Relationship of leptin, growth hormone, and insulin-like growth factor levels with body mass index and disease severity in patients with fibromyalgia syndrome

Association of circulating leptin, growth hormone, and ghrelin with fibromyalgia: A meta-analysis

OBJECTIVE

The aim of this study was to evaluate the relationship between levels of leptin, growth hormone (GH), and ghrelin in the bloodstream and fibromyalgia.

METHODS

We conducted a meta-analysis to compare the serum/plasma levels of leptin, GH, and ghrelin in individuals with fibromyalgia, as compared to healthy controls. The analysis included sixteen articles, which provided data from 697 fibromyalgia patients and 560 controls.

RESULTS

The meta-analysis found that there was no significant difference in leptin levels between fibromyalgia patients and controls overall (SMD = 0.324, 95% CI = -0.264 to 0.913, P = 0.281). However, when subgroup analysis was done based on geographically different populations, it showed a positive association between high leptin levels and fibromyalgia in European populations (SMD = 1.131, 95% CI = 0.197 to 2.064, P = 0.018), while no significant association was found in Latin American populations (SMD = -0.160, 95% CI = -0.847 to 0.528, P = 0.649). As for GH levels, there was no significant difference between fibromyalgia patients and controls overall (SMD = -0.903, 95% CI = -2.036 to 0.231, P = 0.119). However, when subgroup analysis was done based on geographically different populations, it revealed a significant decrease in GH levels in European populations with fibromyalgia (SMD = -2.341, 95% CI = -3.664 to -1.017, P = 0.001), while no significant association was found in North American populations. Lastly, the analysis of ghrelin levels showed no significant association with fibromyalgia overall (SMD = -0.661, 95% CI = -1.382 to 0.059, P = 0.072).

CONCLUSION

This meta-analysis shows that patients with fibromyalgia in Europeans have significantly higher levels of circulating leptin and GH. However, no significant association was found between ghrelin levels and fibromyalgia.

Altered response to Toll-like receptor 4 activation in fibromyalgia: A low-dose, human experimental endotoxemia pilot study

In this pilot study, a human intravenous injection of low-dose endotoxin (lipopolysaccharide, LPS) model was used to test if fibromyalgia is associated with altered immune responses to Toll-like receptor 4 (TLR4) activation. Eight women with moderately-severe fibromyalgia and eight healthy women were administered LPS at 0.1 ng/kg in session one and 0.4 ng/kg in session two. Blood draws were collected hourly to characterize the immune response. The primary analytes of interest, leptin and fractalkine, were assayed via commercial radioimmunoassay and enzyme-linked immunosorbent assay kits, respectively. Exploratory analyses were performed on 20 secreted cytokine assays by multiplex cytokine panels, collected hourly. Exploratory analyses were also performed on testosterone, estrogen, and cortisol levels, collected hourly. Additionally, standard clinical complete blood counts with differential (CBC-D) were collected before LPS administration and at the end of the session. The fibromyalgia group demonstrated enhanced leptin and suppressed fractalkine responses to LPS administration. In the exploratory analyses, the fibromyalgia group showed a lower release of IFN-γ, CXCL10, IL-17A, and IL-12 and higher release of IL-15, TARC, MDC, and eotaxin than the healthy group. The results of this study suggest that fibromyalgia may involve an altered immune response to TLR4 activation.

The relationship between serum leptin, insulin-like growth factor-1, and insulin-like growth factor binding protein-3 levels and clinical parameters in primary fibromyalgia patients

OBJECTIVE

The aim of this study was to investigate the levels of leptin, growth hormone, insulin-like growth factor-1, and insulin-like growth factor binding protein-3 and their relations with clinical parameters in patients with primary fibromyalgia and healthy controls.

METHODS

Our study was performed on 30 female patients with primary fibromyalgia and 30 healthy controls. The levels of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 were measured by a two-site immunoradiometric assay. The serum level of leptin was measured by the ELISA kit.

RESULTS

The serum level of leptin was significantly higher, but the serum levels of insulin-like growth factor-1 were significantly lower in patients with fibromyalgia syndrome than healthy controls (p<0.001). The leptin level was positively correlated with the Visual Analog Scale, Fibromyalgia Impact Questionnaire score, Beck Depression Inventory score, tender point count, age, and duration of disease (p<0.001), but it was negatively correlated with insulin-like growth factor-1 (p<0.001). The insulin-like growth factor-1 level was negatively correlated with age, Visual Analog Scale, Fibromyalgia Impact Questionnaire and Beck Depression Inventory scores, duration of disease, and tender point count (p<0.001).

CONCLUSION

Our results indicate that high levels of serum leptin and low levels of serum insulin-like growth factor-1 may play a role in the physiopathogenesis of fibromyalgia and may be related to some symptoms.

Stress-associated weight gain, fibromyalgia symptoms, cardiometabolic markers, and human growth hormone suppression respond to an amino acid supplement blend: Results of a prospective, cohort study

INTRODUCTION

An orally administered amino acid-based test supplement was recently shown to increase human growth hormone (hGH) in healthy adults. This prospective, observational, single-center, single-arm cohort study investigated the effects of 24 weeks of daily oral administration of the test supplement in individuals with stress-related weight gain, fibromyalgia (FM) and stress-related low-normal hGH production (15-30^th percentile for age-appropriate levels) on insulin-like growth factor 1 (IGF-1), an indicator of hGH levels caused by stress related stimulation of somatostatin.

METHODS

Participants continued to receive standard care. The primary endpoint was the change from baseline to endpoint (Week 24) in serum IGF-1. Additional endpoints included the change in body weight, clinical symptoms (assessed with the Revised Fibromyalgia Impact Questionnaire [FIQR], range 0-100, and Perceived Stress Scale [PSS], range 0-40), fasting cardiometabolic markers, tolerability, and safety. The study enrolled 84 fibromyalgia patients with low-normal age-adjusted IGF-1 serum levels. High mean ± Standard Deviation (SD) baseline FIQR and PSS scores of 76 ± 16 and 32 ± 5, respectively, indicated poor to moderate symptom management with standard care. All individuals completed 24 weeks.

RESULTS

Serum IGF-1 levels increased with a Week 24 mean± Standard Error (SE) change of 28.4 ± 3.0 ng/mL (p<0.001). Body weight was reduced with a Week 24 mean ± SE change of -5.5 ± 0.3 kg (p<0.001) (a 6.5% weight loss from baseline). The change from baseline in FIQR and PSS scores were -29.1 ± 1.1 and -20.0 ± 0.8, respectively (both p<0.001), indicating a substantial improvement. Statistically significant improvements from baseline to Week 24 were observed in systolic and diastolic blood pressure, HbA1c, LDL and HDL cholesterol, and triglycerides (all p<0.001). The supplement was well tolerated; no adverse events were reported.

DISCUSSION

Sustained augmentation of IGF-1 with the test supplement may represent a novel method of improving clinical symptoms, including stress-related weight gain, in individuals with fibromyalgia and stress-associated low-normal hGH.

Potential Role of Insulin-Like Growth Factors in Myofascial Pain Syndrome: A Narrative Review

ABSTRACT

Insulin-like growth factors have diverse functions in skeletal muscles by acting through multiple signaling pathways, including growth regulation and differentiation, anti-inflammation, and antioxidation. Insulin-like growth factors have anti-inflammatory effects and also play roles in nociceptive pathways, determining pain sensitivity, in addition to their protective role against ischemic injury in both the nervous system and skeletal muscle. In skeletal muscle, insulin-like growth factors maintain homeostasis, playing key roles in maintenance, accelerating muscle regeneration, and repair processes. As part of their maintenance role, increased levels of insulin-like growth factors may be required for the repair mechanisms after exercise. Although the role of insulin-like growth factors in myofascial pain syndrome is not completely understood, there is evidence from a recent study that insulin-like growth factor 2 levels in patients with myofascial pain syndrome are lower than those of healthy individuals and are associated with increased levels of inflammatory biomarkers. Importantly, higher insulin-like growth factor 2 levels are associated with increased pain severity in myofascial pain syndrome patients. This may suggest that too low or high insulin-like growth factor levels may contribute to musculoskeletal disorder process, whereas a midrange levels may optimize healing without contributing to pain hypersensitivity. Future studies are required to address the mechanisms of insulin-like growth factor 2 in myofascial pain syndrome and the optimal level as a therapeutic agent.

The Role of Nonshivering Thermogenesis Genes on Leptin Levels Regulation in Residents of the Coldest Region of Siberia

Leptin plays an important role in thermoregulation and is possibly associated with the microevolutionary processes of human adaptation to a cold climate. In this study, based on the Yakut population (n = 281 individuals) living in the coldest region of Siberia (t°minimum -71.2 °C), we analyze the serum leptin levels and data of 14 single nucleotide polymorphisms (SNPs) of 10 genes (UCP1, UCP2, UCP3, FNDC5, PPARGC1A, CIDEA, PTGS2, TRPV1, LEPR, BDNF) that are possibly involved in nonshivering thermogenesis processes. Our results demonstrate that from 14 studied SNPs of 10 genes, 2 SNPs (the TT rs3811787 genotype of the UCP1 gene and the GG rs6265 genotype of the BDNF gene) were associated with the elevated leptin levels in Yakut females (p < 0.05). Furthermore, of these two SNPs, the rs3811787 of the UCP1 gene demonstrated more indications of natural selection for cold climate adaptation. The prevalence gradient of the T-allele (rs3811787) of UCP1 increased from the south to the north across Eurasia, along the shore of the Arctic Ocean. Thereby, our study suggests the potential involvement of the UCP1 gene in the leptin-mediated thermoregulation mechanism, while the distribution of its allelic variants is probably related to human adaptation to a cold climate.