It has long been known that type 2 diabetes is linked to obesity, particularly fat inside the belly. Now, researchers at the Joslin Diabetes Center have found that fat from other areas of the body can actually reduce insulin resistance and improve insulin sensitivity.
In a study published in the May issue of Cell Metabolism, a team lead by C. Ronald Kahn, M.D. found that subcutaneous fat -- fat found below the skin, usually in the hips and thighs -- is associated with reduced insulin levels and improved insulin sensitivity.
“This points to a new opportunity to find substances made by subcutaneous fat that may actually be good for glucose metabolism,’’ said Dr. Kahn, Head of the Joslin Research Section on Obesity and Hormone Action and the Mary K. Iacocca Professor of Medicine at Harvard Medical School. “If we can identify how subcutaneous fat does this, we will have a big clue as to where to look for these substances.”
Kahn noted that obesity in the abdominal or visceral area -- the classic “beer belly” or “apple” shape -- increases the risk of diabetes and mortality, and said it has been thought that obesity in subcutaneous areas -- the “pear” shape -- might decrease such risks.
“We started out to answer the basic question of whether fat inside the belly is bad for you because of where it is located, or is abdominal fat itself different from fat in other places,” said Kahn, an internationally recognized researcher in diabetes and metabolism.
To test if the differences were due to anatomic location or intrinsic properties of the fat deposits themselves, transplantations were performed in mice. The researchers found that when subcutaneous fat was transplanted into the abdominal area, there was a decrease in body weight, fat mass, glucose and insulin levels and an improvement in insulin sensitivity. By contrast, transplantation of abdominal fat into either the abdominal or subcutaneous area had no effect.
The paper concludes that subcutaneous fat is intrinsically different from visceral fat and may produce substances that can improve glucose metabolism.
“The surprising thing was that it wasn’t where the fat was located,” Kahn said. “It was the kind of fat that was the most important variable. Even more surprising, it wasn’t that abdominal fat was exerting negative effects, but that subcutaneous fat was producing a good effect. Animals with more subcutaneous fat didn’t gain as much weight as they aged, had better insulin sensitivity, lower insulin levels and were improved all around.”
Earlier studies in humans had shown that removal of subcutaneous fat by liposuction does not result in improvement of any aspect of metabolic syndrome, a collection of medical problems related to insulin resistance, but none had focused on possible good effects of this subcutaneous fat. However, one human study did show that obese individuals with high levels of both intra-abdominal and subcutaneous fat were more insulin sensitive than those with only high levels of intra-abdominal fat.
In addition, Kahn noted that a class of diabetes drugs called thiazoladines may cause patients to gain weight in the subcutaneous area, yet also improve insulin sensitivity.
Kahn said it is possible that subcutaneous fat may be producing certain hormones, known as adipokines, which produce beneficial effects on metabolism. These effects may offset the negative effects produced by abdominal fat.
The next step is to identify how subcutaneous fat produces these substances that improve metabolism and then find the substances themselves with the idea of creating a drug that can do the same thing.
“We’re already trying to identify through the use of proteomics what is coming out of the different fat cells,” Kahn said.
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Prof. Alexander Kuzin
May 18, 2008 by Anonymous, 1 year 26 weeks ago
Comment id: 29928
UDK 611.81.013 + 611.899.013]:612.824
BBK 28.866
? 89
Edited by Doctor of medical sciences,
corresponding member of the Russian Academy of Medical Sciences,
Professor L.L.Kolesnikov
Reviewers:
Yorg Schultz – Professor, Doctor of Medicine, Medical Head of Helios Clinic, Head of the scientific Counsel of the European Academy of interdisciplinary medicine, Honorary president of the European union of Active anti-ageing;
V.N.Nikolenko – Professor, Doctor of medical sciences, Head of the department of the human anatomy of Saratov State Medical University.
Recommended for edition by the consultative training counsel in anatomy and histology of the Ministry of Health of Russian Federation
and by the Institute of Molecular and Systemic Medicine (Berlin)
A.V.Kuzin, Iu.G.Vasiliev, V.M.Chuchkov, T.G.Shorokhova. Ensemble co-interactions in the central nervous system: Monograph. Izhevsk – Berlin: ANK – 2004. – 160 pp.
ISBN 5–9631–0005–4
The monograph contains the information concerning the structure and function of the neuroglio-vascular ensembles, based on the authors’ investigations, as well as the available published results. While the early and sparse complex investigations of the analogical structures consider the presence of the macroglia as a factor allowing to isolate the functional neuron groups, much attention is given to the function of such ensembles at the level of individual microvascular pools around the bodies of the nervous cells, single or joined into the small groups; new data concerning the structure of the neuro-glio-vascular co-interactions, their formation during the ontogenetic development are represented. The problems of substances’ diffusion modeling in the central nervous system are discussed. The analysis of the correspondence of data, recorded by means of the computer modeling, with the results of morphometric investigations, is represented.
The monograph may be of some interest for the neurobiologists, angiologists, physiologists and pathophysiologists.
???611.81.013 + 611.899.013]:612.824
??? 28.866
© Collective of authors, 2004
© ANK Edition, 2004
CONTENTS
LIST OF THE ABBREVIATIONS 4
INTRODUCTION 5
Chapter I. MATERIALS FOR THE MORPHOLOGICAL EXAMINATION AND THE PARTICULAR FEATURES OF THEIR HISTOLOGICAL AND MORPHOMETRIC PROCESSING 7
I.1. Results of the authors’ investigations. Particularities of the sampling and histological processing of the material 7
I.2. Characteristics of the morphometric analysis used 8
CHAPTER II. STRUCTURE OF THE NEUROGLIO-VASCULAR COMPLEXES 12
II.1. Structure of the neurons in the nucleus pontis and in the nuclei of the mesencephalon 12
II.2. Structure and function of neuroglia in the central nervous system 20
II.3. Relationship between the angioarchitectonic and structural-functional organization of the nuclear centers. Ensemble organization of the nuclear centers 29
CHAPTER III. FORMATION OF THE NEUROGLIO-VASCULAR COMPLEXES DURING THE ONTOGENESIS 100
CHAPTER IV. BRAIN TRANSFER OF THE SUBSTANCES 122
CHAPTER V. MATHEMATICAL MODELLING OF THE TRANSPORTATION FLOW IN THE CENTRAL NERVOUS SYSTEM 124
V.1. Mathematical analysis of the diffusion flows of the oxygen and carbon dioxide 124
V.2. Results obtained during the analysis of the oxygen diffusion flows using the mathematical model 127
V. 3. Carbon dioxide diffusion flows, obtained using the mathematical modeling 131
V. 4. Modeling of the glucose transportation flow in the nervous system 132
V. 5. Results obtained using the analysis of the mathematical model of the glucose transportation 136
V.6. Oxygen distribution modeling in the aniage of the posterior cerebral vesicle 141
CONCLUSION 144
REFERENCES 147
INTRODUCTION
The investigators of the nervous system have recently faced a challenge in the interpretation of the results obtained in studies of the structure and activity of the nervous system. The abundant information concerning cerebral ultrastructural architecture does not allow the authors to make a comprehensive clarification of the brain activities as an integral system (N.S. Kositsin, 1978; A.S. Ba-tuyev, .P. Babmindra, 1993; I.G. Akmayev, 1996; K.K. Sudakov, 1996). The data concerning the neurophysiological processes in the brain are often significantly abstracted of the investigation of morphologic substrate where these processes take place (O.S. Adrianov, 1995; N.N. Bogolepov, 1996). The growing specialization of actual neurological disciplines, one-dimensional interest to a certain line of investigations determines the difficulties in the investigation of brain as a whole. The formation of the complex apprehension of the cerebral processes appears essential. Histology and microanatomy per se, being the descriptive disciplines, are often considered by the authors to be out of date, in many instances having the depleted capabilities (the position that we absolutely disagree with). This is related to the impossibility of investigation of the physiological processes which take place in the examined morphological structure. Until now the above mentioned sciences use insufficiently the methods of mathematical modeling of the biological processes. These methods are limited either by the derivation of the generalizing formulas based upon the average values, or by the determination of the most expressed correlations. Sometimes the researches are concerned with the entropy indicators, which are fairly promising. Nevertheless the high degree of formalization does not allow specifying the concrete processes taking place in the diverse existence conditions of the individual cellular and tissue body structures and those of the nervous system particularly. The number of interesting phenomena existing in the real object, are lost, which results in the impossibility of the mathematical modeling of biological processes as the near-real scientific cognition approach.
The proposed perspective of a more precise examination of the changes in the organism, particularly in the brain, consists in the synthesis or combination of the opportunities of morphology, of mathematics and of physiology. This monograph does not pretend to compose the global system, but here we attempt to propose the new approach to the solution of the problem of complex evaluation of co-interacting structures in the organism, and in the central nervous system particularly. One of directions of the recent neuromor-phology and neurophysiology consists in the investigation of the structural-functional correlations between the neuronal status and the system of glial-trophic environment. The parameters are not developed which could allow performing an objective follow-up of the intensity of blood supply not only in the entire anatomical structure (nerve centers), but in the individual neurons as well. The neural cells can differ by their sizes, structure, mediators and structural rearrangements under the pathologic influences. In case of omission of certain parameters the contradictory estimations of microcirculation state within different periods of ontogenetic development can occur. The blood supply parameters of the nervous centers provided they are nominally considered as isomorphous structures having the similar conditions of local blood circulation, do not allow establishing particular changes in the furnishment of separate compo-nents and cannot take into account the relationship between the neuropil and the neuronal perikaryon. The significance of this investi-gation is also determined by the focal nature of microcirculatory reactions in case of various vascular diseases, when the growth of the microvessels is associated with the phenomena of their obliteration in the adjacent sections (N.V. Vereshchagin, 1999).
Thus far, the value of the large group of biologically active substances is clarified, secreted not only by neurons, but also by neu-rogliocytes and by the endotheliocytes, that are known to exert the significant stabilizing influence on the functional activity and metabolic processes in the nerve tissue (I.N. Bogolepova et al., 1995; P Hamilton Steven, 1994; T.J. Sims, S.A. Gilmore, 1994; A. Rizvi Tilar, Ennis Methhav et al, 1994; Nakaya Yoshifumi, Kaneko Takashi et al, 1994; J Gehrmann, D.L. Yao, 1995; M.C. Jasek, W.H. Griffith, 1998; T Ebendal, S Soderstrom et al, 1998). The importance of macroglia was demonstrated in the mechanisms of the so-called volume signal transfer, of the impulse conversion, of accommodation and synchronization of the neuron ensembles, impli-cated into the adaptive reactions (M.O. Samoilov, A.A. Mokrushin, 1999, B. Ranson, 1992; E.N. Benveniste, 1995; K.E. Bovenkamp, P.A. Lapchac, et al, 1997; J.M. Conner, S Varon, M.S. Hoener 1998). At the same time, in the scientific publications the primary at-tention is given to the structure of neuron ensembles (E.B. Arushanyan, 1979; T.I. Belova, E.L. Golubeva et al., 1980; S.N. Olenev, 1987; V.P.Babmindra, T.A. Bragina et al., 1988; B Dalva Metthew, Grosh Anirvan, J Sharz Curla, 1994; K Seto, K Kamino et al, 1998; N.N. Bogolepov, V.M. Chuchkov, 2003). The other research trends concern the vessels (T.V. Ryasina, 1977; A.D. Bekov, E.G. Aronov et al., 1996), or the glial cells (Caviness Yerne S, Nission JenaPaul, 1991; A. Stendler Dennis, 1993; E. Nexdorf, Bergveiler Barbara, Albrecht Dorotea, Heinemann Uwe, 1994). The comprehensive studies of neuron, glial and vascular structures have the spo-radic nature (A.M. Antonov, 1985; V.M. Chuchkov, 1991; L.K. Semenova, N.S.Shumeyko, 1994; O.Iu. Gurina, Iu.G.Vasil'yev, 1995; Iu.G.Vasil'yev, 1995, 1998; V.M. Chuchkov, 2004).
The difficulty of discovering of all the components of the nervous system is explained by the morphological heterogeneity and complexity of the micro-architectonics of neurons and neuroglia. The optico-electronic analysis, with all its sophistication and accu-racy, cannot result in a comprehensive picture of the three-dimensional variability of these interrelations, since it is allows only study-ing them merely in the small-volume zones, revealing the nature of neuro-glio-vascular co-interactions at limited sites, while the en-tire range of such connections is lost.
In this context, the purpose of this monograph consisted in the attempt of summarization of our own study results and of other au-thors opinions and in the analysis of special features of neuro-glio-vascular interrelations in some zones of mammalian central nerv-ous system, along with the development of quantitative and qualitative methods of their assessment. In the course of this work we developed the mathematical analysis approach to the assessment of the trophic supply at the level of microvascular capillary basins, allowing performing the detailed analysis of blood supply at the level of individual populations of the neuronal perikarya and mi-crovascular basins.
surface fat
May 10, 2008 by Anonymous, 1 year 28 weeks ago
Comment id: 29747
i have had the feeling that if I had some surface fat to store energy, I could keep my blood sugar and energy level more stable.
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