A common polymorphism in the promoter of the IGF-I gene associates with increased fasting serum triglyceride levels in glucose-tolerant subjects

Higher triglyceride levels are associated with the higher prevalence of layered plaques in non-culprit coronary plaques

High triglyceride (TG) levels have been recognized as a risk factor for cardiovascular events in patients with coronary artery disease (CAD). This study aimed to clarify the association between TG levels and characteristics of non-culprit coronary plaques in patients with CAD. A total of 531 consecutive patients with stable CAD who underwent percutaneous coronary intervention for culprit lesions and optical coherence tomography (OCT) assessment of non-culprit plaques in the culprit vessel were included in this study. The morphology of the non-culprit plaques assessed by OCT imaging were compared between the higher TG (TG ≥ 150 mg/dL, n = 197) and lower TG (TG < 150 mg/dL, n = 334) groups. The prevalence of layered plaques (40.1 vs. 27.5%, p = 0.004) was significantly higher in the higher TG group than in the lower TG group, although the prevalence of other plaque components was comparable between the two groups. High TG levels were an independent factor for the presence of layered plaques (odds ratio 1.761, 95% confidence interval 1.213-2.558, p = 0.003) whereas high low-density lipoprotein cholesterol levels (≥ 140 mg/dL) and low eicosapentaenoic acid/arachidonic acid ratios (< 0.4) were independently associated with a higher prevalence of thin-cap fibroatheroma and macrophages. Higher TG levels were associated with a higher prevalence of layered plaques in non-culprit plaques among patients with stable CAD. These results may partly explain the effect of TG on the progression of coronary plaques and the increased incidence of recurrent events in patients with CAD.

The association between serum lipid profile and the prostate cancer risk and aggressiveness

Purpose

This study aims to evaluate the association of serum lipid profile on prostate cancer (PC) risk and aggressiveness.

Methods

Men who underwent prostate biopsy between January 2005 and December 2015 were retrospectively analyzed. The association between lipid profile and the risk, stage, and Gleason grade group (GG) of the PC were investigated. Sensitivity analysis was conducted using univariate and multivariate quantile analysis for lipide profile on the risk and stage of PC.

Results

Of the 1740 study populations, 720 men (41.4%) were diagnosed as PC. From multivariate logistic regression analysis, age, prostate specific antigen, triglyceride (odds ratio (OR):1.05, confidence interval (CI):1.03-1.07, p-value<0.001) significantly increased PC risk, while total cholesterol (OR:0.96, CI:0.92-0.99, p-value=0.011) significantly decreased the PC risk. The increase of serum triglyceride increased the risk of both of locally advanced (OR:1.03, CI:1.00-1.07, p-value=0.025) and metastatic PC (OR:1.14, CI:1.04-1.25, p-value=0.004). The increase of serum triglyceride increased the risk of GG2-3 (OR:1.03, CI:1.00-1.06, p-value=0.027) and GG4-5 (OR:1.04, CI:1.01-1.08, p-value=0.027). Univariate quartile analysis founded serum triglyceride increasing risk of locally advanced disease than organ confined disease. (OR: 1.00, 1.25, 2.04, 4.57 for 1^st, 2^nd, 3^rd and 4^th quartile, p-value<0.001). Adjusted multivariate quartile analysis confirmed statistically significant increasing PC risk of triglyceride (OR: 1.00, 1.25, 2.04, 4.57 for 1^st, 2^nd, 3^rd and 4^th quartile, p-value<0.001).

Conclusions

This study findings suggested increased in triglyceride level increased the risk PC. Increased in triglyceride level also associated with aggressive presentation of PC, with higher stage and GG.

Investigation of the Interplay between Circulating Lipids and IGF-I and Relevance to Breast Cancer Risk: An Observational and Mendelian Randomization Study

BACKGROUND

Circulating lipids and insulin-like growth factor 1 (IGF-I) have been reliably associated with breast cancer. Observational studies suggest an interplay between lipids and IGF-I, however, whether these relationships are causal and if pathways from these phenotypes to breast cancer overlap is unclear.

METHODS

Mendelian randomization (MR) was conducted to estimate the relationship between lipids or IGF-I and breast cancer risk using genetic summary statistics for lipids (low-density lipoprotein cholesterol, LDL-C; high-density lipoprotein cholesterol, HDL-C; triglycerides, TGs), IGF-I and breast cancer from GLGC/UKBB (N = 239,119), CHARGE/UKBB (N = 252,547), and Breast Cancer Association Consortium (N = 247,173), respectively. Cross-sectional observational and MR analyses were conducted to assess the bi-directional relationship between lipids and IGF-I in SHIP (N = 3,812) and UKBB (N = 422,389), and using genetic summary statistics from GLGC (N = 188,577) and CHARGE/UKBB (N = 469,872).

RESULTS

In multivariable MR (MVMR) analyses, the OR for breast cancer per 1-SD increase in HDL-C and TG was 1.08 [95% confidence interval (CI), 1.04-1.13] and 0.94 (95% CI, 0.89-0.98), respectively. The OR for breast cancer per 1-SD increase in IGF-I was 1.09 (95% CI, 1.04-1.15). MR analyses suggested a bi-directional TG-IGF-I relationship (TG-IGF-I β per 1-SD: -0.13; 95% CI, -0.23 to -0.04; and IGF-I-TG β per 1-SD: -0.11; 95% CI, -0.18 to -0.05). There was little evidence for a causal relationship between HDL-C and LDL-C with IGF-I. In MVMR analyses, associations of TG or IGF-I with breast cancer were robust to adjustment for IGF-I or TG, respectively.

CONCLUSIONS

Our findings suggest a causal role of HDL-C, TG, and IGF-I in breast cancer. Observational and MR analyses support an interplay between IGF-I and TG; however, MVMR estimates suggest that TG and IGF-I may act independently to influence breast cancer.

IMPACT

Our findings should be considered in the development of prevention strategies for breast cancer, where interventions are known to modify circulating lipids and IGF-I.

miR‑181d promotes cell proliferation via the IGF1/PI3K/AKT axis in glioma

Glioma is a malignant brain cancer that exhibits high invasive ability and poor prognosis. MicroRNA (miR)-181d has been reported to be involved in the development of glioma. Therefore, the aim of the present study was to investigate whether miR-181d affected cellular progression by influencing the insulin like growth factor (IGF1)/PI3K/AKT axis. Western blot analysis was performed to analyze the expression levels of specific proteins, and a Cell Counting Kit-8 assay was used to assess the proliferative ability of cells. Cell cycle progression and cellular apoptosis were both measured using flow cytometry. The results indicated that miR-181d promoted cellular proliferation and cell cycle progression, while suppressing cellular apoptosis via the IGF1/PI3K/AKT axis. It was demonstrated that the IGF1 and PI3K/AKT inhibitors reversed these observed functions of miR-181d. Furthermore, miR-181d enhanced the growth of glioma xenografts in vivo, promoted cell cycle progression and suppressed cellular apoptosis within glioma xenograft tissues. Therefore, this newly identified miR-181d/IGF1/PI3K/AKT axis may provide novel insights into the pathogenesis of glioma.

IGF1 Gene Is Associated With Triglyceride Levels In Subjects With Family History Of Hypertension From The SAPPHIRe And TWB Projects

Chromosome 12q23-q24 has been linked to triglyceride (TG) levels by previous linkage studies, and it contains the Insulin-like growth factor 1 (IGF1) gene. We investigated the association between IGF1 and TG levels using two independent samples collected in Taiwan. First, based on 954 siblings in 397 families from the Stanford Asian Pacific Program in Hypertension and Insulin Resistance (SAPPHIRe), we found that rs978458 was associated with TG levels (β = -0.049, p = 0.0043) under a recessive genetic model. Specifically, subjects carrying the homozygous genotype of the minor allele had lower TG levels, compared with other subjects. Then, a series of stratification analyses in a large sample of 13,193 unrelated subjects from the Taiwan biobank (TWB) project showed that this association appeared in subjects with a family history (FH) of hypertension (β = -0.045, p = 0.0000034), but not in subjects without such an FH. A re-examination of the SAPPHIRe sample confirmed that this association appeared in subjects with an FH of hypertension (β = -0.068, p = 0.0025), but not in subjects without an FH. The successful replication in two independent samples indicated that IGF1 is associated with TG levels in subjects with an FH of hypertension in Taiwan.

Insulin-like growth factor 1 gene (CA)n repeats and a variable number of tandem repeats of the insulin gene in Brazilian children born small for gestational age

OBJECTIVE

To investigate the influence of (CA)n repeats in the insulin-like growth factor 1 gene and a variable number of tandem repeats of the insulin gene on birth size in children who are small or adequate-sized for gestational age and to correlate these polymorphisms with serum insulin-like growth factor 1 levels and insulin sensitivity in children who are small for gestational age, with and without catch-up growth.

PATIENTS AND METHODS

We evaluated 439 infants: 297 that were adequate-sized for gestational age and 142 that were small for gestational age (66 with and 76 without catch-up). The number of (CA)n repeat in the insulin-like growth factor 1 gene and a variable number of tandem repeats in the insulin gene were analyzed using GENESCAN software and polymerase chain reaction followed by enzymatic digestion, respectively. Clinical and laboratory data were obtained from all patients.

RESULTS

The height, body mass index, paternal height, target height and insulin-like growth factor 1 serum levels were higher in children who were small for gestational age with catch-up. There was no difference in the allelic and genotypic distributions of both polymorphisms between the adequate-sized and small infants or among small infants with and without catch-up. Similarly, the polymorphisms were not associated with clinical or laboratory variables.

CONCLUSION

Polymorphisms of the (CA)n repeats of the insulin-like growth factor 1 gene and a variable number of tandem repeats of the insulin gene, separately or in combination, did not influence pre- or postnatal growth, insulin-like growth factor 1 serum levels or insulin resistance.

Genetic association and sequencing of the insulin-like growth factor 1 gene in bipolar affective disorder

Insulin-like growth factor 1 (IGF1) has been shown to have an important role in brain development and function. Studies of IGF1 administration in rodents have shown that it has an anxiolytic and antidepressant effect. A genome-wide association study (GWAS) of the first University College London (UCL) cohort of 506 bipolar affective disorder subjects and 510 controls was carried out. The exons and flanking regions of IGF1 were resequenced, any new polymorphisms found were genotyped in an enlarged UCL sample of 937 cases and 941 controls. GWAS data gave good evidence of allelic and haplotypic association between multiple IGF1 SNP's and bipolar disorder (BD). New polymorphisms were found by resequencing IGF1 region. Data from GWAS and the new markers showed that twelve out of 43 SNPs showed association with BD with the four most significant SNPs having values of 3.7 × 10(-5) , 8.4 × 10(-4) , 2.6 × 10(-4) , and 2.5 × 10(-4) . A 5' promoter microsatellite polymorphism previously correlated with plasma lipoprotein concentration was also associated with BD (P = 0.013). Haplotypic association confirmed association with BD with significance values similar to the single marker SNP values. The marker rs12426318 has also been found to be associated with BD in a second sample. A test of gene wide significance with permutation testing for all markers genotyped at IGF1 was also significant. These data implicate IGF1 as a candidate gene to cause genetic susceptibility to BD.

Molecular genetics of human growth hormone, insulin-like growth factors and their pathways in common disease

The human growth hormone gene (GH1) and the insulin-like growth factor 1 and 2 genes (IGF1 and IGF2) encode the central elements of a key pathway influencing growth in humans. This "growth pathway" also includes transcription factors, agonists, antagonists, receptors, binding proteins, and endocrine factors that constitute an intrincate network of feedback loops. GH1 is evolutionarily coupled with other genes in linkage disequilibrium in 17q24.2, and the same applies to IGF2 in 11p15.5. In contrast, IGF1 in 12q22-24.1 is not in strong linkage disequilibrium with neighbouring genes. Knowledge of the functional architecture of these regions is important for the understanding of the combined evolution and function of GH1, IGF2 and IGF1 in relation to complex diseases. A number of mutations accounting for rare Mendelian disorders have been described in GH-IGF elements. The constellation of genes in this key pathway contains potential candidates in a number of complex diseases, including growth disorders, metabolic syndrome, diabetes (notably IGF2BP2) cardiovascular disease, and central nervous system diseases, and in longevity, aging and cancer. We review these genes and their associations with disease phenotypes, with special attention to metabolic risk traits.

Impaired skeletal growth in mice with haploinsufficiency of IGF-I: genetic evidence that differences in IGF-I expression could contribute to peak bone mineral density differences

Although it is well established that there is considerable inter-individual variation in the circulating levels of IGF-I in normal, healthy individuals and that a genetic component contributes substantially to this variation, the direct evidence that inter-individual variation in IGF-I contributes to differences in peak bone mineral density (BMD) is lacking. To examine if differences in IGF-I expression could contribute to peak BMD differences, we measured skeletal changes at days 23 (prepubertal), 31 (pubertal) and 56 (postpubertal) in mice with haploinsufficiency of IGF-I (+/-) and corresponding control mice (+/+). Mice (MF1/DBA) heterozygous for the IGF-I knockout allele were bred to generate +/+ and +/- mice (n=18-20 per group). Serum IGF-I was decreased by 23% (P<0.001) in mice with IGF-I haploinsufficiency (+/-) group at day 56 compared with the control (+/+) group. Femoral bone mineral content and BMD, as determined by dual energy X-ray absorptiometry, were reduced by 20% (P<0.001) and 12% respectively in the IGF-I (+/-) group at day 56 compared with the control group. The peripheral quantitative computed tomography measurements at the femoral mid-diaphysis revealed that periosteal circumference (7%, P<0.01) and total volumetric BMD (5%, P<0.05) were decreased significantly in the +/- group compared with the +/+ group. Furthermore, serum IGF-I showed significant positive correlations with both areal BMD (r=0.55) and periosteal circumference (r=0.66) in the pooled data from the +/+ and +/- groups. Our findings that haploinsufficiency of IGF-I caused significant reductions in serum IGF-I level, BMD and bone size, together with the previous findings, are consistent with the notion that genetic variations in IGF-I expression could, in part, contribute to inter-individual differences in peak BMD among a normal population.