Interaction between insulin-like growth factor-1 and atherosclerosis and vascular aging

The Association Between Oxidative Stress and Sperm Parameters in Patients with Acromegaly

OBJECTIVE

Spermatozoa are susceptible to oxidative radicals when antioxidant defenses are inadequate. The extent to which oxidative radicals contribute to sperm damage in patients with acromegaly remains unclear. This study aimed to investigate and elucidate this relationship.

METHODS

The overall status of oxidants and antioxidants in both seminal plasma and serum of patients with acromegaly compared to a control group of healthy individuals was investigated. In addition, sperm parameters, including important measures such as growth hormone and insulin-like growth factor-1 concentrations.

RESULTS

Twenty-two patients with acromegaly with controlled disease and 14 healthy controls were included. The total oxidant status was significantly higher in the semen samples of the patients with acromegaly. A negative correlation was found between sperm total oxidant status and total sperm count and sperm concentration. Similarly, a negative correlation was found between the total sperm count and the sperm oxidative stress index. In individuals diagnosed with acromegaly, there was a statistically significant increase in sperm growth hormone levels. Conversely, the level of insulin-like growth factor 1 was significantly increased in the sperm of the control group, which consisted of healthy individuals. The correlation analysis revealed a significant relationship between venous total oxidant status and growth hormone levels in semen.

CONCLUSION

The elevated levels of reactive oxygen radicals in individuals with acromegaly suggest a possible link between oxidative stress and its effects on semen quality.

New Insights into IGF-1 Signaling in the Heart

Insulin-like growth factor-1 (IGF-1) signaling has multiple physiological roles in cellular growth, metabolism, and aging. Myocardial hypertrophy, cell death, senescence, fibrosis, and electrical remodeling are hallmarks of various heart diseases and contribute to the progression of heart failure. This review highlights the critical role of IGF-1 and its cognate receptor in cardiac hypertrophy, aging, and remodeling.

The involvement of Akt, mTOR, and S6K in the in vivo effect of IGF-1 on the regulation of rat cardiac Na+/K+-ATPase

BACKGROUND

We previously demonstrated that insulin-like growth factor-1 (IGF-1) regulates sodium/potassium adenosine triphosphatase (Na+/K+-ATPase) in vascular smooth muscle cells (VSMC) via phosphatidylinositol-3 kinase (PI3K). Taking into account that others' work show that IGF-1 activates the PI3K/protein kinase B (Akt) signaling pathway in many different cells, we here further questioned if the Akt/mammalian target of rapamycin (mTOR)/ribosomal protein p70 S6 kinase (S6K) pathway stimulates Na+/K+-ATPase, an essential protein for maintaining normal heart function.

METHODS AND RESULTS

There were 14 adult male Wistar rats, half of whom received bolus injections of IGF-1 (50 μg/kg) for 24 h. We evaluated cardiac Na+/K+-ATPase expression, activity, and serum IGF-1 levels. Additionally, we examined the phosphorylated forms of the following proteins: insulin receptor substrate (IRS), phosphoinositide-dependent kinase-1 (PDK-1), Akt, mTOR, S6K, and α subunit of Na+/K+-ATPase. Additionally, the mRNA expression of the Na+/K+-ATPase α1 subunit was evaluated. Treatment with IGF-1 increases levels of serum IGF-1 and stimulates Na+/K+-ATPase activity, phosphorylation of α subunit of Na+/K+-ATPase on Ser23, and protein expression of α2 subunit. Furthermore, IGF-1 treatment increased phosphorylation of IRS-1 on Tyr1222, Akt on Ser473, PDK-1 on Ser241, mTOR on Ser2481 and Ser2448, and S6K on Thr421/Ser424. The concentration of IGF-1 in serum positively correlates with Na+/K+-ATPase activity and the phosphorylated form of mTOR (Ser2448), while Na+/K+-ATPase activity positively correlates with the phosphorylated form of IRS-1 (Tyr1222) and mTOR (Ser2448).

CONCLUSION

These results indicate that the Akt/mTOR/S6K signalling pathway may be involved in the IGF-1 regulating cardiac Na+/K+-ATPase expression and activity.

GWAS-identified hyperuricemia-associated IGF1R variant rs6598541 has a limited role in urate mediated inflammation in human mononuclear cells

Gout is a common autoinflammatory joint diseases characterized by deposition of monosodium urate (MSU) crystals which trigger an innate immune response mediated by inflammatory cytokines. IGF1R is one of the loci associated with both urate levels and gout susceptibility in GWAS to date, and IGF-1-IGF-1R signaling is implicated in urate control. We investigate the role of IGF-1/IGF1R signaling in the context of gouty inflammation. Also, we test the gout and urate-associated IGF1R rs6598541 polymorphism for association with the inflammatory capacity of mononuclear cells. For this, freshly isolated human peripheral blood mononuclear cells (PBMCs) were exposed to recombinant IGF-1 or anti-IGF1R neutralizing antibody in the presence or absence of solubilized urate, stimulated with LPS/MSU crystals. Also, the association of rs6598541 with IGF1R and protein expression and with ex vivo cytokine production levels after stimulation with gout specific stimuli was tested. Urate exposure was not associated with IGF1R expression in vitro or in vivo. Modulation of IGF1R did not alter urate-induced inflammation. Developing urate-induced trained immunity in vitro was not influenced in cells challenged with IGF-1 recombinant protein. Moreover, the IGF1R rs6598541 SNP was not associated with cytokine production. Our results indicate that urate-induced inflammatory priming is not regulated by IGF-1/IGF1R signaling in vitro. IGF1R rs6598541 status was not asociated with IGF1R expression or cytokine production in primary human PBMCs. This study suggests that the role of IGF1R in gout is tissue-specific and may be more relevant in the control of urate levels rather than in inflammatory signaling in gout.

Growth Hormone, Atherosclerosis and Peripheral Arterial Disease: Exploring the Spectrum from Acromegaly to Growth Hormone Deficiency

Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are increasingly recognised for their role in cardiovascular (CV) physiology. The GH-IGF-1 axis plays an essential role in the development of the CV system as well as in the complex molecular network that regulates cardiac and endothelial structure and function. A considerable correlation between GH levels and CV mortality exists even among individuals in the general population without a notable deviation in the GHIGF- 1 axis functioning. In addition, over the last decades, evidence has demonstrated that pathologic conditions involving the GH-IGF-1 axis, as seen in GH excess to GH deficiency, are associated with an increased risk for CV morbidity and mortality. A significant part of that risk can be attributed to several accompanying comorbidities. In both conditions, disease control is associated with a consistent improvement of CV risk factors, reduction of CV mortality, and achievement of standardised mortality ratio similar to that of the general population. Data on the prevalence of peripheral arterial disease in patients with acromegaly or growth hormone deficiency and the effects of GH and IGF-1 levels on the disease progression is limited. In this review, we will consider the pivotal role of the GH-IGF-1 axis on CV system function, as well as the far-reaching consequences that arise when disorders within this axis occur, particularly in relation to the atherosclerosis process.

New insights on the cardiovascular effects of IGF-1

INTRODUCTION

Cardiovascular (CV) disorders are steadily increasing, making them the world's most prevalent health issue. New research highlights the importance of insulin-like growth factor 1 (IGF-1) for maintaining CV health.

METHODS

We searched PubMed and MEDLINE for English and non-English articles with English abstracts published between 1957 (when the first report on IGF-1 identification was published) and 2022. The top search terms were: IGF-1, cardiovascular disease, IGF-1 receptors, IGF-1 and microRNAs, therapeutic interventions with IGF-1, IGF-1 and diabetes, IGF-1 and cardiovascular disease. The search retrieved original peer-reviewed articles, which were further analyzed, focusing on the role of IGF-1 in pathophysiological conditions. We specifically focused on including the most recent findings published in the past five years.

RESULTS

IGF-1, an anabolic growth factor, regulates cell division, proliferation, and survival. In addition to its well-known growth-promoting and metabolic effects, there is mounting evidence that IGF-1 plays a specialized role in the complex activities that underpin CV function. IGF-1 promotes cardiac development and improves cardiac output, stroke volume, contractility, and ejection fraction. Furthermore, IGF-1 mediates many growth hormones (GH) actions. IGF-1 stimulates contractility and tissue remodeling in humans to improve heart function after myocardial infarction. IGF-1 also improves the lipid profile, lowers insulin levels, increases insulin sensitivity, and promotes glucose metabolism. These findings point to the intriguing medicinal potential of IGF-1. Human studies associate low serum levels of free or total IGF-1 with an increased risk of CV and cerebrovascular illness. Extensive human trials are being conducted to investigate the therapeutic efficacy and outcomes of IGF-1-related therapy.

DISCUSSION

We anticipate the development of novel IGF-1-related therapy with minimal side effects. This review discusses recent findings on the role of IGF-1 in the cardiovascular (CVD) system, including both normal and pathological conditions. We also discuss progress in therapeutic interventions aimed at targeting the IGF axis and provide insights into the epigenetic regulation of IGF-1 mediated by microRNAs.

Declining Levels and Bioavailability of IGF-I in Cardiovascular Aging Associate With QT Prolongation-Results From the 1946 British Birth Cohort

Background

As people age, circulating levels of insulin-like growth factors (IGFs) and IGF binding protein 3 (IGFBP-3) decline. In rat cardiomyocytes, IGF-I has been shown to regulate sarcolemmal potassium channel activity and late sodium current thus impacting cardiac repolarization and the heart rate-corrected QT (QTc). However, the relationship between IGFs and IGFBP-3 with the QTc interval in humans, is unknown.

Objectives

To examine the association of IGFs and IGFBP-3 with QTc interval in an older age population-based cohort.

Methods

Participants were from the 1946 Medical Research Council (MRC) National Survey of Health and Development (NSHD) British birth cohort. Biomarkers from blood samples at age 53 and 60-64 years (y, exposures) included IGF-I/II, IGFBP-3, IGF-I/IGFBP-3 ratio and the change (Δ) in marker levels between the 60-64 and 53y sampled timepoints. QTc (outcome) was recorded from electrocardiograms at the 60-64y timepoint. Generalized linear multivariable models with adjustments for relevant demographic and clinical factors, were used for complete-cases and repeated after multiple imputation.

Results

One thousand four hundred forty-eight participants were included (48.3% men; QTc mean 414 ms interquartile range 26 ms). Univariate analysis revealed an association between low IGF-I and IGF-I/IGFBP-3 ratio at 60-64y with QTc prolongation [respectively: β -0.30 ms/nmol/L, (95% confidence intervals -0.44, -0.17), p < 0.001; β-28.9 ms/unit (-41.93, -15.50), p < 0.001], but not with IGF-II or IGFBP-3. No association with QTc was found for IGF biomarkers sampled at 53y, however both ΔIGF-I and ΔIGF-I/IGFBP-3 ratio were negatively associated with QTc [β -0.04 ms/nmol/L (-0.08, -0.008), p = 0.019; β -2.44 ms/unit (-4.17, -0.67), p = 0.007] while ΔIGF-II and ΔIGFBP-3 showed no association. In fully adjusted complete case and imputed models (reporting latter) low IGF-I and IGF-I/IGFBP-3 ratio at 60-64y [β -0.21 ms/nmol/L (-0.39, -0.04), p = 0.017; β -20.14 ms/unit (-36.28, -3.99), p = 0.015], steeper decline in ΔIGF-I [β -0.05 ms/nmol/L/10 years (-0.10, -0.002), p = 0.042] and shallower rise in ΔIGF-I/IGFBP-3 ratio over a decade [β -2.16 ms/unit/10 years (-4.23, -0.09), p = 0.041], were all independently associated with QTc prolongation. Independent associations with QTc were also confirmed for other previously known covariates: female sex [β 9.65 ms (6.65, 12.65), p < 0.001], increased left ventricular mass [β 0.04 ms/g (0.02, 0.06), p < 0.001] and blood potassium levels [β -5.70 ms/mmol/L (-10.23, -1.18) p = 0.014].

Conclusion

Over a decade, in an older age population-based cohort, declining levels and bioavailability of IGF-I associate with prolongation of the QTc interval. As QTc prolongation associates with increased risk for sudden death even in apparently healthy people, further research into the antiarrhythmic effects of IGF-I on cardiomyocytes is warranted.

Molecular basis of the effect of atorvastatin pretreatment on stem cell therapy in chronic ischemic diseases - critical limb ischemia

Autologous stem cell therapy is the most promising alternative treatment in patients with chronic ischemic diseases, including ischemic heart disease and critical limb ischemia, which are characterized by poor prognosis related to serious impair of quality of life, high risk of cardiovascular events and mortality rates. However, one of the most serious shortcomings of stem cell transplantation are low survival after transplantation to the site of injury, as large number of stem cells are lost within 24 hours after delivery. Multiple studies suggest that combination of lipid-lowering drugs, statins, and stem cell transplantation might improve therapeutic efficacy in regenerative medicine. Statins are inhibitors of HMG-CoA reductase and belong to recommended therapy in all patients suffering from critical limb ischemia. Statins possess non-lipid effects which involve improvement of endothelial function, decrease of vascular inflammation and oxidative stress, anti-cancer and stem cell modulation capacities. These non-lipid effects are explained by inhibition of mevalonate synthesis via blocking isoprenoid intermediates synthesis, such as farnesylpyrophospate and geranylgeranylpyrophospate and result in modulation of the PI3K/Akt pathway. Moreover, statin-mediated microRNA regulation may contribute to the pleiotropic functions. MicroRNA interplay in gene regulatory network of IGF/Akt pathway may be of special significance for the treatment of critical limb ischemia. We assume further studies are needed for detailed analysis of statin interactions with microRNA at the molecular level and their link to PI3K/Akt and IGF/Akt pathway in stem cells, which are currently the most promising treatment strategy used in chronic ischemic diseases.

Vascular Aging in Rodent Models: Contrasting Mechanisms Driving the Female and Male Vascular Senescence

Increasing scientific interest has been directed to sex as a biological and decisive factor on several diseases. Several different mechanisms orchestrate vascular function, as well as vascular dysfunction in cardiovascular and metabolic diseases in males and females. Certain vascular sex differences are present throughout life, while others are more evident before the menopause, suggesting two important and correlated drivers: genetic and hormonal factors. With the increasing life expectancy and aging population, studies on aging-related diseases and aging-related physiological changes have steeply grown and, with them, the use of aging animal models. Mouse and rat models of aging, the most studied laboratory animals in aging research, exhibit sex differences in many systems and physiological functions, as well as sex differences in the aging process and aging-associated cardiovascular changes. In the present review, we introduce the most common aging and senescence-accelerated animal models and emphasize that sex is a biological variable that should be considered in aging studies. Sex differences in the cardiovascular system, with a focus on sex differences in aging-associated vascular alterations (endothelial dysfunction, remodeling and oxidative and inflammatory processes) in these animal models are reviewed and discussed.

Trends in Natural Nutrients for Oxidative Stress and Cell Senescence

Due to the increase in the aged population and increased life expectancy, the underlying mechanisms involved in the aging process and cell senescence and the ways for modulating these processes in age-related diseases become important. One of the main mechanisms involved in aging and cell senescence, especially in the diseases related to aging, is the oxidative stress process and the following inflammation. Hence, the effects of antioxidants are highlighted in the literature due to their beneficial impacts on inhibiting telomere shortening or DNA damage and other processes related to aging and cell senescence in age-related diseases. Dietary components, foods, and dietary patterns rich in antioxidants can modulate the aging process and delay the progression of some chronic diseases such as cardiovascular diseases, diabetes, and Alzheimer's disease. Foods high in polyphenols, vitamin C, or carotenoids, olive oil, seeds, nuts, legumes, dietary supplements such as CoQ10, and some other dietary factors are the most important nutritional sources that have high antioxidant contents which can positively affect cell senescence and disease progression. Plant dietary patterns including Mediterranean diets can also inhibit telomere shortening following oxidative damages, and this can delay cell aging and senescence in age-related diseases. Further, olive oil can inhibit protein aggregation in Alzheimer's disease. It can be concluded that nutrition can delay the process of cell senescence in age-related diseases via inhibiting oxidative and inflammatory pathways. However, more studies are needed to better clarify the underlying mechanisms of nutrition and dietary components on cell senescence, aging, and disease progression, especially those related to age.

Acromegaly, inflammation and cardiovascular disease: a review

Acromegaly is characterized by Growth Hormone (GH) and Insulin-like Growth Factor 1 (IGF-1) excess. Uncontrolled acromegaly is associated with a strongly increased risk of cardiovascular disease (CVD), and numerous cardiovascular risk factors remain present after remission. GH and IGF-1 have numerous effects on the immune and cardiovascular system. Since endothelial damage and systemic inflammation are strongly linked to the development of CVD, and have been suggested to be present in both controlled as uncontrolled acromegaly, they may explain the presence of both micro- and macrovascular dysfunction in these patients. In addition, these changes seem to be only partially reversible after remission, as illustrated by the often reported presence of endothelial dysfunction and microvascular damage in controlled acromegaly. Previous studies suggest that insulin resistance, oxidative stress, and endothelial dysfunction are involved in the development of CVD in acromegaly. Not surprisingly, these processes are associated with systemic inflammation and respond to GH/IGF-1 normalizing treatment.

lncRNA NR2F1-AS1 promotes breast cancer angiogenesis through activating IGF-1/IGF-1R/ERK pathway

Long non‐coding RNAs (lncRNAs) take various effects in cancer mostly through sponging with microRNAs (miRNAs). lncRNA NR2F1‐AS1 is found to promote tumour progression in hepatocellular carcinoma, endometrial cancer and thyroid cancer. However, the role of lncRNA NR2F1‐AS1 in breast cancer angiogenesis remains unknown. In this study, we found lncRNA NR2F1‐AS1 was positively related with CD31 and CD34 in breast cancer through Pearson's correlation analysis, while lncRNA NR2F1‐AS1 transfection promoted human umbilical vascular endothelial cell (HUVEC) tube formation. In breast cancer cells, lncRNA NR2F1‐AS1 enhanced the HUVEC proliferation, tube formation and migration ability through tumour‐conditioned medium (TCM). In zebrafish model, lncRNA NR2F1‐AS1 increased the breast cancer cell‐related neo‐vasculature and subsequently promoted the breast cancer cell metastasis. In mouse model, lncRNA NR2F1‐AS1 promoted the tumour vessel formation, increased the micro vessel density (MVD) and then induced the growth of primary tumour. Mechanically, lncRNA NR2F1‐AS1 increased insulin‐like growth factor‐1 (IGF‐1) expression through sponging miRNA‐338‐3p in breast cancer cells and then activated the receptor of IGF‐1 (IGF‐1R) and extracellular signal‐regulated kinase (ERK) pathway in HUVECs. These results indicated that lncRNA NR2F1‐AS1 could promote breast cancer angiogenesis through IGF‐1/IGF‐1R/ERK pathway.

Combined network pharmacology and virtual reverse pharmacology approaches for identification of potential targets to treat vascular dementia

Dementia is a major cause of disability and dependency among older people. If the lives of people with dementia are to be improved, research and its translation into druggable target are crucial. Ancient systems of healthcare (Ayurveda, Siddha, Unani and Sowa-Rigpa) have been used from centuries for the treatment vascular diseases and dementia. This traditional knowledge can be transformed into novel targets through robust interplay of network pharmacology (NetP) with reverse pharmacology (RevP), without ignoring cutting edge biomedical data. This work demonstrates interaction between recent and traditional data, and aimed at selection of most promising targets for guiding wet lab validations. PROTEOME, DisGeNE, DISEASES and DrugBank databases were used for selection of genes associated with pathogenesis and treatment of vascular dementia (VaD). The selection of new potential drug targets was made by methods of NetP (DIAMOnD algorithm, enrichment analysis of KEGG pathways and biological processes of Gene Ontology) and manual expert analysis. The structures of 1976 phytomolecules from the 573 Indian medicinal plants traditionally used for the treatment of dementia and vascular diseases were used for computational estimation of their interactions with new predicted VaD-related drug targets by RevP approach based on PASS (Prediction of Activity Spectra for Substances) software. We found 147 known genes associated with vascular dementia based on the analysis of the databases with gene-disease associations. Six hundred novel targets were selected by NetP methods based on 147 gene associations. The analysis of the predicted interactions between 1976 phytomolecules and 600 NetP predicted targets leaded to the selection of 10 potential drug targets for the treatment of VaD. The translational value of these targets is discussed herewith. Twenty four drugs interacting with 10 selected targets were identified from DrugBank. These drugs have not been yet studied for the treatment of VaD and may be investigated in this field for their repositioning. The relation between inhibition of two selected targets (GSK-3, PTP1B) and the treatment of VaD was confirmed by the experimental studies on animals and reported separately in our recent publications.

Impact of home- and center- based physical training program on cardio-metabolic health and IGF-1 level in elderly women

Background

Data in the literature concerning the effects of physical activity on lipid and IGF-1levels are controversial in postmenopausal women. The aim of the present study was to determine the combined effects of a 12 weeks home-based walking program aiming to achieve 10,000 steps daily and a center- based aerobic exercise training on functional capacity, some important cardio-metabolic parameters, IGF-1 level and psychological items among elderly female patients. Sixty female patients (67.4 ± 5 years) with moderate to high cardiovascular risk were randomly assigned either to an exercise training program for 12 weeks or to the control group.

Results

Our organized training program resulted in a significantly improved daily physical activity (4232 [IQR: 3162–7219] to 8455 [IQR: 6757–11,488]; p < 0.001 ft-steps), functional capacity (MET) (8.17 ± 1.57 to 8.87 ± 1.76) (p = 0.002), metabolic status including total cholesterol (5.17 ± 1.13 to 4.77 ± 1.12 mmol/l), LDL cholesterol (3.37 ± 1.05 to 2.81 ± 0.98 mmol/l), triglyceride (1.68 ± 0.71 to 1.28 ± 0.71 mmol/l) and HgbA1c (6.24 ± 0.67 to 6.06 ± 0.58 mmol/l), as well as IGF-1 (59.68 ± 27.37 to 66.79 ± 22.74 ng/ml) levels (p < 0.05) in the training group. From psychological tests only physical functionality improved significantly (p = 0.03) in the training group. The training group significantly differed from the control group in four parameters including MET (p = 0.003), LDL-cholesterol (p = 0.046), triglyceride (p = 0.001) and IGF-1 levels (p < 0.001) after the intervention.

Conclusion

The applied home-, and- center based training program effectively increased the daily physical activity of the elderly female patients and improved several cardio-metabolic parameters. Further investigations are needed on larger patient population to establish our findings and examine how these positive changes may decrease CV events and mortality.

Smooth muscle cell and arterial aging: basic and clinical aspects

Arterial aging engages a plethora of key signalling pathways that act in concert to induce vascular smooth muscle cell (VSMC) phenotypic changes leading to vascular degeneration and extracellular matrix degradation responsible for alterations of the mechanical properties of the vascular wall. This review highlights proof-of-concept examples of components of the extracellular matrix, VSMC receptors which connect extracellular and intracellular structures, and signalling pathways regulating changes in mechanotransduction and vascular homeostasis in aging. Furthermore, it provides a new framework for understanding how VSMC stiffness and adhesion to extracellular matrix contribute to arterial stiffness and how interactions with endothelial cells, platelets, and immune cells can regulate vascular aging. The identification of the key players of VSMC changes operating in large and small-sized arteries in response to increased mechanical load may be useful to better elucidate the causes and consequences of vascular aging and associated progression of hypertension, arteriosclerosis, and atherosclerosis.

IGF-1 and cardiovascular disease

Atherosclerosis is an inflammatory arterial pathogenic condition, which leads to ischemic cardiovascular diseases, such as coronary artery disease and myocardial infarction, stroke, and peripheral arterial disease. Atherosclerosis is a multifactorial disorder and its pathophysiology is highly complex. Changes in expression of multiple genes coupled with environmental and lifestyle factors initiate cascades of adverse events involving multiple types of cells (e.g. vascular endothelial cells, smooth muscle cells, and macrophages). IGF-1 is a pleiotropic factor, which is found in the circulation (endocrine IGF-1) and is also produced locally in arteries (endothelial cells and smooth muscle cells). IGF-1 exerts a variety of effects on these cell types in the context of the pathogenesis of atherosclerosis. In fact, there is an increasing body of evidence suggesting that IGF-1 has beneficial effects on the biology of atherosclerosis. This review will discuss recent findings relating to clinical investigations on the relation between IGF-1 and cardiovascular disease and basic research using animal models of atherosclerosis that have elucidated some of the mechanisms underlying atheroprotective effects of IGF-1.

Diagnosis of obesity and use of obesity biomarkers in science and clinical medicine

The global epidemic of obesity is a major public health problem today. Obesity increases the risk of many chronic diseases, such as type 2 diabetes, coronary heart disease, and certain types of cancer, and is associated with lower life expectancy. The body mass index (BMI), which is currently used to classify obesity, is only an imperfect measure of abnormal or excessive body fat accumulation. Studies have shown that waist circumference as a measure of fat distribution may improve disease prediction. More elaborate techniques such as magnetic resonance imaging are increasingly available to assess body fat distribution, but these measures are not readily available in routine clinical practice, and health-relevant cut-offs not yet been established. The measurement of biomarkers that reflect the underlying biological mechanisms for the increased disease risk may be an alternative approach to characterize the relevant obesity phenotype. The insulin/insulin-like growth factor (IGF) axis and chronic low-grade inflammation have been identified as major pathways. In addition, specific adipokines such as leptin, adiponectin and resistin have been related to obesity-associated health outcomes. This biomarker research, which is currently further developed with the application of high throughput methods, gives important insights in obesity-related disease etiology and pathophysiological pathways and may be used to better characterize obese persons at high risk of disease development and target disease-causing biomarkers in personalized prevention strategies.

Neuropsychology of aging

All people want to age "successfully," maintaining functional capacity and quality of life as they reach advanced age. Achieving this goal depends on preserving optimal cognitive and brain functioning. Yet, significant individual differences exist in this regard. Some older adults continue to retain most cognitive abilities throughout their lifetime. Others experience declines in cognitive and functional capacity that range from mild decrements in certain cognitive functions over time to severe dementia among those with neurodegenerative diseases. Even among relatively healthy "successful agers," certain cognitive functions are reduced from earlier levels. This is particularly true for cognitive functions that are dependent on cognitive processing speed and efficiency. Working memory and executive and attentional functions tend to be most vulnerable. Learning and memory functions are also usually reduced, although in the absence of neurodegenerative disease learning and retrieval efficiency rather than memory storage are affected. Other functions, such as visual perception, language, semantics, and knowledge, are often well preserved. Structural, functional, and physiologic/metabolic brain changes correspond with age-associated cognitive decline. Physiologic and metabolic mechanisms, such as oxidative stress and neuroinflammation, may contribute to these changes, along with the contribution of comorbidities that secondarily affect the brain of older adults. Cognitive frailty often corresponds with physical frailty, both affected by multiple exogenous and endogenous factors. Neuropsychologic assessment provides a way of measuring the cognitive and functional status of older adults, which is useful for monitoring changes that may be occurring. Neuroimaging is also useful for characterizing age-associated structural, functional, physiologic, and metabolic brain changes, including alterations in cerebral blood flow and metabolite concentrations. Some interventions that may enhance cognitive function, such as cognitive training, neuromodulation, and pharmacologic approaches, exist or are being developed. Yet, preventing, slowing, and reversing the adverse effects of cognitive aging remains a challenge.

Whole Body Vibration Retards Progression of Atherosclerosis via Insulin-Like Growth Factor 1 in Apolipoprotein E-Deficient Mice

Whole body vibration (WBV) has a marked impact on lipid metabolism and the endocrine system, which is related to the progression of atherosclerosis (AS). To investigate the effects of WBV, we measured the atherosclerotic plaque area of apolipoprotein E-knockout (ApoE^−/−) AS mice, which were trained by WBV (15 Hz, 30 min) for 12 weeks. Simultaneously, serum levels of lipids, insulin-like growth factor 1 (IGF-1), insulin-like growth factor 1 receptor (IGF-1R), interleukin 6 (IL-6), and the mRNA and protein levels of the same in the aorta were compared between the control and WBV groups. The results indicated that WBV significantly reduced the atherosclerotic plaque area with lower very low-density lipoprotein (VLDL) and oxidized low-density lipoprotein (ox-LDL) in the blood. Moreover, the levels of IGF-1 in serum and expression of IL-6, IGF-1R, and p-IGF-1R protein in the mice aorta decreased significantly in the WBV group. In addition, we found that serum IGF-1 in mice increased to the highest concentration in 30 min after WBV for 10, 30, 60, and 120 minutes. These results suggested that appropriate WBV may delay the progression of AS, which was associated with acutely elevated serum IGF-1 and lower levels of IGF-1 and IL-6 in the aorta for long-term treatment.

Insulin-like growth factor-1 (IGF1) in systemic lupus erythematosus: relation to disease activity, organ damage and immunological findings

Background Insulin growth factor-1 (IGF1) activates cell proliferation pathways and inhibits apoptosis. IGF1 is involved in tumour growth and required for T-cell independent activation of B cells. Activated B cells and autoantibody production are a hallmark of systemic lupus erythematosus (SLE). To investigate the possible role of IGF1 in SLE, we studied IGF1 across clinical characteristics, immunological biomarkers, disease activity and organ damage in SLE patients. Method In a cross-sectional study, we collected clinical characteristics, medication, disease activity (SLEDAI-2K) and organ damage (SDI) for 94 SLE patients. Autoantibodies and cytokines were measured by ELISA, and levels of IGF1 and IGF binding protein 3 (IGFBP3) by chemiluminescence. Free IGF1 was estimated by the IGF1:IGFBP3 ratio. Healthy controls served as a comparator group. Results There was a significant age-related decline in IGF1, IGFBP3 and free IGF1 (IGF1:IGFBP3 ratio) that was similar in SLE patients and controls with very few outliers. Free IGF1 was inversely related to blood pressure (Rs -0.327, p < 0.01) and HbA1c (Rs -0.31, p < 0.01). Free IGF1 was higher in disease-modifying antirheumatic drug-treated patients ( p < 0.01), but there was no significant association between the IGF1 axis and autoantibody profiles, cytokine levels or SLEDAI-2K or SDI categories. IGF1 correlated inversely with BAFF level and B, natural killer and CD8 + cell counts. Conclusion Free IGF1 levels in SLE patients declined appropriately with age. IGF1 levels were not associated with disease activity, severity or autoantibody levels in SLE. Free IGF1 had positive metabolic effects in SLE and may play an indirect role in dampening the cellular immune response by downregulating B- and T-cell activity.

Addressing the Perfect Storm: Biomarkers in Obesity and Pathophysiology of Cardiometabolic Risk

BACKGROUND

The worldwide rise of obesity has provoked intensified research to better understand its pathophysiology as a means for disease prevention. Several biomarkers that may reflect various pathophysiological pathways that link obesity and cardiometabolic diseases have been identified over the past decades.

CONTENT

We summarize research evidence regarding the role of established and novel obesity-related biomarkers, focusing on recent epidemiological evidence for detrimental associations with cardiometabolic diseases including obesity-related cancer. The reviewed biomarkers include biomarkers of glucose–insulin homeostasis (insulin, insulin-like growth factors, and C-peptide), adipose tissue biomarkers (adiponectin, omentin, apelin, leptin, resistin, and fatty-acid-binding protein-4), inflammatory biomarkers (C-reactive protein, interleukin 6, tumor necrosis factor α), and omics-based biomarkers (metabolites and microRNAs).

SUMMARY

Although the evidence for many classical obesity biomarkers, including adiponectin and C-reactive protein (CRP), in disease etiology has been initially promising, the evidence for a causal role in humans remains limited. Further, there has been little demonstrated ability to improve disease prediction beyond classical risk factors. In the era of “precision medicine,” there is an increasing interest in novel biomarkers, and the extended list of potentially promising biomarkers, such as adipokines, cytokines, metabolites, and microRNAs, implicated in obesity may bring new promise for improved, personalized prevention. To further evaluate the role of obesity-related biomarkers as etiological and early-disease-prediction targets, well-designed studies are needed to evaluate temporal associations, replicate findings, and test clinical utility of novel biomarkers. In particular, studies to determine the therapeutic implications of novel biomarkers beyond established metabolic risk factors are highly warranted.

The emerging role of alternative splicing in senescence and aging

Deregulation of precursor mRNA splicing is associated with many illnesses and has been linked to age-related chronic diseases. Here we review recent progress documenting how defects in the machinery that performs intron removal and controls splice site selection contribute to cellular senescence and organismal aging. We discuss the functional association linking p53, IGF-1, SIRT1, and ING-1 splice variants with senescence and aging, and review a selection of splicing defects occurring in accelerated aging (progeria), vascular aging, and Alzheimer's disease. Overall, it is becoming increasingly clear that changes in the activity of splicing factors and in the production of key splice variants can impact cellular senescence and the aging phenotype.

Mexican case report of a never-treated Laron syndrome patient evolving to metabolic syndrome, type 2 diabetes, and stroke

Glucose and lipid profile together with blood pressure should always be considered for low sera‐IGF‐1 patients. Even when adulthood is reached, IGF‐1 therapy in these patients should be pursued as metabolic and protective cellular effects could be triggered. Real incidence of growth hormone insensitivity is still to be uncovered.

IGF1 potentiates the pro-inflammatory response in human peripheral blood mononuclear cells via MAPK

Acromegaly is characterized by growth hormone (GH) and insulin-like growth factor 1 (IGF1) excess and is accompanied by an increased cardiovascular diseases (CVD) risk. As innate immune responses are crucial in CVD development, and IGF1 is linked to subclinical inflammation, we hypothesized that GH/IGF1 excess contributes to CVD development by potentiating systemic inflammation. We aimed to assess the effects of GH/IGF1 on inflammatory cytokine production. Whole blood from acromegaly patients and healthy volunteers and peripheral blood mononuclear cells (PBMCs) from healthy volunteers were stimulated with Toll-like receptor (TLR) ligands, with or without adding GH or IGF1 (in PBMC). Cytokine concentrations were measured by ELISA. The underlying signalling pathways were investigated by the inhibition of downstream targets of the IGF1 receptor. The following results were obtained. GH or IGF1 alone did not influence cytokine production in PBMCs. GH did not affect TLR-induced cytokine production, but co-stimulation with IGF1 dose dependently increased the TLR ligand-induced production of IL6 (P < 0.01), TNF alpha (P = 0.02) and IFNg (P < 0.01), as well as the production of the anti-inflammatory cytokine IL10 (P = 0.01). IGF1 had no effect on IL1B, IL17 and IL22 production. Inhibition of the MAPK pathway, but not mTOR, completely abrogated the synergistic effect of IGF1 on the LPS-induced IL6 and TNF alpha production. In whole blood of acromegaly patients, ex vivo IL6 production was increased (P < 0.01). In conclusion, IGF1, but not GH, has pro-inflammatory effects, probably via the MAPK signalling pathway and might be involved in the pathogenesis of atherosclerosis in acromegaly. The increased IL10 production possibly counteracts the pro-inflammatory effects.

Insulin-like Growth Factor 1 in relation to future hearing impairment: findings from the English Longitudinal Study of Ageing

Insulin-like Growth Factor 1 (IGF-1) is associated with cardiovascular disease, itself a risk factor for hearing impairment, and, in animal studies, molecular evidence suggests a role for IGF-1 in hearing function. However, the link between IGF-1 and the occurrence of hearing impairment is untested in population-based studies of humans. A total of 4390 participants aged ≥50 y (mean [SD] age 64.2 [8.0] years at baseline, 55% women) from the English Longitudinal Study of Ageing provided serum levels of IGF-1 in 2008 and again in 2012. Hearing acuity was assessed by an objective hearing test (HearCheck handheld device) in 2014 when the prevalence was 38.2%. In the full cohort, IGF-1 was not associated with subsequent hearing impairment (OR_{5nmol/L increase}; 95% CI: 1.01; 0.94, 1.09). However, this relationship appeared to differ by age (p-value for interaction = 0.03). Thus, in younger participants (aged 50–60 y, n = 1400), IGF-1 was associated with lower odds of hearing impairment (0.86; 0.73, 1.00) after adjustment for a range of potential confounders. Among people ≥60 y (n = 2990) there was a non-significant ‘J’-shaped association. Our observational evidence that higher levels of IGF-1 appeared to confer some protection against hearing impairment in some older adults warrants replication in other prospective cohort studies.

IGF-1R signalling contributes to IL-6 production and T cell dependent inflammation in rheumatoid arthritis

BACKGROUND

Signalling through insulin-like growth factor 1 receptor (IGF-1R) is essential for cell survival, but may turn pathogenic in uncontrolled tissue growth in tumours. In rheumatoid arthritis (RA), the IGF-1R signalling is activated and supports expansion of the inflamed synovia.

AIM

In the present study, we assess if disruption of IGF-1R signalling resolves arthritis.

MATERIAL AND METHODS

Clinical associations of IGF-1R expression in leukocytes of the peripheral blood were studied in 84 RA patients. Consequences of the IGF-1R signalling inhibition for arthritis were studied in mBSA immunised Balb/c mice treated with NT157 compound promoting degradation of insulin receptor substrates.

RESULTS

In RA patients, high expression of IGF-1R in leukocytes was associated with systemic inflammation as verified by higher expression of NF-kB, serum levels of IL6 and erythrocyte sedimentation rate, and higher pain perception. Additionally, phosphorylated IGF-1R and STAT3 enriched T cells infiltrate in RA synovia. Treatment with NT157 inhibited the phosphorylation of IGF-1R and STAT3 in synovia, and alleviated arthritis and joint damage in mice. It also reduced expression of IGF-1R and despaired ERK and Akt signalling in spleen T cells. This limited IL-6 production, changed RoRgt/FoxP3 balance and IL17 levels.

CONCLUSION

IGF-1R signalling contributes to T cell dependent inflammation in arthritis. Inhibition of IGF-1R on the level of insulin receptor substrates alleviates arthritis by restricting IL6-dependent formation of Th17 cells and may open for new treatment strategies in RA.

Associations between levels of insulin-like growth factor 1 and sinusoidal obstruction syndrome after allogeneic haematopoietic stem cell transplantation

Allogeneic myeloablative haematopoietic stem cell transplantation (HSCT) is challenged by severe adverse events, as cytotoxic effects of the conditioning may result in systemic inflammation, leaky epithelial barriers and organ toxicities, contributing to treatment-related morbidity and mortality. We hypothesised that insulin-like growth factor-1 (IGF-1), a mediator of growth and proliferation of various tissues, may attenuate chemotherapy-induced tissue damage after HSCT. We prospectively measured plasma levels of IGF-1 and its binding protein 3 (IGFBP-3) in 41 patients undergoing myeloablative HSCT. IGF-1 and IGFBP-3 levels were inversely correlated with C-reactive protein and interleukin-6 levels post HSCT. In multivariate analyses, low levels of IGF-1 and IGFBP-3 before conditioning were associated with increased risk of developing sinusoidal obstruction syndrome (SOS; OR=5.00 per 1 SDS decrease in IGF-1 (95% CI: 1.45-16.67), P=0.011 and OR=5.00 (1.37-20.00), P=0.015, respectively). Furthermore, low pre-transplant levels of IGF-1 and IGFBP-3 were associated with increased fluid retention during the first 21 days post transplant (OR=7.69 (95% CI: 1.59-33.33), P=0.012, and OR=2.94 (1.03-8.33), P=0.045). These data suggest that high levels of IGF-1 and IGFBP-3 may have a protective effect against fluid retention and SOS, possibly by attenuating systemic inflammation, and may prove useful as predictive biomarkers of SOS.

The Role of Insulin Receptor Isoforms in Diabetes and Its Metabolic and Vascular Complications

The insulin receptor (IR) presents by alternative splicing two isoforms: IRA and IRB. The differential physiological and pathological role of both isoforms is not completely known, and it is determinant the different binding affinity for insulin-like growth factor. IRB is more abundant in adult tissues and it exerts mainly the metabolic actions of insulin, whereas IRA is mainly expressed in fetal and prenatal period and exerts mitogenic actions. However, the change in the expression profile of both IR isoforms and its dysregulation are associated with the development of different pathologies, such as cancer, insulin resistance, diabetes, obesity, and atherosclerosis. In some of them, there is a significant increase of IRA/IRB ratio conferring a proliferative and migratory advantage to different cell types and favouring IGF-II actions with a sustained detriment in the metabolic effects of insulin. This review discussed specifically the role of IR isoforms as well as IGF-IR in diabetes and its associated complications as obesity and atherosclerosis. Future research with new IR modulators might be considered as possible targets to improve the treatment of diabetes and its associated complications.

CRIM1 is necessary for coronary vascular endothelial cell development and homeostasis

Endothelial cells form a critical component of the coronary vasculature, yet the factors regulating their development remain poorly defined. Here we reveal a novel role for the transmembrane protein CRIM1 in mediating cardiac endothelial cell development. In the absence of Crim1 in vivo, the coronary vasculature is malformed, the number of endothelial cells reduced, and the canonical BMP pathway dysregulated. Moreover, we reveal that CRIM1 can bind IGFs, and regulate IGF signalling within endothelial cells. Finally, loss of CRIM1 from human cardiac endothelial cells results in misregulation of endothelial genes, predicted by pathway analysis to be involved in an increased inflammatory response and cytolysis, reminiscent of endothelial cell dysfunction in cardiovascular disease pathogenesis. Collectively, these findings implicate CRIM1 in endothelial cell development and homeostasis in the coronary vasculature.

Insulin-like growth factor 1 and risk of depression in older people: the English Longitudinal Study of Ageing

Depressive disorders are a leading cause of disability in older age. Although the role of psychosocial and behavioural predictors has been well examined, little is known about the biological origins of depression. Findings from animal studies have implicated insulin-like growth factor 1 (IGF-1) in the aetiology of this disorder. A total of 6017 older adults (mean age of 65.7 years; 55% women) from the English Longitudinal Study of Ageing provided serum levels of IGF-1 (mean=15.9 nmol l(-1), s.d. 5.7) during a nurse visit in 2008. Depression symptoms were assessed in the same year and again in 2012 using the eight-item Center for Epidemiologic Studies Depression Scale. Self-reports of a physician-diagnosis of depression were also collected at both time points. In separate analyses for men and women, the results from both the cross-sectional and longitudinal analyses revealed a 'U'-shaped pattern of association, such that lower and higher levels of IGF-1 were associated with a slightly elevated risk of depression, whereas the lowest risk was seen around the median levels. Thus, in men, with the lowest quintile of IGF-1 as the referent, the age-adjusted odds ratios (95% confidence interval) of developing depression symptoms after 4 years of follow-up, for increasing quintiles of IGF-1, were: 0.51 (0.28-0.91), 0.50 (0.27-0.92), 0.63 (0.35-1.15) and 0.63 (0.35-1.13) (P-value for quadratic association 0.002). Some attenuation of these effects was apparent after adjustment for co-morbidity, socioeconomic status and health behaviours. In conclusion, in the present study of older adults, there was some evidence that moderate levels of IGF-1 levels conferred a reduced risk of depression.

High-dose atorvastatin is associated with lower IGF-1 levels in patients with type 1 diabetes

INTRODUCTION

Insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 (IGFBP-1) play an important role in vascular health. Many patients with type 1 diabetes are medicated with HMG-CoA reductase inhibitors, statins, in order to prevent vascular complications. Yet little is known about the effect of statins on the IGF-1/IGFBP-1 axis in these patients.

OBJECTIVES

The aim of this study was to evaluate the effect of atorvastatin treatment on IGF-1 and IGFBP-1 with regards to microvascular function.

DESIGN

Twenty patients with type 1 diabetes received either placebo or 80mg atorvastatin for two months in a double-blinded cross-over study. IGF-1 and IGFBP-1 levels were assessed before and after each treatment period. Skin microcirculation was studied using Doppler perfusion imaging during iontophoresis of acetylcholine and sodium nitroprusside to assess endothelium-dependent and endothelium-independent microvascular reactivity, respectively.

RESULTS

Treatment with high-dose atorvastatin was associated with a significant decrease in IGF-1 levels compared to placebo (p<0.05, ANOVA repeated measures), whereas no effect was seen on IGFBP-1 or the IGF-1/IGFBP-1 ratio. These variables did not correlate with measurements of skin microvascular reactivity.

CONCLUSIONS

The study found that treatment with high-dose atorvastatin was associated with reduced IGF-1 levels, which may indicate a potential negative effect on microvascular function and long-term risk of microangiopathy development.

Senescent endothelial cells: Potential modulators of immunosenescence and ageing

Recent studies have demonstrated that the accumulation of senescent endothelial cells may be the primary cause of cardiovascular diseases. Because of their multifunctional properties, endothelial cells actively take part in stimulating the immune system and inflammation. In addition, ageing is characterized by the progressive deterioration of immune cells and a decline in the activation of the immune response. This results in a loss of the primary function of the immune system, which is eliminating damaged/senescent cells and neutralizing potential sources of harmful inflammatory reactions. In this review, we discuss cellular senescence and the senescence-associated secretory phenotype (SASP) of endothelial cells and summarize the link between endothelial cells and immunosenescence. We describe the possibility that age-related changes in Toll-like receptors (TLRs) and microRNAs can affect the phenotypes of senescent endothelial cells and immune cells via a negative feedback loop aimed at restraining the excessive pro-inflammatory response. This review also addresses the following questions: how do senescent endothelial cells influence ageing or age-related changes in the inflammatory burden; what is the connection between ECs and immunosenescence, and what are the crucial hypothetical pathways linking endothelial cells and the immune system during ageing.

IGF-Binding Proteins in Type-1 Diabetes Are More Severely Altered in the Presence of Complications

AIMS

Reduced levels of free and total insulin-like growth factor 1 (IGF-I) have been observed in type-1 diabetes (T1D) patients. The bioavailability of IGF-I from the circulation to the target cells is controlled by multifunctional IGF-binding proteins (IGFBPs). The aim of this study was to profile serum IGFBPs in T1D and its complications.

DESIGN

We measured the IGFBP levels in 3662 patient serum samples from our ongoing Phenome and Genome of Diabetes Autoimmunity (PAGODA) study. IGFBP levels of four different groups of T1D patients (with 0, 1, 2, and ≥3 complications) were compared with healthy controls.

RESULTS

Three serum IGFBPs (IGFBP-1, -2, and -6) are significantly higher in T1D patients, and these alterations are greater in the presence of diabetic complications. IGFBP-3 is lower in patients with diabetic complications. Analyses using quintiles revealed that risk of T1D complications increases with increasing concentrations of IGFBP-2 (fifth quintile ORs: 18-60, p < 10(-26)), IGFBP-1 (fifth quintile ORs: 8-20, p < 10(-15)), and IGFBP-6 (fifth quintile ORs: 3-148, p < 10(-3)). IGFBP-3 has a negative association with T1D complications (fifth quintile ORs: 0.12-0.25, p < 10(-5)).

CONCLUSION

We found that elevated serum levels of IGFBP-1, -2, and -6 were associated with T1D, and its complications and IGFBP-3 level was found to be decreased in T1D with complications. Given the known role of these IGFBPs, the overall impact of these alterations suggests a negative effect on IGF signaling.