A body shape index is useful for BMI-independently identifying Japanese patients with obesity at high risk of cardiovascular disease.

BACKGROUND AND AIM: Obesity with multiple metabolic syndrome (MetS) components and/or with skeletal muscle loss is at high risk of cardiovascular disease (CVD). This study aimed to clarify the utility of anthropometric indices for identifying patients with overweight/obese at high risk of CVD based on having multiple MetS components and skeletal muscle loss. METHODS & RESULTS: This cross-sectional study included 188 overweight/obese (BMI ≥25 kg/m2, Japanese patients; 73 men and 115 women, mean age 55.7 years). First, we performed correlation analysis among seven anthropometric indices, body mass index (BMI), percentage body fat, waist circumference (WC), waist-to-hip ratio (WHpR), waist-to-height ratio (WHtR), a body shape index (ABSI), and body roundness index (BRI). Unlike the others, only ABSI was not correlated with BMI. Then, we conducted receiver operating characteristic analysis to assess the predictive abilities of anthropometric indices for having multiple MetS components. WC, WHpR, WHtR, BRI, and ABSI had significant predictive abilities for having multiple MetS components. Furthermore, multiple regression analysis showed that only ABSI had significantly negative associations with all sarcopenia-evaluated indices (skeletal muscle mass index [SMI], handgrip strength [HGS], and muscle quality [MQ]), irrespective of sex and age. Finally, an analysis of covariance showed that the high ABSI group had significantly lower SMI and HGS than the low ABSI group, irrespective of sex and age. CONCLUSION: ABSI was deemed useful for BMI-independently identifying Japanese patients with overweight/obese at high risk of CVD based on having multiple MetS components and skeletal muscle loss. Clinical trials (the unique trial number and the name of the registry) ID: UMIN000042726.

A case of osteogenesis imperfecta caused by a COL1A1 variant, coexisting with pituitary stalk interruption syndrome.

Osteogenesis imperfecta (OI) is a rare hereditary bone fragility disorder that affects 6-7 per 100,000 populations, and pituitary stalk interruption syndrome (PSIS) is a rare congenital defect with varying degrees of pituitary hormone deficiency, affecting approximately 0.5 in every 100,000 births. Currently, only two cases of these complications have been reported. A 46-year-old male who had experienced more than 20 fractures (peripheral and vertebral) during adolescence visited our hospital for close examination. He presented with blue sclerae and long bone deformations. We suspected OI because his mother and sister, who were being treated for osteoporosis, also had blue sclerae. Genetic testing identified a heterozygous variant (c.757C > T, p.Arg253Ter) in the COL1A1 gene, leading to the diagnosis of OI. His mother and sister also had the same variant. Considering that he underwent GH replacement therapy for his short stature during his childhood, his pituitary hormone levels were also evaluated to know if GH deficiency impacted low bone density; hypopituitarism was then suspected. The pituitary function test results led to the diagnoses of hypothalamic GH deficiency, hypogonadism, hypothyroidism, and hypoadrenocorticism. Furthermore, magnetic resonance imaging showed anterior pituitary atrophy, pituitary stalk loss, and ectopic posterior pituitary, leading to the diagnosis of PSIS. The combination of OI and hypopituitarism may have caused further bone fragility. Therefore, although rare, clinicians should keep in mind that patients with OI can possibly have concomitant pituitary insufficiency, which can lead to developmental and growth retardation.

Visceral-to-subcutaneous fat ratio is a possible prognostic factor for type 1 endometrial cancer.

BACKGROUND: Associations have been observed between obesity defined by the body mass index (BMI) and the incidence of endometrial cancer. However, the impact of obesity on the prognosis of endometrial cancer is not yet clear. Recently, visceral fat has been considered to have a greater impact on malignant disease in obese patients than subcutaneous fat. In this study, we investigated the association between prognostic factors of type 1 and type 2 endometrial cancer and obesity parameters. METHODS: The impacts of clinical factors on the progression-free survival (PFS) and overall survival (OS) were analyzed retrospectively in 145 primary endometrial cancer patients. The factors included age, BMI, pathological findings, Federation of Gynecology and Obstetrics (FIGO) stage, status of lymph node metastasis, and the amounts of visceral and subcutaneous fat obtained from computed tomography (CT) data. RESULTS: Only the visceral-to-subcutaneous fat ratio (V/S ratio) (cutoff value 0.5) corresponded to a significant difference in OS and PFS in type 1 endometrial cancer (p = 0.0080, p = 0.0053) according to the results of log-rank tests of Kaplan-Meier curves. The COX regression univariate analysis revealed that only the V/S ratio was a significant prognostic factor for PFS, but not OS (p = 0.033 and p = 0.270, respectively). CONCLUSION: A V/S ratio > 0.5 is a possible factor for poor prognosis in type 1 endometrial cancer. Further research is needed to investigate the preventive and therapeutic effects of reducing visceral fat on the prognosis of this type of cancer.

Prediction of long-term biochemical cure in patients with unilateral primary hyperaldosteronism treated surgically based on the early post-operative plasma aldosterone value.

In 2017, the Primary Aldosteronism Surgical Outcome (PASO) investigators proposed consensus criteria for clinical and biochemical outcomes. However, 6 to 12 months need to pass in order to assess for the outcome in patients who have undergone surgery for the management of primary hyperaldosteronism. This study aims to evaluate the post-operative biochemical and clinical outcomes of primary aldosteronism (PA) on the basis of the laboratory findings obtained within 10 days after surgery. We retrospectively studied 59 consecutive patients with unilateral PA who underwent adrenalectomy and were assessed for plasma aldosterone concentration (PAC) and plasma renin activity both at the initial assessment (1-10 days after surgery) and the final assessment (6-12 months after surgery). When comparing the complete biochemical success group (n = 51) and the partial or absent biochemical success group (n = 8), the median post-operative PAC at the initial assessment was significantly greater in the partial or absent biochemical success group (12.7 ng/dL; interquartile range [IQR], 10.6-14.5) than that in the complete biochemical success group (6.3 ng/dL; IQR, 5.0-7.9) (p < 0.001), while no significant differences were observed in other factors. The receiver operating characteristic curves of post-operative PAC at the initial assessment, which was used to predict biochemical outcomes, indicated that 8.1 ng/dL is the optimal PAC cut-off for biochemical success (sensitivity, 76.5%; specificity, 100%). Low post-operative PAC at the initial assessment may predict the biochemical cure of PA.

Pleiotropic neuroprotective effects of taxifolin in cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) results from amyloid-ß deposition in the cerebrovasculature. It is frequently accompanied by Alzheimer's disease and causes dementia. We recently demonstrated that in a mouse model of CAA, taxifolin improved cerebral blood flow, promoted amyloid-ß removal from the brain, and prevented cognitive dysfunction when administered orally. Here we showed that taxifolin inhibited the intracerebral production of amyloid-ß through suppressing the ApoE-ERK1/2-amyloid-ß precursor protein axis, despite the low permeability of the blood-brain barrier to taxifolin. Higher expression levels of triggering receptor expressed on myeloid cell 2 (TREM2) were associated with the exacerbation of inflammation in the brain. Taxifolin suppressed inflammation, alleviating the accumulation of TREM2-expressing cells in the brain. It also mitigated glutamate levels and oxidative tissue damage and reduced brain levels of active caspases, indicative of apoptotic cell death. Thus, the oral administration of taxifolin had intracerebral pleiotropic neuroprotective effects on CAA through suppressing amyloid-ß production and beneficially modulating proinflammatory microglial phenotypes.

Serum Soluble Triggering Receptor Expressed on Myeloid Cells 2 as a Biomarker for Incident Dementia: The Hisayama Study.

OBJECTIVE: To investigate the association between serum soluble triggering receptor expressed on myeloid cells 2 (sTREM2), a soluble type of an innate immune receptor expressed on the microglia, and the risk of dementia. METHODS: A total of 1,349 Japanese community residents aged 60 and older without dementia were followed prospectively for 10 years (2002-2012). Serum sTREM2 levels were quantified by using an enzyme-linked immunosorbent assay and divided into quartiles. Cox proportional hazards model was used to estimate the hazard ratios (HRs) of serum sTREM2 levels on the risk of dementia. RESULTS: During the follow-up, 300 subjects developed all-cause dementia; 193 had Alzheimer's disease (AD), and 85 had vascular dementia (VaD). The age- and sex-adjusted incidences of all-cause dementia, AD, and VaD elevated significantly with higher serum sTREM2 levels (all p for trend < 0.012). These associations were not altered after adjustment for confounding factors, including high-sensitive C-reactive protein. Subjects with the highest quartile of serum sTREM2 levels had significantly higher multivariable-adjusted risks of developing all-cause dementia, AD, and VaD than those with the lowest quartile (HR = 2.03, 95% confidence interval [CI] = 1.39-2.97, p < 0.001 for all-cause dementia; HR = 1.62, 95% CI = 1.02-2.55, p = 0.04 for AD; HR = 2.85, 95% CI = 1.35-6.02, p = 0.006 for VaD). No significant heterogeneity in the association of serum sTREM2 levels with the development of dementia was observed among the other risk factor subgroups (all p for heterogeneity > 0.11). INTERPRETATION: The present findings suggest a significant association between increased serum sTREM2 levels and the risk of developing all-cause dementia, AD, and VaD in the general elderly Japanese population. ANN NEUROL 2019;85:47-58.

Seated saline infusion test in predicting subtype diagnosis of primary aldosteronism.

CONTEXT: Although saline infusion test is widely used as a confirmatory test for primary aldosteronism (PA), it is reportedly less sensitive in patients in whom aldosterone is responsive to the upright position by performing it in recumbent position. Based on a single-centre experience, seated saline infusion test (SSIT) has been reported to be highly sensitive and superior to recumbent testing in identifying both unilateral and bilateral forms of PA. However, due to limited participants number, the utility of SSIT needs to be validated in other series. OBJECTIVE: This study aimed to evaluate the accuracy of SSIT in determining the PA subtypes compared with adrenocorticotropic hormone stimulation test under dexamethasone suppression (Dex-AT). PATIENTS AND SETTING: Sixty-four patients with PA who underwent both SSIT and Dex-AT were included. Subtype diagnosis of PA was determined by adrenal venous sampling (AVS) (16 unilateral and 48 bilateral forms). MAIN OUTCOME MEASURE: Plasma aldosterone concentrations (PACs) were measured after SSIT and Dex-AT. RESULTS: The area under the receiver operating characteristic (ROC) curve for diagnosing unilateral PA was greater in SSIT than that in Dex-AT (0.907 vs. 0.755; P = .023). ROC curve analysis predicted optimal cut-off PACs of 13.1 ng/dL (sensitivity, 93.8%; specificity, 79.2%) for SSIT and 34.2 ng/dL (sensitivity, 75.0%; specificity, 68.8%) for Dex-AT. CONCLUSIONS: Seated saline infusion test has superior accuracy in subtype diagnosis of PA compared with Dex-AT. SSIT can be a sensitive test for determining patients who require AVS prior to surgery.

α-Linolenic acid-derived metabolites from gut lactic acid bacteria induce differentiation of anti-inflammatory M2 macrophages through G protein-coupled receptor 40.

Among dietary fatty acids with immunologic effects, ω-3 polyunsaturated fatty acids, such as α-linolenic acid (ALA), have been considered as factors that contribute to the differentiation of M2-type macrophages (M2 macrophages). In this study, we examined the effect of ALA and its gut lactic acid bacteria metabolites 13-hydroxy-9(Z),15(Z)-octadecadienoic acid (13-OH) and 13-oxo-9(Z),15(Z)-octadecadienoic acid (13-oxo) on the differentiation of M2 macrophages from bone marrow-derived cells (BMDCs) and investigated the underlying mechanisms. BMDCs were stimulated with ALA, 13-OH, or 13-oxo in the presence of IL-4 or IL-13 for 24 h, and significant increases in M2 macrophage markers CD206 and Arginase-1 (Arg1) were observed. In addition, M2 macrophage phenotypes were less prevalent following cotreatment with GPCR40 antagonists or inhibitors of PLC-ß and MEK under these conditions, suggesting that GPCR40 signaling is involved in the regulation of M2 macrophage differentiation. In further experiments, remarkable M2 macrophage accumulation was observed in the lamina propria of the small intestine of C57BL/6 mice after intragastric treatments with ALA, 13-OH, or 13-oxo at 1 g/kg of body weight per day for 3 d. These findings suggest a novel mechanism of M2 macrophage differentiation involving fatty acids from gut lactic acid bacteria and GPCR40 signaling.-Ohue-Kitano, R., Yasuoka, Y., Goto, T., Kitamura, N., Park, S.-B., Kishino, S., Kimura, I., Kasubuchi, M., Takahashi, H., Li, Y., Yeh, Y.-S., Jheng, H.-F., Iwase, M., Tanaka, M., Masuda, S., Inoue, T., Yamakage, H., Kusakabe, T., Tani, F., Shimatsu, A., Takahashi, N., Ogawa, J., Satoh-Asahara, N., Kawada, T. α-Linolenic acid-derived metabolites from gut lactic acid bacteria induce differentiation of anti-inflammatory M2 macrophages through G protein-coupled receptor 40.

CRISPR/Cas9-mediated Angptl8 knockout suppresses plasma triglyceride concentrations and adiposity in rats.

Angiopoietin-like protein (ANGPTL)8 is a liver- and adipocyte-derived protein that controls plasma triglyceride (TG) levels. Most animal studies have used mouse models. Here, we generated an Angptl8 KO rat model using a clustered regulatory interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) (CRISPR/Cas9) system to clarify the roles of ANGPTL8 in glucose and lipid metabolism. Compared with WT rats, Angptl8 KO rats had lower body weight and fat content, associated with impaired lipogenesis in adipocytes; no differences existed between the groups in food intake or rectal temperature. Plasma TG levels in both the fasted and refed states were significantly lower in KO than in WT rats, and an oral fat tolerance test showed decreased plasma TG excursion in Angptl8 KO rats. Higher levels of lipase activity in the heart and greater expression of genes related to ß-oxidation in heart and skeletal muscle were observed in Angptl8 KO rats. However, there were no significant differences between KO and WT rats in glucose metabolism or the histology of pancreatic ß-cells on both standard and high-fat diets. In conclusion, we demonstrated that Angptl8 KO in rats resulted in lower body weight and plasma TG levels without affecting glucose metabolism. ANGPTL8 might be an important therapeutic target for obesity and dyslipidemia.

False-positive TSH receptor antibody-a pitfall of third-generation TSH receptor antibody measurements in neonates.

Maternal Graves' disease (GD) during pregnancy may influence thyroid function in fetuses. Neonates born to mothers with high serum TSH receptor antibody (TRAb) levels have been reported to develop 'neonatal GD'. Therefore, evaluations of serum thyroid hormone and TRAb levels in neonates upon birth are crucial for a prompt diagnosis. At delivery, we measured TRAb with third-generation TRAb test using an M22 human monoclonal antibody in neonates by collecting umbilical cord blood in a blood collection tube with lithium-heparin, which provides a whole blood/plasma sample. In recent years, we have encountered positive TRAb levels (more than 2.0 IU/L) in nineteen neonates born to mothers with GD whose thyroid hormone levels were almost within the reference range and serum TRAb levels were less than 10 IU/L. All the neonates with positive TRAb levels did not exhibit thyrotoxicosis. However, when we measured TRAb levels with serum sample in six out of the nineteen cases, their serum TRAb levels were all negative, suggesting a discrepancy of TRAb levels between in lithium-heparin plasma from umbilical cord blood and serum. Moreover, this discrepancy was observed in neonates born to euthyroid mothers, adult active GD patients and healthy volunteers. Since lithium-heparin plasma from umbilical cord blood is widely used in laboratory tests at delivery, we may encounter 'false-positive' TRAb, which may, in turn, lead to a misdiagnosis of neonatal GD. This is a pitfall of third-generation TRAb measurements in neonates, particularly at delivery, and needs to be considered by obstetricians and neonatologists.

Seipin is necessary for normal brain development and spermatogenesis in addition to adipogenesis.

Seipin, encoded by BSCL2 gene, is a protein whose physiological functions remain unclear. Mutations of BSCL2 cause the most-severe form of congenital generalized lipodystrophy (CGL). BSCL2 mRNA is highly expressed in the brain and testis in addition to the adipose tissue in human, suggesting physiological roles of seipin in non-adipose tissues. Since we found BSCL2 mRNA expression pattern among organs in rat is similar to human while it is not highly expressed in mouse brain, we generated a Bscl2/seipin knockout (SKO) rat using the method with ENU (N-ethyl-N-nitrosourea) mutagenesis. SKO rats showed total lack of white adipose tissues including mechanical fat such as bone marrow and retro-orbital fats, while physiologically functional brown adipose tissue was preserved. Besides the lipodystrophic phenotypes, SKO rats showed impairment of spatial working memory with brain weight reduction and infertility with azoospermia. We confirmed reduction of brain volume and number of sperm in human patients with BSCL2 mutation. This is the first report demonstrating that seipin is necessary for normal brain development and spermatogenesis in addition to white adipose tissue development.

Omega-3 polyunsaturated fatty acids suppress the inflammatory responses of lipopolysaccharide-stimulated mouse microglia by activating SIRT1 pathways.

Obesity and diabetes are known risk factors for dementia, and it is speculated that chronic neuroinflammation contributes to this increased risk. Microglia are brain-resident immune cells modulating the neuroinflammatory state. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the major ω-3 polyunsaturated fatty acids (PUFAs) of fish oil, exhibit various effects, which include shifting microglia to the anti-inflammatory phenotype. To identify the molecular mechanisms involved, we examined the impact of EPA, DHA, and EPA+DHA on the lipopolysaccharide (LPS)-induced cytokine profiles and the associated signaling pathways in the mouse microglial line MG6. Both EPA and DHA suppressed the production of the pro-inflammatory cytokines TNF-α and IL-6 by LPS-stimulated MG6 cells, and this was also observed in LPS-stimulated BV-2 cells, the other microglial line. Moreover, the EPA+DHA mixture activated SIRT1 signaling by enhancing mRNA level of nicotinamide phosphoribosyltransferase (NAMPT), cellular NAD+ level, SIRT1 protein deacetylase activity, and SIRT1 mRNA levels in LPS-stimulated MG6. EPA+DHA also inhibited phosphorylation of the stress-associated transcription factor NF-κB subunit p65 at Ser536, which is known to enhance NF-κB nuclear translocation and transcriptional activity, including cytokine gene activation. Further, EPA+DHA increased the LC3-II/LC3-I ratio, an indicator of autophagy. Suppression of TNF-α and IL-6 production, inhibition of p65 phosphorylation, and autophagy induction were abrogated by a SIRT1 inhibitor. On the other hand, NAMPT inhibition reversed TNF-α suppression but not IL-6 suppression. Accordingly, these ω-3 PUFAs may suppress neuroinflammation through SIRT1-mediated inhibition of the microglial NF-κB stress response and ensue pro-inflammatory cytokine release, which is implicated in NAMPT-related and -unrelated pathways.

Development of ghrelin transgenic mice for elucidation of clinical implication of ghrelin.

To elucidate the clinical implication of ghrelin, we have been trying to generate variable models of transgenic (Tg) mice overexpressing ghrelin. We generated Tg mice overexpressing des-acyl ghrelin in a wide variety of tissues under the control of ß-actin promoter. While plasma des-acyl ghrelin level in the Tg mice was 44-fold greater than that of control mice, there was no differences in the plasma ghrelin level between des-acyl ghrelin Tg and the control mice. The des-acyl ghrelin Tg mice exhibited the lower body weight and the shorter body length due to modulation of GH-IGF-1 axis. We tried to generate Tg mice expressing a ghrelin analog, which possessed ghrelin-like activity (Trp3-ghrelin Tg mice). The plasma Trp3-ghrelin concentration in Trp3-ghrelin Tg mice was approximately 85-fold higher than plasma ghrelin (acylated ghrelin) concentration seen in the control mice. Because Trp3-ghrelin is approximately 24-fold less potent than ghrelin, the plasma Trp3-ghrelin concentration in Trp3-ghrelin Tg mice was calculated to have approximately 3.5-fold biological activity greater than that of ghrelin (acylated ghrelin) in the control mice. Trp3-ghrelin Tg mice did not show any phenotypes except for reduced insulin sensitivity in 1-year old. After the identification of ghrelin O-acyltransferase (GOAT), we generated doubly Tg mice overexpressing both mouse des-acyl ghrelin and mouse GOAT in the liver by cross-mating the two kinds of Tg mice. The plasma ghrelin concentration of doubly Tg mice was approximately 2-fold higher than that of the control mice. No apparent phenotypic changes in body weight and food intake were observed in doubly Tg mice. Further studies are ongoing in our laboratory to generate Tg mice with the increased plasma ghrelin level to a greater extent. The better understanding of physiological and pathophysiological significance of ghrelin from experiments using an excellent animal model may provide a new therapeutic approach for human diseases.

Prediction of functional profiles of gut microbiota from 16S rRNA metagenomic data provides a more robust evaluation of gut dysbiosis occurring in Japanese type 2 diabetic patients.

We assessed whether gut microbial functional profiles predicted from 16S rRNA metagenomics differed in Japanese type 2 diabetic patients. A total of 22 Japanese subjects were recruited from our outpatient clinic in an observational study. Fecal samples were obtained from 12 control and 10 type 2 diabetic subjects. 16S rRNA metagenomic data were generated and functional profiles predicted using "Phylogenetic Investigation of Communities by Reconstruction of Unobserved States" software. We measured the parameters of glucose metabolism, gut bacterial taxonomy and functional profile, and examined the associations in a cross-sectional manner. Eleven of 288 "Kyoto Encyclopedia of Genes and Genomes" pathways were significantly enriched in diabetic patients compared with control subjects (p<0.05, q<0.1). The relative abundance of almost all pathways, including the Insulin signaling pathway and Glycolysis/Gluconeogenesis, showed strong, positive correlations with hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) levels. Bacterial taxonomic analysis showed that genus Blautia significantly differed between groups and had negative correlations with HbA1c and FPG levels. Our findings suggest a novel pathophysiological relationship between gut microbial communities and diabetes, further highlighting the significance and utility of combining prediction of functional profiles with ordinal bacterial taxonomic analysis (UMIN Clinical Trails Registry number: UMIN000026592).

Leptin restores the insulinotropic effect of exenatide in a mouse model of type 2 diabetes with increased adiposity induced by streptozotocin and high-fat diet.

Leptin may reduce pancreatic lipid deposition, which increases with progression of obesity and can impair ß-cell function. The insulinotropic effect of glucagon-like peptide-1 (GLP-1) and the efficacy of GLP-1 receptor agonist are reduced associated with impaired ß-cell function. In this study, we examined whether leptin could restore the efficacy of exenatide, a GLP-1 receptor agonist, in type 2 diabetes with increased adiposity. We chronically administered leptin (500 µg·kg⁻¹·day⁻¹) and/or exenatide (20 µg·kg⁻¹·day⁻¹) for 2 wk in a mouse model of type 2 diabetes with increased adiposity induced by streptozotocin and high-fat diet (STZ/HFD mice). The STZ/HFD mice exhibited hyperglycemia, overweight, increased pancreatic triglyceride level, and reduced glucose-stimulated insulin secretion (GSIS); moreover, the insulinotropic effect of exenatide was reduced. However, leptin significantly reduced pancreatic triglyceride level, and adding leptin to exenatide (LEP/EX) remarkably enhanced GSIS. These results suggested that the leptin treatment restored the insulinotropic effect of exenatide in the mice. In addition, LEP/EX reduced food intake, body weight, and triglyceride levels in the skeletal muscle and liver, and corrected hyperglycemia to a greater extent than either monotherapy. The pair-feeding experiment indicated that the marked reduction of pancreatic triglyceride level and enhancement of GSIS by LEP/EX occurred via mechanisms other than calorie restriction. These results suggest that leptin treatment may restore the insulinotropic effect of exenatide associated with the reduction of pancreatic lipid deposition in type 2 diabetes with increased adiposity. Combination therapy with leptin and exenatide could be an effective treatment for patients with type 2 diabetes with increased adiposity.

Cross-sectional association of skeletal muscle mass and strength with dietary habits and physical activity among first-year university students in Japan: Results from the KEIJI-U study.

OBJECTIVE: Recently, the high prevalence of young Japanese individuals who are underweight has received attention because of the potential risk for sarcopenia. The aim of this study was to examine the prevalence and characteristics of sarcopenia in Japanese youth. METHODS: In this cross-sectional study, we measured skeletal muscle mass using a multifrequency bioelectrical impedance analysis device and handgrip strength (HGS) and administered questionnaires on dietary habits and physical activity in 1264 first-year university students ages 18 to 20 y (838 men and 426 women). Sarcopenia was confirmed based on the presence of both low skeletal muscle mass and weak muscle strength. RESULTS: In all, 145 men (17%) and 69 women (16%) were diagnosed as underweight. Sarcopenia was diagnosed in 8 men (1%) and 5 women (1%). There was a significantly higher prevalence of low skeletal muscle mass index (SMI) and/or weak HGS in underweight individuals than in those in other body mass index (BMI) ranges. The multivariate analyses indicated that SMI and HGS were significantly associated with BMI in both sexes. Furthermore, after adjusting for BMI, both SMI and HGS were significantly associated with physical activity in men, and SMI was significantly associated with energy intake in women. CONCLUSIONS: First-year university students showed a high incidence of being underweight with low SMI and/or weak HGS, but the prevalence of sarcopenia was low in both sexes. There may be sex differences in factors related to muscle mass and strength, but further research is needed to clarify this.

Generation of leptin-deficient Lepmkyo/Lepmkyo rats and identification of leptin-responsive genes in the liver.

Leptin is one of the key molecules in maintaining energy homeostasis. Although genetically leptin-deficient Lep(ob)/Lep(ob) mice have greatly contributed to elucidating leptin physiology, the use of more than one species can improve the accuracy of analysis results. Using the N-ethyl-N-nitrosourea mutagenesis method, we generated a leptin-deficient Lep(mkyo)/Lep(mkyo) rat that had a nonsense mutation (Q92X) in leptin gene. Lep(mkyo)/Lep(mkyo) rats showed obese phenotypes including severe fatty liver, which were comparable to Lep(ob)/Lep(ob) mice. To identify genes that respond to leptin in the liver, we performed microarray analysis with Lep(mkyo)/Lep(mkyo) rats and Lep(ob)/Lep(ob) mice. We sorted out genes whose expression levels in the liver of Lep(mkyo)/Lep(mkyo) rats were changed from wild-type (WT) rats and were reversed toward WT rats by leptin administration. In this analysis, livers were sampled for 6 h, a relatively short time after leptin administration to avoid the secondary effect of metabolic changes such as improvement of fatty liver. We did the same procedure in Lep(ob)/Lep(ob) mice and selected genes whose expression patterns were common in rat and mouse. We verified their gene expressions by real-time quantitative PCR. Finally, we identified eight genes that primarily respond to leptin in the liver commonly in rat and mouse. These genes might be important for the effect of leptin in the liver.

Leptin activates hepatic 5'-AMP-activated protein kinase through sympathetic nervous system and α1-adrenergic receptor: a potential mechanism for improvement of fatty liver in lipodystrophy by leptin.

BACKGROUND: AMPK activation promotes glucose and lipid metabolism. RESULTS: Hepatic AMPK activities were decreased in fatty liver from lipodystrophic mice, and leptin activated the hepatic AMPK via the α-adrenergic effect. CONCLUSION: Leptin improved the fatty liver possibly by activating hepatic AMPK through the central and sympathetic nervous systems. SIGNIFICANCE: Hepatic AMPK plays significant roles in the pathophysiology of lipodystrophy and metabolic action of leptin. Leptin is an adipocyte-derived hormone that regulates energy homeostasis. Leptin treatment strikingly ameliorates metabolic disorders of lipodystrophy, which exhibits ectopic fat accumulation and severe insulin-resistant diabetes due to a paucity of adipose tissue. Although leptin is shown to activate 5'-AMP-activated protein kinase (AMPK) in the skeletal muscle, the effect of leptin in the liver is still unclear. We investigated the effect of leptin on hepatic AMPK and its pathophysiological relevance in A-ZIP/F-1 mice, a model of generalized lipodystrophy. Here, we demonstrated that leptin activates hepatic AMPK through the central nervous system and α-adrenergic sympathetic nerves. AMPK activities were decreased in the fatty liver of A-ZIP/F-1 mice, and leptin administration increased AMPK activities in the liver as well as in skeletal muscle with significant reduction in triglyceride content. Activation of hepatic AMPK with A769662 also led to a decrease in hepatic triglyceride content and blood glucose levels in A-ZIP/F-1 mice. These results indicate that the down-regulation of hepatic AMPK activities plays a pathophysiological role in the metabolic disturbances of lipodystrophy, and the hepatic AMPK activation is involved in the therapeutic effects of leptin.