Circulating irisin levels in functional hypothalamic amenorrhea: a new bone damage index? A pilot study

Abstract

Purpose Patients with functional hypothalamic amenorrhea (FHA) could commonly have bone damage, often preceded by metabolic alterations due to a relative energy deficit state. To date, there are no markers capable of predicting osteopenia before it is manifested on DXA. Irisin is a myokine that promotes the differentiation of osteoblastic cells and appears to be inversely correlated with the incidence of bone fragility and fractures in postmenopausal women. The aim of this study was to measure irisin levels in FHA patients and to correlate it with bone density parameters. Methods Thirty-two patients with FHA and 19 matched controls underwent the same clinical and laboratory evaluation. Results Irisin and body mass index (BMI) were significantly lower in the case group than in healthy controls (2.03 ± 0.12 vs. 2.42 ± 0.09 p < 0.05 and 19.43 ± 2.26 vs. 22.72 ± 0.67 p < 0.05, respectively). Additionally, total body mass density (BMD g/cm2) was significantly lower in the case group than in the healthy controls (1.09 ± 0.08 vs. 1.14 ± 0.05, p < 0.05), without signs of osteopenia. Conclusions The FHA group showed lower irisin levels associated with significantly reduced BMD parameters that did not reach the severity of osteopenia. Therefore, we could speculate that irisin could predict DXA results in assessing modifications of body composition parameters. Future research is warranted to study these parameters in a larger population to confirm our results, so that irisin could be used as a predictor and screening method for bone deprivation. Furthermore, irisin is strictly related to energy metabolism and could be an indirect marker of nutritional status in FHA patients, identifying earlier states of energy deficit.

Irisin and Bone in Sickness and in Health: A Narrative Review of the Literature

“…Irisin levels were positively associated with metrics of BMD and bone strength and structure in both athletes across all groups [96]. A more recent study revisited the subject of irisin changes in FHA, removing the factor of physical exercise [99]. Patients with FHA displayed significantly lower BMIs and irisin concentrations when compared to healthy aged-matched controls associated with lower BMDs, which, however, did not reach the osteopenic range [99].…”

“…A more recent study revisited the subject of irisin changes in FHA, removing the factor of physical exercise [99]. Patients with FHA displayed significantly lower BMIs and irisin concentrations when compared to healthy aged-matched controls associated with lower BMDs, which, however, did not reach the osteopenic range [99]. Of note, a similar decrease in irisin levels has not been reported in the context of anorexia nervosa (AN), which appears counterintuitive.…”

The Role of Irisin throughout Women’s Life Span

“…Another study showed lower irisin levels in non-athletes and non-anorexic women with FHA, compared to healthy controls [70]. The authors considered physical exercise and eating disorders as confounding factors because they influence serum irisin levels independently, and decided to focus on patients with FHA due to psychogenic stress.…”

“…The FHA group showed lower irisin levels associated with significantly reduced BMD parameters that did not reach the severity of osteopenia. Therefore, the authors hypothesized that irisin could predict DXA outcomes and, in turn, irisin measurement could allow earlier targeted therapies, to avoid osteoporosis [70].…”

Exercise Intervention for Alzheimer’s Disease: Unraveling Neurobiological Mechanisms and Assessing Effects

“…Exercise activates PGC-1α, up-regulating FNDC5/Irisin and reducing amyloid-beta (Aβ) production [74,75]. Irisin levels rise in response to exercise, potentially improving cognitive functions via various mechanisms, including promoting neuronal growth and reducing inflammation [76][77][78][79][80][81][82][83][84][85][86][87][88][89]. Irisin also influences the production of BDNF, a factor crucial for neuronal health [90][91][92].…”