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Junichi Hayashi

Bio: Junichi Hayashi is an academic researcher from Kyorin University. The author has contributed to research in topics: Blood pressure & Morning. The author has an hindex of 8, co-authored 15 publications receiving 291 citations.

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Journal ArticleDOI
TL;DR: It is shown that in opposition to previous findings, 30-min treadmill running at 70% of age-predicted maximum heart rate resulted in a significant increase in circulating IL-15 level in untrained healthy young men, suggesting that IL- 15 might play a role in the systemic anti-obesogenic and insulin-sensitizing effects of endurance exercise.
Abstract: The beneficial effects of endurance exercise include insulin-sensitization and reduction of fat mass Limited knowledge is available about the mechanisms by which endurance exercise exerts the salutary effects Myokines, cytokines secreted by skeletal muscle, have been recognized as a potential mediator Recently, a role of skeletal muscle-derived interleukin-15 (IL-15) in improvement of fat-lean body mass composition and insulin sensitivity has been proposed Yet, previous studies have reported that endurance training does not increase production or secretion of IL-15 in skeletal muscle Here, we show that in opposition to previous findings, 30-min treadmill running at 70% of age-predicted maximum heart rate resulted in a significant increase in circulating IL-15 level in untrained healthy young men These findings suggest that IL-15 might play a role in the systemic anti-obesogenic and insulin-sensitizing effects of endurance exercise, not only as a paracrine and autocrine but also as an endocrine factor

117 citations

Journal ArticleDOI
TL;DR: Exercise-augmented SIPA is probably dependent on an increase in vWF larger multimers rather than platelet alpha2-receptor activation and prevention of the interaction between vWF and its platelet receptors may play some role in decreasing the risk of coronary thrombosis during exercise.
Abstract: Platelet activation induced by shear forces occurring in a stenosed coronary artery is one of the mechanisms of coronary thrombosis. We evaluated the shear-induced platelet aggregation (SIPA) dynamics in patients with effort angina during treadmill exercise. SIPA was measured by a rotational cone-plate aggregometer. SIPA was markedly increased by exercise from 71.2 +/- 8.9% to 81.9 +/- 7.6% (p < 0.01) in the patient group. Although epinephrine concentrations were elevated, its rate of increase was not correlated with that of SIPA. Yohimbine partially inhibited the exercise-induced increase in SIPA. In contrast, a significant correlation between the changing rate of plasma von Willebrand factor (vWF) larger multimers and that of SIPA (r = 0.74, p < 0.05) was observed. Exercise-augmented SIPA is probably dependent on an increase in vWF larger multimers rather than platelet alpha2-receptor activation. Prevention of the interaction between vWF and its platelet receptors may play some role in decreasing the risk of coronary thrombosis during exercise.

59 citations

Journal ArticleDOI
TL;DR: The Arterial Stiffness Index could be a useful predictor of cardiovascular events in hypertensive subjects with multiple risk factors and was significantly increased in diabetic subjects with hypertension in comparison to those without hypertension.
Abstract: We investigated the relation of arterial stiffness, considered an independent predictor of cardiovascular events, to cardiovascular risk factors in a population-based study of 1023 subjects. An Arterial Stiffness Index (ASI) was developed to evaluate arterial stiffness based on an analysis of the pulse wave amplitude pattern acquired from measurements of brachial blood pressure. In control subjects (n = 266) without any major risk factors, the ASI was 46 ± 11, and increased with age (r = 0.346). The ASI was significantly higher in women ranging from 50 to 54 years of age than in age-matched men. The ASI rose in correlation with the number of risk factors. Subjects with two risk factors showed a significantly higher ASI than those without any risk factors (54 ± 26 vs. 46 ± 11). The ASI was significantly increased in diabetic subjects with hypertension in comparison to those without hypertension. Furthermore, hyperlipidemic subjects with hypertension showed significantly higher values than those without hypertension. ASI could be a useful predictor of cardiovascular events in hypertensive subjects with multiple risk factors.

29 citations

Journal ArticleDOI
TL;DR: It is found that pioglitazone improved abnormal arterial stiffness in patients with type 2 diabetes mellitus via a mechanism beyond the metabolic improvement, which may have important clinical implications in the use of piog litazone in patientswith type 2abetes mellitus.
Abstract: Pioglitazone, a peroxisome proliferator-activated receptor gamma agonist, not only improves insulin resistance and glycemic control, but may also have additional beneficial vascular effects in patients with type 2 diabetes mellitus. We investigated whether pioglitazone had an influence on arterial stiffness, which is an independent predictor of cardiovascular events, in 204 patients with type 2 diabetes mellitus. A prospective, nonrandomized, open-label trial was performed that involved 41 patients treated with pioglitazone, 46 patients receiving sulfonylureas, 67 patients on insulin, and 50 patients on diet/exercise only. The follow-up period was 56 +/- 3 months. Arterial stiffness was evaluated by using the arterial stiffness index (ASI), which was based on analysis of the pulse wave amplitude pattern obtained during automated blood pressure measurement in the upper limb. The 4 groups had a similar baseline ASI, which was greater than the reference range in each group. Although antidiabetic therapies improved hemoglobin A(1c) and low-density lipoprotein cholesterol, ASI only decreased significantly in the pioglitazone group. Thus, pioglitazone improved abnormal arterial stiffness in patients with type 2 diabetes mellitus via a mechanism beyond the metabolic improvement. These findings may have important clinical implications in the use of pioglitazone in patients with type 2 diabetes mellitus.

24 citations

Journal ArticleDOI
TL;DR: Impaired RBC deformability may be associated with a dysfunction in the NO pathway that is partially dependent upon the accumulation of ADMA in RBC, and exogenous NO pathway activators may improve the microcirculation by restoring R BC deformability in the presence of hypercholesterolemia.
Abstract: The pathophysiological effects of the activation or inhibition of the nitric oxide (NO)-mediated pathway on the deformability of red blood cells (RBC) were evaluated in the presence of hypercholesterolemia induced in rabbits fed a cholesterol-rich diet. RBC deformability was assessed using a microchannel array flow analyzer system. The maximum passage time (MPT) by flowing a suspension of RBC through the microchannels was used as an index of RBC deformability. During cholesterol feeding for 12 weeks, MPT gradually increased with no significant elevation in the serum asymmetric dimethylarginine (ADMA) and arginine/ADMA ratio. The reduction in RBC deformability associated with hypercholesterolemia was significantly improved during incubation with each of three different NO pathway activators: a NO donor, 8-bromo-cyclic GMP, and arginine; however, no additional reduction was observed with ADMA administration. The inhibition of NO synthase due to ADMA caused a significant reduction in the deformability of normal RBC, which was reversed with NO pathway activation. These results suggest that impaired RBC deformability may be associated with a dysfunction in the NO pathway that is partially dependent upon the accumulation of ADMA in RBC, and exogenous NO pathway activators may improve the microcirculation by restoring RBC deformability in the presence of hypercholesterolemia.

20 citations


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TL;DR: The following article summarizes the main principles of PDT considering the most recent developments and provides a comprehensive synopsis of the present status of the use of PDT in dermatology.
Abstract: The combination of light and chemicals to treat skin diseases is widely practiced in dermatology. Within this broad use of light and drugs, in recent years the concept of photodynamic therapy (PDT) has emerged. PDT is a promising modality for the management of various tumors and nonmalignant diseases, based on the combination of a photosensitizer that is selectively localized in the target tissue and illumination of the lesion with visible light, resulting in photodamage and subsequent cell death. Moreover, the fluorescence of photosensitizing compounds is also utilized as a helpful diagnostic tool for the detection of neoplastic tissue. Intensive basic and clinical research culminated in the worldwide approval of PDT for bladder, esophageal, and lung cancer. The expanding use of this relatively new therapeutic modality in dermatology at many centers around the world has revealed its efficacy for the treatment of cutaneous precancer and cancer, as well as selected benign skin disorders. The following article summarizes the main principles of PDT considering the most recent developments and provides a comprehensive synopsis of the present status of the use of PDT in dermatology. (J Am Acad Dermatol 2000;42:389-413.) Learning Objective: At the conclusion of this learning activity, participants should be able to describe the basic concepts of PDT, including fundamental knowledge of the most relevant photosensitizers, the light sources, the mechanisms involved in PDT-mediated cell destruction, as well as the indications and limitations of photodynamic treatment of skin diseases.

450 citations

Journal ArticleDOI
TL;DR: This review summarizes the current literature regarding the most discussed contraction-regulated moykines like IL-6, IL-15, irisin, BDNF, ANGPTL4, FGF21, myonectin and MCP-1 and tries to elaborate on the question why pro-inflammatory adipokines on the one hand are upregulated in the obese state, and have beneficial effects after exercise on the other hand.
Abstract: This review summarizes the current literature regarding the most discussed contraction-regulated moykines like IL-6, IL-15, irisin, BDNF, ANGPTL4, FGF21, myonectin and MCP-1. It is suggested that the term myokine is restricted to proteins secreted from skeletal muscle cells, excluding proteins that are secreted by other cell types in skeletal muscle tissue and excluding proteins which are only described on the mRNA level. Interestingly, many of the contraction-regulated myokines described in the literature are additionally known to be secreted by adipocytes. We termed these proteins adipo-myokines. Within this review, we try to elaborate on the question why pro-inflammatory adipokines on the one hand are upregulated in the obese state, and have beneficial effects after exercise on the other hand. Both, adipokines and myokines do have autocrine effects within their corresponding tissues. In addition, they are involved in an endocrine crosstalk with other tissues. Depending on the extent and the kinetics of adipo-myokines in serum, these molecules seem to have a beneficial or an adverse effect on the target tissue.

279 citations

Journal ArticleDOI
TL;DR: The role of AMPK in skeletal muscle during exercise and in exercise recovery is focused on and adaptations to exercise training, including skeletal muscle plasticity, are addressed, highlighting novel concepts and future perspectives that need to be investigated.
Abstract: Skeletal muscle possesses a remarkable ability to adapt to various physiologic conditions. AMPK is a sensor of intracellular energy status that maintains energy stores by fine-tuning anabolic and catabolic pathways. AMPK's role as an energy sensor is particularly critical in tissues displaying highly changeable energy turnover. Due to the drastic changes in energy demand that occur between the resting and exercising state, skeletal muscle is one such tissue. Here, we review the complex regulation of AMPK in skeletal muscle and its consequences on metabolism ( e.g., substrate uptake, oxidation, and storage as well as mitochondrial function of skeletal muscle fibers). We focus on the role of AMPK in skeletal muscle during exercise and in exercise recovery. We also address adaptations to exercise training, including skeletal muscle plasticity, highlighting novel concepts and future perspectives that need to be investigated. Furthermore, we discuss the possible role of AMPK as a therapeutic target as well as different AMPK activators and their potential for future drug development.-Kjobsted, R., Hingst, J. R., Fentz, J., Foretz, M., Sanz, M.-N., Pehmoller, C., Shum, M., Marette, A., Mounier, R., Treebak, J. T., Wojtaszewski, J. F. P., Viollet, B., Lantier, L. AMPK in skeletal muscle function and metabolism.

262 citations

Journal ArticleDOI
01 Jun 2013-Gut
TL;DR: Findings suggest that exercise stimulates SPARC secretion from muscle tissues and that SPARC inhibits colon tumorigenesis by increasing apoptosis.
Abstract: Objective Several epidemiological studies have shown that regular exercise can prevent the onset of colon cancer, although the underlying mechanism is unclear. Myokines are secreted skeletal muscle proteins responsible for some exercise-induced health benefits including metabolic improvement and anti-inflammatory effects in organs. The purpose of this study was to identify new myokines that contribute to the prevention of colon tumorigenesis. Methods To identify novel secreted muscle-derived proteins, DNA microarrays were used to compare the transcriptome of muscle tissue in sedentary and exercised young and old mice. The level of circulating secreted protein acidic and rich in cysteine (SPARC) was measured in mice and humans that performed a single bout of exercise. The effect of SPARC on colon tumorigenesis was examined using SPARC-null mice. The secretion and function of SPARC was examined in culture experiments. Results A single bout of exercise increased the expression and secretion of SPARC in skeletal muscle in both mice and humans. In addition, in an azoxymethane-induced colon cancer mouse model, regular low-intensity exercise significantly reduced the formation of aberrant crypt foci in wild-type mice but not in SPARC-null mice. Furthermore, regular exercise enhanced apoptosis in colon mucosal cells and increased the cleaved forms of caspase-3 and caspase-8 in wild-type mice but not in SPARC-null mice. Culture experiments showed that SPARC secretion from myocytes was induced by cyclic stretch and inhibited proliferation with apoptotic effect of colon cancer cells. Conclusions These findings suggest that exercise stimulates SPARC secretion from muscle tissues and that SPARC inhibits colon tumorigenesis by increasing apoptosis.

235 citations

Journal ArticleDOI
29 Aug 2012
TL;DR: It is posited that increased adipokine and decreased IL-15 levels during aging constitute a common mechanism for sarcopenia, obesity, and immune senescence.
Abstract: Human aging is characterized by both physical and physiological frailty. A key feature of frailty, sarcopenia is the age-associated decline in skeletal muscle mass, strength, and endurance that characterize even the healthy elderly. Increases in adiposity, particularly in visceral adipose tissue, are almost universal in aging individuals and can contribute to sarcopenia and insulin resistance by increasing levels of inflammatory cytokines known collectively as adipokines. Aging also is associated with declines in adaptive and innate immunity, known as immune senescence, which are risk factors for cancer and all-cause mortality. The cytokine interleukin-15 (IL-15) is highly expressed in skeletal muscle tissue and declines in aging rodent models. IL-15 inhibits fat deposition and insulin resistance, is anabolic for skeletal muscle in certain situations, and is required for the development and survival of natural killer (NK) lymphocytes. We review the effect that adipokines and myokines have on NK cells, with special emphasis on IL-15. We posit that increased adipokine and decreased IL-15 levels during aging constitute a common mechanism for sarcopenia, obesity, and immune senescence.

221 citations