Singh, Ravinder

Background: Decreased testosterone (TTST) and sex hormone binding globin (SHBG) contribute to development of cardiometabolic disorders in obese men. We aimed to determine the effect of weight gain and weight loss on TTST and SHBG in healthy men and to examine their relationship with endothelial function. Method: 25 normal weight healthy men underwent an overfeeding protocol to gain 5% body weight over 8 weeks. Following weight gain, they underwent 8 weeks of weight loss. TTST, SHBG and endothelial function (brachial artery flow‐mediated dilation, FMD) were measured at baseline (T1), after weight gain (T2) and after weight loss (T3). Results: Volunteers gained 4 ± 1.3 kg and subsequently lost 3.2 ± 1.5 kg of body weight. TTST levels did not change (T1: 18.85 ± 6.2 nmol/L, T2: 19.3 ± 6.9 nmol/L, T3: 20.3 ± 7.6 nmol/L). However, SHBG decreased during weight gain (p=0.04) and increased during weight loss (p=0.0005) (T1: 22.8 ± 10.5 nmol/L, T2: 20.8 ± 11.1 nmol/L, T3: 25.58 ± 11.5 nmol/L). Furthermore, SHBG reduction during weight gain tended to correlate with decreases in FMD (p=0.06; R 2 =0.15). During weight loss, increases in SHBG correlate negatively with changes in FMD (p=0.008; R 2 =0.32). Conclusion : In normal weight healthy men, SHBG decreases with modest weight gain and increases with weight loss. TTST does not change. Changes in SHBG partly predict improvements in endothelial function with weight loss. Grant Funding Source : Supported by AHA 11SDG7260046, R21 DK81014, AHA 13POST16420009

Abstract Background: Frailty is characterized by an increased vulnerability and a decline in physiological reserve. Frailty has been previously linked to cortisol concentrations and blunted diurnal cortisol secretion. Our objective was to determine the association of urine steroid metabolome and its diurnal variation with frailty and prefrailty in older adults. Methods: Cross-sectional study of community-dwelling adults ≥ 50 years. Participants with adrenal disorders, end-stage renal or liver disease, on exogenous steroids or drugs affecting steroid metabolism were excluded. All participants completed day and night separate urine collection. Frailty was assessed using a phenotype model (weight loss, exhaustion, grip strength, low physical activity, and slow walking pace). Participants were characterized as frail if they met at least three criteria, pre-frail if they fulfilled one or two criteria, and robust if no criteria were met. Urine samples were analyzed with the liquid-chromatography, high-resolution, accurate-mass mass spectrometry for 25 urine steroid metabolites. Results: Of 119 participants, 60 (50.4%) were women, without sex differences in age or education status. On frailty assessment, 5 (4.2%) participants were frail and 33 (27.7%) were prefrail, with equal sex distribution. Urine steroid metabolome analysis demonstrated 21/25 steroids were higher in men vs women. In an age adjusted model, presence of prefrailty or frailty was associated with a higher ratio of total cortisol metabolites/total androgen metabolites (TCM/TAM) in men (estimate 0.64, P-value= 0.0004), but not in women. In men, after adjusting for age, among cortisol metabolites, lower day to night ratio of 5α-Tetrahydrocortisol (estimate -0.36, P-value= 0.0419) and β-Cortol (estimate -0.35, P-value= 0.0238) were associated with frail or prefrail phenotype. After adjusting for age, higher ratio of TCM/TAM was associated lower gait speed in men (estimate -1.2, P-value= 0.046) and women (estimate -3.9, P-value= 0.012); and lower hand grip strength in men (estimate -0.04, P-value= 0.046) but not in women. Conclusion: We showed that a higher glucocorticoid to androgen ratio and a flattened circadian steroid variation were associated with presence of frail or prefrail phenotype in men. Further studies should examine the role of steroid metabolism and HPA axis impairment, and the associated sex differences, in the functional decline in aging population.

Abstract Background: Elevated urine cortisol (<1% of urinary steroid metabolome) was reported to predict future development of dementia. Our objective was to determine the association of urine steroid metabolome and its diurnal variation with cognitive function in men and women. Methods: Cross-sectional study of community-dwelling adults ≥ 50 years. Participants with adrenal disorders, end-stage renal or liver disease, on exogenous steroids or drugs affecting steroid metabolism were excluded. All participants completed day and night separate urine collection. A series of seven IPad-based tests using the National Institute of Health Toolbox Cognition Battery were administered to evaluate five key domains; performance was reported using fully corrected T-scores for age, sex, education, and race with a national normative mean of 50. T-scores were generated for the two summary measures: 1) fluid cognition (includes executive function, episodic memory, working memory, and processing speed), and 2) total composite (composite of fluid and language score). Urine samples were analyzed with the liquid-chromatography, high-resolution, accurate-mass mass spectrometry for 25 urine steroid metabolites. Results: Of 109 participants, 56 (51%) were women, and age and educational status were similar in men and women. On cognitive assessment, men and women had similar median composite cognition (T-score of 53 vs 54, p=0.74) and fluid cognition (T-score of 53 vs 51, p-value 0.96). Urine steroid metabolome analysis demonstrated 21/25 steroids were higher in men vs women. In both women and men, the ratio of total cortisol metabolites/total androgen metabolites (TCM/TAM) was associated with lower fluid cognition (women: ρ= -0.34, p=0.01, men: ρ= -0.43, p=0.001) and composite cognition (women: ρ= -0.27, p=0.04, men: ρ= -0.39, p=0.004). Higher ratio of day to night TCM were associated with a better fluid cognition in men (ρ= 0.35, p=0.01), but not in women (ρ= -0.11, p=0.41). Steroid ratios suggesting a relative enzymatic deficiency of 5α-Reductase type 2 was associated with lower fluid cognition in women (ρ= -0.29, p=0.03). In men, the fluid composite score was associated with a relative deficiency in 21-Hydroxylase (ρ= 0.42, p=0.002), 3β-Hydroxysteroid dehydrogenase (ρ= 0.43, p=0.001), and P450oxidoreductase (ρ= -0.35, p=0.01). Conclusion: We showed that a higher glucocorticoid to androgen ratio and a flattened circadian steroid variation were associated with lower global and fluid cognition score. Steroid ratios reflecting steroidogenesis enzymatic activity demonstrated sex differences in relation to cognition. Additional studies should examine whether the steroid fingerprint associated with lower cognition is predictive of a future dementia onset.

Abstract Mutations in any of the genes encoding the four subunits of succinate dehydrogenase (SDH), a mitochondrial membrane‐bound enzyme complex that is involved in both the tricarboxylic acid cycle and the electron transport chain, can lead to a variety of disorders. Recognized conditions with such mutations include Leigh syndrome and hereditary tumors such as pheochromocytoma and paraganglioma (PPGL), renal cell carcinoma, and gastrointestinal stromal tumor. Tumors appear in SDH mutation carriers with dominant inheritance due to loss of heterozygosity in susceptible cells. Here, we describe a mouse model intended to reproduce hereditary PPGL through Cre‐mediated loss of SDHC in cells that express tyrosine hydroxylase (TH), a compartment where PPGL is known to originate. We report that while there is modest expansion of TH + glomus cells in the carotid body upon SDHC loss, PPGL is not observed in such mice, even in the presence of a conditional dominant negative p53 protein and chronic hypoxia. Instead, we report an unexpected phenotype of nondiabetic obesity beginning at about 20 weeks of age. We hypothesize that this obesity is caused by TH + cell loss or altered phenotype in key compartments of the central nervous system responsible for regulating feeding behavior, coupled with metabolic changes due to loss of peripheral catecholamine production.

Increased gut permeability has been suggested in patients with celiac disease (CD). We aimed to compare gut permeability in children using the lactulose/rhamnose permeability test. We prospectively recruited 55 children into 3 groups; 27 in group 1 (children with newly diagnosed celiac disease, 12 in group 2 (siblings of children with celiac disease) and 16 in group 3 (control group). The median age of participants was 11 years 2 months in group 1, 9 years 5 months in group 2 and 10 years 3 months in group 3. Standardized median delta rhamnose was lower in CD group as compared to control group (147.5 vs 3153.1, P = 0.040). The low median rhamnose absorption in children with celiac disease as compared to other groups suggests that this test can differentiate between damaged and healthy mucosa, hence can it potentially can be used as a noninvasive test of mucosal healing in children with celiac disease.

AbstractObjectivesMatrix differences among serum samples from non-pregnant and pregnant patients could bias measurements. Standard Reference Material 1949, Frozen Human Prenatal Serum, was developed to provide a quality assurance material for the measurement of hormones and nutritional elements throughout pregnancy.MethodsSerum from non-pregnant women and women in each trimester were bottled into four levels based on pregnancy status and trimester. Liquid chromatography tandem mass spectrometry (LC-MS/MS) methods were developed and applied to the measurement of thyroid hormones, vitamin D metabolites, and vitamin D-binding protein (VDBP). Copper, selenium, and zinc measurements were conducted by inductively coupled plasma dynamic reaction cell MS. Thyroid stimulating hormone (TSH), thyroglobulin (Tg), and thyroglobulin antibody concentrations were analyzed using immunoassays and LC-MS/MS (Tg only).ResultsCertified values for thyroxine and triiodothyronine, reference values for vitamin D metabolites, VDBP, selenium, copper, and zinc, and information values for reverse triiodothyronine, TSH, Tg, and Tg antibodies were assigned. Significant differences in serum concentrations were evident for all analytes across the four levels (p≤0.003).TSH measurements were significantly different (p<0.0001) among research-only immunoassays. Tg concentrations were elevated in research-only immunoassays vs. Federal Drug Administration-approved automated immunoassay and LC-MS/MS. Presence of Tg antibodies increased differences between automated immunoassay and LC-MS/MS.ConclusionsThe analyte concentrations’ changes consistent with the literature and the demonstration of matrix interferences in immunoassay Tg measurements indicate the functionality of this material by providing a relevant matrix-matched reference material for the different stages of pregnancy.

Abstract Objective: The aim of the study was to quantify baseline estradiol (E2) and estrone (E1) concentrations according to selected patient characteristics in a substudy nested within the MAP.3 chemoprevention trial. Methods: E2 and E1 levels were measured in 4,068 postmenopausal women using liquid chromatography-tandem mass spectrometry. Distributions were described by age, years since menopause, race, body mass index (BMI), smoking status, and use and duration of hormone therapy using the Kruskal-Wallis test. Multivariable linear regression was also used to identify characteristics associated with estrogen levels. Results: After truncation at the 97.5th percentile, the mean (SD)/median (IQR) values for E2 and E1 were 5.41 (4.67)/4.0 (2.4-6.7) pg/mL and 24.7 (14.1)/21 (15-31) pg/mL, respectively. E2 and E1 were strongly correlated (Pearson correlation [ r ] = 0.8, P < 0.01). The largest variation in E2 and E1 levels was by BMI; mean E2 and E1 levels were 3.5 and 19.1 pg/mL, respectively for women with BMI less than 25 and 7.5 and 30.6 pg/mL, respectively, for women with BMI greater than 30. E2 and E1 varied by age, BMI, smoking status, and prior hormone therapy in multivariable models ( P < 0.01). Conclusions: There was large interindividual variability observed for E2 and E1 that varied significantly by participant characteristics, but with small absolute differences except in the case of BMI. Although the majority of participant characteristics were independently associated with E1 and E2, together, these factors only explained about 20% of the variation in E1 and E2 levels.

Abstract OBJECTIVE: Low dose dexamethasone suppression testing (DST) is standard of care in patients with adrenal incidentalomas or suspected endogenous hypercortisolism. False positive total serum cortisol (TC) results occur due to poor absorption, rapid metabolism or estrogen use. Free serum cortisol (FC) measurement is an alternative, but optimal cut-offs are unknown. We aimed to establish the optimal serum dexamethasone concentrations (DEXA) to interpret TC and FC results and identify reasons for discrepancies between TC and FC values in healthy male and female (with and without oral contraceptive therapy, OCT) subjects. METHODS: Single center prospective study of healthy subjects &gt;17 years old undergoing assessment with DST between 2016 and 2019. Measurement of FC and DEXA was performed by tandem mass spectrometry and TC by immune-enzymatic assay at 8 AM following overnight administration of 1 mg dexamethasone at 11pm. Subjects were excluded if they had a known adrenal adenoma, any form of endogenous cortisol excess, or exogenous steroid use. RESULTS: DST was performed in 165 healthy volunteers, median age of 29.5 (18-74) years; 53 men (32%) and 112 (67%) women, median BMI 25 (18-42) kg/m2, 47 (42%) of which were taking OCT (median daily ethinyl-estradiol dose of 30 (20-35) mcg). The median DEXA was 0.34 (0.09-1.12) mcg/dl, median TC was 0.8 (0.25-15.7) mcg/dl and median FC was 24 (4-714) ng/ml. TC and FC measurements were highly correlated (r2=0.89, p&lt;0.0001). The median FC/TC was 3% (0.3-6.7), lowest in women on OCT (median 2.5% vs 3.3% in women not on OCT and men, p&lt;0.0001). TC&gt;1.8 mcg/dl was demonstrated in 18 (11%) healthy subjects (men: 3/53, 5.7% vs women not on OCT: 3/65, 4.6% and women on OCT: 12/47, 25.5%, p=0.0007). Excluding women on OCT, the proportion of subjects with TC&gt;1.8 was higher when DEXA was &lt;0.2mcg/dl (4/15, 27%) vs when DEXA was &gt;0.2mcg/dl (2/101, 2%),(p&lt;0.0001). After excluding 24 (14%) healthy subjects with DEXA &lt;0.2 mcg/dl, in the remaining 142 subjects (51 (35%) men, 54 (38%) women not on OCT and 39 (27%) women on OCT), median TC was 0.75 (0.25-4.6) mcg/dl and median FC was 23 (4-103) ng/ml). Significant differences were noted in both TC and FC following DST within subgroups: men vs women not on OCT vs women on OCT, TC: 0.6 vs 0.7 vs 1.3 mcg/dl, (p&lt;0.0001) and FC: median 20 vs 22 vs 31 ng/ml, (p&lt;0.0001). All men and all women not on OCT demonstrated post-DST FC &lt;50 ng/ml (97.5% cutoff of 47 and 37), while women on OCT demonstrated post-DST FC &lt;50 in 80% and FC&lt;75 in 95%. CONCLUSION: Post-DST TC&gt;1.8 mcg/dl was demonstrated in 11% of all healthy subjects, of which 1 in 4 were women on OCT and 1 in 4 had DEXA&lt;0.2 mcg/dl. Simultaneous measurement of serum DEXA during DST may be valuable when false positive results are suspected. Despite a lower FC/TC ratio in women on OCT, post-DST FC cutoffs were higher in women on OCT. Measurement of FC after DST may be helpful in some but not all women on OCT.

The worldwide prevalence of type 2 diabetes (T2D) is increasing. Despite normal to higher bone density, patients with T2D paradoxically have elevated fracture risk resulting, in part, from poor bone quality. Advanced glycation endproducts (AGEs) and inflammation as a consequence of enhanced receptor for AGE (RAGE) signaling are hypothesized culprits, although the exact mechanisms underlying skeletal dysfunction in T2D are unclear. Lack of inducible models that permit environmental (in obesity) and temporal (after skeletal maturity) control of T2D onset has hampered progress. Here, we show in C57BL/6 mice that a onetime pharmacological intervention (streptozotocin, STZ) initiated in adulthood combined with high-fat diet–induced (HFD-induced) obesity caused hallmark features of human adult-onset T2D, including prolonged hyperglycemia, insulin resistance, and pancreatic β cell dysfunction, but not complete destruction. In addition, HFD/STZ (i.e., T2D) resulted in several changes in bone quality that closely mirror those observed in humans, including compromised bone microarchitecture, reduced biomechanical strength, impaired bone material properties, altered bone turnover, and elevated levels of the AGE CML in bone and blood. Furthermore, T2D led to the premature accumulation of senescent osteocytes with a unique proinflammatory signature. These findings highlight the RAGE pathway and senescent cells as potential targets to treat diabetic skeletal fragility.