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ID PMID Title PublicationDate abstract
16844318 Possible association of psoriasis and reduced bone mineral density due to increased TNF-al 2006 Psoriasis is a chronic erythematosquamous disease affecting about 2-3% of the population. It is generally considered to be a T cell-mediated disorder. Psoriasis is characterized by Th1-type cytokine pattern with the predominant secretion of IL-2, IL-6, IFN-gamma and TNF-alpha. Such cytokine pattern is sufficient in inducing keratinocyte hyperproliferation, a hallmark of psoriasis. It seems that development of psoriatic lesions is mediated by TNF-alpha and proliferation of local T cells is dependent on local TNF-alpha production. IL-6 enhances activation, proliferation and chemotaxis of T cells into psoriatic lesions. It is also a direct keratinocyte mitogen that could directly stimulate keratinocyte proliferation. Data of possible association between psoriasis and reduced bone mineral density (BMD) are limited and therefore, not fully conclusive. The major limitation of two studies reported so far was small sample size. Based on increased concentrations of TNF-alpha and IL-6 in psoriasis we hypothesized that these patients are more prone to osteoporosis than healthy subjects. TNF-alpha enhances bone resorption via stimulating osteoclast development and activity as well as bone formation. On the other hand, IL-6 is also a potent stimulator of bone resorption. Moreover, increased production of TNF-alpha and IL-6 has been found in postmenopausal women with osteoporosis. Several lines of evidence support our hypothesis; higher value of IL-6 was recorded in children with idiopathic osteoporosis than in healthy controls; TNF-alpha knock-out mice do not lose bone after ovariectomy; polymorphism of TNFRSF1B gene which encodes 75 Kd TNF receptor is associated with BMD; treatment with anti-TNF-alpha antibody exert beneficial effect on bone metabolism in patients with rheumatoid arthritis and finally, raloxifene inhibit osteoclast activity by reducing TNF-alpha and IL-6 synthesis. However, our hypothesis raised number of questions. Are increased serum concentrations of TNF-alpha and IL-6 mirrored by increased concentrations of these cytokines on the local level? Furthermore, could other cytokines relevant in the pathogenesis of the psoriasis, first of all IFN-gamma, modulate the risk of osteoporosis? Thus, a large prospective, case-control study with the data on BMD, biochemical parameters of bone turnover and fractures have to be done to test our hypothesis.
16828606 Long-term outcomes in difficult-to-treat patients with recurrent pericarditis. 2006 Jul 15 Patients with many recurrences of acute pericarditis are commonly alarmed by the fear of constriction. We studied their long-term outcome and the possible presence of systemic diseases. Sixty-one Italian patients (36 men) were followed for an average of 8.3 years according to a predefined protocol, including testing for autoimmune diseases and familial Mediterranean fever. Symptomatic pericarditis lasted from 1 to 43 years (mean 5.4 years). Fifty-two patients had been referred to us after failure of previous therapies, including steroids. We observed 378 attacks with a mean of 1.6 per patient per year and 156 hospital admissions. Thirteen patients had a post-cardiac injury syndrome. In 43 (70.5%), the pericarditis remained idiopathic, whereas we made a new diagnosis of rheumatoid arthritis in 1 and of Sjogren's syndrome in 4 patients, but in these patients pericarditis represented the dominant clinical manifestation. Cardiac tamponade occurred during the initial attacks in 4 patients (6.5%) but never recurred. Pleural effusions were present during the first attack in 22 patients (36.0%) and liver involvement in 5 (8%). No patients developed constrictive pericarditis. Echocardiographic examination produced no evidence of chronic myocardial disease. Response to therapy was good. Thirty-one patients (50.8%) are in sustained remission, without any therapy; their total observation period has averaged 10.3 years. In idiopathic patients, antinuclear antibodies were present in 56.2% and anti-Ro/SSA in 8.3%. Mutations linked to familial Mediterranean fever were absent. In conclusion, in this large series of difficult patients with recurrent acute pericarditis and a very long follow-up, the long-term prognosis is good.
16755653 Tumor necrosis factor-alpha protects synovial cells from nitric oxide induced apoptosis th 2006 Jun OBJECTIVE: To investigate the anti-apoptotic role of tumor necrosis factor-a (TNF-a) and its signaling pathways in cultured human fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis. METHODS: FLS were cultured in Dulbecco's modified Eagle's medium. Apoptotic cells were identified by TUNEL assay and Hoechst staining. Cell viability was determined by the MTT method. Expression of phospho-Akt and phospho-BAD was measured by Western blotting. RESULTS: A 24-h TNF-a treatment prevented FLS apoptosis induced by nitric oxide (NO) donor sodium nitroprusside dihydrate (SNP), achieving 70% protection. At 1-10 ng x ml-1 concentrations, TNF-a induced phosphorylation of Akt and BAD in a time and concentration-dependent manner. This effect was blocked by treatment with both LY294002 and nuclear factor-kB inhibitor pyrrolidine-dithiocarbamate. CONCLUSION: TNF-a has an anti-apoptotic effect in human FLS. Activation of Akt and BAD may have an important role in this process.
16601548 Basic science for the clinician 37: Protecting against autoimmunity-tolerance: mechanisms 2006 Apr As noted in previous articles in this series, tolerance, the ability of the immune system to differentiate self from nonself and leave the former alone, is a vital characteristic of a successful (and safe) immune system. With the detection of the molecule called aire (autoimmune regulator), the mechanism whereby autoreactive thymocytes encounter extrathymic proteins within the thymus and therefore are deleted, is now far better understood; aire was the subject of a prior article in this series. The absence of aire leads to autoimmune polyendocrinopathy, proof that aire is the center of an amazing "filtering" system. However, there are other mechanisms at work. Irregularities in expression of other proteins such as hypoxia-induced factor-1 (HIF-1) and CTLA4, have been implicated in autoimmune disease, the former in rheumatoid arthritis, the latter in autoimmune thyroid disease and lupus. Defects in intracellular factors involved in transcription of key apoptotic proteins have also been implicated in the escape of autoreactive thymocytes from the thymus, leading to autoimmune and lymphoproliferative syndromes as well. Changes in the proteins that oversee acetylation of histone lead to differential patterns of gene expression. At least 2 proteins involved in this process, HDAC and nur77, have been implicated in changes in survival of thymocytes. Yet again, there are multiple layers at work in the immune system; I have no idea how many more will be brought to light, which are phylogenetically most ancient or which will prove the most clinically relevant. For now, it is enough to bask in our new-found knowledge and know that the time from laboratory oddity, to animal model development, to therapeutic and/or diagnostic applications grows shorter each year since the molecular biologic revolution.
15912352 Complications of transpedicular screw fixation in the cervical spine. 2006 Mar Today, posterior stabilization of the cervical spine is most frequently performed by lateral mass screws or spinous process wiring. These techniques do not always provide sufficient stability, and anterior fusion procedures are added secondarily. Recently, transpedicular screw fixation of the cervical spine has been introduced to provide a one-stage stable posterior fixation. The aim of the present prospective study is to examine if cervical pedicle screw fixation can be done by low risk and to identify potential risk factors associated with this technique. All patients stabilized by cervical transpedicular screw fixation between 1999 and 2002 were included. Cervical disorders included multisegmental degenerative instability with cervical myelopathy in 16 patients, segmental instability caused by rheumatoid arthritis in three, trauma in five and instability caused by infection in two patients. In most cases additional decompression of the spinal cord and bone graft placement were performed. Pre-operative and post-operative CT-scans (2-mm cuts) and plain X-rays served to determine changes in alignment and the position of the screws. Clinical outcome was assessed in all cases. Ninety-four cervical pedicle screws were implanted in 26 patients, most frequently at the C3 (26 screws) and C4 levels (19 screws). Radiologically 66 screws (70%) were placed correctly (maximal breach 1 mm) whereas 20 screws (21%) were misplaced with reduction of mechanical strength, slight narrowing of the vertebral artery canal (<25%) or the lateral recess without compression of neural structures. However, these misplacements were asymptomatic in all cases. Another eight screws (9%) had a critical breach. Four of them showed a narrowing of the vertebral artery canal of more then 25%, in all cases without vascular problems. Three screws passed through the intervertebral foramen, causing temporary paresis in one case and a new sensory loss in another. In the latter patient revision surgery was performed. The screw was loosened and had to be corrected. The only statistically significant risk factor was the level of surgery: all critical breaches were seen from C3 to C5. Percutaneous application of the screws reduced the risk for misplacement, although this finding was not statistically significant. There was also a remarkable learning curve. Instrumentation with cervical transpedicular screws results in very stable fixation. However, with the use of new techniques like percutaneous screw application or computerized image guidance there remains a risk for damaging nerve roots or the vertebral artery. This technique should be reserved for highly selected patients with clear indications and to highly experienced spine surgeons.
19169789 [Matrix-associated autologous chondrocyte transplantation (MACT). Minimally invasive techn 2008 Sep OBJECTIVE: Repair of localized cartilage defects in the knee. INDICATIONS: Localized partial or full-thickness cartilage defects in the knee or osteochondral lesions (osteochondritis dissecans [OD]). CONTRAINDICATIONS: Generalized cartilage defects, osteoarthritis, bacterial and rheumatoid arthritis, uncorrected axis deformities, ligament instability, patella instability, meniscectomy. SURGICAL TECHNIQUE: Two-step procedure. 1. Diagnostic arthroscopy and cartilage biopsy for cell cultivation. 2. Minimalized arthrotomy. Defect debridement. Autologous cancellous bone grafting in OD. Glueing of the cell-loaded scaffold into the defect. POSTOPERATIVE MANAGEMENT: Early functional rehabilitation with knee orthosis. Partial weight bearing (20 kg) for 6 weeks. RESULTS: 50 patients (24 female, 26 male, age 14-44 years, mean 30.3 years) with 58 focal cartilage defects (III-IV degrees) of the knee in the medial (n = 32) or lateral condyle (n = 5), patella (n = 14) and/or trochlea (n = 7) underwent matrix-associated autologous chondrocyte implantation (MACI). The mean follow-up was 24 months (21-29 months). The mean defect size was 4.1 cm2(1.6-6.1 cm2). The Lysholm Score improved from 57.3 to 87.4 points, the DGKKT (German Society of Autologous Cartilage and Bone Cell Transplantation) Score from 55.3 to 85.5 points. Pain on a visual analog scale (VAS) diminished from 5.5 to 2.1, while subjective function enhanced from 4.5 to 7.6. All scores were significant (p < 0.01; t-test). In eleven patients (twelve defects), a second-look arthroscopy revealed a mostly fibrocartilaginous regenerative tissue in 41.7% (5/12) and a mixed fibrous/hyaline regenerative tissue in 33.4% (4/12). 54% (27/50) of the patients estimated their result as excellent, 28% (14/50) as good, 16% as fair, and 2% (1/50) as poor.
19100307 Inflammation in methotrexate-induced pulmonary toxicity occurs via the p38 MAPK pathway. 2009 Feb 27 Methotrexate (MTX) has been widely used for the treatment of inflammatory diseases and rheumatoid arthritis (RA), as well as a variety of tumors. However, MTX-induced toxicity is a serious and unpredictable side effect of this therapy and an important clinical problem. We used microarray analysis to examine MTX-induced gene expression in a human lung epithelial cell line (BEAS-2B) and identified 10 differentially expressed genes related to the p38 mitogen-activated protein kinase (MAPK) pathway, including IL-1beta, MKK6, and MAPKAPK2. Differential gene expression was confirmed via real-time RT-PCR. To determine the functional significance of MTX-induced p38 MAPK activation, we used a p38 MAPK inhibitor (SB203580) to block the p38 MAPK cascade. We also used protein array technology to investigate the modulated expression of pro- and anti-inflammatory cytokines in BEAS-2B cells. MTX activated IL-1beta expression and induced the phosphorylation of various proteins in the p38 MAPK cascade, including TAK1, MKK3/MKK6, p38 MAPK, MAPKAPK2, and HSP27. Finally, HSP27 activation may increase IL-8 secretion, resulting in a pulmonary inflammatory response such as pneumonitis. Although IL-1beta and IL-8 expression increased, the expression of IL-4, IL-6, IL-12, TNF-alpha, MIP-1alpha, and MIP-1beta decreased in a dose-dependent manner. These results suggest that the modulation of cytokine expression may play an important role in MTX-induced pulmonary toxicity.
19007292 Signal transduction of hyaluronic acid-peptide conjugate for formyl peptide receptor like 2008 Dec Agonistic and antagonistic peptides for formyl peptide receptor like 1 (FPRL1) receptor have been investigated as novel drug candidates for inflammatory diseases such as sepsis, asthma, and rheumatoid arthritis. In this work, a novel protocol for the synthesis of hyaluronic acid (HA)-peptide (CWRYMVm) conjugate for FPRL1 receptor was successfully developed for further clinical applications of peptide drugs. Aminoethyl methacrylated HA (HAAEMA) was synthesized by the coupling reaction of tetrabutyl ammonium salt of HA (HA-TBA) and AEMA using benzotriazol-1-yloxy-tris(dimethylamino) phosphonium hexafluorophosphate (BOP) in dimethyl sulfoxide (DMSO). Then, HA-AEMA was conjugated with CWRYMVm in water via Michael addition reaction between methacrylate group of HA-AEMA and thiol group in cysteine. The formation of HA-peptide conjugate was confirmed by 1H NMR and gel permeation chromatography (GPC). The average number of conjugated peptide molecules could be controlled from 5 to 23 per single HA chain. The HA-peptide conjugate showed serum stability longer than four days. In Vitro signal transduction activity of the HA-peptide conjugate for FPRL1 receptor was confirmed from the elevated levels of phospho-extracellular signal-regulated kinase (pERK) and calcium ion in FPRL1 overexpressing RBL-2H3 cells. The partially decreased biological activity of HA-peptide conjugates by the steric hindrance of HA was recovered after its degradation by hyaluronidase treatment.
18787303 Thrombin-stimulated proliferation of cultured human synovial fibroblasts through proteolyt 2008 Sep We examined the mechanism of thrombin on proliferation of synovial fibroblasts obtained from rheumatoid arthritis (RA). Thrombin concentration-dependently induced proliferation of synovial fibroblasts. Proliferation in response to thrombin (10 U/ml) was completely blocked by hirudin. TP367 and TP508, peptides corresponding to 2 noncatalytic regions of thrombin, failed to induce cell proliferation. Thrombin did not induce the production of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), and epidermal growth factor (EGF) in synovial fibroblasts. Expression of proteinase-activated receptor (PAR)-1 and PAR-3 mRNAs was observed in synovial fibroblasts. Thrombin and PAR-1 agonist peptide (AP), but not PAR-3 AP, induced intracellular calcium mobilization. PAR-1 AP induced cell proliferation whereas PAR-3 AP and PAR-4 AP had no effect on proliferation. Pertussis toxin (PTX), a Gialpha protein inhibitor; wortmannin, a PI (phosphatidylinositol) 3-kinase inhibitor; and PD98059, a specific MEK [mitogen-activated protein (MAK) kinase kinase] inhibitor, inhibited the thrombin-induced cell proliferation. Furthermore, the proliferation of synovial fibroblasts was suppressed by U-73122, a PLC (phospholipase C) inhibitor; 2-APB, an antagonist of InsP3 (inositol 1,4,5-triphosphate) receptor; and GF-109203X, a PKC (protein kinase C) inhibitor. These results suggest that thrombin induces the proliferation of RA synovial fibroblasts through the activation of PAR-1, leading to the PTX-sensitive G proteins - PI3 kinase pathway and PTX-insensitive G proteins - PLC (InsP3 receptor) Ca(2+)-PKC branch.
18602069 Stemucronatoside K, a novel C(21) steroidal glycoside from Stephanotis mucronata, inhibite 2008 Sep Stephanotis mucronata (Blanco) Merr. has been used for rheumatoid arthritis in Chinese folk herb medicine. Guided by bioactive test, a novel potent immunosuppressive C(21) steroidal glycoside stemucronatoside K (SMK) was isolated from this plant. Its structure was elucidated on the basis of the chemical evidence and extensive spectroscopic methods. We investigated the immunosuppressive effects of SMK in vitro and in vivo. SMK significantly suppressed concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated splenocyte proliferation in vitro in a concentration-dependent manner. ICR mice were immunized subcutaneously with OVA on the first day and administered intraperitoneally with SMK at the doses of 2.5, 5, and 10 mg/kg once daily for 10 days. At 24 h after the last administration, mitogen- and OVA-stimulated splenocyte proliferation, the levels of cytokines from splenocytes, and specific antibody titers in serum were measured. SMK significantly inhibited Con A-, LPS- and OVA-induced splenocyte proliferation in the immunized mice in a dose-dependent manner. OVA-specific IgG, IgG1, and IgG2b antibody titers were significantly reduced by SMK compared with the control group. SMK also significantly decreased OVA-induced interleukin-2 (IL-2), interferon-gamma (IFN-gamma), and IL-4 production from splenocytes in the OVA-immunized mice. These results demonstrated that SMK could suppress the cellular and humoral immune response in mice. This study provided evidence to understand the therapeutic effects of S. mucronata and an immunosuppressive natural product compound to further researches to be developed as immunosuppressant.
18551245 Chronic inflammation and accelerated atherosclerosis as important cofactors in nephrogenic 2008 Oct Nephrogenic systemic fibrosis (NSF) is a rare disorder in patients with chronic kidney disease characterized by an increased tissue deposition of collagen. Its pathogenesis remains unclear. Prior studies indirectly suggested a possible impact of chronic inflammation and accelerated atherosclerosis--a common feature in kidney diseased patients--whereas recent data focused almost exclusively on gadolinium (Gd)-based MR contrast agents. Usually NSF develops a maximum of 2-3 months after Gd. Longer intervals have not yet been described. Therefore, we present the first case with an extraordinary long time course in terms of chronic inflammation. A 52-year-old Caucasian woman with end-stage renal disease was admitted to our hospital with progressive muscle weakness and skin induration resulting in growing immobility. Her past medical history revealed a secondary HPT, multiple vascular complications, a seronegative rheumatoid arthritis, and a pituitary gland adenoma. The latter conditions led to multiple MR examinations with Gd-based contrast agents, the last one more than 4 years ago. Numerous laboratory tests were performed including ESR, CRP, intact parathyroid hormone (iPTH), serum ferritin, cyclic-citrullinated peptide antibodies (CCP), ANA, ANCA, immunoelectrophoresis, and serology for hepatitis as well as human immunodeficiency virus. Eventually a skin biopsy of her left thigh was obtained. The laboratory investigation showed persistently elevated levels of CRP, ESR, serum ferritin, and iPTH, whereas all other parameters were inconspicuous. The hisology displayed typical signs of nephrogenic systemic fibrosis. NSF can occur at any time after Gd exposure in the long term. Gd is a necessary, but not the sole cause of NSF. Certain other cofactors such as chronic inflammation and accelerated atherosclerosis seem to be involved.
18543385 The cardiovascular depression caused by bee venom in Sprague-Dawley rats associated with a 2008 Bee venom (BV) has been used in Oriental medicine to treat inflammatory diseases, such as tendonitis, bursitis, and rheumatoid arthritis, despite the sensitivity of the victims and toxicity of the venom. This study examined the mechanisms for the effects of BV on the cardiovascular system in rats. The arterial pressure and heart rate (HR) were measured in anesthetized rats. In addition, the left ventricular development pressure (LVDP) and total magnesium efflux ([Mg]e) in isolated perfused hearts, the vascular tonic responses in the isolated aorta, and the blood ionic and biochemical changes were determined simultaneously. In the anesthetized rats, the mean arterial pressure, systolic pressure, and pulse pressure were reduced by BV in a dose-dependent manner, even though the HR was increased. BV had no effects on the relaxation of phenylephrine- or KCl-induced contraction of the aortic rings. In the isolated hearts, BV generated a reversible decrease in the LVDP and velocity with changes in pressure, which were accompanied by increases in the HR and [Mg]e. BV increased the plasma ionized and total magnesium concentrations, and decreased the total magnesium level in the red blood cells. The ratio of ionized calcium/ionized magnesium was also decreased by the BV treatment. BV caused a detectable increase in blood creatine kinase, glutamic oxaloacetic transaminase, and lactic dehydrogenase, as well as a decrease in the blood total protein albumin and globulin levels. These results suggest that BV induces cardiovascular depression by decreasing the cardiac pressure and increasing the ionized magnesium concentration in the blood.
18509033 Stress induces a switch of intracellular signaling in sensory neurons in a model of genera 2008 May 28 Stress dramatically exacerbates pain in diseases such as fibromyalgia and rheumatoid arthritis, but the underlying mechanisms are unknown. We tested the hypothesis that stress causes generalized hyperalgesia by enhancing pronociceptive effects of immune mediators. Rats exposed to nonhabituating sound stress exhibited no change in mechanical nociceptive threshold, but showed a marked increase in hyperalgesia evoked by local injections of prostaglandin E(2) or epinephrine. This enhancement, which developed more than a week after exposure to stress, required concerted action of glucocorticoids and catecholamines at receptors located in the periphery on sensory afferents. The altered response to pronociceptive mediators involved a switch in coupling of their receptors from predominantly stimulatory to inhibitory G-proteins (G(s) to G(i)), and for prostaglandin E(2), emergence of novel dependence on protein kinase C epsilon. Thus, an important mechanism in generalized pain syndromes may be stress-induced coactivation of the hypothalamo-pituitary-adrenal and sympathoadrenal axes, causing a long-lasting alteration in intracellular signaling pathways, enabling normally innocuous levels of immune mediators to produce chronic hyperalgesia.
18484783 Safety of the nonselective NSAID nabumetone : focus on gastrointestinal tolerability. 2008 Although effective in the treatment of pain associated with rheumatic conditions such as osteoarthritis and rheumatoid arthritis, long-term use of NSAIDs is primarily limited by their association with upper gastrointestinal (GI) toxicity. Adverse effects range from dyspepsia and abdominal pain to ulceration and bleeding. GI damage elicited by NSAIDs arises as the result of biochemically induced topical irritant effects and by topical and systemic pharmacological suppression of gastroprotective prostaglandins. Variation in the physicochemical properties and pharmacological profiles among the individual NSAIDs translate into inter-agent differences regarding propensity to cause adverse GI effects. Nabumetone is a nonselective NSAID that offers distinct advantages over other agents in this class with regard to GI tolerability. Its non-acidic nature and pro-drug formulation, together with the lack of biliary secretion of its active metabolite, 6-methoxy-2-naphthylacetic acid, are thought to contribute to the improved GI tolerability of this drug. In head-to-head trials with other NSAIDs, nabumetone has demonstrated significant benefits regarding the incidence of GI events and more serious perforations, ulcers and bleeds (PUBs). Pooled data from eight postmarketing, randomized, controlled trials demonstrated a lower cumulative frequency of PUBs with nabumetone (0.03%; 95% CI 0.0, 0.08) versus comparator NSAIDs (1.4%; 95% CI 0.5, 2.4). Large-scale database studies also indicate that risk of serious GI complications is lower with nabumetone than comparator NSAIDs. Limited comparative data suggest that nabumetone offers a GI tolerability profile similar to that of cyclo-oxygenase-2 selective NSAIDs (coxibs). Although adverse cardiovascular outcomes appear to be a class effect of the coxibs, conventional NSAIDs may also have the potential for causing atherothrombotic complications. However, based on available data, nabumetone does not appear to be associated with increased cardiovascular risk. Finally, there is no particular concern about the nephrotoxic and hepatotoxic potential of nabumetone. Nonetheless, the potential for adverse drug reactions remains, and hence nabumetone, as with any NSAID, should be used at the lowest dose, which is effective for each patient, and for the shortest time necessary to control symptoms.
18409052 Auranofin, an immunosuppressive drug, inhibits MHC class I and MHC class II pathways of an 2008 Mar Auranofin (AF), an orally administered, gold-based, anti-arthritic agent, has emerged as a clinically useful therapeutic drug for the treatment of rheumatoid arthritis. In the present study, we examined the effects of AF on major histocompatibility complex (MHC)-restricted antigen presentation in dendritic cells (DCs), which are the most important accessory cells for the induction of T cell responses. A mouse dendritic cell line, DC2.4 cells, and DCs that were generated from mouse bone marrow cells by culturing with granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-4 were each pretreated with AF for 2 hr, and then incubated with ovalbumin (OVA). After the 2-hr incubation, the DCs were fixed, and the amounts of OVA peptide-H-2Kb complexes were assessed using OVa-specific CD8+ T cells. AF inhibited MHC class I-restricted presentation of exogenous OVA. This inhibitory activity of AF appeared to be due not only to the inhibition of the phagocytic activity of DCs, but also to the suppression of MHC molecule expression on DCs. AF also inhibited MHC class II-restricted presentation of exogenous OVA. These results show that AF exerts immunosuppressive activity at least in part by inhibiting MHC-restricted antigen presentation in professional antigen-presenting cells.
18347286 A Romanian population isolate with high frequency of vitiligo and associated autoimmune di 2008 Mar OBJECTIVE: To characterize the epidemiology and genetics of vitiligo and associated autoimmune diseases in a population isolate in Romania in which there is a high frequency of these diseases. DESIGN: Prospective and retrospective ascertainment of all patients and extended families with these disorders in the study community. SETTING: A geographically isolated community in the mountains of northern Romania. Patients Fifty-one affected individuals and their close relatives from 35 nuclear families in an extended kindred that effectively constitutes the entire community population. MAIN OUTCOME MEASURES: Demographic, phenotypic, and genetic aspects of vitiligo and other autoimmune diseases in the extended kindred. RESULTS: The frequencies of vitiligo and several other autoimmune diseases, including autoimmune thyroid disease, adult-onset autoimmune diabetes mellitus, and rheumatoid arthritis, are greatly elevated. The age of vitiligo onset in this village is relatively delayed, suggesting that the causes of vitiligo in this community may be somewhat atypical. Genetic segregation analysis is most consistent with a single major locus recessive model, although incomplete penetrance and heritability suggest that other genes and nongenetic factors likely influence occurrence of disease in homozygotes. CONCLUSIONS: The high frequency of vitiligo and other autoimmune diseases in this isolated inbred community and an unusual aspect of the vitiligo phenotype suggest that susceptibility to these disorders in this "special population" may be unusual, likely involving a major recessive gene. Whereas disease susceptibility seems to involve a major genetic component, actual onset of vitiligo in genetically susceptible individuals seems to require exposure to environmental triggers.
18326588 Is folic acid good for everyone? 2008 Mar Fortification of food with folic acid to reduce the number of neural tube defects was introduced 10 y ago in North America. Many countries are considering whether to adopt this policy. When fortification is introduced, several hundred thousand people are exposed to an increased intake of folic acid for each neural tube defect pregnancy that is prevented. Are the benefits to the few outweighed by possible harm to some of the many exposed? In animals, a folic acid-rich diet can influence DNA and histone methylation, which leads to phenotypic changes in subsequent generations. In humans, increased folic acid intake leads to elevated blood concentrations of naturally occurring folates and of unmetabolized folic acid. High blood concentrations of folic acid may be related to decreased natural killer cell cytotoxicity, and high folate status may reduce the response to antifolate drugs used against malaria, rheumatoid arthritis, psoriasis, and cancer. In the elderly, a combination of high folate levels and low vitamin B-12 status may be associated with an increased risk of cognitive impairment and anemia and, in pregnant women, with an increased risk of insulin resistance and obesity in their children. Folate has a dual effect on cancer, protecting against cancer initiation but facilitating progression and growth of preneoplastic cells and subclinical cancers, which are common in the population. Thus, a high folic acid intake may be harmful for some people. Nations considering fortification should be cautious and stimulate further research to identify the effects, good and bad, caused by a high intake of folic acid from fortified food or dietary supplements. Only then can authorities develop the right strategies for the population as a whole.
18072083 Abnormal collagen deposition in synovia after collagen type V immunization in rabbits. 2008 Mar Sinovitis in Scleroderma (SSc) is rare, usually aggressive and fully resembles rheumatoid arthritis. Experimental models of SSc have been used in an attempt to understand its pathogenesis. Previous studies done in our laboratory had already revealed the presence of a synovial remodeling process in rabbits immunized with collagen V. To validate the importance of collagen type V and to explore the quantitative relationship between this factor and synovia remodeling as well as the relationship between collagen type V and other collagens, we studied the synovial tissue in immunized rabbits. Rabbits (N=10) were immunized with collagen V plus Freund's adjuvant and compared with animals inoculated with adjuvant only (N=10). Synovial tissues were submitted to histological analysis, immunolocalization to collagen I, III and V and biochemical analysis by eletrophoresis, immunoblot and densitometric method. The synovial tissue presented an intense remodeling process with deposits of collagen types I, III and V after 75 and 120 days of immunization, mainly distributed around the vessels and interstitium of synovial extracellular matrix. Densitometric analysis confirmed the increased synthesis of collagen I, III and V chains (407.69+/-80.31; 24.46+/-2.58; 70.51+/-7.66, respectively) in immunized rabbits when compared with animals from control group (164.91+/-15.67; 12.89+/-1.05; 32+/-3.57) (p<0.0001). We conclude that synovial remodeling observed in the experimental model can reflect the articular compromise present in patients with scleroderma. Certainly, this experimental model induced by collagen V immunization will bring new insights in to pathogenic mechanisms and allow the testing of new therapeutic strategies to ameliorate the prognosis for scleroderma patients.
18026809 Mortality rate in veterans with multiple chronic conditions. 2007 Dec BACKGROUND: Among patients with multiple chronic conditions, there is increasing appreciation of the complex interrelatedness of diseases. Previous studies have focused on the prevalence and economic burden associated with multiple chronic conditions, much less is known about the mortality rate associated with specific combinations of multiple diseases. OBJECTIVE: Measure the mortality rate in combinations of 11 chronic conditions. DESIGN: Cohort study of veteran health care users. PARTICIPANTS: Veterans between 55 and 64 years that used Veterans Health Administration health care services between October 1999 and September 2000. MEASUREMENTS: Patients were identified as having one or more of the following: COPD, diabetes, hypertension, rheumatoid arthritis, osteoarthritis, asthma, depression, ischemic heart disease, dementia, stroke, and cancer. Mutually exclusive combinations of disease based on these conditions were created, and 5-year mortality rates were determined. RESULTS: There were 741,847 persons included. The number in each group by a count of conditions was: none = 217,944 (29.34%); 1 = 221,111 (29.8%); 2 = 175,228 (23.6%); 3 = 86,447 (11.7%); and 4+ = 41,117 (5.5%). The 5-year mortality rate by the number of conditions was: none = 4.1%; 1 = 6.0%; 2 = 7.8%; 3 = 11.2%; 4+ = 16.7%. Among combinations with the same number of conditions, there was significant variability in mortality rates. CONCLUSIONS: Patients with multiple chronic conditions have higher mortality rates. Because there was significant variation in mortality across clusters with the same number of conditions, when studying patients with multiple coexisting illnesses, it is important to understand not only that several conditions may be present but that specific conditions can differentially impact the risk of mortality.
17965585 Expression and function of transmembrane-4 superfamily (tetraspanin) proteins in osteoclas 2007 Dec BACKGROUND: Osteoclasts are bone-resorbing multinuclear polykaryons essential for bone remodeling, formed through cell fusion of mononuclear macrophage/monocyte lineage precursor cells upon stimulation by the RANK/RANKL system. Recent studies have revealed that a family of tetraspanin proteins, such as CD9, is critically involved in the cell fusion/polykaryon formation of these cell types. Until now, however, there is limited knowledge about the types of tetraspanins expressed in osteoclasts and their precursors. METHODS: The expression of different tetraspanin proteins in a monocyte/macrophage-lineage osteoclast precursor cell line, RAW264.7, was cyclopedically investigated using RT-PCR with specific primers and quantitative real-time RT-PCR. The function of two kinds of tetraspanins, Tspan-5 and NET-6, whose expression pattern was altered by RANKL stimulation, was examined by transfecting gene-specific short-interfering RNAs into these cell types. RESULTS: Of the 17 tetraspanins in mammalian hematopoietic cells, RAW264.7 cells express mRNA for 12 different kinds of tetraspanins, namely, CD9, CD37, CD53, CD63, CD81, CD82, CD151, NAG-2, NET-6, SAS, Tspan-3, and Tspan-5. Interestingly, during their maturation into osteoclasts upon RANKL stimulation, the transcript for Tspan-5 is up-regulated, whereas that for NET-6 is down-regulated. Targeted inhibition of Tspan-5 by using gene-specific RNA interference suppressed RANKL-induced cell fusion during osteoclastogenesis, whereas inhibition of NET-6 augmented the osteoclastogenesis itself. These results suggest that Tspan-5 and NET-6 have a reciprocal function during osteoclastogenesis, i.e., positive and negative regulation by Tspan-5 and NET-6, respectively. RANKL regulates osteoclastogenesis by altering the balances of these tetraspanin proteins. CONCLUSIONS: These data indicate that a diversity of tetraspanins is expressed in osteoclast precursors, and that cell fusion during osteoclastogenesis is regulated by cooperation of distinct tetraspanin family proteins such as Tspan-5 and NET-6. This study indicates that functional alterations of tetraspanin family proteins may have therapeutic potential in diseases where osteoclasts play a major role, such as rheumatoid arthritis and osteoporosis.