Red and White Blood Cell Counts Are Associated With Bone Marrow Adipose Tissue, Bone Mineral Density, and Bone Microarchitecture in Premenopausal Women

Bone marrow adipose tissue (BMAT) resides within the bone marrow microenvironment where its function remains poorly understood. BMAT is elevated in anorexia nervosa, a disease model of chronic starvation, despite depletion of other fat depots. In addition to BMAT, the marrow microenvironment also consists of osteoblast and hematopoietic progenitors. BMAT is inversely associated with bone mineral density (BMD) in multiple populations including women with anorexia nervosa, and regulates hematopoiesis in animal models. We hypothesized that BMAT would be associated with circulating populations of hematopoietic cells (red and white blood cells) in humans and performed a post hoc analysis of two studies—a cross‐sectional study and a longitudinal study—to investigate this hypothesis. We studied 89 premenopausal women cross‐sectionally (median age [interquartile range], 27 [24.5, 31.7] years), including 35 with anorexia nervosa. We investigated associations between red blood cell (RBC) and white blood cell (WBC) counts and BMAT assessed by 1H‐magnetic resonance spectroscopy, BMD assessed by DXA, and bone microarchitecture assessed by HR‐pQCT. In addition, we analyzed longitudinal data in six premenopausal women with anorexia nervosa treated with transdermal estrogen for 6 months and measured changes in BMAT and blood cell counts during treatment. Cross‐sectionally, BMAT was inversely associated with WBC and RBC counts. In contrast, BMD and parameters of bone microarchitecture were positively associated with WBC and RBC. In women with anorexia nervosa treated with transdermal estrogen for 6 months, decreases in BMAT were significantly associated with increases in both RBC and hematocrit (rho = −0.83, p = 0.04 for both). In conclusion, we show that BMAT is inversely associated with WBC and RBC in premenopausal women, and there is a potential association between longitudinal changes in BMAT and changes in RBC. These associations warrant further study and may provide further insight into the role and function of this understudied adipose depot. © 2020 American Society for Bone and Mineral Research.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155991/1/jbmr3986.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155991/2/jbmr3986_am.pd

Serum FGF-21 levels are associated with worsened radial trabecular bone microarchitecture and decreased radial bone strength in women with anorexia nervosa.

BACKGROUND: Anorexia nervosa (AN) is a psychiatric disorder characterized by self-induced starvation and low body weight. Women with AN have impaired bone formation, low bone mass and an increased risk of fracture. FGF-21 is a hormone secreted by the liver in starvation and FGF-21 transgenic mice have significant bone loss due to an uncoupling of bone resorption and bone formation. We hypothesized that FGF-21 may contribute to the low bone mass state of AN. SUBJECTS AND METHODS: We studied 46 women: 20 with AN (median age [interquartile range]: 27.5 [25, 30.75] years) and 26 normal-weight controls (NWC) of similar age (25 [24, 28.5] years). We investigated associations between serum FGF-21 and 1) aBMD measured by dual energy X-ray absorptiometry, 2) parameters of bone microarchitecture in the distal radius and tibia measured by high-resolution peripheral quantitative CT and 3) bone strength, estimated by microfinite element analysis. RESULTS: FGF-21 levels were similar in AN and NWC (AN: 33.1 [18.1, 117.0] pg/ml vs. NWC: 57.4 [23.8, 107.1] pg/ml; p = 0.54). There was a significant inverse association between log FGF-21 and trabecular number in the radius in both AN (R = -0.57, p \u3c 0.01) and NWC (R=-0.53, p \u3c 0.01) and a significant positive association between log FGF-21 and trabecular separation in the radius in AN (R = 0.50, p \u3c 0.03) and NWC (R = 0.52, p \u3c 0.01). Estimates of radial bone strength were inversely associated with log FGF-21 in AN (R = -0.50, p \u3c 0.03 for both stiffness and failure load). There were no associations between FGF-21 and aBMD, cortical parameters or tibial parameters in the AN or NWC groups. CONCLUSIONS: FGF-21 may be an important determinant of trabecular skeletal homeostasis in AN

Treatment With a Ghrelin Agonist in Outpatient Women With Anorexia Nervosa: A Randomized Clinical Trial.

OBJECTIVE: To assess the effects of relamorelin-an agonist of the appetite-stimulating hormone ghrelin, which has effects on gastric emptying-on (1) weight gain and (2) gastric emptying in women with anorexia nervosa. METHODS: In a randomized, double-blind, placebo-controlled design, the effects of the ghrelin agonist relamorelin were studied in 22 outpatient women with anorexia nervosa, diagnosed using DSM-5 criteria. The study was conducted at the Massachusetts General Hospital Clinical Research Center between March 11, 2013, and February 26, 2015. Ten participants were randomly assigned to relamorelin 100 μg subcutaneously daily (mean ± SEM age: 28.9 ± 2.4 y), and 12 were randomly assigned to placebo (28.9 ± 1.9 y). We measured changes in weight and gastric emptying time using a gastric emptying breath test (GEBT) for relamorelin versus placebo after 4 weeks of treatment. RESULTS: At baseline, subjects did not differ in weight, plasma ghrelin levels, or gastric emptying time. Three subjects randomized to relamorelin stopped use of the study medication due to reported feelings of increased hunger. After 4 weeks, there was a trend toward an increase in weight in participants randomized to relamorelin (mean ± SEM change: 0.86 ± 0.40 kg) compared to placebo (0.04 ± 0.28 kg; P = .07), and gastric emptying time was significantly shorter in patients taking relamorelin (median [interquartile range]: 58.0 [51.0, 78.0] minutes) compared to placebo (85.0 [75.8,100.5] minutes; P = .03). CONCLUSIONS: Treatment with a ghrelin agonist in women with anorexia nervosa significantly decreases gastric emptying time, leads to a trend in weight gain after only 4 weeks, and is well-tolerated. Further study is necessary to determine the long-term safety and efficacy of a ghrelin agonist in the treatment of anorexia nervosa. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01642550

The Upregulation of Molecules Related to Tumor Immune Escape in Human Pituitary Adenomas

Human pituitary adenomas are one of the most common intracranial neoplasms. Although most of these tumors are benign and can be treated medically or by transsphenoidal surgery, a subset of these tumors are fast-growing, aggressive, recur, and remain a therapeutic dilemma. Because antibodies against immune checkpoint receptors PD-1 and CLTA-4 are now routinely used for cancer treatment, we quantified the expression of mRNA coding for PD-1, CLTA-4, and their ligands, PD-L1, PD-L2, CD80, and CD86 in human pituitary adenomas and normal pituitary glands, with the ultimate goal of exploiting immune checkpoint therapy in aggressive pituitary adenomas. Aggressive pituitary adenomas demonstrated an increased expression of PD-L2, CD80, and CD86 in compared to that of normal human pituitary glands. Furthermore, aggressive pituitary tumors demonstrated significantly higher levels of CD80 and CD86 compared to non-aggressive tumors. Our results establish a rationale for studying a potential role for immune checkpoint inhibition therapy in the treatment of pituitary adenomas