Serum growth hormone and insulin but not insulin-like growth factor-1 levels are elevated 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.

Potential role of blood biomarkers in patients with fibromyalgia: a systematic review with meta-analysis

ABSTRACT

Fibromyalgia (FM) is a complex chronic pain condition. Its symptoms are nonspecific, and to date, no objective test exists to confirm FM diagnosis. Potential objective measures include the circulating levels of blood biomarkers. This systematic review and meta-analysis aim to review studies assessing blood biomarkers' levels in patients with FM compared with healthy controls. We systematically searched the PubMed, MEDLINE, EMBASE, and PsycINFO databases. Fifty-four studies reporting the levels of biomarkers in blood in patients with FM were included. Data were extracted, and the methodological quality was assessed independently by 2 authors. The methodological quality of 9 studies (17%) was low. The results of most studies were not directly comparable given differences in methods and investigated target immune mediators. Thus, data from 40 studies only were meta-analyzed using a random-effects model. The meta-analysis showed that patients with FM had significantly lower levels of interleukin-1 β and higher levels of IL-6, IL-8, tumor necrosis factor-alpha, interferon gamma, C-reactive protein, and brain-derived neurotrophic factor compared with healthy controls. Nevertheless, this systematic literature review and meta-analysis could not support the notion that these blood biomarkers are specific biomarkers of FM. Our literature review, however, revealed that these same individual biomarkers may have the potential role of identifying underlying pathologies or other conditions that often coexist with FM. Future research is needed to evaluate the potential clinical value for these biomarkers while controlling for the various confounding variables.

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

OBJECTIVE

A high prevalence of obesity in fibromyalgia syndrome (FMS) predisposes patients to metabolic changes. It is not clear how the clinical manifestations of the disease affect metabolism. This study aimed to investigate leptin, growth hormone (GH), and insulin-like growth factor (IGF-1) levels in FMS, and their relationship with body mass index (BMI) and disease severity.

METHOD

This case-control study included 60 patients with FMS and 42 age- and sex-matched healthy controls. BMIs were recorded for all participants. The disease severity was assessed using the Fibromyalgia Impact Questionnaire (FIQ) and a visual analog scale (VAS). The serum levels of leptin, GH, and IGF-1 of all participants were measured using specific enzyme-linked immunosorbent assays.

RESULTS

Both groups had similar age (p = 0.058), sex (p = 0.25), and BMI (p = 0.29) distribution. The mean age of the FMS and the control groups was 40.7 ± 10.8 years and 36.2 ± 13.6 years, respectively. The mean BMI was 26.7 kg/m² in the FMS group. The GH (p = 0.037) and IGF-1 (p = 0.002) levels were statistically lower, and leptin (p = 0.002) levels were considerably higher in the FMS group than in the control group. The leptin values were positively correlated with age (p = 0.001; r = 0.386) and BMI (p < 0.001; r = 445). Insulin-like growth factor levels were negatively correlated with age (p < 0.001; r = - 0.605) and BMI (p < 0.001; r = - 0.564). Similarly, GH levels were negatively correlated with age (p = 0.040; r = - 0.243) and BMI (p < 0.001; p = - 0.420). None of the three hormones were associated with FIQ and VAS.

CONCLUSION

We found that leptin (high), GH (low), and IGF-1 (low) levels were statistically different, together with being independent of disease severity (FIQ, VAS), and correlated with BMI in the FMS group. These findings may be related with hypothalamo-pituitary axis dysfunction, BMI, and energy metabolism.

A Systematic Review of Growth Hormone in Pain Medicine: From Rodents to Humans

Objective

Growth hormone (GH) and GH-related signaling molecules play an important role in nociception and development of chronic pain. This review aims to examine the potential molecular mechanisms through which GH-related signaling modulates sensory hypersensitivity in rodents, the clinical pharmacology of GH, and the clinical evidence of GH treatment for several common pain syndromes.

Methods

A search was conducted using the PUBMED/MEDLINE database, Scopus, and the Cochrane library for all reports published in English on GH in pain management from inception through May 2018. A critical review was performed on the mechanisms of GH-related signaling and the pharmacology of GH. The levels of clinical evidence and implications for recommendations of all of the included studies were graded.

Results

The search yielded 379 articles, of which 201 articles were deemed irrelevant by reading the titles. There were 53 reports deemed relevant after reading abstracts. All of these 53 articles were retrieved for the analysis and discussion.

Conclusions

Dysfunction of the GH/insulin-like growth factor 1 (IGF-1)/ghrelin axis was linked to hyperalgesia and several common clinical pain syndromes. Low levels of GH and IGF-1 were linked to pain hypersensitivity, whereas ghrelin appeared to provide analgesic effects. Pretreatment of GH reversed mechanical and thermal hypersensitivity in an animal model of inflammatory pain. Clinical trials support GH treatment in a subgroup of patients with fibromyalgia syndrome (level of evidence: 1B+) or chronic lower back pain syndrome (level of evidence: 2C+).

GH/IGF1 axis disturbances in the fibromyalgia syndrome: is there a rationale for GH treatment?

Fibromyalgia Syndrome (FMS) is a frequent idiopathic condition in which patients experience intense pain in specific tender points, profound fatigue and sleep disturbances. Although pain had not account so far in growth hormone deficiency syndrome (GHD) description, symptoms of FMS are very similar; and there is strong evidence of decreased GH secretion at least in a subset of FMS patients. Is there an overlap of the two diseases? A systematic Medline/Embase search for preliminary proof-of-concept trials, but also larger placebo-controlled studies, have shown that GH replacement in low-IGF1 patients can significantly improve some symptoms of FMS and quality of life, suggesting a direct causal effect of GH deficiency. Despite the use of relatively high doses of GH in these patients, treatment seems to be well tolerated. Several mechanisms of action for GH in FMS relief have been suggested, including both central modulation of pain and peripheral musculo-tendinous effects, as already described in classic GHD.

[Etiology and pathophysiology of fibromyalgia syndrome and chronic widespread pain]

OBJECTIVE

To write a systematic review on the etiology and pathophysiology of the fibromyalgia syndrome (FMS) and of chronic widespread pain (CWP).

METHODS

An interdisciplinary level-3 guideline (i.e. systematic literature search and assessment, logic analysis, formal consensus procedure) for the diagnosis and therapy of FMS was created in cooperation with 10 medical and psychological societies and 2 patient self-help organizations. A literature search was performed covering all available review articles on the etiology and pathophysiology of FMS and CWP using the Cochrane Collaboration Reviews (1993-12/2006), Medline (1980-2006), PsychInfo (1966-12/2006), and Scopus (1980-12/2006). For the assignment of evidence classes the system of the Oxford Centre for Evidence-Based Medicine was applied. Consensus was achieved by a multi-step nominal group procedure.

RESULTS

FMS aggregates in families (evidence level 2c). Physical and psychological stress at the workplace are risk factors for the development of CWP and FMS. Affective disorders are risk factors for the development and maintenance of FMS. Operant learning mechanisms and sensitization are risk factors for the chronification of FMS (evidence levels 2b). Several factors are associated with the pathophysiology of FMS, but the causal relationship is unclear. This includes alterations of central pain pathways, hyporeactivity of the hypothalamus-pituitary-adrenal axis, increased systemic pro-inflammatory and reduced anti-inflammatory cytokine profiles and disturbances in the dopaminergic and serotonergic systems.

CONCLUSIONS

FMS is the common final product of various etiological factors and pathophysiological mechanisms.

ATP, calcium and magnesium levels in platelets of patients with primary fibromyalgia

OBJECTIVES

To evaluate the intracellular levels of the high energy adenosine triphosphate nucleotide ATP and essential divalent cations, calcium and magnesium, in platelets of patients affected by primary fibromyalgia syndrome (FMs).

DESIGN AND METHOD

Platelet ATP and cation concentrations were measured in 25 patients affected by FMs and 25 healthy volunteers through a chemiluminescent and a fluorimetric assay, respectively.

RESULTS

Significant lower ATP levels were observed inside platelets of FM patients (fmol ATP/plt: 0.0169+/-0.0012 vs. healthy controls, fmol ATP/plt: 0.0306+/-0.0023, mean+/-SEM) (*** P<0.0001). A trend towards higher calcium concentrations (P=0.06) together with significant increased magnesium levels were also reported in platelets of patients by comparison with controls (P=0.02).

CONCLUSIONS

This preliminary study suggests that disturbances in the homeostasis of platelet ATP metabolism-signaling and calcium-magnesium flows might have a relevance in the pathogenesis of FMs.

Serum ghrelin levels but not GH, IGF-1 and IGFBP-3 levels are altered in patients with fibromyalgia syndrome

INTRODUCTION

Both hypothalamo-pituitary-insulin-like growth factor-1 (IGF-1) axis and ghrelin levels may be altered in fibromyalgia syndrome (FMS) due to increased somatostatin tone. The aim of this study is to compare hypothalamo-pituitary-IGF-1 axis, ghrelin concentrations and their relations in premenopausal women with FMS and premenopausal healthy controls.

METHODS

Seventy-five women (47 FMS and 28 healthy women) were enrolled in the study. Fasting plasma glucose, serum growth hormone (GH), insulin, C-peptide, IGF-1, insulin-like growth factor binding protein-3 (IGFBP-3) and ghrelin levels were measured. Depressive symptoms were assessed using beck depression inventory. Pain intensity and sleep disturbance were recorded on a visual analog scale. The activity of daily living was assessed by fibromyalgia impact questionnaire.

RESULTS

There were no significant differences in GH, IGF-1, IGFBP-3, glucose, insulin, and C-peptide levels between patients and controls (p>0.05), whereas ghrelin levels were significantly lower in patients than controls (p<0.05). Ghrelin levels were not correlated with GH, IGF-1, IGFBP-3, glucose, insulin, and C-peptide levels while they were positively correlated with tender point score and sleep disturbance score and negatively correlated with pain intensity score.

CONCLUSION

Our results suggest that low levels of ghrelin in FMS are not related to the changes in hypothalamo-pituitary-IGF-1 axis but may be related to some symptoms of FMS. Our results need to be clarified by further studies.

Growth Hormone Perturbations in Fibromyalgia: A Review

OBJECTIVE

Fibromyalgia (FM) is a syndrome characterized by chronic widespread pain, fatigue, disrupted sleep, depression, and physical deconditioning. In this article, we review the literature on the normal activity of the hypothalamic-pituitary-growth hormone-insulin-like growth factor-1 (HP-GH-IGF-1) axis and its perturbations in FM subjects.

METHODS

Studies included in this review were accessed through an English language search of Cochrane Collaboration Reviews. Keyword MeSH terms included "fibromyalgia," "growth hormone" (GH), or "insulin-like growth factor-1" (IGF-1).

RESULTS

Twenty-six studies enrolling 2006 subjects were reviewed. Overall, low levels of IGF-1 were found in a subgroup of subjects. Growth hormone stimulation tests often revealed a suboptimal response, which did not always correlate with IGF-1 levels. No consistent defects in pituitary function were found. Of the 3 randomized placebo controlled studies, only 9 months of daily injectable recombinant GH reduced FM symptoms and normalized IGF-1.

CONCLUSIONS

These studies suggest that pituitary function is normal in FM and that reported changes in the HP-GH-IGF-1 axis are most likely hypothalamic in origin. The therapeutic efficacy of supplemental GH therapy in FM requires further study before any solid recommendations can be made.

Is further evaluation for growth hormone (GH) deficiency necessary in fibromyalgia patients with low serum insulin-like growth factor (IGF)-I levels?

OBJECTIVE

Fibromyalgia (FM) is characterized by diffuse pain, fatigue, and sleep disturbances; symptoms that resemble the adult growth hormone (GH) deficiency syndrome. Many FM patients have low serum GH levels, with a hypothesized aetiology of dysregulated GH/insulin-like growth factor (IGF)-I axis. The aim of this study was to assess the GH reserve in FM patients with low serum IGF-I levels using the GH-releasing hormone (GHRH)-arginine test.

DESIGN

We retrospectively reviewed the GHRH-arginine data of 77 FM patients with low serum IGF-I levels referred to our tertiary unit over a 4-year period.

RESULTS

Of the 77 FM patients, 13 patients (17%) failed the GHRH-arginine test. Further evaluation with pituitary imaging revealed normal pituitary glands (n=7), coincident microadenomas (n=4), empty sella (n=1) and pituitary cyst (n=1), and relevant medical histories such as previous head injury (n=4), Sheehan's syndrome (n=1), and whiplash injury (n=1). In contrast, the remaining 64 patients (83%) that responded to the GHRH-arginine test demonstrated higher peak GH levels compared to age and BMI-matched controls (n=24).

CONCLUSION

Our data shows that a subpopulation of FM patients with low serum IGF-I levels will fail the GHRH-arginine test. We, thus, recommend that the GH reserve of these patients should be evaluated further, as GH replacement may potentially improve the symptomatology of those with true GH deficiency. Additionally, the increased GH response rates to GHRH-arginine stimulation in the majority of FM patients with low serum IGF-I levels further supports the hypothesis of a dysregulated GH/IGF-I axis in the pathophysiology of FM.

Role of the Growth Hormone/Insulin-like Growth Factor-1 Paracrine Axis in Rheumatic Diseases

OBJECTIVES

Hypothalamic-pituitary axis abnormalities have been associated with systemic disturbances in several rheumatic diseases. Longitudinal analysis of erythrocyte, serum, urinary and synovial fluid growth hormone (GH), insulin-like growth factor-1 (IGF-1), and somatostatin levels could provide important surrogate measures of disease activity in rheumatic diseases.

METHODS

The authors reviewed the population and longitudinal studies literature on GH, IGF-1, and somatostatin levels in rheumatic disorders using the PubMed and Medlines databases from the National Library of Medicine. In addition to the literature search, primary data were analyzed for basal somatostatin levels in patients with hand, knee, and spine osteoarthritis (OA) as well as primary and secondary hip OA.

RESULTS

A review of the literature supports the view that hypothalamic-pituitary axis dysfunction accompanies clinical symptoms in many rheumatic diseases. In studies from our laboratory, serum GH levels were elevated in patients with OA, rheumatoid arthritis (RA), fibromyalgia, and diffuse idiopathic skeletal hyperostosis but not in patients with gout, pseudogout, or systemic lupus erythematosus. In OA and RA, synovial fluid GH levels exceeded serum GH levels. However, the literature remains controversial regarding the significance of changes in IGF-1 levels in rheumatic disorders. Many studies support an inverse relationship between age and IGF-1. Elevated serum GH levels in various rheumatic diseases were not coupled to changes in serum IGF-1 in diffuse idiopathic skeletal hyperostosis, RA, and fibromyalgia. In particular, serum IGF-1 levels in OA were shown to be lower or no different compared with age-matched normal subjects. Further, in OA, impaired articular chondrocyte response to IGF-1 was attributed, in part, to low synovial fluid IGF-1 that further compromised IGF-1 chondrocyte responses as a result of increased levels of synovial fluid IGF-1 binding proteins. Of note, serum somatostatin levels and "specific" somatostatin receptor levels were often lower in RA and systemic lupus erythematosus, but basal serum somatostatin levels were generally not altered in OA.

CONCLUSIONS

The results of these analyses support the view that some rheumatic diseases such as OA and diffuse idiopathic skeletal hyperostosis, heretofore considered to be purely focal and degenerative, could be reclassified as systemic metabolic disturbances. We propose that serum GH, IGF-1, and somatostatin levels be monitored on a longitudinal basis during the course of medical therapy of rheumatic diseases to determine the extent to which changes in clinical symptoms (exemplified by reduced pain and inflammation and improved range of joint motion) are accompanied by changes in the basal concentration of these hypothalamic/pituitary-related hormones.

Age-related changes in serum growth hormone, insulin-like growth factor-1 and somatostatin in system lupus erythematosus

BACKGROUND

Systemic lupus erythematosus is an age- and gender-associated autoimmune disorder. Previous studies suggested that defects in the hypothalamic/pituitary axis contributed to systemic lupus erythematosus disease progression which could also involve growth hormone, insulin-like growth factor-1 and somatostatin function. This study was designed to compare basal serum growth hormone, insulin-like growth factor-1 and somatostatin levels in female systemic lupus erythematosus patients to a group of normal female subjects.

METHODS

Basal serum growth hormone, insulin-like growth factor-1 and somatostatin levels were measured by standard radioimmunoassay.

RESULTS

Serum growth hormone levels failed to correlate with age (r2 = 3.03) in the entire group of normal subjects (i.e. 20 - 80 years). In contrast, serum insulin-like growth factor-1 levels were inversely correlated with age (adjusted r2 = 0.092). Of note, serum growth hormone was positively correlated with age (adjusted r2 = 0.269) in the 20 - 46 year range which overlapped with the age range of patients in the systemic lupus erythematosus group. In that regard, serum growth hormone levels were not significantly higher compared to either the entire group of normal subjects (20 - 80 yrs) or to normal subjects age-matched to the systemic lupus erythematosus patients. Serum insulin-like growth factor-1 levels were significantly elevated (p < 0.001) in systemic lupus erythematosus patients, but only when compared to the entire group of normal subjects. Serum somatostatin levels differed from normal subjects only in older (i.e. >55 yrs) systemic lupus erythematosus patients.

CONCLUSIONS

These results indicated that systemic lupus erythematosus was not characterized by a modulation of the growth hormone/insulin-like growth factor-1 paracrine axis when serum samples from systemic lupus erythematosus patients were compared to age- matched normal female subjects. These results in systemic lupus erythematosus differ from those previously reported in other musculoskeletal disorders such as rheumatoid arthritis, osteoarthritis, fibromyalgia, diffuse idiopathic skeletal hyperostosis and hypermobility syndrome where significantly higher serum growth hormone levels were found. Somatostatin levels in elderly systemic lupus erythematosus patients may provide a clinical marker of disease activity in these patients.