Dimethyl sulfoxide: a review of its use in the rheumatic disorders

Granzyme A in Chikungunya and Other Arboviral Infections

Granzyme A (GzmA) is secreted by cytotoxic lymphocytes and has traditionally been viewed as a mediator of cell death. However, a growing body of data suggests the physiological role of GzmA is promotion of inflammation. Here, we show that GzmA is significantly elevated in the sera of chikungunya virus (CHIKV) patients and that GzmA levels correlated with viral loads and disease scores in these patients. Serum GzmA levels were also elevated in CHIKV mouse models, with NK cells the likely source. Infection of mice deficient in type I interferon responses with CHIKV, Zika virus, or dengue virus resulted in high levels of circulating GzmA. We also show that subcutaneous injection of enzymically active recombinant mouse GzmA was able to mediate inflammation, both locally at the injection site as well as at a distant site. Protease activated receptors (PARs) may represent targets for GzmA, and we show that treatment with PAR antagonist ameliorated GzmA- and CHIKV-mediated inflammation.

Dimethyl sulfoxide (DMSO) as intravesical therapy for interstitial cystitis/bladder pain syndrome: A review

AIMS

The purpose of this review is to update the current understanding of dimethyl sulfoxide (DMSO) and its role in the treatment of interstitial cystitis (IC).

METHODS

A systematic review was conducted using the PRIMSA checklist to identify published articles involving intravesical DMSO for the treatment of IC.

RESULTS

Thirteen cohort studies and three randomized-controlled trials were identified. Response rates relying on subjective measurement scores range from 61 to 95%. No increased efficacy was found with "cocktail" DMSO therapy. Great variation existed in diagnostic criteria, DMSO instillation protocols and response measurements.

CONCLUSIONS

The current evidence backing DMSO is a constellation of cohort studies and a single randomized-controlled trial versus placebo. The optimal dose, dwell time, type of IC most likely to respond to DMSO, definitions of success/failure and the number of treatments are not universally agreed upon. Improvements in study design, phenotyping patients based on symptoms, as well as the emergence of reliable biomarkers of the disease may better guide the use of DMSO in the future.

DMSO Represses Inflammatory Cytokine Production from Human Blood Cells and Reduces Autoimmune Arthritis

Dimethyl sulfoxide (DMSO) is currently used as an alternative treatment for various inflammatory conditions as well as for cancer. Despite its widespread use, there is a paucity of data regarding its safety and efficacy as well as its mechanism of action in human cells. Herein, we demonstrate that DMSO has ex-vivo anti-inflammatory activity using Escherichia coli- (E. coli) and herpes simplex virus-1 (HSV-1)-stimulated whole human blood. Specifically, we found that between 0.5%-2%, DMSO significantly suppressed the expression of many pro-inflammatory cytokines/chemokines and prostaglandin E2 (PGE2). However, a significant reduction in monocyte viability was also observed at 2% DMSO, suggesting a narrow window of efficacy. Anti-inflammatory concentrations of DMSO suppressed E. coli-induced ERK1/2, p38, JNK and Akt phosphorylation, suggesting DMSO acts on these signaling pathways to suppress inflammatory cytokine/chemokine production. Although DMSO induces the differentiation of B16/F10 melanoma cells in vitro, topical administration of DMSO to mice subcutaneously implanted with B16 melanoma cells was ineffective at reducing tumor growth, DMSO was also found to block mouse macrophages from polarizing to either an M1- or an M2-phenotype, which may contribute to its inability to slow tumor growth. Topical administration of DMSO, however, significantly mitigated K/BxN serum-induced arthritis in mice, and this was associated with reduced levels of pro-inflammatory cytokines in the joints and white blood cell levels in the blood. Thus, while we cannot confirm the efficacy of DMSO as an anti-cancer agent, the use of DMSO in arthritis warrants further investigation to ascertain its therapeutic potential.

Serum Metabolite Profiles Are Altered by Erlotinib Treatment and the Integrin α1-Null Genotype but Not by Post-Traumatic Osteoarthritis

The risk of developing post-traumatic osteoarthritis (PTOA) following joint injury is high. Furthering our understanding of the molecular mechanisms underlying PTOA and/or identifying novel biomarkers for early detection may help to improve treatment outcomes. Increased expression of integrin α1β1 and inhibition of epidermal growth factor receptor (EGFR) signaling protect the knee from spontaneous OA; however, the impact of the integrin α1β1/EGFR axis on PTOA is currently unknown. We sought to determine metabolic changes in serum samples collected from wild-type and integrin α1-null mice that underwent surgery to destabilize the medial meniscus and were treated with the EGFR inhibitor erlotinib. Following (1)H nuclear magnetic resonance spectroscopy, we generated multivariate statistical models that distinguished between the metabolic profiles of erlotinib- versus vehicle-treated mice and the integrin α1-null versus wild-type mouse genotype. Our results show the sex-dependent effects of erlotinib treatment and highlight glutamine as a metabolite that counteracts this treatment. Furthermore, we identified a set of metabolites associated with increased reactive oxygen species production, susceptibility to OA, and regulation of TRP channels in α1-null mice. Our study indicates that systemic pharmacological and genetic factors have a greater effect on serum metabolic profiles than site-specific factors such as surgery.

Formyl peptide receptors from immune and vomeronasal system exhibit distinct agonist properties

The formyl peptide receptor (Fpr) family is well known for its contribution to immune defense against pathogens in human and rodent leukocytes. Recently, several structurally related members of these receptors were discovered in sensory neurons of the mouse vomeronasal organ (VNO), key detectors of pheromones and related semiochemicals. Although the biological role of vomeronasal Fprs is not yet clear, the known contribution of other Fprs to host immune defense suggested that they could contribute to vomeronasal pathogen sensing. Precise knowledge about the agonist properties of mouse Fprs is required to determine their function. We expressed all seven mouse and three human Fprs using an in vitro system and tested their activation with 32 selected compounds by conducting high throughput calcium measurements. We found an intriguing functional conservation between human and mouse immune Fprs that is most likely a consequence of closely similar biological constraints. By contrast, our data suggest a neofunctionalization of the vomeronasal Fprs. We show that the vomeronasal receptor mFpr-rs1 can be activated robustly by W-peptide and structural derivatives but not by other typical ligands of immune Fprs. mFpr-rs1 exhibits a stereo-selective preference for peptides containing d-amino acids. The same peptide motifs are contained in pathogenic microorganisms. Thus, the ligand profile of mFpr-rs1 is consistent with a role in vomeronasal pathogen sensing.

Meta-analysis of the related nutritional supplements dimethyl sulfoxide and methylsulfonylmethane in the treatment of osteoarthritis of the knee

Dimethyl sulphoxide and methylsulfonylmethane are two related nutritional supplements used for symptomatic relief of osteoarthritis (OA). We conducted a meta-analysis to evaluate their efficacy in reducing pain associated with OA. Randomized or quasi-randomized controlled trials (RCTs), identified by systematic electronic searches, citation tracking and searches of clinical trial registries, assessing these supplements in osteoarthritis of any joint were considered for inclusion. Meta-analysis, based on difference in mean pain related outcomes between treatment and comparator groups, was carried out based on a random effect model. Seven potential trials were identified of which three RCTs, two DMSO and one MSM (total N = 326 patients) were eligible for inclusion. All three trials were considered high methodological quality. A significant degree of heterogeneity (χ(2) = 6.28, P = .043) was revealed. Two studies demonstrated statistically significant (but not clinically relevant) reduction in pain compared with controls; with one showing no group difference. The meta-analysis confirmed a non significant reduction of pain on visual analogue scale of 6.34 mm (SE = 3.49, 95% CI, -0.49, 13.17). The overall effect size of 1.82 was neither statistically nor clinically significant. Current evidence suggests DMSO and MSM are not clinically effective in the reduction of pain in the treatment of OA. No definitive conclusions can currently be drawn from the data due to the mixed findings and the use of inadequate dosing periods.

Dysregulation of the immune system caused by silica and asbestos

Silica and asbestos cause pneumoconioses known as silicosis and asbestosis, respectively, that are each characterized by progressive pulmonary fibrosis. While local effects of inhaled silica particles alter the function of alveolar macrophages and sequential cellular and molecular biological events, general systemic immunological effects may also evolve. One well-known health outcome associated with silica exposure/silicosis is an increase in the incidence of autoimmune disorders. In addition, while exposure to silica--in the crystalline form--has also been seen to be associated with the development of lung cancers, it remains unclear as to whether or not silicosis is a necessary condition for the elevation of silica-associated lung cancer risks. Since asbestos is a mineral silicate, it would be expected to also possess generalized immunotoxicological effects similar to those associated with silica particles. However, asbestos-exposed patients are far better known than silicotic patients for development of malignant diseases such as lung cancer and mesothelioma, and less so for the development of autoimmune disorders. With both asbestos and crystalline silica, one important dysregulatory outcome that needs to be considered is an alteration in tumor immunity that allows for silica- or asbestos- (or asbestos-associated agent)-induced tumors to survive and thrive in situ. In this review, the immunotoxicological effects of both silica and asbestos are presented and contrasted in terms of their abilities to induce immune system dysregulation that then are manifest by the onset of autoimmunity or by alterations in host-tumor immunity.

Systematic review of the nutritional supplements dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM) in the treatment of osteoarthritis

OBJECTIVE

Conventional treatment of osteoarthritis (OA) with non-steroidal anti-inflammatory drugs is associated with serious gastrointestinal side effects and in view of the recent withdrawal of some cyclo-oxygenase-2 inhibitors, identifying safer alternative treatment options is needed. The objective of this systematic review is to evaluate the existing evidence from randomised controlled trials of two chemically related nutritional supplements, dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM) in the treatment of OA to determine their efficacy and safety profile.

METHODS

The electronic databases [Cochrane Library, Medline, Embase, Amed, Cinahl and NeLH (1950 to November 2007)] were searched. The search strategy combined terms: osteoarthritis, degenerative joint disorder, dimethyl sulfoxide, DMSO, methylsulfonylmethane, MSM, clinical trial; double-blind, single blind, RCT, placebo, randomized, comparative study, evaluation study, control. Inclusion and exclusion criteria were applied. Data were extracted and quality was assessed using the JADAD scale.

RESULTS

Six studies were included [evaluating a total of 681 patients with OA of the knee for DMSO (N=297 on active treatment); 168 patients for MSM (N=52 on active treatment)]. Two of the four DMSO trials, and both MSM trials reported significant improvement in pain outcomes in the treatment group compared to comparator treatments, however, methodological issues and concerns over optimal dosage and treatment period, were highlighted.

CONCLUSION

No definitive conclusion can currently be drawn for either supplement. The findings from all the DMSO studies need to be viewed with caution because of poor methodology including; possible unblinding, and questionable treatment duration and dose. The data from the more rigorous MSM trials provide positive but not definitive evidence that MSM is superior to placebo in the treatment of mild to moderate OA of the knee. Further studies are now required to identify both the optimum dosage and longer-term safety of MSM and DMSO, and definitive efficacy trials.

Dimethyl sulfoxide-induced hydroxyapatite formation: a biological model of matrix vesicle nucleation to screen inhibitors of mineralization

To elucidate the inhibition mechanisms of hydroxyapatite (HA), a biological model mimicking the mineralization process was developed. The addition of 4% (v/v) dimethyl sulfoxide (DMSO) in synthetic cartilage lymph (SCL) medium containing 2 mM calcium and 3.42 mM inorganic phosphate (P(i)) at pH 7.6 and 37 degrees C produced HA as matrix vesicles (MVs) under physiological conditions. Such a model has the advantage of monitoring the HA nucleation process without interfering with other processes at the cellular or enzymatic level. Turbidity measurements allowed us to follow the process of nucleation, whereas infrared spectra and X-ray diffraction permitted us to identify HA. Mineral formation induced by DMSO and by MVs in the SCL medium produced crystalline HA in a similar manner. The nucleation model served to evaluate the inhibition effects of ATP, GTP, UTP, ADP, ADP-ribose, AMP, and pyrophosphate (PP(i)). Here 10 microM PP(i), 100 microM nucleotide triphosphates (ATP, GTP, UTP), and 1 mM ADP inhibited HA formation directly, whereas 1 mM ADP-ribose and 1 mM AMP did not. This confirmed that the PP(i) group is a potent inhibitor of HA formation. Increasing the PP(i) concentration from 100 microM to 1 mM induced calcium pyrophosphate dihydrate. We propose that DMSO-induced HA formation could serve to screen putative inhibitors of mineral formation.

Reactive oxygen intermediates are involved in IL-8 production induced by hyperosmotic stress in human bronchial epithelial cells

Changes in the osmolarity of the airway surface fluid have been described to be involved in the pathogenesis of exercise induced asthma, and are suggested as the major cause of the lung disease in cystic fibrosis. In this study, we examined the signaling pathway of hyperosmotic challenge to interleukin-8 (IL-8). Hyperosmolarity (NaCl) caused a time- and concentration-dependent increase in IL-8 expression and secretion in bronchial epithelial cells. These effects could be blocked by antioxidants, such as DMSO, DMTU, DTT, and beta-mercaptoethanol, suggesting an involvement of reactive oxygen intermediates (ROI) in the signal transduction of hyperosmolarity-induced IL-8 synthesis. Since IL-8 is regulated by MAP kinases, we examined the influence of MAP kinase inhibitors on hyperosmolarity-induced IL-8 expression. The results show that this induction is regulated by p38 MAPK and not by ERK1/2. Furthermore, antioxidants blocked the activation of p38 MAPK induced by hyperosmolarity. These results suggest that ROIs are critical for p38 MAPK mediated IL-8 expression by hyperosmolarity.

Topical agents in the treatment of rheumatic disorders

Topical drug delivery may be the optimal route for the treatment of localized musculoskeletal disorders because higher drug concentrations can be achieved at the sites of clinical significance. The rationale for the use of topical salicylates and other nonsteroidal anti-inflammatory drugs (NSAIDs) in the treatment of soft-tissue rheumatic complaints and osteoarthritis is reviewed. Topical capsaicin offers another potentially beneficial therapy for the treatment of osteoarthritis of selected joints. Although there are extensive, uncontrolled experiences with DMSO that suggests its effectiveness in the treatment of musculoskeletal disorders, controlled trials yield conflicting results. The basis for the use of physical modalities such as phonophoresis and iontophoresis to improve topical drug efficacy is summarized.

Alternative Therapeutic Approaches to the Treatment of Arthritis

Alternative therapies are widely used for the treatment of arthritis. Some examples of these are acupuncture/acupressure, animal venoms, copper bracelets, dimethyl sulfoxide, herbal products, magnets, and nutritional therapy. Many products used for alternative therapies are not regulated in the United States and can vary greatly in their content. They may contain toxic contaminants, induce allergic reactions, or interact with prescription medications. Much of the support for their use is based on testimonials and poorly controlled trials. The Office of Alternative Medicine was established under the National Institutes of Health to promote study and evaluation of unconventional therapies.

Reactive oxygen intermediates stimulate interleukin-6 production in human bronchial epithelial cells

Reactive oxygen intermediates (ROIs) play an important role in the initiation and progression of lung diseases. In this study, we investigated whether ROIs were involved in the induction of interleukin (IL)-6 in human bronchial epithelial cells. We exposed normal human bronchial epithelial cells as well as a human bronchial epithelial cell line, HS-24, to ROIs. We measured the amount of IL-6 in the culture supernatants using ELISA and the IL-6 mRNA levels using RT-PCR. Superoxide anions (O-2), but not hydrogen peroxide (H2O2), increased IL-6 production. To examine whether it is a cell type-specific mechanism of airway epithelial cells, the experiments were also performed in human lung fibroblasts, WI-38-40. In WI-38-40 cells, neither O-2 nor H2O2 increased IL-6 production. In contrast, tumor necrosis factor (TNF)-alpha (200 U/ml) induced IL-6 at the protein and mRNA levels in both airway epithelial cells and lung fibroblasts. This cytokine-induced IL-6 production was significantly suppressed by several antioxidants, including dimethyl sulfoxide (DMSO), in airway epithelial cells. In WI-38-40 cells, DMSO was not able to suppress IL-6 production induced by TNF-alpha. Pretreatment with DMSO recovered the TNF-alpha-induced depletion of intracellular reduced glutathione in HS-24 cells. These findings indicate that oxidant stress specifically induces IL-6 production in human bronchial epithelial cells and that in these cells ROIs may be involved in IL-6 production after stimulation with cytokines such as TNF-alpha. Presumably, ROIs participate in the local immune response in lung diseases via IL-6 release from bronchial epithelial cells.

Dimethyl sulfoxide increases the survival of primarily ischemic island skin flaps

There is ample evidence of the involvement of free radicals in mediating skin flap necrosis. Dimethyl sulfoxide (DMSO) is a well-tolerated, safe drug that is a powerful scavenger of the hydroxyl free radical. The current study investigated the effect of DMSO on the survival of 9 x 4 cm skin flaps based on the epigastric vessels subjected to primary venous occlusion. Forty-seven skin flaps were elevated and the epigastric vein was occluded by a microvascular clamp for 8 hours. Group 1 received DMSO (1.5 gm/kg) intraperitoneally at reperfusion. Group 2 received saline solution, group 3 received DMSO at reperfusion and every day for 5 days, group 4 received DMSO preoperatively and then as in group 3, and group 5 was the saline solution control for groups 3 and 4. DMSO did not increase percent flap survival when given as a single dose at reperfusion (40.6% +/- 42.7%) compared with saline solution (33.7% +/- 41.2%). When DMSO was continued in the postoperative period, group 3 (86.2% +/- 25.8%) and group 4 (78.0% +/- 32.5%) had significantly better survival than the saline solution control group (32.6% +/- 39.8%) (p < 0.01 and p < 0.03, respectively). There was no significant difference between groups 3 and 4. DMSO administered at reperfusion and postoperatively for 5 days significantly increased flap survival. It is hypothesized that this occurs through scavenging deleterious free radical species. This effect may have clinical significance.

Therapy of amyloid diseases

Deposition of amyloid in the organism can lead to severe clinical symptoms and syndromes which are referred to as amyloidosis. However, amyloidosis is not a pathogenetically single disease entity. Various amyloid diseases are known which can clearly be distinguished by identifying the protein from which the amyloid is derived. Since the amyloid syndromes are pathogenetically diverse, each of the different amyloid diseases needs to be treated differently, and a type-specific amyloid therapy is mandatory. Unfortunately, an efficient therapy is not yet available for most amyloid syndromes. It is the purpose of this review to show how the different amyloid syndromes are distinguished definitively from each other and what has been successful in the effort to establish an efficient therapy of the various amyloid deposits and different amyloidoses.

Oxygen radical scavengers selectively inhibit interleukin 8 production in human whole blood

The hydroxyl radical (OH.) scavenger dimethyl sulfoxide (DMSO) was found to dose-dependently inhibit interleukin 8 (IL-8) production in LPS-stimulated human whole blood. At a concentration of 1% (vol/vol), DMSO blocked IL-8 release by approximately 90% in the presence of 1 microgram/ml LPS at a 24-h time point, but did not affect cell viability or reduce the production of tumor necrosis factor (TNF), interleukin 6, or interleukin-1 beta (IL-1 beta). DMSO was found to directly inhibit IL-8 expression at the level of transcription. Furthermore, this effect was not LPS-specific, in that IL-8 production was reduced by DMSO to a similar extent upon stimulation of blood with phytohemagglutinin, aggregated immune complexes, TNF, or IL-1 beta. Other oxygen radical scavengers that have been shown to inhibit OH.-dependent reactions (dimethyl thiourea, thiourea, mannitol, and ethanol) also inhibited IL-8 production. Conversely, addition of H2O2 caused a dose-dependent stimulation of IL-8 release. These results provide evidence that reactive oxygen metabolites play an important role in the regulation of IL-8 production and suggest that reduction of IL-8 release may contribute to the beneficial effects of antioxidants in experimental models of inflammation and ischemia/reperfusion injury.

Immunologic alterations in MRL/lpr mice after chronic dimethyl sulfoxide administration

Dimethyl sulfoxide (DMSO) in 1 and 2% concentration was added to the drinking water of 30-100 day MRL/lpr mice. In comparison to control mice, the DMSO treated mice had a 78% increase in their response to exogenous IL-2 and a 64% increase in production of IL-2. Con A stimulated cells had a net help effect in the untreated mice, which was suppressed from 82-26% after DMSO treatment. There was no marked change in Thy 1.2, Lyt 1 and Lyt 2 percentages after treatment. The anti-DNA decreased from 29.0 +/- 17.0% to 13.2 +/- 7.8% after DMSO treatment. We conclude that chronic DMSO administration to MRL/lpr mice can induce immunologic alterations with possible clinical implications.