Cardiac Xenotransplantation: Challenges, Evolution, and Advances.

The increased need for heart transplantation in patients with advanced heart failure has introduced demand for a greater supply of donor hearts. Progress in cross-species experimental models has led to promise for ushering in the clinical use of xenotransplantation (XTx) as a potential solution to the organ shortage worldwide. In this review, the authors first highlight the historical advances that led to the first pig-to-human heart transplantation, a landmark moment in the field of advanced heart failure. The authors discuss immunologic, infectious, and physiological challenges for implementation of XTx, as well as innovations in the science of genetic manipulation that allowed clinical translation of this therapy. The authors consider ongoing barriers that affect ongoing translation of this technology into clinical care in the current era. Finally, the authors propose a framework for advancing clinical application of XTx.

An in vitro human mammary epithelial cell permeability assay to assess drug secretion into breast milk.

Determining the amount of a drug transferred into breast milk is critical for benefit-risk analysis of breastfeeding when a lactating mother takes medications. In this study, we developed a human mammary epithelial cell (MEC)-based permeability assay to assess drug permeability across the mammary epithelium. Human MEC cell MCF10F formed tight junctions when cultured on Transwells with culture medium containing insulin, hydrocortisone and epidermal growth factor (EGF). Formation of integral cell barrier and morphology of the cells were confirmed by assessing trans-epithelial electrical resistance (TEER), flux of fluorescent tracers and imaging with transmission electron microscopy (TEM). MCF10F cells showed consistent P-glycoprotein (P-gp) transporter expression when culturing on Transwell inserts versus on petri dish. A few P-gp transporter drug substrates were used to estimate the permeability from this assay. Human plasma and breast milk were used as incubation medium in basolateral and apical chambers respectively to mimic physiological conditions. The predicted milk to plasma (M/P) ratios were reasonably good. The current effort to develop the MEC-based permeability assay to facilitate M/P ratio prediction showed promising results. This assay may have a potential to be developed as a useful in vitro technique for determining the transfer of small-molecule therapeutic drugs into breast milk.

The controversial role of the vagus nerve in mediating ghrelin's actions: gut feelings and beyond.

Ghrelin is a stomach-derived peptide hormone that acts via the growth hormone secretagogue receptor (GHSR) and displays a plethora of neuroendocrine, metabolic, autonomic and behavioral actions. It has been proposed that some actions of ghrelin are exerted via the vagus nerve, which provides a bidirectional communication between the central nervous system and peripheral systems. The vagus nerve comprises sensory fibers, which originate from neurons of the nodose and jugular ganglia, and motor fibers, which originate from neurons of the medulla. Many anatomical studies have mapped GHSR expression in vagal sensory or motor neurons. Also, numerous functional studies investigated the role of the vagus nerve mediating specific actions of ghrelin. Here, we critically review the topic and discuss the available evidence supporting, or not, a role for the vagus nerve mediating some specific actions of ghrelin. We conclude that studies using rats have provided the most congruent evidence indicating that the vagus nerve mediates some actions of ghrelin on the digestive and cardiovascular systems, whereas studies in mice resulted in conflicting observations. Even considering exclusively studies performed in rats, the putative role of the vagus nerve in mediating the orexigenic and growth hormone (GH) secretagogue properties of ghrelin remains debated. In humans, studies are still insufficient to draw definitive conclusions regarding the role of the vagus nerve mediating most of the actions of ghrelin. Thus, the extent to which the vagus nerve mediates ghrelin actions, particularly in humans, is still uncertain and likely one of the most intriguing unsolved aspects of the field.

Complicated Clinical Course in Incipient Gigantism Due to Treatment-resistant Aryl Hydrocarbon Receptor-Interacting Protein-mutated Pediatric Somatotropinoma.

Background: Our objective was to describe the clinical course and treatment challenges in a very young patient with a pituitary adenoma due to a novel aryl hydrocarbon receptor-interacting protein (AIP) gene mutation, highlighting the limitations of somatostatin receptor immunohistochemistry to predict clinical responses to somatostatin analogs in acromegaly. Case Report: We report the case of a 7-year-old boy presenting with headache, visual field defects, and accelerated growth following failure to thrive. The laboratory results showed high insulin-like growth factor I (IGF-I) (standardised deviation scores ( +3.49) and prolactin levels (0.5 nmol/L), and magnetic resonance imaging identified a pituitary macroadenoma. Tumoral/hormonal control could not be achieved despite 3 neurosurgical procedures, each time with apparent total resection or with lanreotide or pasireotide. IGF-I levels decreased with the GH receptor antagonist pegvisomant. The loss of somatostatin receptor 5 was observed between the second and third tumor resection. In vitro, no effect on tumoral GH release by pasireotide (with/without cabergoline) was observed. Genetic analysis revealed a novel germline AIP mutation: p.Tyr202∗ (pathogenic; class 4). Discussion: In vitro response of tumor tissue to somatostatin may better predict tumoral in vivo responses of somatostatin analogs than somatostatin receptor immunohistochemistry. Conclusion: We identified a novel pathologic AIP mutation that was associated with incipient acrogigantism in an extremely young patient who had a complicated course of disease. Growth acceleration can be masked due to failure to thrive. Tumoral growth hormone release in vivo may be predicted with in vitro exposure to somatostatin receptor analogs, as it cannot be assumed that all AIP-mutated somatotropinomas respond well to pasireotide.

Relationship between the serum GDF-15 concentration and muscle function in female patients receiving aortic valve replacement (TAVR, SAVR): Comparison with healthy elderly female subjects.

Purpose: Sarcopenia is closely associated with postoperative prognosis in patients undergoing cardiovascular surgery. Growth differentiation factor (GDF)-15 is involved in the pathogenesis of cardiovascular disease. We examined the relationship between the serum GDF-15 concentration and muscle function in patients receiving aortic valve replacement and healthy elderly subjects. Methods: Forty-three female patients undergoing aortic valve surgery (79.9 ± 6.4 years; transcatheter aortic valve replacement [TAVR] n = 19, conventional surgical aortic valve replacement [SAVR] n = 24) and 64 healthy elderly female subjects (75.9 ± 6.1 years) were included. Walking speed, grip strength, and skeletal muscle mass index (SMI) by a multifrequency bioelectrical impedance analyzer were measured to determine the presence of sarcopenia. Preoperative serum GDF-15 concentration was measured by enzyme-linked immunosorbent assay. Results: The GDF-15 level was higher in patients receiving aortic valve replacement than in healthy elderly subjects (aortic valve replacement: 1624 ± 1186 pg/mL vs. healthy: 955 ± 368 pg/mL, p < 0.001). Multivariate linear regression analysis showed that the serum GDF-15 level determined grip strength independently of the high-sensitivity C-reactive protein level and eGFR, even after adjusting for age (ß = -0.318, p = 0.025). Sarcopenia was found in 12.5% of healthy elderly subjects, 83.3% of patients with TAVR, and 64.3% of patients with SAVR. The GDF-15 concentration that defined sarcopenia was 1109 pg/mL in subjects including patients receiving aortic valve replacement. Conclusions: The preoperative serum GDF-15 concentration, which was higher in female patients receiving aortic valve replacement than in healthy elderly subjects, may be a serum marker of sarcopenia.

Recurrent Acromegaly in a Patient With a CHEK2 Mutation.

Background/Objective: CHEK2 is a cell-cycle checkpoint kinase and is part of the ATM-CHEK2-p53 cascade, which is protective against carcinogenesis. We describe a germline CHEK2 mutation in a patient with acromegaly and other tumors. Case Report: We present a woman with a germline CHEK2∗ 110delC mutation previously diagnosed with fibroadenoma of the breast and papillary thyroid carcinoma. She presented with acromegaly at age 48 (insulin-like growth factor 1, 556 mcg/L [reference range, 90-360] and lack of growth hormone suppression on glucose tolerance testing) and underwent transsphenoidal resection of a somatotroph microadenoma. Four years after surgery, she developed recurrent growth hormone excess. She was treated with cabergoline, which was discontinued due to intolerance, and transitioned to lanreotide depot, which was switched to pegvisomant because of prediabetes. Her insulin-like growth factor 1 levels remained normal on pegvisomant. Follow-up magnetic resonance imaging examinations showed no evidence of tumor progression. Shortly after the diagnosis of acromegaly, the patient was diagnosed with endometrial carcinoma, bilateral ovarian cystadenomas, and uterine leiomyomas. She was additionally found to have a nonfunctioning adrenal nodule and hyperplastic and adenomatous colon polyps. There are multiple family members with malignancies, including colon, thyroid, and lung cancer. Discussion: This is a novel report of a patient with a pathogenic germline CHEK2 mutation and multiple malignant and benign tumors, including recurrent acromegaly. Conclusion: Our data raise the possibility that CHEK2 mutations may be involved in the development of acromegaly. Additional studies are needed to elucidate the potential role of CHEK2 mutations in the pathogenesis of somatotroph adenomas.

Cystic fibrosis related liver disease and endocrine considerations.

Cystic fibrosis-liver disease (CFLD) is one of the most common non-pulmonary complications in the CF population, is associated with significant morbidity and represents the third leading cause of mortality in those with CF. CFLD encompasses a broad spectrum of hepatobiliary manifestations ranging from mild transaminitis, biliary disease, hepatic steatosis, focal biliary cirrhosis and multilobular biliary cirrhosis. The diagnosis of CFLD and prediction of disease progression remains a clinical challenge. The identification of novel CFLD biomarkers as well as the role of newer imaging techniques such as elastography to allow for early detection and intervention are active areas of research focus. Biliary cirrhosis with portal hypertension represents the most severe spectrum of CFLD, almost exclusively develops in the pediatric population, and is associated with a decline in pulmonary function, poor nutritional status, and greater risk of hospitalization. Furthermore, those with CFLD are at increased risk for vitamin deficiencies and endocrinopathies including CF-related diabetes, CF-related bone disease and hypogonadism, which can have further implications on disease outcomes and management. Effective treatment for CFLD remains limited and current interventions focus on optimization of nutritional status, identification and treatment of comorbid conditions, as well as early detection and management of CFLD specific sequelae such as portal hypertension or variceal bleeding. The extent to which highly effective modulator therapies may prevent the development or modify the progression of CFLD remains an active area of research. In this review, we discuss the challenges with defining and evaluating CFLD and the endocrine considerations and current management of CFLD.

Pycnodysostosis: A Growth Hormone Responsive Skeletal Dysplasia.

OBJECTIVE: Pycnodysostosis is commonly associated with growth hormone (GH) deficiency and responds well to GH therapy with achievement of normal or near-normal height and restoration of body proportions. CASE REPORT: A 22-month-old extremely short (-4.05 height standard deviation score) disproportionate boy with skeletal dysplasia presented to clinic. Skeletal survey, genetic panel, magnetic resonance imaging, and an insulin-like growth factor generation tests were performed. RESULTS: Skeletal survey showed increased bone density with classic features of pycnodysostosis, subsequently confirmed to be due to a deleterious homozygous frameshift mutation in CTSK. Uniquely among skeletal dysplasias, GH deficiency is a common association, secondary to pituitary hypoplasia. Magnetic resonance imaging confirmed pituitary hypoplasia and he subsequently underwent an insulin-like growth factor generation test that demonstrated biochemical responsiveness to GH therapy. This was thought to be safer than a classic GH stimulation test, in view of his very small size. Subsequently, his height has markedly improved on GH therapy. His height is now -2.25 SD, with an annualized growth velocity of 9.65 cm/y over a period of 18 months . CONCLUSION: It is important to consider GH therapy in children with pycnodysostosis, with the greatest benefit seen in children started at a young age.

ICAM1-Negative Intravascular Large B-Cell Lymphoma of the Pituitary Gland: A Case Report and Literature Review.

OBJECTIVE: Intravascular large B-cell lymphoma (IVLBCL) is a rare and aggressive type of B-cell lymphoma with large cells growing within the lumen of blood vessels. Although previous reports revealed highly variable symptoms resulting from small-vessel occlusion by neoplastic cells in a variety of organs, there are few reports of IVLBCL with pituitary involvement. METHOD: We present a case of IVLBCL with pituitary infiltration from our institution together with a literature review of similar cases to better understand this rare case of IVLBCL involving the pituitary gland. RESULTS: Our case and the pertinent literature demonstrated that IVLBCL with pituitary involvement predominantly occurred in women at a mean age of 64 years, and most of them showed panhypopituitarism that was reversible after standard therapy of rituximab-containing chemotherapy with intrathecal methotrexate. Notably, the pituitary biopsy in our case revealed that atypical large B-cells found within blood vessels and the pituitary gland were negative for intercellular adhesion molecule 1. Intercellular adhesion molecule 1-negative lymphoid cells may have contributed to panhypopituitarism by extravasation into the pituitary tissues, which do not have a blood-brain barrier and receive abundant blood flow. CONCLUSION: IVLBCL of the pituitary gland is a rare lymphoma with nonspecific manifestations and a dismal prognosis. Recognition of the clinicopathological features is necessary for early clinical diagnosis and appropriate treatment.

Hormonal Contribution to Liver Regeneration.

An understanding of the molecular basis of liver regeneration will open new horizons for the development of novel therapies for chronic liver failure. Such therapies would solve the drawbacks associated with liver transplant, including the shortage of donor organs, long waitlist time, high medical costs, and lifelong use of immunosuppressive agents. Regeneration after partial hepatectomy has been studied in animal models, particularly fumarylacetoacetate hydrolase-deficient (FAH -/-) mice and pigs. The process of regeneration is distinctive, complex, and well coordinated, and it depends on the interplay among several signaling pathways (eg, nuclear factor κß, Notch, Hippo), cytokines (eg, tumor necrosis factor α, interleukin 6), and growth factors (eg, hepatocyte growth factor, epidermal growth factor, vascular endothelial growth factor), and other components. Furthermore, endocrinal hormones (eg, norepinephrine, growth hormone, insulin, thyroid hormones) also can influence the aforementioned pathways and factors. We believe that these endocrinal hormones are important hepatic mitogens that strongly induce and accelerate hepatocyte proliferation (regeneration) by directly and indirectly triggering the activity of the involved signaling pathways, cytokines, growth factors, and transcription factors. The subsequent induction of cyclins and associated cyclin-dependent kinase complexes allow hepatocytes to enter the cell cycle. In this review article, we comprehensively summarize the current knowledge regarding the roles and mechanisms of these hormones in liver regeneration. Articles used for this review were identified by searching MEDLINE and EMBASE databases from inception through June 1, 2019.

Sarcopenia: Clinical implications in ovarian cancer, diagnosis, etiology, and management.

Sarcopenia, loss of skeletal muscle and function, is a common condition among the elderly and is known to cause adverse health outcomes and increased risk of morbidity and mortality. This progressive and generalized disorder imposes a considerable socioeconomic burden. Sarcopenia is observed commonly in cancer patients. As Asia is one of the fastest aging regions in the world, it is clear that incidences of both sarcopenia and ovarian cancer will increase together in Asian countries. Ovarian cancer patients are vulnerable to develop sarcopenia during the treatment course and progress of disease, and a considerable number of patients with ovarian cancer seems to have physical inactivity and sarcopenia already at the time of diagnosis. Therefore, management of sarcopenia should be conducted together in parallel with ovarian cancer treatment and surveillance. Thus, in this article, we will review the clinical importance of sarcopenia in the aspect of ovarian cancer. Definition of sarcopenia, diagnosis, etiology, and intervention will be also introduced.

Microarray analysis of gene expression in the diacylglycerol kinase η knockout mouse brain.

We have revealed that diacylglycerol kinase η (DGKη)-knockout (KO) mice display bipolar disorder (BPD) remedy-sensitive mania-like behaviors. However, the molecular mechanisms causing the mania-like abnormal behaviors remain unclear. In the present study, microarray analysis was performed to determine global changes in gene expression in the DGKη-KO mouse brain. We found that the DGKη-KO brain had 43 differentially expressed genes and the following five affected biological pathways: "neuroactive ligand-receptor interaction", "transcription by RNA polymerase II", "cytosolic calcium ion concentration", "Jak-STAT signaling pathway" and "ERK1/2 cascade". Interestingly, mRNA levels of prolactin and growth hormone, which are augmented in BPD patients and model animals, were most strongly increased. Notably, all five biological pathways include at least one gene among prolactin, growth hormone, forkhead box P3, glucagon-like peptide 1 receptor and interleukin 1ß, which were previously implicated in BPD. Consistent with the microarray data, phosphorylated ERK1/2 levels were decreased in the DGKη-KO brain. Microarray analysis showed that the expression levels of several glycerolipid metabolism-related genes were also changed. Liquid chromatography-mass spectrometry revealed that several polyunsaturated fatty acid (PUFA)-containing phosphatidic acid (PA) molecular species were significantly decreased as a result of DGKη deficiency, suggesting that the decrease affects PUFA metabolism. Intriguingly, the PUFA-containing lysoPA species were markedly decreased in DGKη-KO mouse blood. Taken together, our study provides not only key broad knowledge to gain novel insights into the underlying mechanisms for the mania-like behaviors but also information for developing BPD diagnostics.

Less known aspects of central hypothyroidism: Part 1 - Acquired etiologies.

Central hypothyroidism (CH) is a rare cause of hypothyroidism. CH is frequently overlooked, as its clinical picture is subtle and includes non-specific symptoms; furthermore, if measurement of TSH alone is used to screen for thyroid function, TSH concentrations can be normal or even above the upper normal reference limit. Indeed, certain patients are at risk of developing CH, such as those with a pituitary adenoma or hypophysitis, those who have been treated for a childhood malignancy, have suffered a head trauma, sub-arachnoid hemorrhage or meningitis, and those who are on drugs capable to reduce TSH secretion.

Less known aspects of central hypothyroidism: Part 2 - Congenital etiologies.

Central hypothyroidism (CH) occurs approximately in 1:50,000, and therefore is expected to be one thousand times rarer compared with primary hypothyroidism. Despite its rarity in the general population, it is much more common in certain disorders, in which it is frequently associated with other pituitary hormone deficiencies. The aim of this paper is to provide an updated review on the frequency of congenital CH, which is <1:50,000, and on its etiology, disregarding CH caused by other genetic defects, such as mutations of transcription factors involved in pituitary organogenesis or mutations of the genes encoding TRH or TRH receptor.

Dietary phosphatidylcholine impacts on growth performance and lipid metabolism in adult Genetically Improved Farmed Tilapia (GIFT) strain of Nile tilapia Oreochromis niloticus.

This study aimed to determine the effects of supplementing the diet of adult Nile tilapia Oreochromis niloticus with phosphatidylcholine (PC) on growth performance, body composition, fatty acid composition and gene expression. Genetically Improved Farmed Tilapia fish with an initial body weight of 83·1 (sd 2·9) g were divided into six groups. Each group was hand-fed a semi-purified diet containing 1·7 (control diet), 4·0, 6·5, 11·5, 21·3 or 41·0 g PC/kg diet for 68 d. Supplemental PC improved the feed efficiency rate, which was highest in the 11·5 g PC/kg diet. Weight gain and specific growth rate were unaffected. Dietary PC increased PC content in the liver and decreased crude fat content in the liver, viscera and body. SFA and MUFA increased and PUFA decreased in muscle with increasing dietary PC. Cytoplasmic phospholipase A 2 and secreted phospholipase A 2 mRNA expression were up-regulated in the brain and heart in PC-supplemented fish. PC reduced fatty acid synthase mRNA expression in the liver and visceral tissue but increased expression in muscle. Hormone-sensitive lipase and lipoprotein lipase expression increased in the liver with increasing dietary PC. Growth hormone mRNA expression was reduced in the brain and insulin-like growth factor-1 mRNA expression in liver reduced with PC above 6·5 g/kg. Our results demonstrate that dietary supplementation with PC improves feed efficiency and reduces liver fat in adult Nile tilapia, without increasing weight gain, representing a novel dietary approach to reduce feed requirements and improve the health of Nile tilapia.

Enzyme replacement therapy attenuates disease progression in two Japanese siblings with mucopolysaccharidosis type VI: 10-Year follow up.

Early initiation of enzyme replacement therapy (ERT) has demonstrated clinical benefit in patients with mucopolysaccharidosis type VI (MPS VI), a progressive, multisystem autosomal recessive lysosomal disorder caused by N-acetylgalactosamine-4-sulphatase (ASB) deficiency and the consequent accumulation of glycosaminoglycan. A previous case report highlighted that 3 years of ERT with recombinant human ASB (galsulfase) was well tolerated and effective in two Japanese siblings with MPS VI who initiated ERT at 5.6 years and 6 weeks of age, respectively. This report describes 10-year follow-up data from these two siblings who continued ERT with weekly infusions of galsulfase 1 mg/kg. Ten years of ERT was well tolerated, and the older sibling reached puberty. He had typical MPS VI phenotypic features, but exhibited significant improvement in shoulder range of motion and had largely unchanged hearing and cardiac function. His skeletal deformity remained unchanged. In contrast, in the younger sibling, typical symptoms of MPS VI, including progressive dysmorphic facial features, hepatosplenomegaly, and hearing impairment were largely absent. Her joint mobility was preserved, although skeletal deformity, including claw-hand deformity, was observed. Both siblings had progressive corneal clouding. The observations in these two patients suggest that early ERT initiated in newborns can be well tolerated and effective in preventing or slowing MPS VI disease progression, but is limited in terms of its effects on bone symptoms. For this, new approaches or bone-targeting treatments would be necessary.

Hepatocyte-Specific Deletion of Mouse Lamin A/C Leads to Male-Selective Steatohepatitis.

BACKGROUND & AIMS: Lamins are nuclear intermediate filament proteins that comprise the major components of the nuclear lamina. Mutations in LMNA, which encodes lamins A/C, cause laminopathies, including lipodystrophy, cardiomyopathy, and premature aging syndromes. However, the role of lamins in the liver is unknown, and it is unclear whether laminopathy-associated liver disease is caused by primary hepatocyte defects or systemic alterations. METHODS: To address these questions, we generated mice carrying a hepatocyte-specific deletion of Lmna (knockout [KO] mice) and characterized the KO liver and primary hepatocyte phenotypes by immunoblotting, immunohistochemistry, microarray analysis, quantitative real-time polymerase chain reaction, and Oil Red O and Picrosirius red staining. RESULTS: KO hepatocytes manifested abnormal nuclear morphology, and KO mice showed reduced body mass. KO mice developed spontaneous male-selective hepatosteatosis with increased susceptibility to high-fat diet-induced steatohepatitis and fibrosis. The hepatosteatosis was associated with up-regulated transcription of genes encoding lipid transporters, lipid biosynthetic enzymes, lipid droplet-associated proteins, and interferon-regulated genes. Hepatic Lmna deficiency led to enhanced signal transducer and activator of transcription 1 (Stat1) expression and blocked growth hormone-mediated Janus kinase 2 (Jak2), signal transducer and activator of transcription 5 (Stat5), and extracellular signal-regulated kinase (Erk) signaling. CONCLUSIONS: Lamin A/C acts cell-autonomously to maintain hepatocyte homeostasis and nuclear shape and buffers against male-selective steatohepatitis by positively regulating growth hormone signaling and negatively regulating Stat1 expression. Lamins are potential genetic modifiers for predisposition to steatohepatitis and liver fibrosis. The microarray data can be found in the Gene Expression Omnibus repository (accession number: GSE93643).

Hypothalamic growth hormone receptor (GHR) controls hepatic glucose production in nutrient-sensing leptin receptor (LepRb) expressing neurons.

OBJECTIVE: The GH/IGF-1 axis has important roles in growth and metabolism. GH and GH receptor (GHR) are active in the central nervous system (CNS) and are crucial in regulating several aspects of metabolism. In the hypothalamus, there is a high abundance of GH-responsive cells, but the role of GH signaling in hypothalamic neurons is unknown. Previous work has demonstrated that the Ghr gene is highly expressed in LepRb neurons. Given that leptin is a key regulator of energy balance by acting on leptin receptor (LepRb)-expressing neurons, we tested the hypothesis that LepRb neurons represent an important site for GHR signaling to control body homeostasis. METHODS: To determine the importance of GHR signaling in LepRb neurons, we utilized Cre/loxP technology to ablate GHR expression in LepRb neurons (LeprEYFPΔGHR). The mice were generated by crossing the Leprcre on the cre-inducible ROSA26-EYFP mice to GHRL/L mice. Parameters of body composition and glucose homeostasis were evaluated. RESULTS: Our results demonstrate that the sites with GHR and LepRb co-expression include ARH, DMH, and LHA neurons. Leptin action was not altered in LeprEYFPΔGHR mice; however, GH-induced pStat5-IR in LepRb neurons was significantly reduced in these mice. Serum IGF-1 and GH levels were unaltered, and we found no evidence that GHR signaling regulates food intake and body weight in LepRb neurons. In contrast, diminished GHR signaling in LepRb neurons impaired hepatic insulin sensitivity and peripheral lipid metabolism. This was paralleled with a failure to suppress expression of the gluconeogenic genes and impaired hepatic insulin signaling in LeprEYFPΔGHR mice. CONCLUSION: These findings suggest the existence of GHR-leptin neurocircuitry that plays an important role in the GHR-mediated regulation of glucose metabolism irrespective of feeding.

Nutrition, infection and stunting: the roles of deficiencies of individual nutrients and foods, and of inflammation, as determinants of reduced linear growth of children.

The regulation of linear growth by nutritional and inflammatory influences is examined in terms of growth-plate endochondral ossification, in order to better understand stunted growth in children. Linear growth is controlled by complex genetic, physiological, and nutrient-sensitive endocrine/paracrine/autocrine mediated molecular signalling mechanisms, possibly including sleep adequacy through its influence on growth hormone secretion. Inflammation, which accompanies most infections and environmental enteric dysfunction, inhibits endochondral ossification through the action of mediators including proinflammatory cytokines, the activin A-follistatin system, glucocorticoids and fibroblast growth factor 21 (FGF21). In animal models linear growth is particularly sensitive to dietary protein as well as Zn intake, which act through insulin, insulin-like growth factor-1 (IGF-1) and its binding proteins, triiodothyronine, amino acids and Zn2+ to stimulate growth-plate protein and proteoglycan synthesis and cell cycle progression, actions which are blocked by corticosteroids and inflammatory cytokines. Observational human studies indicate stunting to be associated with nutritionally poor, mainly plant-based diets. Intervention studies provide some support for deficiencies of energy, protein, Zn and iodine and for multiple micronutrient deficiencies, at least during pregnancy. Of the animal-source foods, only milk has been specifically and repeatedly shown to exert an important influence on linear growth in both undernourished and well-nourished children. However, inflammation, caused by infections, environmental enteric dysfunction, which may be widespread in the absence of clean water, adequate sanitation and hygiene (WASH), and endogenous inflammation associated with excess adiposity, in each case contributes to stunting, and may explain why nutritional interventions are often unsuccessful. Current interventions to reduce stunting are targeting WASH as well as nutrition.