Severe Inflammatory Disorders Research Articles

Selective resistance to different glucocorticoids in severe autoimmune disorders

Resistance to glucocorticoids often occurs in patients with severe inflammatory disorders. Occasionally, this resistance could be overcome by switching to a different glucocorticoid, but the mechanisms of this selectivity are not clear. We studied this condition in three patients with severe inflammatory disorders, who responded satisfactorily to betamethasone, but could not be switched to equipotent doses of methylprednisolone or prednisone. While betamethasone displayed similar activity on lymphocyte proliferation in cells obtained from the three patients and controls, higher concentrations of methylprednisolone were needed to inhibit proliferation in patients' cells. In a competition study, the concentration of methylprednisolone that inhibited 50% of specific [(3)H]dexamethasone binding was increased in patients' lymphocytes. Higher Rhodamine-123 efflux was demonstrated in CD4 T cells from two patients, suggesting that an increased activity of membrane transporters could be responsible for the selective response to different glucocorticoids, even if P-glycoprotein and MRP1 expression was not increased.

Protective mechanisms of activated protein C in severe inflammatory disorders

The protein C system is an important natural anticoagulant mechanism mediated by activated protein C (APC) that regulates the activity of factors VIIIa and Va. Besides well-defined anticoagulant properties, APC also demonstrates anti-inflammatory, anti-apoptotic and endothelial barrier-stabilizing effects that are collectively referred to as the cytoprotective effects of APC. Many of these beneficial effects are mediated through its co-receptor endothelial protein C receptor, and the protease-activated receptor 1, although exact mechanisms remain unclear and are likely pleiotropic in nature. Increased insight into the structure-function relationships of APC facilitated design of APC variants that conserve cytoprotective effects and reduce anticoagulant features, thereby attenuating the risk of severe bleeding with APC therapy. Impairment of the protein C system plays an important role in acute lung injury/acute respiratory distress syndrome and severe sepsis. The pathophysiology of both diseases states involves uncontrolled inflammation, enhanced coagulation and compromised fibrinolysis. This leads to microvascular thrombosis and organ injury. Administration of recombinant human APC to correct the dysregulated protein C system reduced mortality in severe sepsis patients (PROWESS trial), which stimulated further research into its mechanisms of action. Several other clinical trials evaluating recombinant human APC have been completed, including studies in children and less severely ill adults with sepsis as well as a study in acute lung injury. On the whole, these studies have not supported the use of APC in these populations and challenge the field of APC research to search for additional answers.

Vascular and dendritic cell coagulation signaling in sepsis progression.

The intrinsic signaling networks of the coagulation pathways have recently emerged as crucial determinants for survival in sepsis and systemic inflammatory response syndromes. Protease activated receptor (PAR) 1 is central to both lethality promoting and vascular protective signaling. In the vascular anticoagulant pathway, EPCR/aPC-PAR1 signaling prevents vascular leakage and genetic or acute deficiencies in this pathway promote lethality. In addition, coagulation signaling acts directly on cells of the innate immune system. Dendritic cell (DC) thrombin-PAR1 signaling is coupled to the migration promoting sphingosine 1 phosphate receptor 3 (S1P3). Thrombin generated in the lymphatic compartment perturbs DCs to promote systemic inflammation and disseminated intravascular coagulation in severe sepsis. Signaling-selective aPC variants and selective modulators of the S1P receptor system attenuate sepsis lethality, suggesting novel therapeutic approaches that can be employed to rebalance alterations in the coagulation signaling pathways in severe inflammatory disorders.

The role of FoxP3 +CD4 +CD25 hi Tregs in the pathogenesis of myasthenia gravis

CD4 +CD25 + regulatory T cells (CD4 +CD25 + Tregs) play a critical role in the maintenance of peripheral self-tolerance and the regulation of immune responses. Genetic defects that primarily affect the development and/or function of CD4 +CD25 + Tregs result in severe autoimmune diseases and inflammatory disorders. In this study, we investigated whether the peripheral pool and the function of CD4 +CD25 + Tregs are altered in patients of myasthenia gravis (MG), a chronic autoimmune disorder that results in progressive skeletal muscle weakness. Here we showed that both mRNA and protein expression level of FoxP3 in CD4 +CD25 + Tregs are dramatically down-regulated, accompanied by an severe functional defect in CD4 +CD25 + Tregs regulatory activity when cocultured with autologous CD4 +CD25 − T cells, although the reservoir of CD4 +CD25 + Tregs is not changed in peripheral blood from MG patients. Since FoxP3 is a pivotal transcription factor that indispensable for the generation and the regulatory function of CD4 +CD25 + Tregs, our data suggested that the functional activity of CD4 +CD25 + Tregs is inhibited in MG patients and that MG might originate from the dysfunction of CD4 +CD25 + Tregs. Although the underlying molecular basis for the reduced expression of FoxP3 in CD4 +CD25 + Tregs from MG patients remains unknown, this study provided a potential target for MG therapy.

Construction and characterization of the HMGB1 mutant as a competitive antagonist to HMGB1 induced cytokines release

Recent studies indicate that the High Mobility Group Box-1 protein (HMGB1) acts as a potent proinflammatory cytokine that contributes to the pathogenesis of diverse inflammatory and infectious disorders. The proinflammatory cytokine activity of HMGB1 has become a therapeutic target. In this study, we cloned the cDNA encoding human HMGB1 and constructed HMGB1 mutants using a one-step opposite direction PCR. The binding of the HMGB1 mutants to THP-1 cell and the cytokine activities of these HMGB1 mutants were observed. Results showed that the HMGB1 Mut (102–105), one of the HMGB1 mutants, in which amino acids 102–105 (FFLF) were replaced with two Glys, significantly decreased the full-length HMGB1 protein induced TNF-α release in human monocyte cultures. The results indicate that we have developed a novel recombinant HMGB1 mutant that competitively antagonizes the proinflammatory activity of HMGB1. This may be of significant importance in providing a new anti-inflammatory strategy for the treatment of severe sepsis and other inflammatory disorders.

Bcl‐3 Inhibits Toll‐like Receptor Signaling and Inflammation By Blocking NF‐kB p50 Ubiquitination

Toll‐like receptor (TLR) activation triggers the production of inflammatory cytokines and shapes the adaptive and innate immunity to pathogens. However, uncontrolled activation of TLR can lead to severe inflammatory disorders. We report here that B cell leukemia (Bcl)‐3 serves as an essential negative regulator of TLR4 signaling. Bcl‐3‐deficient macrophages are hyper‐responsive to TLR4 activation and are unable to develop tolerance to lipopolysacchrides (LPS). In the absence of Bcl‐3, the inhibitory p50 homodimer of the nuclear factor (NF)‐kB family is ineffective in suppressing gene expression because it is rapidly ubiquitinated and degraded upon binding to DNA. Bcl‐3 effectively inhibits K48 polyubiquitination of the p50 homodimer and stabilizes its interaction with DNA through the formation of a stable Bcl‐3:(p50)2:DNA complex. By controlling stimulatory NF‐kB dimer loading and dimer exchange at the site of gene promoters, the stabilized Bcl‐3:(p50)2:DNA complex confers a state of long‐lasting promoter hypo‐responsiveness (tolerance) to TLR signaling. In addition, Bcl3−/− mice are more susceptible to autoimmune diabetes and display increased chemokine production and defective Th2, but not Th1 responses. These data establish that Bcl‐3 is a key regulator of NF‐kB transcriptional activity during autoimmune diabetes and acute or chronic infections. Supported by grants from NIH, USA.

On interaction of activated protein C with human aortic smooth muscle cells attenuating the secretory group IIA phospholipase A 2 expression

Introduction Pharmacological restriction of secretory group IIA phospholipase A 2 (sPLA 2-IIA) expression is thought to be beneficial in the treatment of inflammatory diseases such as sepsis and septic shock. In this study we investigated the effects of activated protein C (APC) on sPLA 2-IIA expression, phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, and on DNA-binding activities of nuclear factor-κB (NF-κB) and CCAAT box enhancer binding protein-β (C/EBP-β) in human aortic smooth muscle cells (HASMC). Materials and methods To achieve elevated sPLA 2-IIA production as occurring during inflammation, HASMC were stimulated with interferon-γ (IFN-γ) alone and in combination with other inductors, thus modeling the strong sPLA 2-IIA elevation by inflammation. Results and conclusions APC inhibited the stimulated expression of sPLA 2-IIA in HASMC dose-dependently (1–300 nM). At the same time, APC increased the phosphorylation of ERK 1/2 and decreased NF-κB and C/EBP-β DNA-binding activities in these cells, as compared with respective stimulated controls. Reverse transcriptase-polymerase chain reaction and cell-based ELISA reveal an endothelial protein C receptor (EPCR) expression in HASMC. Application of antibodies against EPCR and protease-activated receptor-1 (PAR-1) reduced the APC-induced ERK 1/2 activation and the treatment of cells with a PAR-1 antagonist diminished the sPLA 2-IIA inhibition. The obtained results show that APC effectively suppresses the up-regulated sPLA 2-IIA expression, which might contribute to the reported beneficial effects of APC in the treatment of severe inflammatory disorders.

Detection of Fibrin Deposits in Horse Tissues by Immunohistochemistry

Background: Histochemical and immunohistochemical techniques have been used to detect fibrin deposits in different tissues in humans and experimental animal models with disseminated intravascular coagulation (DIC). Fibrin deposits also have been observed in horses with severe ischemic and inflammatory disorders by histochemical stainings (phosphotungstic acid hematoxylin [PTAH]). Hypothesis: Immunohistochemical (IHC) methods can be used to accurately detect fibrin deposits in horses at risk of DIC. Animals: Tissue‐organ samples collected on postmortem examination from 87 horses with severe inflammatory and ischemic gastrointestinal disorders. In addition, tissue samples from 13 horses with colic and colonic obstructions or displacements and from 13 slaughter horses were used as controls. Methods: Tissue samples (kidney, lung, and liver) were stained with PTAH and IHC for blinded histologic examination and comparison. A fibrin score (grades 0 to 4) was established for each tissue sample and for each horse for both techniques. Results: When the IHC method was used, fibrin deposition was observed in 47.1% of the horses with colic with a poor prognosis, compared with 41.4% with PTAH. An agreement of 70% was achieved when both methods were compared, and the lung was confirmed as the most affected organ. Almost none of the colic and slaughter control horses had fibrin deposits in their tissues. Conclusions and Clinical Importance: IHC technique for fibrin antigens was very effective in the detection and identification of fibrin deposits in equine tissues and may be a reliable technique for the postmortem diagnosis of DIC.

Adrenocorticotropin Hormone Stimulates Interleukin-18 Expression in Human HaCaT Keratinocytes

The hypothalamic-pituitary-adrenal (HPA) axis is activated by stress. This involves the production of corticotropin releasing hormone (CRH) with the subsequent release of proopiomelanocortin (POMC) peptides, of which adrenocorticotropin hormone (ACTH) is most important. Although the skin has the capacity to produce CRH and POMC peptides, the immunomodulatory roles of ACTH in skin are yet unknown. IL-18 has been known to affect cells involved in the inflammatory response. In this study, we aimed to identify the regulatory effect of ACTH on IL-18 expression of skin keratinocytes. Exposure of HaCaT cells to ACTH stimulated formation of IL-18 mRNA transcript and its protein products in a dose-dependent manner. Furthermore, we suggest that ACTH-induced IL-18 production is via the caspase-1 activation pathway, as IL-18 production induced by ACTH could be suppressed by caspase-1 inhibitor, and ACTH could increase caspase-1 activity. The effect of ACTH on IL-18 production was blocked by specific inhibitors of p38 kinase (SB203580) or extracellular signal-regulated kinase (ERK) (PD98059). In addition, ACTH-induced rapid phosphorylation of p38 kinase and ERK, and ACTH signaling occurred via melanocortin receptor 1 (MC1R) and receptor 2 (MC2R). These results suggest that ACTH stimulates IL-18 expression in human keratinocytes, which provides an insight into the interaction between ACTH and inflammatory mediators.

Detection of Fibrin Deposits in Horse Tissues by Immunohistochemistry

Histochemical and immunohistochemical techniques have been used to detect fibrin deposits in different tissues in humans and experimental animal models with disseminated intravascular coagulation (DIC). Fibrin deposits also have been observed in horses with severe ischemic and inflammatory disorders by histochemical stainings (phosphotungstic acid hematoxylin [PTAH]). Immunohistochemical (IHC) methods can be used to accurately detect fibrin deposits in horses at risk of DIC. Tissue-organ samples collected on postmortem examination from 87 horses with severe inflammatory and ischemic gastrointestinal disorders. In addition, tissue samples from 13 horses with colic and colonic obstructions or displacements and from 13 slaughter horses were used as controls. Tissue samples (kidney, lung, and liver) were stained with PTAH and IHC for blinded histologic examination and comparison. A fibrin score (grades 0 to 4) was established for each tissue sample and for each horse for both techniques. When the IHC method was used, fibrin deposition was observed in 47.1% of the horses with colic with a poor prognosis, compared with 41.4% with PTAH. An agreement of 70% was achieved when both methods were compared, and the lung was confirmed as the most affected organ. Almost none of the colic and slaughter control horses had fibrin deposits in their tissues. IHC technique for fibrin antigens was very effective in the detection and identification of fibrin deposits in equine tissues and may be a reliable technique for the postmortem diagnosis of DIC.

Intraocular complications of IFN-α and ribavirin therapy in patients with chronic viral hepatitis C

We report a panel of severe inflammatory and vascular intraocular disorders occurring during interferon-alpha (IFN-alpha) treatment in eight hepatitis C virus (HCV)-infected patients. These events include three cases of Vogt-Koyanagi-Harada like (VKH) disease (an association of panuveitis, retinal detachment, ear and meningeal detachment and skin and hair changes), two cases of central retinal vein occlusion, one case of central retinal artery occlusion, one case of severe hypertensive retinopathy and one case of bilateral ischemic optic neuropathy with severe visual impairment. Rare as they are, such severe ophthalmological complications require a close follow-up of HCV-infected patients under IFN-alpha treatment with ophthalmological monitoring if any ocular manifestation occurs.

Neuropeptide Mimetics and Antagonists in the Treatment of Inflammatory Disease: Focus on VIP and PACAP

Corticosteroids are the mainstay treatment for most severe inflammatory disorders. Due to the considerable toxicity associated with their long-term use, there is a great need for alternative treatments. Recently, two closely related neuropeptides with potent neuromodulatory activities, vasoactive intestinal peptide (VIP) and pituitary adenylyl cyclase activating peptide (PACAP) have emerged as candidate molecules for the treatment of such pathologies. These peptides act primarily on three high affinity receptor subtypes expressed on multiple immune cell types, and orchestrate a cytokine response that is primarily anti-inflammatory. In this regard, systemic treatment with these peptides has been shown to greatly reduce the clinical symptoms and alter the pathogenic and cytokine profiles in animal models of rheumatoid arthritis, Crohn's disease, septic shock, and multiple sclerosis. Likewise, VIP and PACAP receptor knockout and overexpressing mice show altered immune responses in different models. We review here data demonstrating the potential effectiveness of these peptides in immune disorders, discuss receptor pharmacology and signaling pathways, describe the development of receptor specific agonists and antagonists, and discuss pharmaceutical considerations relevant to the specific delivery of analogs to the appropriate targets.

Novel ligands: fine tuning the transcriptional activity of the glucocorticoid receptor.

Glucocorticoids are the first line medication used in the therapy of many severe inflammatory disorders. They exert their activity through binding to the glucocorticoid receptor, a ligand-dependent transcription factor, and result in either activation or repression of a large set of glucocorticoid responsive genes. The desired immunosuppressive effect is apparently due largely to the down-regulation of a variety of pro-inflammatory factors, whereas adverse reactions such as corticoid-induced diabetes and osteoporosis could be connected to the inappropriate activation of genes involved in the control of metabolic processes. The discovery of improved glucocorticoids, which maintain beneficial therapeutic activity together with a diminished risk of side effects, focuses on ligands that lead to repression rather than activation of genes targeted by the glucocorticoid receptor. Current drug-screening programs have yielded a number of molecules including steroidal as well as non-steroidal compounds, which preferentially induce receptor-mediated repression. The characterization of these novel glucocorticoids in several in vitro and in vivo models for their immune modulating activity marks an important step towards the development of a new class of safer glucocorticoid preparations.

Human leukocyte elastase and cathepsin G are specific inhibitors of C5a‐dependent neutrophil enzyme release and chemotaxis

Circulating human neutrophils from patients with severe inflammatory disorders such as erysipelas and sepsis are specifically desensitized to complement factor C5a stimulation but not to stimulation with other stimuli like N-formyl-methionyl-leucyl-phenylalanine (FMLP), interleukin-8 (IL-8), leukotriene B4 (LTB4), or platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine). In this study, we raised the question whether factors released from polymorphonuclear leukocytes (PMNs) can specifically down-regulate C5a-dependent neutrophil functions. When neutrophils were preincubated with either neutrophil lysates or neutrophil degranulation supernatants, a complete inhibition of C5a-stimulated beta-glucuronidase release and chemotaxis could be observed, whereas FMLP-, IL-8-, LTB4- or PAF-dependent functions were not affected. Serine protease inhibitors like phenylmethylsulfonyl fluoride, antileukoprotease, or elafin abolished this effect. High-performance liquid chromatography of neutrophil degranulation supernatants revealed pronounced inhibition of C5a-dependent neutrophil functions in fractions exerting elastase or cathepsin G activity, but not in fractions exerting proteinase 3 activity. Using purified human leukocyte elastase (HLE), C5a responses like intracellular calcium influx, beta-glucuronidase release, and chemotaxis were also specifically inhibited. Our experiments show that the release of HLE or cathepsin G from neutrophils specifically down-regulates the responsiveness of neutrophils to C5a. Elastase and cathepsin G may therefore play an important role in the down-regulation of acute inflammation.

Procalcitonin: improved biochemical severity stratification and postoperative monitoring in severe abdominal inflammation and sepsis.

Infections and sepsis are among the most devastating complications in abdominal surgery and significantly contribute to morbidity and mortality. Early and reliable diagnosis of septic complications is notoriously difficult, and the search for novel approaches to overcome this problem is still a compelling issue for clinicians. Among a large array of inflammatory parameters, procalcitonin (PCT), the 116-amino-acid pro-peptide of calcitonin, has gained considerable importance in identifying patients at risk of developing infection and sepsis in clinical practice. Along with the latest insights into pathophysiological aspects of this pro-hormone, the literature as well as our own experience on the usefulness of PCT determinations in patients with severe inflammatory abdominal disorders was reviewed. Although the term "sepsis" does not embrace the integral properties of PCT, a remarkable number of clinical studies have demonstrated the pivotal role of this parameter in the host response to microbial and fungal infections. In acute pancreatitis PCT allows early severity stratification and closely correlates with the development of subsequent pancreatic infections. In patients with peritonitis PCT reflects overall disease severity and is an early and reliable indicator of overall prognosis. Postoperative monitoring of PCT is a helpful tool to identify patients with evolving or persisting septic complications after elective and emergency abdominal surgery. Compared with established biochemical routine variables, PCT significantly contributes to earlier and better stratification of patients at risk of developing septic complications and provides excellent prognostic assessment in severe abdominal inflammation. The currently available test systems render PCT an applicable and readily available parameter under clinical routine and emergency conditions.

Dysregulation of T lymphocyte function in itchy mice: a role for Itch in TH2 differentiation

Itch is an E3 ubiquitin ligase that is disrupted in nonagouti-lethal or itchy mice. Itch deficiency leads to severe immune and inflammatory disorders and constant itching of the skin. Here we show that Itchminus sign/minus sign T cells show an activated phenotype and enhanced proliferation. Production of the type 2 T helper (TH2) cell cytokines interleukin 4 (IL-4) and IL-5 by Itchminus sign/minus sign T cells was augmented upon stimulation, and the TH2-dependent serum concentrations of immunoglobulin G1 (IgG1) and IgE in itchy mice were also increased. Molecularly, Itch associated with and induced ubiquitination of JunB, a transcription factor that is involved in TH2 differentiation. These results provide a molecular link between Itch deficiency and the aberrant activation of immune responses in itchy mice.

C1-Inhibitor and Transplantation

Excessive activation of the protein cascade systems has been associated with post-transplantation inflammatory disorders. There is increasing evidence that complement not only significantly contributes to ischemia/reperfusion injury upon cold storage of the organ but also, although to a different degree, to allograft rejection. Complement activation is most fulminant in hyperacute rejection but seems also to contribute to acute transplant rejection. Therapeutic substitution of appropriate regulators, therefore, appears to be a reasonable approach to reduce undesirable inflammatory reactions in the grafted organ. C1-inhibitor, a multifunctional regulator of the various kinin-generating cascade systems (for review see: E. Hack, chapter in this issue), is frequently reduced in patients suffering from severe inflammatory disorders. Studies applying pathophysiologically relevant animal models of allo- and xenotransplantation as well as promising first clinical results from successful allotransplantation now provide evidence that C1-inhibitor may also serve as an effective means to protect the grafted organ against inflammatory tissue injury. In xenotransplantation, complement inhibition by specific regulators such as C1-inhibitor may help to overcome hyperacute graft rejection. After a brief introduction on the significance of complement to allo- and xenotransplantation the following review will focus on the impact of C1-inhibitor treatment on transplantation-associated inflammatory disorders, where complement contributes to the pathogenesis.

Interleukin-18 regulates both Th1 and Th2 responses.

Although interleukin-18 is structurally homologous to IL-1 and its receptor belongs to the IL-1R/Toll-like receptor (TLR) superfamily, its function is quite different from that of IL-1. IL-18 is produced not only by types of immune cells but also by non-immune cells. In collaboration with IL-12, IL-18 stimulates Th1-mediated immune responses, which play a critical role in the host defense against infection with intracellular microbes through the induction of IFN-gamma. However, the overproduction of IL-12 and IL-18 induces severe inflammatory disorders, suggesting that IL-18 is a potent proinflammatory cytokine that has pathophysiological roles in several inflammatory conditions. IL-18 mRNA is expressed in a wide range of cells including Kupffer cells, macrophages, T cells, B cells, dendritic cells, osteoblasts, keratinocytes, astrocytes, and microglia. Thus, the pathophysiological role of IL-18 has been extensively tested in the organs that contain these cells. Somewhat surprisingly, IL-18 alone can stimulate Th2 cytokine production as well as allergic inflammation. Therefore, the functions of IL-18 in vivo are very heterogeneous and complicated. In principle, IL-18 enhances the IL-12-driven Th1 immune responses, but it can also stimulate Th2 immune responses in the absence of IL-12.

Recognition and management of myositis.

Polymyositis and dermatomyositis are severe inflammatory muscle disorders of unknown cause, with possible life-threatening complications. Prognosis and response to therapy may be predicted not only from the clinical and pathological diagnostic group to which a patient belongs, but also from the patient's myositis-specific antibody status, extraskeletal muscle involvement, and the interval between onset of muscle weakness and the start of the treatment. Corticosteroids are the mainstay of treatment, providing recovery of normal muscular function in about 60% of patients. However, adequate dose, duration of therapy and gradual tapering of corticosteroids are required to produce favourable biochemical and clinical outcomes. In patients refractory to or intolerant of corticosteroids, additional therapy, often involving an immunosuppressive agent or intravenous immunoglobulin, is required. The potential roles of plasmapheresis and total body irradiation must be balanced by their inconclusive efficacies and adverse effects.

Oxidative Stress: Pathogenetic Mechanisms

Radical and nonradical ‘reactive oxygen species (ROS)’ are normally occurring intermediates of aerobic cellular metabolism. Under physiologic conditions, they are kept from causing noticeable damage by antioxidant enzymes and small molecular weight compounds. Oxidative stress develops when antioxidants are overwhelmed by ROS. This may occur via overproduction of the latter and/or by deficiency of antioxidant defense. ROS in excess, especially the highly reactive hydroxyl radical (HO·), which is usually generated with the catalytic help of transition metals such as ferrous ions, can attack virtually all biological structures. Consequences may be functionally relevant when sensitive macromolecules are altered by ROS, in particular DNA (e.g. mutations, base modifications), proteins (formation of disulfide bridges etc.), lipids (lipid peroxidation), and polysaccharides (depolymerisation). Type and severity of the damage and cellular responses to it, including adaptive enzyme induction, determine the outcome in terms of cellular dysfunction or death. Many human disorders are thought to be associated with oxidative stress. ROS seem to play a predominant role, for instance, in radiation effects, damage by oxidant chemicals (many poisons and chemotherapeutic drugs), lung lesions due to hyperbaric oxygen, and chronic deficiencies of selenium and vitamin E. Oxidative stress is also thought to be important in other diseases and processes, e.g. in ischemia-reperfusion damage, central nervous system injury and stroke, severe chronic inflammatory disorders (for example rheumatoid arthritis), the development of arterial atherosclerosis, cancero-genesis, and ageing.