Effects of dimethyl sulfoxide, pyrrolidine dithiocarbamate, and methylprednisolone on nuclear factor-kappaB and heat shock protein 70 in a rat model of hemorrhagic shock

Immunomodulatory effects and potential clinical applications of dimethyl sulfoxide

Dimethyl sulfoxide (DMSO) was discovered during the 19th century by the German chemical industry. DMSO comprises a highly polar group and two non-polar domains, which render it soluble in both aqueous solutions and organic solutions. Furthermore, DMSO can penetrate the cell membrane of both the mammalian cells and the non-mammalian cells and prevent freeze-thaw injuries to the cells. Thus, it is frequently used for the cryopreservation of cells and tissues for laboratory and clinical applications. In contrast to this traditional application, DMSO has recently been shown to possess immunomodulatory effects, such as immune enhancement, and anti-inflammatory effects in the innate immunity. In addition, DMSO also affects the adaptive immunity by regulating the expression of transcription factors in immune cells. This review briefly summarizes and highlights the roles and immunomodulatory effects of DMSO on the immune system and reveals the future clinical therapeutic potential of DMSO treatment in cancer, in autoimmune diseases and in chronic inflammatory diseases.

Triggering receptor expressed on myeloid cells-1 as a new therapeutic target during inflammatory diseases

The Triggering Receptor Expressed on Myeloid cells (TREM)-1 is a recently identified molecule involved in monocytic activation and inflammatory response. It belongs to a family related to Natural Killer cell-receptors and is expressed on neutrophils, mature monocytes and macrophages. The engagement of TREM-1 synergizes with several Toll Like Receptors (TLR) and/or NOD Like Receptors (NLR) activation in amplifying the inflammatory response mediated by microbial components or danger signals. The implication of TREM-1 during experimental models of acute or chronic inflammatory conditions, as well as during cancer, begins to understand. Furthermore, the modulation of the TREM-1 signaling pathway by the use of small synthetic peptides derived from its extracellular moiety confers interesting survival advantages during experimental murine septic shock and protects from organ damage during other inflammatory diseases. This review summarizes the recent advances on TREM-1 biology and highlights the promises of its therapeutic modulation.

Hepatic effects of an open lung strategy and cardiac output restoration in an experimental lung injury

BACKGROUND

Ventilation with high positive end-expiratory pressure (PEEP) can lead to liver dysfunction. We hypothesized that an open lung concept (OLC) using high PEEP impairs liver function and integrity dependent on the stabilization of cardiac output.

METHODS

Juvenile female Pietrain pigs instrumented with flow probes around the common hepatic artery and portal vein, pulmonary and hepatic vein catheters underwent a lavage-induced lung injury. Ventilation was continued with a conventional approach (CON) using pre-defined combinations of PEEP and inspiratory oxygen fraction or with an OLC using PEEP set above the lower inflection point of the lung. Volume replacement with colloids was guided to maintain cardiac output in the CON(V+) and OLC(V+) groups or acceptable blood pressure and heart rate in the OLC(V-) group. Indocyanine green plasma disappearance rate (ICG-PDR), blood gases, liver-specific serum enzymes, bilirubin, hyaluronic acid and lactate were tested. Finally, liver tissue was examined for neutrophil accumulation, TUNEL staining, caspase-3 activity and heat shock protein 70 mRNA expression.

RESULTS

Hepatic venous oxygen saturation was reduced to 18 + or - 16% in the OLC(V-) group, while portal venous blood flow decreased by 45%. ICG-PDR was not reduced and serum enzymes, bilirubin and lactate were not elevated. Liver cell apoptosis was negligible. Liver sinusoids in the OLC(V+) and OLC(V-) groups showed about two- and fourfold more granulocytes than the CON(V+) group. Heat shock protein 70 tended to be higher in the OLC(V-) group.

CONCLUSIONS

Open lung ventilation elicited neutrophil infiltration, but no liver dysfunction even without the stabilization of cardiac output.

Evidence for a role of heat shock protein-90 in toll like receptor 4 mediated pain enhancement in rats

Spinal cord microglial toll-like receptor 4 (TLR4) has been implicated in enhancing neuropathic pain and opposing morphine analgesia. The present study was initiated to explore TLR4-mediated pain modulation by intrathecal lipopolysaccharide, a classic TLR4 agonist. However, our initial study revealed that intrathecal lipopolysaccharide failed to induce low-threshold mechanical allodynia in naive rats, suggestive that TLR4 agonism may be insufficient to enhance pain. These studies explore the possibility that a second signal is required; namely, heat shock protein-90 (HSP90). This candidate was chosen for study given its known importance as a regulator of TLR4 signaling. A combination of in vitro TLR4 cell signaling and in vivo behavioral studies of pain modulation suggest that TLR4-enhancement of neuropathic pain and TLR4-suppression of morphine analgesia each likely require HSP90 as a cofactor for the effects observed. In vitro studies revealed that dimethyl sulfoxide (DMSO) enhances HSP90 release, suggestive that this may be a means by which DMSO enhances TLR4 signaling. While 2 and 100 microg lipopolysaccharide intrathecally did not induce mechanical allodynia across the time course tested, co-administration of 1 microg lipopolysaccharide with a drug that enhances HSP90-mediated TLR4 signaling now induced robust allodynia. In support of this allodynia being mediated via a TLR4/HSP90 pathway, it was prevented or reversed by intrathecal co-administration of a HSP90 inhibitor, a TLR4 inhibitor, a microglia/monocyte activation inhibitor (as monocyte-derived cells are the predominant cell type expressing TLR4), and interleukin-1 receptor antagonist (as this proinflammatory cytokine is a downstream consequence of TLR4 activation). Together, these results suggest for the first time that TLR4 activation is necessary but not sufficient to induce spinally mediated pain enhancement. Rather, the data suggest that TLR4-dependent pain phenomena may require contributions by multiple components of the TLR4 receptor complex.

Pharmacology of dimethyl sulfoxide in cardiac and CNS damage

The pharmacological effects of dimethyl sulfoxide (DMSO) administration include some desirable properties that may be useful in the treatment of medical disorders resulting in tissue injury and compromised organ systems. These properties include the reported effects of DMSO on impaired blood flow, suppression of cytotoxicity from excess glutamate release that may result in lethal NMDA-AMPA activation, restriction of cytotoxic Na(+) and Ca(2+) entry into damaged cells, blocking tissue factor (TF) from contributing to thrombosis, reduction of intracranial pressure, tissue edema, and inflammatory reactions, and inhibition of vascular smooth muscle cell migration and proliferation that can lead to atherosclerosis of the coronary, peripheral, and cerebral circulation. A review of the basic and clinical literature on the biological actions of DMSO in cardiac and central nervous system (CNS) damage or dysfunction indicates that this agent, alone or in combination with other synergistic molecules, has been reported to neutralize or attenuate pathological complications that harmed or can further harm these two organ systems. The effects of DMSO make it potentially useful in the treatment of medical disorders involving head and spinal cord injury, stroke, memory dysfunction, and ischemic heart disease.