The association between insulin-like growth factor I and bone turnover markers in the general adult population

Biomarkers and Periodontal Regenerative Approaches

The ultimate goal in periodontal therapy is the complete re-establishment of the lost tissues. Dental researchers and clinicians are continuously working to develop current therapeutic techniques and technologies that can regenerate damaged periodontal tissues. Predicting the outcome of the treatment is a challenging endeavor, because a variety of local and systemic variables can affect the success of the applied regenerative therapy. To real-time monitor the biological changes during periodontitis or after periodontal treatment, various biomarkers have been studied in periodontology. This article discusses the available evidence on the use of biomarkers in the detection of periodontal regeneration.

Insulin-like growth factor-1 positively associated with bone formation markers and creatine kinase in adults with general physical activity

BACKGROUND

The Insulin-like growth factor-1 (IGF-1) is primarily synthesized by hepatocytes in a growth hormone (GH)-dependent manner, it is also produced by bone and muscle. The effects of exercise on the associations between IGF-1 levels and bone turnover markers (BTM) were found in the previous studies. However, the associations between the levels of IGF-1 and BTM, liver function tests, and skeletal muscle markers in adults with general physical activity were not clear.

METHODS

Ninety-four participants were recruited from healthy survey. Blood samples were collected to analyze the levels of IGF-1, total protein (TP), albumin (Alb), total bilirubin (T-Bil), direct bilirubin (D-Bil), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), bone alkaline phosphatase (BALP), lactate dehydrogenase (LDH), creatine kinase (CK), creatinine (CRTN), and glucose. Urine samples were collected to analyze the CRTN and deoxypyridinoline (Dpd) levels.

RESULTS

The positively significant associations were found between the IGF-1 levels and the levels of ALP, BALP, and CK, respectively. No significant associations were found between the IGF-1 levels and the levels of TP, Alb, A/G, T-Bil, D-Bil, AST, ALT, LDH, glucose, urinary CRTN, urinary Dpd, and Dpd/CRTN ratios, respectively.

CONCLUSION

The serum IGF-1 levels associated with the levels of skeletal muscle and bone formation markers (BFM), not the bone resorption markers under general physical activity in the healthy adults. The physician needs to consider the effects of bone formation and skeletal muscle markers on the IGF-1 levels in the management of IGF-1-related disorders.

Are the Effects of Oral and Vaginal Contraceptives on Bone Formation in Young Women Mediated via the Growth Hormone-IGF-I Axis?

Purpose: Combined hormonal contraceptive therapy has been associated with negative bone mineral density outcomes that may be route-dependent [i.e., combined oral contraception (COC) vs. contraceptive vaginal ring (CVR)] and involve the hepatic growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis. The objective of the pilot study was to assess the impact of route of contraceptive administration on IGF-I and procollagen type I N-terminal propeptide (PINP) responses to an IGF-I Generation Test. We hypothesized that the peak rise in IGF-I and PINP concentration and area under the curve (AUC) would be attenuated following COC, but not CVR, use. Methods: Healthy, premenopausal women not taking hormonal contraception were recruited. Women were enrolled in the control group (n = 8) or randomly assigned to COC (n = 8) or CVR (n = 8) for two contraceptive cycles. IGF-I Generation Tests were used as a probe to stimulate IGF-I release and were completed during the pre-intervention and intervention phases. Serum IGF-I and PINP were measured during both IGF-I Generation Tests. The study was registered at ClinicalTrials.gov (NCT02367833). Results: Compared to the pre-intervention phase, peak IGF-I concentration in response to the IGF-I Generation Test in the intervention phase was suppressed in the COC group (p < 0.001), but not the CVR or Control groups (p > 0.090). Additionally, compared to the pre-intervention phase, PINP AUC during the intervention phase was suppressed in both COC and CVR groups (p < 0.001), while no difference was observed in the control group (p = 0.980). Conclusion: These data suggest that changes in recombinant human GH-stimulated hepatic IGF-I synthesis in response to combined hormonal contraception (CHC) use are dependent on route of CHC administration, while the influence on PINP is route-independent. Future research is needed to expand these results with larger randomized control trials in all age ranges of women who utilize hormonal contraception. Clinical Trial Registration: www.ClinicalTrials.gov registration NCT02367833.

Caloric restriction induces anabolic resistance to resistance exercise

Purpose

Weight loss can result in the loss of muscle mass and bone mineral density. Resistance exercise is commonly prescribed to attenuate these effects. However, the anabolic endocrine response to resistance exercise during caloric restriction has not been characterized.

Methods

Participants underwent 3-day conditions of caloric restriction (15 kcal kg FFM⁻¹) with post-exercise carbohydrate (CRC) and with post-exercise protein (CRP), and an energy balance control (40 kcal kg FFM⁻¹) with post-exercise carbohydrate (CON). Serial blood draws were taken following five sets of five repetitions of the barbell back squat exercise on day 3 of each condition.

Results

In CRC and CRP, respectively, growth hormone peaked at 2.6 ± 0.4 and 2.5 ± 0.9 times the peak concentrations observed during CON. Despite this, insulin-like growth factor-1 concentrations declined 18.3 ± 3.4% in CRC and 27.2 ± 3.8% in CRP, which was greater than the 7.6 ± 3.6% decline in CON, over the subsequent 24 h. Sclerostin increased over the first 2 days of each intervention by 19.2 ± 5.6% in CRC, 21.8 ± 6.2% in CRP and 13.4 ± 5.9% in CON, but following the resistance exercise bout, these increases were attenuated and no longer significant.

Conclusion

During caloric restriction, there is considerable endocrine anabolic resistance to a single bout of resistance exercise which persists in the presence of post-exercise whey protein supplementation. Alternative strategies to restore the sensitivity of insulin-like growth factor-1 to growth hormone need to be explored.

Electronic supplementary material

The online version of this article (10.1007/s00421-020-04354-0) contains supplementary material, which is available to authorized users.

The association of testosterone, sex hormone-binding globulin, and insulin-like growth factor-1 with bone parameters in Korean men aged 50 years or older

Testosterone and insulin-like growth factor-1 (IGF-1) are essential factors for the maintenance of bone health in men. However, the results for the association of testosterone and IGF-1 with bone parameters were not consistent in prior studies. We evaluated the relationship of testosterone, sex hormone-binding globulin (SHBG), and IGF-1 with bone mineral density (BMD) and bone turnover markers (BTMs) in Korean men. We enrolled 1227 men aged ≥50 years in this cross-sectional study. Serum levels of total testosterone (TT), SHBG, IGF-1, osteocalcin, and C-terminal cross-linking telopeptide of type I collagen (CTX) were measured. Free testosterone (FT) was calculated using Vermeulen's method. BMD was measured by dual-energy X-ray absorptiometry. TT level was not related to BMD or BTMs in the unadjusted model; however, after adjusting for SHBG and IGF-1, the association between TT and BTMs was significant (β = -0.139 for osteocalcin and β = -0.204 for CTX). SHBG levels were negatively associated with lumbar BMD, and positively associated with BTMs in all models. As SHBG level increased, the prevalence of osteopenia or osteoporosis defined by BMD significantly increased (OR of 1SD change, 1.24). IGF-1 levels were significantly related with BMD, but not with BTMs. Meanwhile, FT levels were positively associated with BMD and negatively associated with BTMs. In conclusion, SHBG levels were independently related with bone parameters and osteopenia in men aged ≥50 years. IGF-1 levels were positively associated with BMD, but not with BTMs. SHBG may play a role in regulating age-related bone loss in men after middle-age.

Insulin-Like Growth Factor I Does Not Drive New Bone Formation in Experimental Arthritis

Introduction

Insulin like growth factor (IGF)-I can act on a variety of cells involved in cartilage and bone repair, yet IGF-I has not been studied extensively in the context of inflammatory arthritis. The objective of this study was to investigate whether IGF-I overexpression in the osteoblast lineage could lead to increased reparative or pathological bone formation in rheumatoid arthritis and/or spondyloarthritis respectively.

Methods

Mice overexpressing IGF-I in the osteoblast lineage (Ob-IGF-I^+/-) line 324–7 were studied during collagen induced arthritis and in the DBA/1 aging model for ankylosing enthesitis. Mice were scored clinically and peripheral joints were analysed histologically for the presence of hypertrophic chondrocytes and osteocalcin positive osteoblasts.

Results

90–100% of the mice developed CIA with no differences between the Ob-IGF-I^+/- and non-transgenic littermates. Histological analysis revealed similar levels of hypertrophic chondrocytes and osteocalcin positive osteoblasts in the ankle joints. In the DBA/1 aging model for ankylosing enthesitis 60% of the mice in both groups had a clinical score 1<. Severity was similar between both groups. Histological analysis revealed the presence of hypertrophic chondrocytes and osteocalcin positive osteoblasts in the toes in equal levels.

Conclusion

Overexpression of IGF-I in the osteoblast lineage does not contribute to an increase in repair of erosions or syndesmophyte formation in mouse models for destructive and remodeling arthritis.

Markers of bone turnover in patients with epilepsy and their relationship to management of bone diseases induced by antiepileptic drugs

Data from cross-sectional and prospective studies revealed that patients with epilepsy and on long-term treatment with antiepileptic drugs (AEDs) are at increased risk for metabolic bone diseases. Bone diseases were reported in about 50% of patients on AEDs. Low bone mineral density, osteopenia/osteoporosis, osteomalacia, rickets, altered concentration of bone turnover markers and fractures were reported with phenobarbital, phenytoin, carbamazepine, valproate, oxcarbazepine and lamotrigine. The mechanisms for AEDs-induced bone diseases are heterogeneous and include hypovitaminosis D, hypocalcemia and direct acceleration of bone loss and/or reduction of bone formation. This article reviews the evidence, predictors and mechanisms of AEDs-induced bone abnormalities and its clinical implications. For patients on AEDs, regular monitoring of bone health is recommended. Prophylactic administration of calcium and vitamin D is recommended for all patients. Treatment doses of calcium and vitamin D and even anti-resorptive drug therapy are reserved for patients at high risk of pathological fracture.

Differences in bone mineral density, markers of bone turnover and extracellular matrix and daily life muscular activity among patients with recent motor-incomplete versus motor-complete spinal cord injury

Spinal cord injury (SCI) leads to severe bone loss, but the associated mechanisms are poorly described in incomplete SCI individuals. The purpose of the study is to compare alterations in bone mineral density (BMD) and serum biomarkers of bone turnover in recent motor-incomplete to -complete SCI men, as well as to describe their physical activity and spasticity. We studied 31 men with acute SCI. Whole-body DXA scans, serum biomarkers and self-reported activity and spasticity were examined 1 and/or 3 and 12 months after the injury. We observed a decrease in proximal femur BMD (p < 0.02) in both the groups. Serum phosphate and carboxy-terminal-collagen crosslinks were significantly lower in motor-incomplete versus complete SCI men, whereas albumin-corrected Ca(2+) (p = 0.02) were lower only 3 months after injury. When data from all 31 SCI participants were pooled, we observed increased serum matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of MMP-2 (TIMP-2) (p < 0.02) whereas TIMP-1 decreased (p = 0.03). BMD correlated positively with self-reported activity (r = 0.59, p = 0.04) and negatively with spasticity (r = 0.74, p = 0.02) 12 months after injury. As a summary, men with motor-incomplete SCI developed significant proximal femur bone loss 12 months after injury and exhibited increased bone resorption throughout the first year after the injury. Compared with complete SCI men, incomplete SCI men show attenuated bone resorption. Our pooled data show increased turnover of extracellular matrix after injury and that increased exercise before and after injury correlated with reduced bone loss.

A scallop IGF binding protein gene: molecular characterization and association of variants with growth traits

Background

Scallops represent economically important aquaculture shellfish. The identification of genes and genetic variants related to scallop growth could benefit high-yielding scallop breeding. The insulin-like growth factor (IGF) system is essential for growth and development, with IGF binding proteins (IGFBPs) serving as the major regulators of IGF actions. Although an effect of IGF on growth was detected in bivalve, IGFBP has not been reported, and members of the IGF system have not been characterized in scallop.

Results

We cloned and characterized an IGFBP (PyIGFBP) gene from the aquaculture bivalve species, Yesso scallop (Patinopecten yessoensis, Jay, 1857). Its full-length cDNA sequence was 1,445 bp, with an open reading frame of 378 bp, encoding 125 amino acids, and its genomic sequence was 10,193 bp, consisting of three exons and two introns. The amino acid sequence exhibited the characteristics of IGFBPs, including multiple cysteine residues and relatively conserved motifs in the N-terminal and C-terminal domains. Expression analysis indicated that PyIGFBP was expressed in all the tissues and developmental stages examined, with a significantly higher level in the mantle than in other tissues and a significantly higher level in gastrulae and trochophore larvae than in other stages. Furthermore, three single nucleotide polymorphisms (SNPs) were identified in this gene. SNP c.1054A>G was significantly associated with both shell and soft body traits in two populations, with the highest trait values in GG type scallops and lowest in AG type ones.

Conclusion

We cloned and characterized an IGFBP gene in a bivalve, and this report also represents the first characterizing an IGF system gene in scallops. A SNP associated with scallop growth for both the shell and soft body was identified in this gene. In addition to providing a candidate marker for scallop breeding, our results also suggest the role of PyIGFBP in scallop growth.

Serum sclerostin levels are decreased in adult patients with different types of osteogenesis imperfecta

CONTEXT

There are no specific biochemical bone markers available for osteogenesis imperfecta (OI), and the role of sclerostin as a key regulator of bone formation in OI is unknown.

OBJECTIVES

We aimed to evaluate the role of sclerostin and its association with bone turnover markers as well as body composition parameters in adult patients with different types of OI.

DESIGN, SETTING, AND PARTICIPANTS

This was a case-control study in 27 adult patients and 50 healthy age- and gender-matched controls.

MAIN OUTCOME MEASURES

Serum sclerostin levels and bone turnover markers including serum osteocalcin, amino terminal propeptide of type I procollagen, and CrossLaps as well as body composition parameters were determined in mild OI stage I (OI-I) and moderate-severe OI stages III-IV (OI-III-IV), according to Sillence classification. Data were compared with healthy controls.

RESULTS

Sclerostin levels were significantly lower in OI-I (19.9 ± 10.9 pmol/L; P < .001) and OI-III-IV (13.3 ± 10.0 pmol/L; P < .001) compared with healthy adults (45.3 ± 14.9 pmol/L), even after adjustment for age, sex, bone mineral content, and body mass index. CrossLaps and PTH were significantly lower in OI-I (0.197 ± 0.15 ng/L; P = .007 and 33.7 ± 19.1 pg/L; P = .033, respectively) and OI-III-IV (0.221 ± 0.18 ng/L; P = .039, and 27.9 ± 14.7 pg/L; P = .001, respectively) than in healthy controls (0.322 ± 0.15 ng/L and 45.0 ± 16.6 pg/L). Amino-terminal propeptide of type I procollagen was below the reference range for OI-I and OI-III-IV. Patients with OI were shorter and lighter and had a decreased bone mineral content (P < .001) but similar fat distribution and lean body mass, compared with controls. Serum sclerostin levels were not related to any bone marker except osteocalcin, the number of prevalent fractures, or body composition readings.

CONCLUSION

Decreased sclerostin levels in OI might reflect a down-regulation or negative feedback mechanism to prevent further bone loss.

The polymorphism of Insulin-like growth factor-I (IGF-I) is related to osteoporosis and bone mineral density in postmenopausal population

OBJECTIVE

It has been shown that Insulin-like growth factor-1 (IGF-1) may be related with bone mineral density (BMD) or osteoporosis. But there are few evidences on the role of genetic variation of IGF-1 on the BMD or osteoporosis. We observed the relationship between polymorphisms of IGF-1(rs35767, rs2288377 and rs5742612) with osteoporosis and BMD in the postmenopausal female population in our study.

METHODS

A total of 216 postmenopausal women with a primary diagnosis of osteoporosis and 220 normal healthy women were included in the study. Genomic DNA of IGF-1 rs35767, rs2288377 and rs5742612 was extracted from the whole blood using QIAamp blood DNA mini kits (QIAGEN, Hilden, Germany) according to the methods recommended by the manufacturer.

RESULTS

We found that T allele of rs35767 had higher increased risk of osteoporosis (OR=1.34, 95%CI=1.0-1.81). Those carrying T allele of rs35767 had a significant lower BMD at L1-L4 vertebrae, femoral neck, total hip and trochanter when compared with those carrying C allele (P < 0.05). In addition, the BMD of L1-L4 vertebrae, femoral neck, total hip and trochanter decreased by 2.09%, 3.74%, 3.52% and 2.54% in women carrying T alleles compared with those carrying C alleles.

CONCLUSION

Our study suggests that polymorphism in IGF-I rs35767 was significantly associated with BMD and osteoporosis in postmenopausal female population, and polymorphism of rs35767 could be a marker for lower BMD and risk of osteoporosis.

Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis

Background. Growth hormone (GH) and insulin-like growth factor (IGF-1) are fundamental in skeletal growth during puberty and bone health throughout life. GH increases tissue formation by acting directly and indirectly on target cells; IGF-1 is a critical mediator of bone growth. Clinical studies reporting the use of GH and IGF-1 in osteoporosis and fracture healing are outlined. Methods. A Pubmed search revealed 39 clinical studies reporting the effects of GH and IGF-1 administration on bone metabolism in osteopenic and osteoporotic human subjects and on bone healing in operated patients with normal GH secretion. Eighteen clinical studies considered the effect with GH treatment, fourteen studies reported the clinical effects with IGF-1 administration, and seven related to the GH/IGF-1 effect on bone healing. Results. Both GH and IGF-1 administration significantly increased bone resorption and bone formation in the most studies. GH/IGF-1 administration in patients with hip or tibial fractures resulted in increased bone healing, rapid clinical improvements. Some conflicting results were evidenced. Conclusions. GH and IGF-1 therapy has a significant anabolic effect. GH administration for the treatment of osteoporosis and bone fractures may greatly improve clinical outcome. GH interacts with sex steroids in the anabolic process. GH resistance process is considered.