictor of total cholesterol and total/HDL-cholesterol ratio, the IGF-I/IGFBP-3 molar ratio was the best predictor of triglycerides levels. The z-scores of IGF-I and IGFBP-3 were the second best predictors of mean IMT after age. In conclusion, IGF-I and IGFBP-3 were negatively correlated with common cardiovascular risk factors, studied as total/HDL-cholesterol ratio, and/or early atherosclerosis, studied as IMT at common carotid arteries. The prevalence of atherosclerotic plaques, though not hemodinamically significant, was higher in the subjects having a z-score of IGF-I of < or = -2 to -1. Our results support a role of the IGF/IGFBP-3 axis in the pathogenesis of atherosclerosis.

PMID: 16075928

[Mind]

I don't have a study to link to (so feel free to delete this post if it doesn't fit within your thread), but as seems to be the case with all growth factors and hormones used for anti-aging/rejuvenation there seems to be a built in resistance to use by average healthy individuals. HGH, IGF, other hormones, etc...are generally villified, I think, because they are not "natural" treatments...and by that I mean these things do not naturally occur in high levels in people who is older than 25. They can be used to enhance athletic and mental performance, and many people are uncomfortable with that.

[liorrh]

....many people are also uncomfortable with immortality.
what are yous saying my friend? "not natural"? is that the argument?I agree that chronic systematic IGF thrapy is usually too crude i.e. has too many effects,. but some may benefit, including in the LE category, and even more so GH.

[liorrh]

IGF inversly correlated to ischemic stroke risk

J Clin Endocrinol Metab. 2005 Nov;90(11):5937-41. Epub 2005 Aug 30. Related Articles, Links 

Insulin-like growth factor (IGF) I, -II, and IGF binding protein-3 and risk of ischemic stroke.

Johnsen SP, Hundborg HH, Sorensen HT, Orskov H, Tjonneland A, Overvad K, Jorgensen JO.

Department of Clinical Epidemiology, Aarhus University Hospital, Ole Worms Alle 150, DK-8000 Aarhus C, Denmark. spj@dce.au.dk

BACKGROUND: Low IGF-I levels may be associated with the development of stroke; however, prospective data appear to be unavailable. METHODS: This was a nested case-control study within a Danish follow-up study, including 57,053 men and women. Baseline data included circulating IGF-I, IGF-II, and IGF binding protein (IGFBP)-3 concentrations as well as lifestyle factors and medical history. We identified 254 cases with incident ischemic stroke and 254 gender- and age-matched controls. RESULTS: Participants in the bottom quartiles of IGF-I and IGFBP-3 levels (median concentrations, 72 and 2937 ng/ml, respectively) were at increased risk of ischemic stroke, e.g. adjusted odds ratios (ORs) of 2.06 [95% confidence interval (CI), 1.05-4.03] and 2.29 (95% CI, 1.17-4.49), respectively, when compared with participants in the top quartiles (median concentrations, 125 and 4835 ng/ml, respectively). A negative, although weaker, association was also found for IGF-II (adjusted OR 1.44, 95% CI 0.79-2.64) when comparing the bottom quartile with the top quartile. No substantial associations were seen for IGF-I and IGF-II when also adjusting for IGFBP-3; adjusting IGFBP-3 for IGF-I and -II had only a minor impact on the risk estimates. CONCLUSION: These findings give some support to the hypothesis that the IGF axis is involved in the pathogenesis of ischemic stroke.

PMID: 16131586