Mechanical Injury (mechanical + injury)

Distribution by Scientific Domains


Selected Abstracts


CYSTATIN ACCUMULATION IN TOMATO LEAVES AFTER METHYL JASMONATE TREATMENT OR MECHANICAL INJURY

JOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2002
JU WEN WU
The elicitation of cystatin accumulation in tomato leaves was studied with mature and seedling cv. Bonnie Best. Repetitive mechanical injury (MI) or methyl jasmonate (MJ) treatment of seedlings elicited plentiful cystatin accumulation in the leaves when plants were held at 30C under continuous lighting. Cystatin accumulation in leaves of MI seedlings decreased by 50% when incubated at a reduced light period of 12 h light/day. Cystatin accumulation in MJ treated plants was not influenced by reducing the light period from 24 h to 12 h/day. Cystatin accumulation after MJ treatment was optimal at 35C and negligible at 40C. At ambient field conditions (I8,33C), MJ treated seedlings still accumulated a significant amount of cystatin; however, very little cystatin accumulated in leaves of MI seedlings under these conditions of lower temperature and light exposure. The leaves of mature plants accumulated less cystatin after MJ or MI treatment than did those of seedlings. [source]


EARLY ACTIVATION OF INTERNAL MEDIAL SMOOTH MUSCLE CELLS IN THE RABBIT AORTA AFTER MECHANICAL INJURY: RELATIONSHIP WITH INTIMAL THICKENING AND PHARMACOLOGICAL APPLICATIONS

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2006
Huguette Louis
SUMMARY 1Smooth muscle cells (SMC) participate in both inflammatory and dedifferentiation processes during atherosclerosis, as well as during mechanical injury following angioplasty. In the latter, we studied medial SMC differentiation and inflammation processes implicated early after de-endothelialization in relation to mechanical stresses. We hypothesized that activation of a subpopulation of SMC within the media plays a crucial role in the early phase of neointimal formation. 2For this purpose, we used a rabbit model of balloon injury to study activation and differentiation of medial SMC in the early time after denudation and just before neointima thickening. Inflammation was evaluated by the expression of vascular cell adhesion molecule (VCAM)-1, integrin a4b1 and nuclear factor (NF)-kB. Myosin isoforms and 2P1A2 antigen, a membrane protein expressed by rabbit dedifferentiated SMC, were used as markers of differentiation. 3On day 2 after de-endothelialization, VCAM-1, a4b1 and NF-kB were coexpressed by a well-defined subpopulation of SMC of the internal part of the media, in the vicinity of the blood stream. At the same time, the majority of SMC throughout the media expressed non-muscle myosin heavy chain-B (nm-MHC-B) and 2P1A2 antigen. On day 7, when intimal thickening appeared, SMC of the media were no longer activated, whereas some intimal SMC expressed the activation markers. Thus, after de-endothelialization, early dedifferentiation occurs in most of the medial SMC, whereas activation concerned only a subpopulation of SMC located in the internal media. Using the T-type voltage-operated calcium channel blocker mibefradil (0.1,1 mmol/L) in SMC culture, we showed that this agent exhibited an antiproliferative effect in a dose-dependant manner only on undifferentiated cells. 4In conclusion, the results suggest that the activated SMC represent cells that are potentially able to migrate and participate in the intimal thickening process. Thus, the medial SMC inflammatory process, without any contribution of inflammatory cells, may represent a major mechanism underlying the development of intimal thickening following mechanical stress. In humans, inhibition of T-type calcium channels may be a tool to prevent the early proliferation step leading to neointimal formation. [source]


Identification of substrates for transglutaminase in Physarum polycephalum, an acellular slime mold, upon cellular mechanical damage

FEBS JOURNAL, Issue 11 2007
Fumitaka Wada
Transglutaminases are Ca2+ -dependent enzymes that post-translationally modify proteins by crosslinking or polyamination at specific polypeptide-bound glutamine residues. Physarum polycephalum, an acellular slime mold, is the evolutionarily lowest organism expressing a transglutimase whose primary structure is similar to that of mammalian transglutimases. We observed transglutimase reaction products at injured sites in Physarum macroplasmodia upon mechanical damage. With use of a biotin-labeled primary amine, three major proteins constituting possible transglutimase substrates were affinity-purified from the damaged slime mold. The purified proteins were Physarum actin, a 40 kDa Ca2+ -binding protein with four EF-hand motifs (CBP40), and a novel 33 kDa protein highly homologous to the eukaryotic adenine nucleotide translocator, which is expressed in mitochondria. Immunochemical analysis of extracts from the damaged macroplasmodia indicated that CBP40 is partly dimerized, whereas the other proteins migrated as monomers on SDS/PAGE. Of the three proteins, CBP40 accumulated most significantly around injured areas, as observed by immunofluoresence. These results suggested that transglutimase reactions function in the response to mechanical injury. [source]


Suppression of NF-,B-dependent gene expression by a hexamethylene bisacetamide-inducible protein HEXIM1 in human vascular smooth muscle cells

GENES TO CELLS, Issue 2 2003
Rika Ouchida
Background: Neointima formation is a characteristic feature of atherosclerosis and post-angioplasty restenosis, in which various soluble factors and mechanical injury stimulate signalling pathways in vascular smooth muscle cells (VSMC), promoting their migration and proliferation, and the eventual formation of the neointima. The transcription factor NF-,B has been shown to play a pivotal role in this process. Hexamethylene bisacetamide, an inhibitor of VSMC proliferation, induces the mRNA expression of HEXIM1 (hexamethylene bisacetamide-inducible protein 1). However, the protein expression and function of HEXIM1 remain unknown. Results: In the present study, we demonstrated that HEXIM1 localizes in the cytoplasm and nucleus, and its nuclear expression is restricted to discrete speckled areas. Treatment of VSMC with hexamethylene bisacetamide up-regulated HEXIM1 expression, not only in mRNA but also protein levels. Moreover, HEXIM1 is shown to suppress the transcriptional activity of NF-,B via its C-terminal leucine-rich domain. A glutathione-S-transferase pull down assay indicated that HEXIM1 interacts with the p65 subunit of NF-,B. In VSMC, treatment with hexamethylene bisacetamide resulted in a down-modulation of the transcription of NF-,B target genes. Conclusion: We may therefore conclude that HEXIM1 plays an inhibitory role in NF-,B-dependent gene expression in VSMC and is the candidate of a novel therapeutic target for inhibition of VSMC proliferation. [source]


MUC4 involvement in ErbB2/ErbB3 phosphorylation and signaling in response to airway cell mechanical injury,

JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2009
George Theodoropoulos
Abstract The receptor tyrosine kinases ErbB2 and ErbB3 are phosphorylated in response to injury of the airway epithelium. Since we have shown that the membrane mucin MUC4 can act as a ligand/modulator for ErbB2, affecting its localization in polarized epithelial cells and its phosphorylation, we questioned whether Muc4 was involved, along with ErbB2 and ErbB3, in the damage response of airway epithelia. To test this hypothesis, we first examined the localization of MUC4 in human airway samples. Both immunocytochemistry and immunofluorescence showed a co-localization of MUC4 and ErbB2 at the airway luminal surface. Sequential immunoprecipitation and immunoblotting from airway cells demonstrated that the MUC4 and ErbB2 are present as a complex in airway epithelial cells. To assess the participation of MUC4 in the damage response, cultures of NCI-H292 or airway cells were scratch-wounded, then analyzed for association of phospho-ErbB2 and -ErbB3 with MUC4 by sequential immunoprecipitation and immunoblotting. Wounded cultures exhibited increased phosphorylation of both receptors in complex with MUC4. Scratch wounding also increased activation of the downstream pathway through Akt, as predicted from our previous studies on Muc4 effects on ErbB2 and ErbB3. The participation of MUC4 in the phosphorylation response was also indicated by siRNA repression of MUC4 expression, which resulted in diminution of the phosphorylation of ErbB2 and ErbB3. These studies provide a new model for the airway epithelial damage response, in which the MUC4,ErbB2 complex is a key element in the sensor mechanism and phosphorylation of the receptors. J. Cell. Biochem. 107: 112,122, 2009. © 2009 Wiley-Liss, Inc. [source]


CYSTATIN ACCUMULATION IN TOMATO LEAVES AFTER METHYL JASMONATE TREATMENT OR MECHANICAL INJURY

JOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2002
JU WEN WU
The elicitation of cystatin accumulation in tomato leaves was studied with mature and seedling cv. Bonnie Best. Repetitive mechanical injury (MI) or methyl jasmonate (MJ) treatment of seedlings elicited plentiful cystatin accumulation in the leaves when plants were held at 30C under continuous lighting. Cystatin accumulation in leaves of MI seedlings decreased by 50% when incubated at a reduced light period of 12 h light/day. Cystatin accumulation in MJ treated plants was not influenced by reducing the light period from 24 h to 12 h/day. Cystatin accumulation after MJ treatment was optimal at 35C and negligible at 40C. At ambient field conditions (I8,33C), MJ treated seedlings still accumulated a significant amount of cystatin; however, very little cystatin accumulated in leaves of MI seedlings under these conditions of lower temperature and light exposure. The leaves of mature plants accumulated less cystatin after MJ or MI treatment than did those of seedlings. [source]


Review of Pododermatitis Circumscripta (Ulceration of the Sole) in Dairy Cows

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 4 2006
Sarel R. van Amstel
Sole ulcers are among the most frequent causes of lameness in dairy cattle. They are found most commonly in the hind lateral claw, are frequently bilateral, and have a high rate of reoccurrence. The pathogenesis of sole ulceration is primarily based on mechanical injury by the 3rd phalanx to the corium, basement membrane, and basal layers of the sole epidermis as a result of failure of the suspensory apparatus in the claw. The main pathways in the failure of the suspensory system include inflammatory (dermal vascular changes followed by disruption of keratinocyte proliferation and differentiation caused by local and systemic mediators) and noninflammatory (hormonal and biochemical changes in the peripartum period resulting in alterations of connective tissue in the suspensory system) pathways. Sole ulcers tend to occur in specific locations; the most reported site is the junction of the axial heel and sole. Other locations include the apex of the toe and the heel. Varying degrees of lameness may result, and the most severe are seen with complicated cases in which ascending infection affects the deeper structures of the claw. Pathologic changes at the ulcer site include dyskeratosis and dilated horn tubules with microcracks. Vascular changes include dilatation and thrombosis of capillaries with "neocapillary formation." Areas of dyskeratosis may remain for as long as 50 days at the ulcer site. Treatment includes corrective trimming and relief of weight bearing. Complicated cases may require surgical intervention. [source]


REVIEW ARTICLE: Inflammation and Implantation

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2010
Nava Dekel
Approximately half of all human embryo implantations result in failed pregnancy. Multiple factors may contribute to this failure, including genetic or metabolic abnormalities of the embryo. However, many of these spontaneous early abortion cases are attributed to poor uterine receptivity. Furthermore, although many fertility disorders have been overcome by a variety of assisted reproductive techniques, implantation remains the rate-limiting step for the success of the in vitro fertilization (IVF) treatments. It has been demonstrated that endometrial biopsies performed either during the spontaneous, preceding cycle, or during the IVF cycle itself, significantly improve the rate of implantation, clinical pregnancies and live births. These observations suggest that mechanical injury of the endometrium may enhance uterine receptivity by provoking the immune system to generate an inflammatory reaction. In strong support of this idea, we recently found that dendritic cells (DCs), an important cellular component of the innate immune system, play a critical role in successful implantation in a mouse model. In this review, we discuss the hypothesis that the injury-derived inflammation in the biopsy-treated patients generates a focus for uterine DCs accumulation that, in turn, enhances the endometrial expression of essential molecules, which facilitate the interaction between the embryo and the uterine epithelium. [source]


The piercing-sucking herbivores Lygus hesperus and Nezara viridula induce volatile emissions in plants ,,

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2005
Livy Williams III
Abstract Plant volatiles induced by herbivory are often used as olfactory cues by foraging herbivores and their natural enemies, and thus have potential for control of agricultural pests. Compared to chewing insects and mites, little is known about plant volatile production following herbivory by insects with piercing-sucking mouthparts. Here, we studied factors (insect life stage, gender, the role of salivary glands, and type of bioassay used for volatile induction) that influence the induction of plant volatiles by two agriculturally important hemipterans, Lygus hesperus and Nezara viridula. Feeding on intact cotton by virgin females of L. hesperus induced 2.6-fold greater volatile response compared to that induced by mated females, possibly due to increased feeding activity by virgin females. This plant volatile response was associated with elicitors present in the insect's salivary glands as well as to the degree of mechanical injury. Feeding injury by N. viridula females also increased volatile emissions in intact maize by approximately 2-fold compared to control plants. Maize seedlings injured by N. viridula emitted higher amounts of the monoterpene linalool, the sesquiterpenes (E)-,-caryophyllene, ,- trans -bergamotene, and (E,E)-,-farnesene, and the homoterpene (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, but not amounts of green leaf volatiles, compared to uninjured plants. Emissions from intact maize injured by adult males were lower than those emitted by adult females of the same age and did not differ from those emitted by uninjured plants. Similarly, feeding by virgin female N. viridula followed by excision led to 64% higher quantities of volatiles compared to untreated plants. Volatile emission in excised plants, however, was considerably greater than in intact plants, suggesting that careful consideration must be given to bioassay design in studies of herbivore-induced plant volatiles. Salivary gland extracts of N. viridula led to sesquiterpene emissions approximately 2.5-fold higher than for controls, although no significant differences were observed for green leaf volatiles, monoterpenes, and homoterpenes. These results indicate that L. hesperus and female N. viridula feeding induce volatile production in plants, and that volatile production is affected by gender and life stage of the bug. Although oviposition and mechanical injury by stylets may increase release of volatiles, elicitors from salivary glands of L. hesperus and N. viridula also seem to play a role in the emission of plant volatiles. Arch. Insect Biochem. Physiol. 58:84,96, 2005. Published 2005 Wiley-Liss, Inc. [source]


Mechanical injury potentiates proteoglycan catabolism induced by interleukin-6 with soluble interleukin-6 receptor and tumor necrosis factor , in immature bovine and adult human articular cartilage

ARTHRITIS & RHEUMATISM, Issue 10 2009
Yihong Sui
Objective Traumatic joint injury can damage cartilage and release inflammatory cytokines from adjacent joint tissue. The present study was undertaken to study the combined effects of compression injury, tumor necrosis factor , (TNF,), and interleukin-6 (IL-6) and its soluble receptor (sIL-6R) on immature bovine and adult human knee and ankle cartilage, using an in vitro model, and to test the hypothesis that endogenous IL-6 plays a role in proteoglycan loss caused by a combination of injury and TNF,. Methods Injured or uninjured cartilage disks were incubated with or without TNF, and/or IL-6/sIL-6R. Additional samples were preincubated with an IL-6,blocking antibody Fab fragment and subjected to injury and TNF, treatment. Treatment effects were assessed by histologic analysis, measurement of glycosaminoglycan (GAG) loss, Western blot to determine proteoglycan degradation, zymography, radiolabeling to determine chondrocyte biosynthesis, and Western blot and enzyme-linked immunosorbent assay to determine chondrocyte production of IL-6. Results In bovine cartilage samples, injury combined with TNF, and IL-6/sIL-6R exposure caused the most severe GAG loss. Findings in human knee and ankle cartilage were strikingly similar to those in bovine samples, although in human ankle tissue, the GAG loss was less severe than that observed in human knee tissue. Without exogenous IL-6/sIL-6R, injury plus TNF, exposure up-regulated chondrocyte production of IL-6, but incubation with the IL-6,blocking Fab significantly reduced proteoglycan degradation. Conclusion Our findings indicate that mechanical injury potentiates the catabolic effects of TNF, and IL-6/sIL-6R in causing proteoglycan degradation in human and bovine cartilage. The temporal and spatial evolution of degradation suggests the importance of transport of biomolecules, which may be altered by overload injury. The catabolic effects of injury plus TNF, appeared partly due to endogenous IL-6, since GAG loss was partially abrogated by an IL-6,blocking Fab. [source]


Role of p53 in human chondrocyte apoptosis in response to shear strain

ARTHRITIS & RHEUMATISM, Issue 8 2009
Shingo Hashimoto
Objective Chondrocyte apoptosis plays an important role in cartilage degeneration in osteoarthritis (OA), and mechanical injury to cartilage induces chondrocyte apoptosis. In response to DNA damage, p53 expression is up-regulated, transcription activity is increased, and apoptosis signals are initiated. The p53-regulated apoptosis-inducing protein 1 (p53AIP-1) is one of the p53-regulated genes, and is activated in response to DNA damage. This study was undertaken to analyze p53 function after induction of apoptosis by shear strain in chondrocytes. Methods OA cartilage samples were obtained from subjects undergoing total knee replacement surgery, and normal cartilage samples were obtained from subjects undergoing surgery for femoral neck fracture. Chondrocytes were isolated from human cartilage and cultured. Expression of p53 and p53AIP in chondrocytes was detected by reverse transcriptase,polymerase chain reaction and Western blotting. Shear strain was introduced in normal human knee chondrocytes. To explore p53 function, normal human knee chondrocytes were pretreated with pifithrin-, or p53 small interfering RNA (siRNA) before induction of shear strain. Chondrocyte apoptosis was detected by expression of cleaved caspase 9 with Western blotting and TUNEL staining. Expression of p53 and p53AIP-1 was analyzed by Western blotting. Results OA and normal chondrocytes expressed p53. OA chondrocytes showed much higher expression of p53 and p53AIP-1 than did normal chondrocytes. TUNEL-positive cells and expression of p53, p53AIP-1, and cleaved caspase 9 were increased by shear strain, but chondrocyte apoptosis was suppressed after pretreatment with pifithrin-, or p53 siRNA. Conclusion Our findings indicate that p53 and p53AIP-1 play important roles in human chondrocyte apoptosis. Down-regulation of p53 expression prevents cartilage from undergoing apoptosis introduced by shear strain. [source]


Fibroblast growth factor 2 is an intrinsic chondroprotective agent that suppresses ADAMTS-5 and delays cartilage degradation in murine osteoarthritis

ARTHRITIS & RHEUMATISM, Issue 7 2009
Shi-Lu Chia
Objective We have previously identified in articular cartilage an abundant pool of the heparin-binding growth factor, fibroblast growth factor 2 (FGF-2), which is bound to the pericellular matrix heparan sulfate proteoglycan, perlecan. This pool of FGF-2 activates chondrocytes upon tissue loading and is released following mechanical injury. In vitro, FGF-2 suppresses interleukin-1,driven aggrecanase activity in human cartilage explants, suggesting a chondroprotective role in vivo. We undertook this study to investigate the in vivo role of FGF-2 in murine cartilage. Methods Basal characteristics of the articular cartilage of Fgf2,/, and Fgf2+/+ mice were determined by histomorphometry, nanoindentation, and quantitative reverse transcriptase,polymerase chain reaction. The articular cartilage was graded histologically in aged mice as well as in mice in which osteoarthritis (OA) had been induced by surgical destabilization of the medial meniscus. RNA was extracted from the joints of Fgf2,/, and Fgf2+/+ mice following surgery and quantitatively assessed for key regulatory molecules. The effect of subcutaneous administration of recombinant FGF-2 on OA progression was assessed in Fgf2,/, mice. Results Fgf2,/, mice were morphologically indistinguishable from wild-type (WT) animals up to age 12 weeks; the cartilage thickness and proteoglycan staining were equivalent, as was the mechanical integrity of the matrix. However, Fgf2,/, mice exhibited accelerated spontaneous and surgically induced OA. Surgically induced OA in Fgf2,/, mice was suppressed to levels in WT mice by subcutaneous administration of recombinant FGF-2. Increased disease in Fgf2,/, mice was associated with increased expression of messenger RNA of Adamts5, the key murine aggrecanase. Conclusion These data identify FGF-2 as a novel endogenous chondroprotective agent in articular cartilage. [source]


Modulation of lubricin biosynthesis and tissue surface properties following cartilage mechanical injury

ARTHRITIS & RHEUMATISM, Issue 1 2009
Aled R. C. Jones
Objective To evaluate the effects of injurious compression on the biosynthesis of lubricin at different depths within articular cartilage and to examine alterations in structure and function of the articular surface following mechanical injury. Methods Bovine cartilage explants were subdivided into level 1, with intact articular surface, and level 2, containing middle and deep zone cartilage. Following mechanical injury, lubricin messenger RNA (mRNA) levels were monitored by quantitative reverse transcriptase,polymerase chain reaction, and soluble or cartilage-associated lubricin protein was analyzed by Western blotting and immunohistochemistry. Cartilage morphology was assessed by histologic staining, and tissue functionality was assessed by friction testing. Results Two days after injury, lubricin mRNA expression was up-regulated ,3-fold for level 1 explants and was down-regulated for level 2 explants. Lubricin expression in level 1 cartilage returned to control levels after 6 days in culture. Similarly, lubricin protein synthesis and secretion increased in response to injury for level 1 explants and decreased for level 2 cartilage. Histologic staining revealed changes in the articular surface of level 1 explants following injury, with respect to glycosaminoglycan and collagen content. Injured level 1 explants displayed an increased coefficient of friction relative to controls. Conclusion Our findings indicate that increased lubricin biosynthesis appears to be an early transient response of surface-layer cartilage to injurious compression. However, distinct morphologic changes occur with injury that appear to compromise the frictional properties of the tissue. [source]


EARLY ACTIVATION OF INTERNAL MEDIAL SMOOTH MUSCLE CELLS IN THE RABBIT AORTA AFTER MECHANICAL INJURY: RELATIONSHIP WITH INTIMAL THICKENING AND PHARMACOLOGICAL APPLICATIONS

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2006
Huguette Louis
SUMMARY 1Smooth muscle cells (SMC) participate in both inflammatory and dedifferentiation processes during atherosclerosis, as well as during mechanical injury following angioplasty. In the latter, we studied medial SMC differentiation and inflammation processes implicated early after de-endothelialization in relation to mechanical stresses. We hypothesized that activation of a subpopulation of SMC within the media plays a crucial role in the early phase of neointimal formation. 2For this purpose, we used a rabbit model of balloon injury to study activation and differentiation of medial SMC in the early time after denudation and just before neointima thickening. Inflammation was evaluated by the expression of vascular cell adhesion molecule (VCAM)-1, integrin a4b1 and nuclear factor (NF)-kB. Myosin isoforms and 2P1A2 antigen, a membrane protein expressed by rabbit dedifferentiated SMC, were used as markers of differentiation. 3On day 2 after de-endothelialization, VCAM-1, a4b1 and NF-kB were coexpressed by a well-defined subpopulation of SMC of the internal part of the media, in the vicinity of the blood stream. At the same time, the majority of SMC throughout the media expressed non-muscle myosin heavy chain-B (nm-MHC-B) and 2P1A2 antigen. On day 7, when intimal thickening appeared, SMC of the media were no longer activated, whereas some intimal SMC expressed the activation markers. Thus, after de-endothelialization, early dedifferentiation occurs in most of the medial SMC, whereas activation concerned only a subpopulation of SMC located in the internal media. Using the T-type voltage-operated calcium channel blocker mibefradil (0.1,1 mmol/L) in SMC culture, we showed that this agent exhibited an antiproliferative effect in a dose-dependant manner only on undifferentiated cells. 4In conclusion, the results suggest that the activated SMC represent cells that are potentially able to migrate and participate in the intimal thickening process. Thus, the medial SMC inflammatory process, without any contribution of inflammatory cells, may represent a major mechanism underlying the development of intimal thickening following mechanical stress. In humans, inhibition of T-type calcium channels may be a tool to prevent the early proliferation step leading to neointimal formation. [source]


Elevated Serum Cardiac Troponin in Non-acute Coronary Syndrome

CLINICAL CARDIOLOGY, Issue 1 2009
Yeshitila Agzew MD
Abstract Cardiac troponins (CTn) are the most sensitive and specific biochemical markers of myocardial injury and risk stratification. The assay for troponin T (cTnI) is standardized, and results obtained from different institutions are comparable. This is not the case with troponin I (cTnT), and clinicians should be aware that each institution must analyze and standardize its own results. Elevated cTn levels indicate cardiac injury, but do not define the mechanical injury. The differentiation of cTn elevation caused by coronary events from those not related to an acute coronary syndrome (ACS) is tiresome, at times vexing, and often costly. Elevation of cTn in non-ACS is a marker of increased cardiac and all-cause morbidity and mortality. The cause of these elevations may involve serious medical conditions that require meticulous diagnostic evaluation and aggressive therapy. At present, there are no guidelines to treat patients with elevated troponin levels and no coronary disease. The current strategy of treatment of patients with elevated troponin and non-ACS involves treating the underlying causes. Copyright © 2009 Wiley Periodicals, Inc. [source]