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Sleeve gastrectomy (SG) has many metabolic benefits and leads to improvements in testosterone levels, which means improvement in the Leydig cell function of the testis. However, data about the effects of SG on Sertoli cell function (as assessed by inhibin B) are not available. In this preliminary study, we evaluate, for the first time, the effect of SG in adolescents after SG. We evaluate 16 adolescent and young adult males, six of whom underwent SG and followed them for 2 years. We report that Leydig cell function (as assessed by testosterone levels) improved and was associated with degree of weight loss. Sertoli cell function improved only slightly in SG group and did not change compared to the nonsurgical controls, and these changes were not associated with degree of weight loss. Thus, we conclude that larger and long-term follow-up studies are required to evaluate the changes in Sertoli cell function after SG as that is integral to male fertility.Clinical Trial Registration: NCT02557438

In mice, FGF21 is rapidly induced by fasting, mediates critical aspects of the adaptive starvation response, and displays a number of positive metabolic properties when administered pharmacologically. In humans, however, fasting does not consistently increase FGF21, suggesting a possible evolutionary divergence in FGF21 function. Moreover, many key aspects of FGF21 function in mice have been identified in the context of transgenic overexpression or administration of supraphysiologic doses, rather than in a physiologic setting. Here, we explored the dynamics and function of FGF21 in human volunteers during a 10-day fast. Unlike mice, which show an increase in circulating FGF21 after only 6 hours, human subjects did not have a notable surge in FGF21 until 7 to 10 days of fasting. Moreover, we determined that FGF21 induction was associated with decreased thermogenesis and adiponectin, an observation that directly contrasts with previous reports based on supraphysiologic dosing. Additionally, FGF21 levels increased after ketone induction, demonstrating that endogenous FGF21 does not drive starvation-mediated ketogenesis in humans. Instead, a longitudinal analysis of biologically relevant variables identified serum transaminases--markers of tissue breakdown--as predictors of FGF21. These data establish FGF21 as a fasting-induced hormone in humans and indicate that FGF21 contributes to the late stages of adaptive starvation, when it may regulate the utilization of fuel derived from tissue breakdown.

Background Body composition differs between men and women, with women having proportionally more fat mass and men more muscle mass. Although men and women are both susceptible to obesity, health consequences differ between the sexes. The purpose of our study was to assess sex differences in body composition using anatomic and functional imaging techniques, and its relationship to cardiometabolic risk markers in subjects with overweight/obesity. Methods After written informed consent, we prospectively recruited 208 subjects with overweight/obesity who were otherwise healthy (94 men, 114 women, age 37 ± 10 years, BMI 35 ± 6 kg/m 2 ). Subjects underwent dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) for fat and muscle mass, proton MR spectroscopy (1H-MRS) for intrahepatic (IHL) and intramyocellular lipids (IMCL), an oral glucose tolerance test, serum insulin, lipids, and inflammatory markers. Men and women were compared by Wilcoxon signed rank test. Linear correlation and multivariate analyses between body composition and cardiometabolic risk markers were performed. Results Women and men were of similar mean age and BMI ( p  ≥ 0.2). Women had higher %fat mass, extremity fat, and lower lean mass compared to men ( p  ≤ 0.0005). However, men had higher visceral adipose tissue (VAT) and IMCL and higher age-and BMI-adjusted IHL ( p  < 0.05). At similar age and BMI, men had a more detrimental cardiometabolic risk profile compared to women ( p  < 0.01). However, VAT in women, and IMCL in men, were more strongly associated with cardiometabolic risk markers, while more lower extremity fat was associated with a more favorable cardiometabolic profile in women compared to men ( p  ≤ 0.03). Conclusions Although the male pattern of fat distribution is associated with a more detrimental cardiometabolic risk profile compared to women of similar age and BMI, VAT is more strongly associated with cardiometabolic risk markers in women, while IMCL are more detrimental in men. Lower extremity fat is relatively protective, in women more than in men. This suggests that detailed anatomic and functional imaging, rather than BMI, provides a more complete understanding of metabolic risk associated with sex differences in fat distribution.

Marrow adipose tissue (MAT) accumulates in diverse clinical conditions but remains poorly understood. Here we show region-specific variation in MAT adipocyte development, regulation, size, lipid composition, gene expression and genetic determinants. Early MAT formation in mice is conserved, whereas later development is strain dependent. Proximal, but not distal tibial, MAT is lost with 21-day cold exposure. Rat MAT adipocytes from distal sites have an increased proportion of monounsaturated fatty acids and expression of Scd1/Scd2 , Cebpa and Cebpb . Humans also have increased distal marrow fat unsaturation. We define proximal ‘regulated’ MAT (rMAT) as single adipocytes interspersed with active haematopoiesis, whereas distal ‘constitutive’ MAT (cMAT) has low haematopoiesis, contains larger adipocytes, develops earlier and remains preserved upon systemic challenges. Loss of rMAT occurs in mice with congenital generalized lipodystrophy type 4, whereas both rMAT and cMAT are preserved in mice with congenital generalized lipodystrophy type 3. Consideration of these MAT subpopulations may be important for future studies linking MAT to bone biology, haematopoiesis and whole-body metabolism. Bone marrow contains adipocytes, which have been thought to form one type of marrow adipose tissue (MAT). Here, the authors identify two MAT subpopulations in mice and humans—‘regulated’ and ‘constitute’ MAT—which show distinct phenotypic and cellular traits, and respond differently to cold exposure.

Mentorship plays a critical role in the success of academic radiologists. Faculty members with mentors have better career opportunities, publish more papers, receive more research grants, and have greater overall career satisfaction. However, with the increasing focus on clinical productivity, pressure on turn-around times, and the difficult funding climate, effective mentoring in academic radiology can be challenging. The high prevalence of “burnout” among radiologists makes mentorship even more important. This article reviews benefits and challenges of mentorship in academic radiology, discusses how to institute a faculty mentoring program, examines different types of mentoring, and reviews challenges related to diversity and inclusion.

Oxytocin (OXT), an anorexigenic hormone, is also bone anabolic. Further, OXT administration results in increases in lean mass (LM) in adults with sarcopenic obesity. We examine, for the first time, associations of OXT with body composition and bone endpoints in 25 youth 13–25 years old with severe obesity who underwent sleeve gastrectomy (SG) and 27 non-surgical controls (NS). Forty participants were female. Subjects underwent fasting blood tests for serum OXT and DXA for areal bone mineral density (aBMD) and body composition. At baseline, SG vs. NS had higher median body mass index (BMI) but did not differ for age or OXT levels. Over 12 months, SG vs. NS had greater reductions in BMI, LM, and fat mass (FM). OXT decreased in SG vs. NS 12 months post-SG. While baseline OXT predicted a 12-month BMI change in SG, decreases in OXT levels 12 months post-SG were not associated with decreases in weight or BMI. In SG, decreases in OXT were positively associated with decreases in LM but not with decreases in FM or aBMD. Loss of LM, a strong predictor of BMD, after bariatric surgery may reduce functional and muscular capacity. OXT pathways may be targeted to prevent LM loss following SG.

The coronavirus disease 2019 (COVID‐19) pandemic has dramatically changed our lives and the delivery of healthcare. The pandemic also led to widespread disruption in the research activities and training of pre‐doctoral, post‐doctoral, and early career faculty researchers. This mini‐review uses the Local Adaptive Capacity Framework to describe successful practices, challenges, and lessons learned on how Clinical and Translational Science Award (CTSA) hubs have used their expertise, resources, and collaborations to advance clinical and translational science research and workforce development while facing and adapting to a pandemic. Data for this mini‐review were taken from the scientific literature (23 articles) and the Research Performance Progress Reports of 50 unique CTSA hubs (40 TL1 and 50 KL2 awards). Institutions responded in innovative ways to the disruption of the COVID‐19 pandemic. Electronic and virtual platforms were used to overcome challenges related to physical distancing, laboratory closures, and travel bans. The importance of mentorship and well‐being led to the creation of new virtual programs to expand mentoring and networking beyond the home institution and to promote well‐being and resilience. These solutions to translational workforce development can be implemented to address future public health emergencies.

Patients with neurofibromatosis 1 (NF1), NF2, and schwannomatosis are at risk for multiple nerve sheath tumors and premature mortality. Traditional magnetic resonance imaging (MRI) has limited ability to assess disease burden accurately. The aim of this study was to establish an international cohort of patients with quantified whole-body internal tumor burden and to correlate tumor burden with clinical features of disease. We determined the number, volume, and distribution of internal nerve sheath tumors in patients using whole-body MRI (WBMRI) and three-dimensional computerized volumetry. We quantified the distribution of tumor volume across body regions and used unsupervised cluster analysis to group patients based on tumor distribution. We correlated the presence and volume of internal tumors with disease-related and demographic factors. WBMRI identified 1286 tumors in 145/247 patients (59%). Schwannomatosis patients had the highest prevalence of tumors (P = 0.03), but NF1 patients had the highest median tumor volume (P = 0.02). Tumor volume was unevenly distributed across body regions with overrepresentation of the head/neck and pelvis. Risk factors for internal nerve sheath tumors included decreasing numbers of café-au-lait macules in NF1 patients (P = 0.003) and history of skeletal abnormalities in NF2 patients (P = 0.09). Risk factors for higher tumor volume included female gender (P = 0.05) and increasing subcutaneous neurofibromas (P = 0.03) in NF1 patients, absence of cutaneous schwannomas in NF2 patients (P = 0.06), and increasing age in schwannomatosis patients (p = 0.10). WBMRI provides a comprehensive phenotype of neurofibromatosis patients, identifies distinct anatomic subgroups, and provides the basis for investigating molecular biomarkers that correlate with unique disease manifestations.

ObjectiveTo evaluate clinical and radiological features of pathology-proven extraskeletal osteosarcomas.MethodsThis retrospective study was IRB-approved and HIPAA-compliant. Our pathology database was queried for cases of extraskeletal osteosarcoma. Tumor location, size, imaging appearance, presence of metastases, and clinical outcome were documented.ResultsNineteen patients met inclusion criteria (age 59 ± 15 (range 28–85) years; 15 male, 4 female). Tumors occurred in the lower extremities (12 out of 19, 63%), pelvis/gluteal region (3 out of 19, 16%), upper extremity (2 out of 19, 5%), thorax (1 out of 19, 5%), and neck (1 out of 19, 5%). Two out of 19 (11%) patients had undergone radiation to the tumor site previously. According to pathology, 16 out of 19 tumors were high-grade (84%). Tumors presented as soft-tissue masses measuring 9.5 ± 6.8 (2–29) cm. Tumor mineralization was present in 5 out of 19 cases (26%) and local invasion was found in 1 out of 19 cases (6%). On MRI, tumors typically appeared hyperintense on T2-weighted sequences with enhancement in 15 out of 15 (100%) contrast-enhanced studies, and with central necrosis in 10 out of 19 (53%) cases. Low-grade tumors were smaller (<4 cm; 3 out of 3, 100%) and lacked central necrosis (3 out of 3, 100%). 8 out of 19 patients (42%) had metastases, most commonly to the lung (7 out of 19, 37%) and bone (2 out of 19,11%). Two out of 8 patients (25%) with metastases and 8 out of 11 (73%) without metastases achieved recurrence-free survival (mean follow-up 3.8 ± 4.0 [0.2–14.2]) years. No metastases or deaths occurred in patients with low-grade histology.ConclusionsExtraskeletal osteosarcomas are rare, typically high-grade malignancies that commonly metastasize to lung and bones. Low-grade tumors and those without metastases have a good prognosis. MRI appearance is nonspecific, with T2 hyperintense signal and heterogeneous enhancement. Unlike conventional osteosarcoma, mineralization is rare.

The ability of research networks and individual institutions to effectively and efficiently prepare, respond, and adapt to emergent challenges is essential for the biomedical research enterprise. At the beginning of 2021, a special Working Group was formed by individuals in the Clinical and Translational Science Award (CTSA) consortium and approved by the CTSA Steering Committee to explore “Adaptive Capacity and Preparedness (AC&P) of CTSA Hubs.” The AC&P Working Group took a pragmatic Environmental Scan (E-Scan) approach of utilizing the diverse data that had been collected through existing mechanisms. The Local Adaptive Capacity framework was adapted to illustrate the interconnectedness of CTSA programs and services, while exposing how the demands of the pandemic forced them to quickly pivot and adapt. This paper presents a synopsis of the themes and lessons learned that emerged from individual sections of the E-Scan. Lessons learned from this study may improve our understanding of adaptive capacity and preparedness at different levels, as well as help strengthen the core service models, strategies, and foster innovation in clinical and translational science research.