The slow-aging growth hormone receptor/binding protein gene-disrupted (GHR-KO) mouse is protected from aging-resultant neuromusculoskeletal frailty

Neuromusculoskeletal (physical) frailty is an aging-attributable biomedical issue of extremely high import, from both public health and individual perspectives. Yet, it is rarely studied in nonhuman research subjects and very rarely studied in animals with extended longevity. In an effort to address this relatively neglected area, we have conducted a longitudinal investigation of the neuromusculoskeletal healthspan in mice with two senescence-slowing interventions: growth hormone (GH) resistance, produced by GH receptor “knockout” (GHR-KO), and caloric restriction (CR). We report marked improvements in the retention of strength, balance, and motor coordination by the longevity-conferring GHR/BP gene disruption, CR regimen, or a combination of the two. Specifically, GHR-KO mice exhibit superior grip strength, balance, and motor coordination at middle age, and CR mice display superior grip strength at middle age. The advantageous effects established by middle-age are more pronounced in old-age, and these robust alterations are, generally, not gender-specific. Thus, we show that genetic and/or dietary interventions that engender longevity are also beneficial for the retention of neuromusculoskeletal health and functionality. The translational knowledge to be gained from subsequent molecular or histological investigations of these models of preserved functionality and decelerated senescence is potentially relevant to the efforts to reduce the specter of fear, falls, fracture, and frailty in the elderly.     

Yolk-sac–derived macrophages regulate fetal testis vascularization and morphogenesis

Organogenesis of the testis is initiated when expression of Sry in pre-Sertoli cells directs the gonad toward a male-specific fate. The cells in the early bipotential gonad undergo de novo organization to form testis cords that enclose germ cells inside tubules lined by epithelial Sertoli cells. Although Sertoli cells are a driving force in the de novo formation of testis cords, recent studies in mouse showed that reorganization of the vasculature and of interstitial cells also play critical roles in testis cord morphogenesis. However, the mechanism driving reorganization of the vasculature during fetal organogenesis remained unclear. Here we demonstrate that fetal macrophages are associated with nascent gonadal and mesonephric vasculature during the initial phases of testis morphogenesis. Macrophages mediate vascular reorganization and prune errant germ cells and somatic cells after testis architecture is established. We show that gonadal macrophages are derived from primitive yolk-sac hematopoietic progenitors and exhibit hallmarks of M2 activation status, suggestive of angiogenic and tissue remodeling functions. Depletion of macrophages resulted in impaired vascular reorganization and abnormal cord formation. These findings reveal a previously unappreciated role for macrophages in testis morphogenesis and suggest that macrophages are an intermediary between neovascularization and organ architecture during fetal organogenesis.Mammalian testis morphogenesis is a highly orchestrated process involving pre-Sertoli cells, germ cells, interstitial/mesenchymal cells, and vascular endothelial cells (1), providing an ideal model system to study cellular interactions during fetal organ patterning. In the mouse, cells in the XY (male) gonad undergo extensive cellular rearrangements between embryonic day (E) 11.5 and E12.5 that lead to the formation of testis cords, the precursors of seminiferous tubules in the adult organ (2). Pre-Sertoli cells express sex-determining genes, such as sex determining region of chromosome Y (Sry) and sex determining region Y (SRY)-box 9 (Sox9) (3, 4), and traditionally have been considered the main driving force in generating testicular architecture. However, recent evidence from our laboratory and others suggests that endothelial and other interstitial mesenchymal cells also play critical roles in testis morphogenesis (5–8).Mononuclear phagocytes (MPs) represent a diverse subset of the myeloid immune cell lineage which includes macrophages and dendritic cells. MPs play diverse roles in developmental and disease contexts (9, 10), likely acting through their control of vessel anastomosis, clearing of apoptotic cells and other cellular debris, secretion of cytokines and growth factors, and modulation of extracellular matrix (9, 11). MPs are nearly ubiquitous in adult organs throughout the body and are involved in the morphogenesis of multiple tissues, such as bone, mammary gland ducts, pancreatic islets, and eye vasculature (12–15). However, almost all these processes are postnatal tissue-remodeling events.The origin and function of MPs during fetal organogenesis is poorly understood. Traditional models assumed that hematopoietic stem cells (HSCs) differentiate into monocytes, which circulate through peripheral blood and subsequently are recruited to target tissues via local secretion of cytokines, leading to their differentiation into monocyte-derived lineages, e.g., granulocytes, dendritic cells, or macrophages (reviewed in ref. 10). Definitive hematopoiesis (and the appearance of HSCs) occurs initially in the yolk sac, placenta, and aorta-gonad-mesonephros region (AGM) at different time points between E8.5 and E10.5. HSCs populate the fetal liver shortly thereafter (E11.5–E13.5), before the establishment of the bone marrow. However, “primitive” hematopoiesis, originating from unique yolk-sac–derived progenitor cells, takes place at around E7.5, before definitive hematopoiesis, and gives rise to hematopoietic cell types, including erythrocytes and macrophages, that migrate through the yolk-sac vasculature to colonize the fetus (16). Yolk-sac–derived primitive macrophages can contribute to adult hematopoiesis and adult cell types (17–19). In particular, lineage-tracing analyses showed that adult microglia (brain-specific macrophages) are derived exclusively from primitive yolk-sac precursors (17). Yolk-sac–derived macrophages are distinct from HSC-derived macrophages: Yolk-sac–derived macrophages are F4/80-bright, CD11b-dim, and myeloblastosis oncogene (Myb)- and FMS-like tyrosine kinase 3 (Flt3)-independent, whereas HSC-derived macrophages are F4/80-dim, CD11b-bright, and Myb- and Flt3-dependent (19). It is likely that the distinct origins of these cells impart unique identities and functions.In the postnatal and adult testis, macrophages make up a large portion of the interstitial compartment (20) and are important for Leydig cell development and steroidogenic function (21, 22). However, macrophages have not been detected or functionally characterized during fetal testis morphogenesis. We show that yolk-sac–derived macrophages are the only major myeloid cell type in the fetal gonad during morphogenesis of the testis. These macrophages interacted with multiple cell types but were prominent near developing vasculature. Specific depletion of macrophages resulted in significant vascular and architectural abnormalities in the fetal testis. These studies uncover a previously unidentified role for gonadal–mesonephric macrophages in testis morphogenesis, consistent with a broader role for macrophages in fetal development and organogenesis.     

Management of cervical thoracic duct cyst with cyst-venous anastomosis

INTRODUCTION

Cervical thoracic duct cyst (CTDC) is a rare cause of lateral neck mass. Surgical excision with ligation of the cervical thoracic duct is the current standard for definitive management with symptomatic patients. We report the first case of an alternative method of management performing a cyst venous anastomosis for decompression.

PRESENTATION OF CASE

A 77 year old female presented with a six month history of left arm pain, swelling and a left-sided cystic neck mass. She was treated with cyst-venous anastomosis between the cyst wall and the left internal jugular vein. At two year follow-up, she has had resolution of pain and no recurrence of the mass.

DISCUSSION

Many potential etiologies have been proposed for CTDC, though surgical management of this rare problem has consistently required cyst excision and thoracic duct ligation. Few innovative modes of therapy have been developed to address this problem in a less invasive manor. Maintaining a more natural thoracic duct anatomy decreases the likely of complications associated with duct ligation.

CONCLUSION

Cyst-venous anastomosis for the management of CTDC provides an effective, novel form of treatment which maintains the integrity of the thoracic duct and avoids potential complications associated with duct ligation.     

Discovery of Potent and Simplified Piperidinone-Based Inhibitors of the MDM2–p53 Interaction

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Real-time biofeedback integrated into neuromuscular training reduces high-risk knee biomechanics and increases functional brain connectivity: A preliminary longitudinal investigation

Prospective evidence indicates that functional biomechanics and brain connectivity may predispose an athlete to an anterior cruciate ligament injury, revealing novel neural linkages for targeted neuromuscular training interventions. The purpose of this study was to determine the efficacy of a real-time biofeedback system for altering knee biomechanics and brain functional connectivity. Seventeen healthy, young, physically active female athletes completed 6 weeks of augmented neuromuscular training (aNMT) utilizing real-time, interactive visual biofeedback and 13 served as untrained controls. A drop vertical jump and resting state functional magnetic resonance imaging were separately completed at pre- and posttest time points to assess sensorimotor adaptation. The aNMT group had a significant reduction in peak knee abduction moment (pKAM) compared to controls (p = .03, d = 0.71). The aNMT group also exhibited a significant increase in functional connectivity between the right supplementary motor area and the left thalamus (p = .0473 after false discovery rate correction). Greater percent change in pKAM was also related to increased connectivity between the right cerebellum and right thalamus for the aNMT group (p = .0292 after false discovery rate correction, r² = .62). No significant changes were observed for the controls (ps > .05). Our data provide preliminary evidence of potential neural mechanisms for aNMT-induced motor adaptations that reduce injury risk. Future research is warranted to understand the role of neuromuscular training alone and how each component of aNMT influences biomechanics and functional connectivity.