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Encyclopedia > Inclusion body myositis

Inclusion body myositis
Classification and external resources
ICD-9 728.89
OMIM 147421
DiseasesDB 30691
eMedicine neuro/422 
MeSH D018979

Sporadic inclusion body myositis (sIBM) is an inflammatory muscle disease, characterized by slowly progressive weakness and wasting of the distal and proximal muscles, most apparent in the muscles of the arms and legs. In sporadic inclusion body myositis [MY-oh-sigh-tis] muscle, two processes, one autoimmune and the other degenerative, appear to occur in the muscle cells in parallel. The inflammation aspect is characterized by the cloning of T cells that appear to be driven by specific antigens to invade muscle fibers. The degeneration aspect is characterized by the appearance of holes in the muscle cell (vacuole)s, deposits of amyloid-related proteins within the cells and filamentous inclusions (hence the name inclusion body myositis) of abnormal proteins. The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... eMedicine is an online clinical medical knowledge base that was founded in 1996. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... An abscess on the skin, showing the redness and swelling characteristic of inflammation. ... For other uses of Muscle, see Muscle (disambiguation). ... This article is about the medical term. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... This article is about upper limb of an animal. ... In common usage, a human leg is the lower limb of the body, extending from the hip to the ankle, and including the thigh, the knee, and the cnemis. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... An antigen is any molecule that is recognized by antibodies. ... Schematic of typical animal cell, showing subcellular components: (1) nucleolus (2) nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) Cytoskeleton (8) smooth ER (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles Vacuoles are found in the cytoplasm of most plant cells and...


sIBM is a rare disease, diagnosed in only about 5 people per million, although not much research exists on the number of cases and some doctors feel the numbers are much higher. sIBM is an age-related disease - its incidence increases with age and symptoms usually begin after 50 years of age. Its prevalence rises to about 35 cases per million in people over 50 [1]. It is the most common acquired muscle disorder seen in older people, although about 20% of cases display symptoms before the age of 50. Weakness comes on slowly (over months or years) and progresses steadily and may lead to severe weakness and wasting of arm and leg muscles. It is slightly more common in men than women. Patients may become unable to perform daily living activities and most require assistive devices within 5 to 10 years of symptom onset. sIBM is not considered a fatal disorder - all things being equal, sIBM will not kill you (but the risk of serious injury due to falls is increased). There is no effective treatment for the disease.

Contents

Symptoms

How sIBM affects individuals is quite variable as is the age of onset (which generally varies from the forties upwards). Because sIBM affects different people in different ways and at different rates, there is no "textbook case."


Eventually, sIBM results in general, progressive muscle weakness. The muscles in the thighs called the quadriceps and the muscles in the arms that control finger flexion-- making a fist -- are usually affected early on. Common early symptoms include frequent tripping and falling, weakness going up stairs and trouble manipulating the fingers -- turning doorknobs, gripping keys, etc.


During the course of the illness, the patient's mobility is progressively restricted as it becomes hard for him or her to bend down, reach for things, walk quickly and so on. Many patients say they have balance problems and fall easily, as the muscles cannot compensate for an off-balanced posture. Because sIBM makes the leg muscles weak and unstable, patients are very vulnerable to serious injury from tripping or falling down. Although pain is not part of the "textbook" description, many patients report severe muscle pain, especially in the thighs.


In up to 60 percent of cases, patients with sIBM develop weakness in the pharyngeal muscles, used in swallowing, causing choking [1]


Patients with sIBM usually eventually need to resort to a cane or a walker and in most cases, a wheelchair eventually becomes a necessity.


From a recent article: "The progressive course of s-IBM leads slowly to severe disability. Finger functions can become very impaired, such as for manipulating pens, keys, buttons, and zippers, pulling handles, and firmly grasping handshakes. Arising from a chair becomes difficult. Walking becomes more precarious. Sudden falls, sometimes resulting in major injury to the skull or other bones, can occur, even from walking on minimally-irregular ground or from other minor imbalances outside or in the home, due to weakness of quadriceps and gluteus muscles depriving the patient of automatic posture maintenance. A foot-drop can increase the likelihood of tripping. Dysphagia can occur, usually caused by upper esophageal constriction that often can be symptomatically improved, for several months to years, by bougie dilation per a GI or ENT physician. Respiratory muscle weakness can sometimes eventuate." [2] Dysphagia () is a medical term defined as difficulty swallowing. ...


Types

  • The common type is sIBM (sporadic Inclusion Body Myositis): it strikes individuals apparently at random.
  • There is a type that has been observed in the siblings in several families: termed familial inflammatory sIBM, but is not passed on from generation to generation.
  • There are also several very rare forms of hereditary inclusion body myopathy (hIBM) that are linked to specific genetic defects and that are passed on from generation to generation, each inherited in different ways. See hereditary inclusion body myopathy.

Hereditary Inclusion Body Myopathy (HIBM) is a neuromuscular disorder characterized by muscle weakness developing in young adults. ...

Causes

The causes, of sIBM are currently unknown, though it is likely that it results from the interaction of a number of factors, both genetic and environmental. Our understanding of sIBM is slowly maturing and evolving.


Currently, there are two major theories about how sIBM is caused:


1) Some researchers (e.g., Dr. Dalakas) advocate the theory that the inflammation / immune reaction, caused by an unknown trigger - likely an undiscovered virus or an autoimmune disorder, is the primary, proximal cause of sIBM and that the degeneration of muscle fibres and protein abnormalities are secondary features.[1]


Despite the arguments "in favor of an adaptive immune response in s-IBM, a purely autoimmune hypothesis for s-IBM is untenable because of the disease's resistance to most immunotherapy." [3]


2) Some researchers (e.g., Dr. Engel and Dr. Askanas) advocate the theory that sIBM is a degenerative disorder related to aging of the muscle fibres and that abnormal, potentially pathogenic protein accumulations in myofibers play a key causative role in s-IBM (apparently before the immune system comes into play). This theory emphasizes the abnormal intracellular accumulation of many proteins, protein aggregation and misfolding, proteosome inhibition, and endoplasmic reticulum (ER) stress.[2]


Dalakas (2006) says "we can say that two processes, one autoimmune and the other degenerative, occur in the muscle cells in parallel."[1]


Dalakas (2006) suggests that a chain of events causes IBM -- some sort of virus, likely a retrovirus, triggers the cloning of T cells. These T cells appear to be driven by specific antigens to invade muscle fibers. In people with sIBM, the muscle cells display “flags” telling the immune system that they are infected or damaged (the muscles ubiquitously express MHC class I antigens) and this immune process leads to the death of muscle cells. The chronic stimulation of these antigens also causes stress inside the muscle cell in the endoplasmic reticulum (ER) and this ER stress may be enough to cause a self-sustaining T cell response (even after a virus has dissipated). In addition, this ER stress may cause the misfolding of protein. The ER is in charge of processing and folding molecules carrying antigens. In IBM, muscle fibers are overloaded with these major histocompatibility complex (MHC) molecules that carry the antigen protein pieces, leading to more ER stress and more protein misfolding.[1] Genera Subfamily: Orthoretrovirinae Alpharetrovirus Betaretrovirus Gammaretrovirus Deltaretrovirus Epsilonretrovirus Lentivirus Subfamily: Spumaretrovirinae Spumavirus A retrovirus is any virus belonging to the viral family Retroviridae. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... An antigen is any molecule that is recognized by antibodies. ... The endoplasmic reticulum or ER is an organelle found in all eukaryotic cells that is an interconnected network of tubules, vesicles and cisternae that is responsible for several specialized functions: Protein translation, folding, and transport of proteins to be used in the cell membrane (e. ... Protein images comparing the MHC I (1hsa) and MHC II (1dlh) molecules. ...


Recent research points to a protein called Ubiquitin ligase RNF5 (or RING Finger Protein 5). Scientists have found that RNF5 plays a key role in the progression of IBM. Following this discovery, the team developed three mouse models: one in which the RNF5 gene was missing, and two in which cells could be triggered to overproduce RNF5. Whether RNF5 is the primary cause for sIBM, or an important contributor in the development of this muscle disorder is yet to be determined. Dr. Ronai, lead author of the study, says the link established between ER stress, RNF5 and sIBM strengthen the theory stating that ER stress is causative for the disease and will now allow further study of the mechanisms underlying this disabling and all too common muscle disease. In addition “We now have a great mouse model that can be used to screen for drugs that might alleviate symptoms of sIBM,” says Dr. Ronai.[4]


A self-sustaining T cell response would make sIBM a type of autoimmune disorder. One confusing aspect is that medications that lower the immune response do not improve sIBM symptoms, as we would expect in the case of an autoimmune disorder. Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. ...


When studied carefully, it has not been impossible to detect an ongoing viral infection in the muscles. The new theory is that a chronic viral infection might be the initial triggering factor setting IBM in motion. There have been a handful of IBM cases -- about 15 or so -- that have shown clear evidence of a virus called HTLV-1. This is a complex virus that can cause leukemia but in most cases, lays dormant and people end up being lifelong carriers of the virus. It's too early to say that this is the particular virus directly involved in causing IBM. The Dalakas article says that the best evidence points towards a connection with some type of retrovirus and that a retroviral infection combined with immune recognition of the retrovirus is enough to trigger the inflammation process.[1] Human T-lymphotropic virus (HTLV) is a human, single-stranded RNA retrovirus that causes T-cell leukemia and T-cell lymphoma in adults and may also be involved in certain demyelinating diseases. ...


As mentioned above, in the past, some researchers have suggested that it is the protein changes that are primary and that precede or trigger the abnormal immune response. From an article by Askanas and Engel: "Two hypotheses predominate regarding the key pathogenic mechanisms involved in s-IBM: an amyloid-b-related degenerative process and an immune dysregulation. Ultimately, both may be considered important, and their possible interrelationship may be clarified. An intriguing feature is the accumulation within s-IBM muscle fibers of amyloid-beta (Ab), phosphorylated tau protein, and at least 20 other proteins that are also accumulated in Alzheimer brain. In the s-IBM muscle fibers, there is evidence of misfolding of proteins, pathologic proteinaceous inclusions including aggresomes, abnormalities of the two protein-disposal systems involving the ubiquitin proteasome pathway and the lysosomes, mitochondrial dysfunctions, and oxidative stress. The pronounced T-cell inflammation can be striking, and it is characterized by activated, antigen-driven, cytotoxic CD8+ T-cells.[2][5] Phosphorylation is the addition of a phosphate (PO4) group to a protein or a small molecule or the introduction of a phosphate group into an organic molecule. ... Tau proteins are normal proteins found within the brain. ... Alzheimers disease was first described by psychiatrist Emil Kraepelin and neurologist Alois Alzheimer. ... Ubiquitin is a very conserved small regulatory protein that is ubiquitous in eukaryotes. ... A proteasome is a barrel-shaped multi-protein complex that can digest other proteins into short polypeptides and amino acids in an ATP-driven reaction. ... Lysosomes are organelles in eukaryotic cells that contain digestive enzymes to digest macromolecules. ... ... Oxidative stress is caused by an imbalance between the production of reactive oxygen and a biological systems ability to readily detoxify the reactive intermediates or easily repair the resulting damage. ... CD8 (cluster of differentiation 8) is a molecule that is expressed on the surface of cytotoxic T cells. ... T cells are a subset of lymphocytes that play a large role in the immune response. ...

For other uses, see Amyloid (disambiguation). ... Amyloid beta (Aβ or Abeta) is a protein fragment of 39-42 amino acids that is the main constituent of amyloid plaques in various neurological disorders, most prominently Alzheimers disease. ...

Diagnosis

The term “inclusion body myositis” was originally introduced in 1971. Over the ensuing 35 years, s-IBM has been increasingly recognized and reported, mainly due to increased awareness by doctors and because of improved diagnostic tests. In spite of much progress, sIBM is still often difficult to diagnose and many patients are initially misdiagnosed, often with polymyositis. Year 1971 (MCMLXXI) was a common year starting on Friday (link will display full calendar) of the 1971 Gregorian calendar. ...


A diagnosis is based on clinical signs and testing. The first common clinical signs are falling down and tripping and weakness in the finger flexors - the muscles involved in grip. Several different tests may be done to help diagnose sIBM including a blood test of the level of creatine kinase (CK) (also known as phosphocreatine kinase or creatine phosphokinase (CPK)). This is an enzyme in the blood produced when muscle cells are damaged, normally by the ordinary wear and tear of everyday life. Elevated levels indicate that abnormal muscle damage has occurred, or is occurring. Typically, in sIBM, CK values are about 10 times normal levels but may fall during the course of the disease [1]. An electromyography (EMG) is often done and shows characteristic abnormalities. In this test, a small electric current is put into a muscle and a machine records how the muscle responds. Creatine Kinase Creatine kinase (CK), also known as phosphocreatine kinase or creatine phosphokinase (CPK) is an enzyme (EC 2. ... Human glyoxalase I. Two zinc ions that are needed for the enzyme to catalyze its reaction are shown as purple spheres, and an enzyme inhibitor called S-hexylglutathione is shown as a space-filling model, filling the two active sites. ... For other uses, see Blood (disambiguation). ... Electromyography (EMG) is a technique for evaluating and recording physiologic properties of muscles at rest and while contracting. ...


The best test to diagnose sIBM is a muscle biopsy (MBx). A small piece of muscle is surgically removed and then is studied in the laboratory. Several major changes in the muscle cells are usually visible that are characteristic of sIBM: In medicine, a muscle biopsy is a procedure in which a piece of muscle tissue is removed from an organism and examined microscopically. ...

  • Inflammation is present and inflammatory cells are seen invading the muscle cells
  • Holes ("vacuoles") appear in the muscle fibers ("vacuolar degeneration")
  • Inclusions ("clumps" of material) are found inside the muscle fibers, these are associated with the build-up of several different abnormal proteins, including tau protein and beta amyloid.
  • There are twisted, abnormal filamentous protein strands called "paired-helical filaments" (PHFs). PHFs contain a protein called phosphorylated tau that shows up when the muscle is tested with a stain called SMI-31 monoclonal antibody – this test recognizes p-tau of the PHFs within s-IBM muscle fibers and also in the AD brain.
  • Another abnormal protein is called ubiquitin. Inclusions containing ubiquitin can usually be seen in the muscle biopsies of sIBM patients, but they do not appear in any other muscle illnesses (e.g., not in polymyositis).

Dalakas (2006) says: "If a patient has the typical clinical phenotype of sIBM, but the muscle biopsy shows only features of a chronic inflammatory myopathy (inflammation, large fibers, splitting, and increased connective tissue, but no vacuoles), the diagnosis is probable sIBM. If, however, there is also strong upregulation of major histocompatibility complex (MHC) class I antigens (see below), and amyloid deposits and cytochrome-oxidase-negative fibers are present, the diagnosis of sIBM is rather more certain. . . . Shaking hands with a patient can provide the first indication of sIBM, because of the weak grip. If the patient complains of falls due to weakness at the knees and feet, has atrophic thighs, and does not report paresthesias or cramps, sIBM is very likely. Diagnostic dilemmas arise when the weakness and atrophy are slightly asymmetric or limited to the lower extremities, raising the possibility of a lower motor neuron disease. Motor neuron disorders, however, can be distinguished from IBM by the presence of hyperreflexia, cramps, fasciculations and large motor units on EMG."[1] Vacuoles are large membrane-bound compartments within some eukaryotic cells where they serve a variety of different functions: capturing food materials or unwanted structural debris surrounding the cell, sequestering materials that might be toxic to the cell, maintaining fluid balance (called turgor) within the cell, exporting unwanted substances from the... Tau proteins are normal proteins found within the brain. ... For other uses, see Amyloid (disambiguation). ... Each antibody binds to a specific antigen; an interaction similar to a lock and key. ... Ubiquitin is a very conserved small regulatory protein that is ubiquitous in eukaryotes. ...


Treatment

There have been several attempts to use different medications (immunotherapies) to treat sIBM but in clinical trials, although some have produced minor short term improvements, none has been shown to be effective in the long term. These include the common immunotherapeutic agents, such as corticosteroids, azathioprine, methotrexate, cyclosporine, cyclophosphamide and total lymphoid irradiation. Why this is so is a mystery because based on the theory presented here these drugs should have a better effect in helping IBM. The response of dysphagia to intravenous immunoglobulin (IVIG) can be significant [1]. The mild benefits in muscle strength experienced by HIBM patients after IVIG treatment may be related to the provision of sialic acid supplied by IVIG. Other sources of sialic acid are being explored as treatment options for HIBM.[6]


A 2008 review of management strategies concludes that Inclusion body myositis is refractory to corticosteroids (cortisols) and to several immunomodulating therapies that have been used. Osteoporosis and opportunistic infections pose a significant risk during treatment of patients. This review discusses the clinical manifestations, pathology, and treatment approaches for the inflammatory myopathies.[7] In physiology, corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. ...


Recent 2007 findings that the chemokine receptor profile of the idiopathic inflammatory myopathies (IM) indicates the predominance of Th1-mediated (inflammatory cytokine) cellular immune responses in all three IM. See T helper cell balance. Studies identified three ligand-receptor pairs, as potential targets for chemokine-based therapy in IM.[8] Chemokines are a family of pro-inflammatory activation-inducible cytokines, or small protein signals secreted by cells. ... Cytokines are a category of less-widely-known signalling proteins and glycoproteins that, like hormones and neurotransmitters, are used extensively in cellular communication. ...


No medication has yet been developed specifically for sIBM.


New treatments called Biologic agents (Biologics) are being developed to treat immune disorders -- these are not drugs as we commonly understand them, made from chemicals, they are developed from proteins taken from the cell. [9]One study by Dalakas is now under way is using an agent called Campath (alemtuzumab) to treat IBM [1]. Biologics or biologic therapies are a new class of drugs produced through genetic manipulation. ...


Clinical Trials

Currently (October 2006) a study is being done to examine the safety and effectiveness of alemtuzumab (Campath (Registered Trademark)) for improving muscle strength in patients with sporadic inclusion body myositis (s-IBM). See: [1]


Clinical trials are planned (2008) to investigate lithium as a treatment for IBM [10]


Genetics of sIBM

There are genetic features that do not directly cause IBM but that appear to predispose a person to getting IBM - having this particular combination of genes increases our susceptibility to getting IBM. Some 67% of IBM patients have a particular combination of human leukocyte antigen genes in a section of the 8.1 ancestral haplotype in the center of the MHC class II region Dalakas (2006). sIBM is not passed on from generation to generation, although the susceptibility region of genes may be.[1] HLA region of Chromosome 6 The human leukocyte antigen system (HLA) is the name of the human major histocompatibility complex (MHC). ...


There are also several very rare forms of hereditary inclusion body myopathy (myopathies) that are linked to specific genetic defects and that are passed on from generation to generation. Because these forms do not show inflammation, they are classified as myopathies and not myositis types. Because they do not display inflammation as a primary symptom, they may in fact be similar, but different diseases than sporadic inclusion body myositis. There are several different types, each inherited in different ways. See hereditary inclusion body myopathy. Hereditary Inclusion Body Myopathy (HIBM) is a neuromuscular disorder characterized by muscle weakness developing in young adults. ...


Genetic gene expression is different to genetic alterations polymorphism (biology). Gene expression indicates when a gene is switched on to perform its function. It now possible to determine which genes are switched on or off in certain disease processes and to indicate those that may be considered innappropriate. Gene expression, or simply expression, is the process by which the inheritable information which comprises a gene, such as the DNA sequence, is made manifest as a physical and biologically functional gene product, such as protein or RNA. Several steps in the gene expression process may be modulated, including the... In biology, polymorphism can be defined as the occurrence in the same habitat of two or more forms of a trait in such frequencies that the rarer cannot be maintained by recurrent mutation alone. ...


A 2006 study reported in Proc Natl Acad Sci U S A found cells isolated from IBM, fail to differentiate into skeletal myotubes. These data correlate with lack in connective tissue of IBM muscle of alkaline phosphatase (ALP)-positive cells. A myogenic inhibitory basic helix-loop-helix factor B3 is highly expressed in IBM mesoangioblasts. Indeed, silencing this gene or overexpressing MyoD rescues the myogenic defect of IBM mesoangioblasts, opening novel cell-based therapeutic strategies for this crippling disorder.[11] (see discussion)


The results of a 2008 study suggest that widespread, uncontrolled activation of genes is unlikely to be a component of the pathogenesis (cause) of IBM. [12]


The detection of unexpected gene transcripts (expressions) using microarrays in inflammatory myopathy tissue has led to the discovery of new types and roles of immune system cells present in muscle in these diseases. Plasma cells and myeloid dendritic cells are abundant in polymyositis and inclusion body myositis muscle. The identification of new cells and pathways in inflammatory myopathies has led to deeper mechanistic understanding of these diseases and potential therapeutic approaches.[13][14]


A 2007 review that summarizes current understanding of the contribution of genetic susceptibility factors to the development of sIBM concludes there is no indication that the genes responsible for the familial or hereditary conditions are involved in sIBM.[15]


Other Related Disorders

When sIBM was originally described, the major feature noted was muscle inflammation. Two other disorders were also known to display muscle inflammation, and sIBM was classified along with them. They are dermatomyositis (DM) and polymyositis (PM) and all three illnesses were called idiopathic inflammatory myositis or inflammatory myopathies (idiopathic means they don’t know what causes it). X-Ray of the knee in a patient with dermatomyositis. ... {{ }} Polymyositis is a type of inflammatory myopathy, related to dermatomyositis and inclusion body myositis. ... Idiopathic means arising spontaneously or from an obscure or unknown cause. ...


It appears that sIBM and polymyositis share some common features, especially the initial sequence of immune system activation, however, polmyositis comes on over weeks or months, does not display the subsequent muscle degeneration and protein abnormalities as seen in IBM, and as well, polymyositis tends to respond well to treatments, IBM does not. IBM is often confused with (misdiagnosed as) polymyositis and polymyositis that does not respond to treatment is likely IBM.


Dermatomyositis appears to be a different disease altogether with different root causes unrelated to either PM or sIBM.


Recent Research Advances

(April, 2008):


1). RING Finger Protein 5. Recent research has shown that a protein called RING Finger Protein 5 (RNF5) is important in muscle maintenance and regeneration. This protein is up-regulated (overproduced) in IBM. This protein is involved in the quality control process that scrutinizes protein production in the endoplasmic reticulum. This research team developed 3 mouse models to further research the role of this protein in muscle disorders. Research with these mice demonstrated that overexpression of RNF5 resulted in changes in the muscle consistent with those changes seen in IBM. Overproduction of RNF5 resulted in rapid and significant muscle deterioration, weakness and weight loss. This was followed by extensive muscle regeneration. These changes were also associated with markers of endoplasmic reticulum (ER) stress (ERS), a response to mis-folded protein buildup. Sensing this backup of abnormal protein, the ER recruits a mechanism of helpers through the Unfolded Protein Response mechanism (UPR). These helper chaperones then assist in the process of identifying and marking abnormal proteins for breakdown and recycling. It appears that at some point, the UPR response is overwhelmed and cannot handle the overload of mis-folded proteins, resulting in their buildup.


This research supports the theory that IBM is caused by ER stress and RNF5 may be an early causative link in this chain or possibly to trigger itself. This research opens up a new avenue of investigation for IBM. In addition, the mouse models developed provides an excellent means to test new drugs for their impact on IBM. Finally, the role played by the substrates of RNF5 in human muscle will have to be further investigated and articulated. Reference.[4]


2). A recent study has found that the common drug lithium chloride (usually used to treat bipolar disorder) may be effective in slowing the development of IBM. The study utilized a mouse model that compared motor function in mice six months after receiving lithium chloride compared to non-treated mice. The data demonstrated that the “IBM mice” responded significantly to the treatment. The research demonstrated that an enzyme called GSK-3 beta is responsible for increasing the phosphorylation of tau protein, a hallmark of Alzheimer disease. High phospho-tau levels are also seen in IBM. This research demonstrated that lithium chloride blocks the GSK-3 beta enzyme. The impact in a mouse model was to the delay the rate of muscle decline. When this was observed, researchers performed tests on samples of human muscle tissue that confirmed the role of the enzyme again. This research suggested in conclusion that clinical trials on IBM patients may be indicated. [10] For other uses, see Bipolar. ...


3) Myostatin is a negative regulator of muscle growth. Research on muscle disorders has examined ways to inhibit Myostatin as a method to promote muscle growth and thus compensate for the muscle disease process. Problems such as immune reaction have previously prevented clinical use. Recent research has now demonstrated that Myostatin inhibition through a gene therapy technique increases muscle mass and strength in a mouse model. In this model, focused on Duchenne muscular dystrophy, muscle mass and strength was increased. These results appear promising as a strategy to increase muscle mass in patients who have muscle related disorders, and this technique could be applied to IBM in the future. Reference.[16]


References

  1. ^ a b c d e f g h i j k Dalakas MC (2006). "Sporadic inclusion body myositis--diagnosis, pathogenesis and therapeutic strategies". Nat Clin Pract Neurol 2 (8): 437–47. doi:10.1038/ncpneuro0261. PMID 16932602. 
  2. ^ a b c Askanas V, Engel WK (2006). "Inclusion-body myositis: a myodegenerative conformational disorder associated with Abeta, protein misfolding, and proteasome inhibition". Neurology 66 (2 Suppl 1): S39. doi:10.1212/01.wnl.0000192128.13875.1e. PMID 16432144. 
  3. ^ "eMedicine - Inclusion Body Myositis : Article by M Isabel Periquet Collins". Retrieved on 2008-04-03.
  4. ^ a b Delaunay A, Bromberg KD, Hayashi Y, et al (2008). "The ER-Bound RING Finger Protein 5 (RNF5/RMA1) Causes Degenerative Myopathy in Transgenic Mice and Is Deregulated in Inclusion Body Myositis". PLoS ONE 3 (2): e1609. doi:10.1371/journal.pone.0001609. PMID 18270596. 
  5. ^ Dalakas MC (2006). "Inflammatory, immune, and viral aspects of inclusion-body myositis". Neurology 66 (2 Suppl 1): S33. doi:10.1212/01.wnl.0000192129.65677.87. PMID 16432143. 
  6. ^ Sparks S, Rakocevic G, Joe G, et al (2007). "Intravenous immune globulin in hereditary inclusion body myopathy: a pilot study". BMC Neurol 7: 3. doi:10.1186/1471-2377-7-3. PMID 17261181. 
  7. ^ Greenberg SA (2008). "Inflammatory myopathies: evaluation and management". Semin Neurol 28 (2): 241–9. doi:10.1055/s-2008-1062267. PMID 18351525. 
  8. ^ De Paepe B, Creus KK, De Bleecker JL (2007). "Chemokine profile of different inflammatory myopathies reflects humoral versus cytotoxic immune responses". Ann. N. Y. Acad. Sci. 1109: 441–53. doi:10.1196/annals.1398.050. PMID 17785333. 
  9. ^ Wendling D (2007). "Biologics in the treatment of primary inflammatory myositis". Joint Bone Spine 74 (4): 316–8. doi:10.1016/j.jbspin.2006.11.013. PMID 17590371. 
  10. ^ a b Kitazawa M, Trinh DN, Laferla FM (2008). "Inflammation induces tau pathology in inclusion body myositis model via glycogen synthase kinase-3beta". Ann. Neurol.. doi:10.1002/ana.21325. PMID 18318434. 
  11. ^ Morosetti R, Mirabella M, Gliubizzi C, et al (2006). "MyoD expression restores defective myogenic differentiation of human mesoangioblasts from inclusion-body myositis muscle". Proc. Natl. Acad. Sci. U.S.A. 103 (45): 16995–7000. doi:10.1073/pnas.0603386103. PMID 17077152. 
  12. ^ Hutchinson DO, Jongbloed B (2008). "Two-dimensional gel electrophoresis in inclusion body myositis". J Clin Neurosci 15 (4): 440–4. doi:10.1016/j.jocn.2007.03.006. PMID 18258434. 
  13. ^ Greenberg SA (2007). "A gene expression approach to study perturbed pathways in myositis". Curr Opin Rheumatol 19 (6): 536–41. doi:10.1097/BOR.0b013e3282efe261. PMID 17917532. 
  14. ^ Bradshaw EM, Orihuela A, McArdel SL, et al (2007). "A local antigen-driven humoral response is present in the inflammatory myopathies". J. Immunol. 178 (1): 547–56. PMID 17182595. 
  15. ^ Needham M, Mastaglia FL, Garlepp MJ (2007). "Genetics of inclusion-body myositis". Muscle Nerve 35 (5): 549–61. doi:10.1002/mus.20766. PMID 17366591. 
  16. ^ Haidet AM, Rizo L, Handy C, et al (2008). "Long-term enhancement of skeletal muscle mass and strength by single gene administration of myostatin inhibitors". Proc. Natl. Acad. Sci. U.S.A. 105 (11): 4318–22. doi:10.1073/pnas.0709144105. PMID 18334646. 

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External links


  Results from FactBites:
 
Inclusion Body Myositis Information Page: National Institute of Neurological Disorders and Stroke (NINDS) (456 words)
Inclusion body myositis (IBM) is one of a group of muscle diseases known as the inflammatory myopathies, which are characterized by chronic muscle inflammation accompanied by muscle weakness.
The onset of muscle weakness in IBM is generally gradual (over months or years) and affects both proximal (close to the trunk of the body) and distal (further away from the trunk) muscles.
IBM is generally resistant to all therapies and its rate of progression appears to be unaffected by currently available treatments.
Inclusion body myositis - Wikipedia, the free encyclopedia (1629 words)
Inclusion body myositis (IBM) is an inflammatory muscle disease, characterized by slowly progressive wasting and weakness of the arms and legs.
Inclusions ("clumps" of material) are found inside the muscle fibers, these are associated with the build-up of several different abnormal proteins, including tau protein and beta amyloid.
IBM and polymyositis apparently involve different disease mechanisms than are seen in dermatomyositis.
  More results at FactBites »

 

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