Combined medication of lovastatin with rolipram suppresses severity of experimental autoimmune encephalomyelitis

TB-IRIS pathogenesis and new strategies for intervention: Insights from related inflammatory disorders

In almost one in five HIV/tuberculosis (TB) co-infected patients, initiation of antiretroviral therapy (ART) is complicated by TB immune reconstitution inflammatory syndrome (TB-IRIS). Corticosteroids have been suggested for treatment of severe cases, however no therapy is currently licensed for TB-IRIS. Hence, there is a strong need for more specific therapeutics, and therefore, a better understanding of TB-IRIS pathogenesis. Immune reconstitution following ART is a precariously balanced functional restoration of adaptive immunity. In those patients predisposed to disease, an incomplete activation of the innate immune system leads to a hyper-inflammatory response that comprises partially overlapping innate, adaptive and effector arms, eventually leading to clinical symptoms. Interestingly, many of these pathological mechanisms are shared by related inflammatory disorders. We here describe therapeutic strategies that originate from these other disciplines and discuss their potential application in TB-IRIS. These new avenues of interventions range from final-phase treatment of symptoms to early-phase prevention of disease onset. In conclusion, we propose a novel approach for the discovery and development of therapeutics, based on an updated model of TB-IRIS pathogenesis. Further experimental studies validating the causal relationships in the proposed model could greatly contribute to providing a solid immunological basis for future clinical trials on TB-IRIS therapeutics.

Sildenafil Inhibits Myelin Expression and Myelination of Oligodendroglial Precursor Cells

Phosphodiesterases (PDEs) have previously been implicated in oligodendrocyte maturation and myelination of central nervous system axons. Sildenafil citrate is a phosphodiesterase inhibitor known to block PDE5, which also reduces inflammation in the experimental autoimmune encephalomyelitis demyelinating model. To find out whether this inhibitor might exert beneficial effects on central nervous system myelin repair activities, we investigated to what degree sildenafil modulates differentiation and maturation of cultured primary rat oligodendroglial precursor cells (OPCs). To this end, gene and protein expression of 2',3'-cyclic-nucleotide 3'-phosphodiesterase, myelin basic protein, and myelin oligodendrocyte glycoprotein, as well as of negative regulators of myelin expression (Hes1, Hes5, Id2, Id4, Rock2, and p57Kip2) were measured in OPCs treated with sildenafil. Moreover, the subcellular distribution of the p57kip2 protein was determined after sildenafil treatment, as this revealed to be an early predictor of the oligodendroglial differentiation capacity. In vitro myelination assays were done to measure the myelination capacity of oligodendrocytes treated with sildenafil. We found that sildenafil significantly diminished myelin gene expression and protein expression. Moreover, sildenafil also increased the expression of Id2 and Id4 negative transcriptional regulators, and the degree of OPCs with cytoplasmic p57kip2 protein localization was reduced, providing evidence that the PDE blocker impaired the differentiation capacity. Finally, sildenafil also interfered with the establishment of internodes as revealed by in vitro myelination assays. We therefore conclude that blocking PDE5 activities exerts a negative impact on intrinsic oligodendroglial differentiation processes.

Pigments from Filamentous Ascomycetes for Combination Therapy

Filamentous ascomycetes (Neurospora and Monascus) have been studied for a long time because of their production of secondary metabolites such as microbial pigments. The ascomycetes represent an interesting group of compounds with high potential for medicinal applications. Many recent studies have shown their efficacy in the treatment of serious pathological states such as oncological diseases, neurodegenerative diseases and hyperlipidaemia. Nevertheless, the clinical usability of ascomycetes is still limited. However, this problem can be solved by the use of these compounds with combinations of other therapeutic agents. This strategy can suppress their side effects and improve their therapeutic efficacy. Moreover, their co-application can significantly enhance conventional therapies that are used. This review summarizes and discusses the general principles of this approach, introduced and supported by numerous examples. In addition, the prediction of the future potential application of this methodology is included.

Live Imaging of Immune Responses in Experimental Models of Multiple Sclerosis

Experimental autoimmune encephalomyelitis (EAE) is the most common animal model of multiple sclerosis (MS), a chronic inflammatory autoimmune disease of the central nervous system (CNS) characterized by multifocal perivascular infiltrates that predominantly comprise lymphocytes and macrophages. During EAE, autoreactive T cells first become active in the secondary lymphoid organs upon contact with antigen-presenting cells (APCs), and then gain access to CNS parenchyma, through a compromised blood–brain barrier, subsequently inducing inflammation and demyelination. Two-photon laser scanning microscopy (TPLSM) is an ideal tool for intravital imaging because of its low phototoxicity, deep tissue penetration, and high resolution. In the last decade, TPLSM has been used to visualize the behavior of T cells and their contact with APCs in the lymph nodes (LNs) and target tissues in several models of autoimmune diseases. The leptomeninges and cerebrospinal fluid represent particularly important points for T cell entry into the CNS and reactivation following contact with local APCs during the preclinical phase of EAE. In this review, we highlight recent findings concerning the pathogenesis of EAE and MS, emphasizing the use of TPLSM to characterize T cell activation in the LNs and CNS, as well as the mechanisms of tolerance induction. Furthermore, we discuss how advanced imaging unveils disease mechanisms and helps to identify novel therapeutic strategies to treat CNS autoimmunity and inflammation.

Statins as modulators of regulatory T-cell biology

Statins are pharmacological inhibitors of the activity of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR), an enzyme responsible for the synthesis of cholesterol. Some recent experimental studies have shown that besides their effects on the primary and secondary prevention of cardiovascular diseases, statins may also have beneficial anti-inflammatory effects through diverse mechanisms. On the other hand, the induction and activity of regulatory T cells (Treg) are key processes in the prevention of pathology during chronic inflammatory and autoimmune diseases. Hence, strategies oriented towards the therapeutic expansion of Tregs are gaining special attention among biomedical researchers. The potential effects of statins on the biology of Treg are of particular importance because of their eventual application as in vivo inducers of Treg in the treatment of multiple conditions. In this paper we review the experimental evidence pointing out to a potential effect of statins on the role of regulatory T cells in different conditions and discuss its potential clinical significance.

Renal function in a rat model of neurogenic bladder, effect of statins and phosphodiesterase-5 inhibitors

PURPOSE

Neurogenic bladder is a common complication of several central nervous system injuries. Statins and phosphodiesterase-5 (PDE-5) inhibitors are reportedly beneficial in neural injuries and urinary system dysfunction. The effect of simvastatin, sildenafil and tadalafil on several renal function indices of an animal model of neurogenic bladder was investigated.

METHODS

Forty male rats were assessed in five equal groups. Dura mater and the cord were injured with an aneurysmal clamp at the level of T9-T10 in all rats except in sham group. The sham and control groups (treated by normal saline), simvastatin (4 mg/kg), sildenafil (5 mg/kg), and tadalafil (2 mg/kg) groups received treatment (i.p.) for seven consecutive days following injury. Renal system and motor functions were assessed at day 28 following injury. Data were analyzed by analysis of variance followed by the Student-Newman-Keuls post hoc test.

RESULTS

Simvastatin improved both the renal and the motor function compared with the control group. However, sildenafil and tadalafil could only improve the motor function but could not make any significant differences in renal indices in comparison with the control group.

CONCLUSION

Statins can effectively improve the motor and renal functions in a condition of renal dysfunction in a rat model of neurogenic bladder. PDE-5 inhibitors could help to improve motor function, but are not helpful in renal function, at least in short time.

Effective combination of human bone marrow mesenchymal stem cells and minocycline in experimental autoimmune encephalomyelitis mice

INTRODUCTION

Multiple sclerosis (MS) is the most common inflammatory demyelinating disorder of the central nervous system (CNS). Minocycline ameliorates the clinical severity of MS and exhibits antiinflammatory, neuroprotective activities, and good tolerance for long-term use, whereas it is toxic to the CNS. Recently, the immunomodulation and neuroprotection capabilities of human bone marrow mesenchymal stem cells (hBM-MSCs) were shown in experimental autoimmune encephalomyelitis (EAE). In this study, we evaluated whether the combination of hBM-MSCs and a low-dose minocycline could produce beneficial effects in EAE mice.

METHODS

The sensitivity of hBM-MSCs to minocycline was determined by an established cell-viability assay. Minocycline-treated hBM-MSCs were also characterized with flow cytometry by using MSC surface markers and analyzed for their multiple differentiation capacities. EAE was induced in C57BL/6 mice by using immunization with MOG35-55. Immunopathology assays were used to detect the inflammatory cells, demyelination, and neuroprotection. Interferon gamma (IFN-γ)/tumor necrosis factor alpha (TNF-α) and interleukin-4 (IL-4)/interleukin-10 (IL-10), the hallmark cytokines that direct Th1 and Th2 development, were detected with enzyme-linked immunosorbent assay (ELISA). terminal dUTP nick-end labeling (TUNEL) staining was performed to elucidate the cell apoptosis in the spinal cords of EAE mice.

RESULTS

Minocycline did not affect the viability, surface phenotypes, or differentiation capacity of hBM-MSCs, while minocycline affected the viability of astrocytes at a high dose. In vivo efficacy experiments showed that combined treatment, compared to the use of minocycline or hBM-MSCs alone, resulted in a significant reduction in clinical scores, along with attenuation of inflammation, demyelination, and neurodegeneration. Moreover, the combined treatment with hBM-MSCs and minocycline enhanced the immunomodulatory effects, which suppressed proinflammatory cytokines (IFN-γ, TNF-α) and conversely increased anti-inflammatory cytokines (IL-4, IL-10). In addition, TUNEL staining also demonstrated a significant decrease of the number of apoptotic cells in the combined treatment compared with either treatment alone.

CONCLUSIONS

The combination of hBM-MSCs and minocycline provides a novel experimental protocol to enhance the therapeutic effects in MS.

Controlling immune response and demyelination using highly potent bifunctional peptide inhibitors in the suppression of experimental autoimmune encephalomyelitis

In this study, we investigated the efficacy of new bifunctional peptide inhibitors (BPIs) in suppressing experimental autoimmune encephalomyelitis (EAE) in an animal model. BPI [e.g. proteolipid protein-cyclo(1,8)-CPRGGSVC-NH2 (PLP-cIBR)] is a conjugate between the PLP139-151 peptide derived from proteolipid protein (PLP) and the cIBR7 peptide derived from domain-1 (D1) of intercellular adhesion molecule-1 (ICAM-1). PLP-cIBR is designed to bind to major histocompatibility complex (MHC)-II and leucocyte function-associated antigen-1 (LFA-1) simultaneously to inhibit the formation of the immunological synapse and alter the differentiation and activation of a subpopulation of T cells, thus inducing immunotolerance. The results show that PLP-cIBR is highly potent in ameliorating EAE, even at low concentrations and less frequent injections. Mice treated with PLP-cIBR had a higher secretion of cytokines related to regulatory and/or suppressor cells compared to phosphate-buffered saline (PBS)-treated mice. In contrast, T helper type 1 (Th1) cytokines were higher in mice treated with PBS compared to PLP-cIBR, suggesting that it suppressed Th1 proliferation. Also, we observed significantly less demyelination in PLP-cIBR-treated mice compared to the control, further indicating that PLP-cIBR promoted protection against demyelination.

Combinatorial Effect of Metformin and Lovastatin Impedes T-cell Autoimmunity and Neurodegeneration in Experimental Autoimmune Encephalomyelitis

Multiple Sclerosis (MS) is an incurable central nervous system (CNS) demyelinating disease affecting several million people worldwide. Due to the multifactorial and complex pathology of MS, FDA approved drugs often show limited efficacy inpatients. We earlier documented that both lovastatin (cholesterol lowering drug) and metformin (anti-diabetic drug) attenuate experimental autoimmune encephalomyelitis (EAE), a widely used model of MS via different mechanisms of action. Since combination therapy of two or more agents has advantage over monotherapy, we here assessed the therapeutic efficacy of metformin and lovastatin combination in EAE. We found that suboptimal doses of these drugs in combination had additive effect to attenuate established EAE in treated animals than their individual treatments. Histological, immunohistochemistry and western blotting analyses revealed that the observed demyelination and axonal loss as evident from reduced levels of myelin and neurofilament proteins in the spinal cords of EAE animals were attenuated by treatment with these drugs in combination. Accordingly, the observed infiltration of myelin reactive T cells (CD4 and CD8) and macrophages (CD68) as well as the increased expression of their signatory cytokines in the spinal cords of EAE animals were attenuated by this regimen as revealed by enzyme-linked immune-sorbent assay and real-time PCR analyses. In the periphery, this regimen biased the class of elicited anti-myelin basic protein immunoglobulins from IgG2a to IgG1 and IgG2b, suggesting a Th1 to Th2 shift which was further supported by the increased expression of their signatory cytokines in EAE animals. Taken together, these data imply that metformin and lovastatin combination attenuates T-cell autoimmunity and neurodegeneration in treated EAE animals thereby suggesting that the oral administration of these FDA approved drugs in combination has potential to limit MS pathogenesis.

Vinpocetine inhibits oligodendroglial precursor cell differentiation

BACKGROUND

In multiple sclerosis during periods of remission a limited degree of myelin repair can be observed mediated by oligodendroglial precursor cells. Phosphodiesterase inhibitors act as anti-inflammatory agents and might hold promise for future multiple sclerosis treatment.

AIMS

To investigate whether phosphodiesterase inhibitors could also influence myelin repair.

METHODS

We stimulated primary oligodendroglial precursor cells with cilostazol, rolipram and vinpocetine and assessed their effects on repair related cellular processes.

RESULTS

We found that vinpocetine exerted a strong negative effect on myelin expression while cilostazol and rolipram did not show such effects. In addition, vinpocetine decreased morphological complexities suggesting an overall negative impact on oligodendroglial cell maturation. We provide evidence that this is not mediated via a blockade of phosphodiesterase-1 but rather by inhibition of IĸB kinase.

CONCLUSION

These findings suggest that vinpocetine via IĸB inhibition exerts a strong negative impact on oligodendroglial cell maturation and may therefore provide the rationale to restrict its application during periods of remission in multiple sclerosis patients. This is of particular interest since vinpocetine is widely used as a health supplement thought to act as a cognitive and memory enhancer for healthy people and patients with neurological or muscle diseases.

Rolipram promotes remyelination possibly via MEK-ERK signal pathway in cuprizone-induced demyelination mouse

OBJECTIVE

Rolipram, a 3'-5'-cyclic adenosine monophosphate (cAMP)-dependent phosphodiesterase 4 (PDE4) inhibitor, has long been studied for its immune modulating effects in the treatment of experimental autoimmune encephalomyelitis (EAE). In the current study, we investigated the effects of rolipram on remyelination after cuprizone- or lysolecithin-induced demyelination and the signal transduction pathways potentially modulating this response.

MATERIALS AND METHODS

Cuprizone-induced demyelination in mice and lysolecithin (LPC)-induced demyelination in rat cerebellum slice culture were treated with rolipram. Demyelination was evaluated by Luxol fast blue (LFB) or myelin basic protein (MBP) staining and western blot. Oligodendroglial cells were cultured with different concentrations of rolipram, and 2', 3'-cyclic nucleotide phosphodiesterase (CNPase) activity, MBP expression, and extracellular signal-regulated kinase (ERK) phosphorylation were measured.

RESULTS

Rolipram antagonized lysolecithin (LPC)-induced demyelination in rat cerebellar slice cultures and cuprizone-fed mice. In vitro, rolipram treatment promoted oligodendrocyte precursor cell (OPC) maturation, an effect that was partially blocked by the inhibitors of the mitogen activated protein kinase kinase (MEK).

CONCLUSION

Rolipram promotes the maturation of OPCs, facilitates remyelination, and increases ERK phosphorylation. All of these actions are involved in an action against cuprizone-induced demyelination that may occur partly via the MEK-ERK pathway. Importantly, this may have therapeutic implications for MS.

Interference with RhoA-ROCK signaling mechanism in autoreactive CD4+ T cells enhances the bioavailability of 1,25-dihydroxyvitamin D3 in experimental autoimmune encephalomyelitis

Vitamin D deficiency is a major risk factor for central nervous system (CNS) demyelinating diseases including multiple sclerosis (MS) and its animal model, that of experimental autoimmune encephalomyelitis (EAE). Both vitamin D(3) and 1, 25-dihydroxyviatmin-D(3) (calcitriol) had beneficial effects in EAE/MS. However, the exact cause of vitamin D deficiency in EAE/MS is not clear. Previously, we documented that lovastatin (LOV) provides protection in EAE animals via inhibition of RhoA-ROCK signaling. Herein, we demonstrate that LOV prevents the lowering of circulating 25-hydroxyvitamin-D(3) and 1,25-dihydroxyviatmin-D(3) levels including 1,25-dihydroxyviatmin-D(3) levels in the peripheral lymphoid organs and CNS of treated EAE animals. These effects of LOV were attributed to enhanced expression of vitamin D synthesizing enzyme (1α-hydroxylase) in kidney and the CNS, with corresponding reduction of vitamin D catabolizing enzyme (24-hydorxylase) expression in the CNS of EAE animals via inhibition of RhoA-ROCK signaling. Ex vivo and in vitro studies established that autoreactive Th1/Th17 cells had higher expression of 24-hydroxylase than Th2/T regulatory cells, that was reverted by LOV or ROCK inhibitor. Interestingly, LOV-mediated regulation of vitamin D metabolism had improved vitamin D(3) efficacy to confer protection in EAE animals and that was ascribed to the LOV- and calcitriol-induced immunomodulatory synergy. Together, these data provide evidence that interfering with RhoA-ROCK signaling in autoreactive Th1/Th17 cells can improve vitamin D(3) efficacy in clinical trials of MS and related neurodegenerative disorders.

Selective inhibition of CCR7(-) effector memory T cell activation by a novel peptide targeting Kv1.3 channel in a rat experimental autoimmune encephalomyelitis model

The voltage-gated Kv1.3 K(+) channel in effector memory T cells serves as a new therapeutic target for multiple sclerosis. In our previous studies, the novel peptide ADWX-1 was designed and synthesized as a specific Kv1.3 blocker. However, it is unclear if and how ADWX-1 alleviates experimental autoimmune encephalomyelitis, a model for multiple sclerosis. In this study, the administration of ADWX-1 significantly ameliorated the rat experimental autoimmune encephalomyelitis model by selectively inhibiting CD4(+)CCR7(-) phenotype effector memory T cell activation. In contrast, the Kv1.3-specific peptide had little effect on CD4(+)CCR7(+) cells, thereby limiting side effects. Furthermore, we determined that ADWX-1 is involved in the regulation of NF-κB signaling through upstream protein kinase C-θ (PKCθ) in the IL-2 pathway of CD4(+)CCR7(-) cells. The elevated expression of Kv1.3 mRNA and protein in activated CD4(+)CCR7(-) cells was reduced by ADWX-1 engagement; however, an apparent alteration in CD4(+)CCR7(+) cells was not observed. Moreover, the selective regulation of the Kv1.3 channel gene expression pattern by ADWX-1 provided a further and sustained inhibition of the CD4(+)CCR7(-) phenotype, which depends on the activity of Kv1.3 to modulate its activation signal. In addition, ADWX-1 mediated the activation of differentiated Th17 cells through the CCR7(-) phenotype. The efficacy of ADWX-1 is supported by multiple functions, which are based on a Kv1.3(high) CD4(+)CCR7(-) T cell selectivity through two different pathways, including the classic channel activity-associated IL-2 pathway and the new Kv1.3 channel gene expression pathway.

Role of pro-inflammatory cytokines released from microglia in neurodegenerative diseases

Microglia are activated in response to a number of different pathological states within the CNS including injury, ischemia, and infection. Microglial activation results in their production of pro-inflammatory cytokines such as IL-1, IL-6, and TNF-α. While release of these factors is typically intended to prevent further damage to CNS tissue, they may also be toxic to neurons and other glial cells. Mounting evidence indicates that chronic microglial activation may also contribute to the development and progression of neurodegenerative disorders. Unfortunately, determining the role of pro-inflammatory cytokines in these disorders has been complicated by their dual roles in neuroprotection and neurodegeneration. The purpose of this review is to summarize current understanding of the involvement of cytokines in neurodegenerative disorders and their potential signaling mechanisms in this context. Taken together, recent findings suggest that microglial activation and pro-inflammatory cytokines merit interest as targets in the treatment of neurodegenerative disorders.

Do statins improve outcomes in patients with asthma on inhaled corticosteroid therapy? A retrospective cohort analysis

OBJECTIVES

Animal studies and clinical trials have examined the potential benefits of statins in asthma management with contradictory results. The objective of this study was to determine if asthma patients on concurrent statins are less likely to have asthma-related hospitalisations.

DESIGN

A retrospective cohort study using Mississippi Medicaid data for 2002-2004.

PARTICIPANTS

Asthma patients ≥18 years were identified using the ICD9 code 493.xx from 1 July 2002 through 31 December 2003. The index date for an exposed subject was any date within the identification period, 180 days prior to which the subject had at least one inhaled corticosteroid prescription and at least an 80% adherence rate to statins. Asthma patients on inhaled corticosteroids, but not on statins, were selected as the unexposed population. The two groups were matched and followed for 1 year beginning the index date.

MAIN OUTCOMES MEASURES

Patient outcomes in terms of hospitalisations and ER visits were compared using conditional logistic regression.

RESULTS

After matching, there were 479 exposed subjects and 958 corresponding unexposed subjects. The odds of asthma-related hospitalisation and/or emergency room (ER) visits for asthma patients on concurrent statins were almost half the odds for patients not on statins (OR=0.55; 95% CI (0.37 to 0.84); p=0.0059). Similarly, the odds of asthma-related ER visits were significantly lower for patients on statins (OR=0.48; 95% CI (0.28 to 0.82); p=0.0069).

CONCLUSION

The findings suggest beneficial effects of statins in asthma management. Further prospective investigations are required to provide more conclusive evidence.

Statins amplify TLR-induced responses in microglia via inhibition of cholesterol biosynthesis

Statins inhibit the endogenous intracellular mevalonate pathway and exposure to statins affects innate and adaptive immune responses. Different statins are currently under evaluation as (co)therapy in neuro-inflammatory diseases like multiple sclerosis. However, there are important discrepancies in the reported effects of statins on innate immune responses in different cell types. Studies to characterize such responses in clinically relevant primary cells are currently lacking. In this study, we investigated the effect of statins on Toll-like receptor (TLR)-induced responses of microglia, the resident macrophages of the central nervous system (CNS). Exposure of primary microglia from adult rhesus monkeys to different statins strongly amplified pro-inflammatory cytokine protein and mRNA levels in response to myeloid differentiation primary response gene 88-dependent TLR activation in particular. Rather than affecting nuclear facor-κB activation levels, statin exposure affected stress-activated protein/Jun-amino-terminal and p38 kinase signaling pathways. Mechanistic studies using specific pathway inhibitors and rescue experiments show that statin-induced inhibition of cholesterol biosynthesis, rather than inhibition of isoprenylation, was mainly responsible for the amplified TLR responses. Additionally, microglia were more sensitive to statin-mediated effects than bone marrow-derived macrophages of the same donor. This correlated to lower intrinsic microglial expression levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the enzyme targeted by statins. Amplification of TLR-induced responses in microglia by statin exposure might contribute to the generation of a more pro-inflammatory CNS microenvironment which can be of relevance for the pathogenesis of neuroinflammatory disorders.

The prospects of minocycline in multiple sclerosis

Multiple sclerosis (MS) is the most common inflammatory demyelinating disease of the central nervous system (CNS). Although there are several approved drugs for MS, not all patients respond optimally to these drugs. More effective, well-tolerated therapeutic strategies for MS are necessary, either through the development of new medication or combination of existing ones. Minocycline is a traditional antibiotic with profound anti-inflammatory and neuroprotective effects and good tolerance for long-term use. The encouraging results from the animal model and clinical experiments on minocycline make it a promising candidate for MS treatment whether used alone or combined with other drugs. In this review, we summarized the pharmacological actions of minocycline and focused on its therapeutic effects and safety in experimental autoimmune encephalomyelitis (EAE) and MS. The data obtained here showed that minocycline would be an effective and safe therapy for MS.

Animal models of multiple sclerosis--potentials and limitations

Experimental autoimmune encephalomyelitis (EAE) is still the most widely accepted animal model of multiple sclerosis (MS). Different types of EAE have been developed in order to investigate pathogenetic, clinical and therapeutic aspects of the heterogenic human disease. Generally, investigations in EAE are more suitable for the analysis of immunogenetic elements (major histocompatibility complex restriction and candidate risk genes) and for the study of histopathological features (inflammation, demyelination and degeneration) of the disease than for screening of new treatments. Recent studies in new EAE models, especially in transgenic ones, have in connection with new analytical techniques such as microarray assays provided a deeper insight into the pathogenic cellular and molecular mechanisms of EAE and potentially of MS. For example, it was possible to better delineate the role of soluble pro-inflammatory (tumor necrosis factor-α, interferon-γ and interleukins 1, 12 and 23), anti-inflammatory (transforming growth factor-β and interleukins 4, 10, 27 and 35) and neurotrophic factors (ciliary neurotrophic factor and brain-derived neurotrophic factor). Also, the regulatory and effector functions of distinct immune cell subpopulations such as CD4+ Th1, Th2, Th3 and Th17 cells, CD4+FoxP3+ Treg cells, CD8+ Tc1 and Tc2, B cells and γδ+ T cells have been disclosed in more detail. The new insights may help to identify novel targets for the treatment of MS. However, translation of the experimental results into the clinical practice requires prudence and great caution.

Potential role of statins for the management of immune reconstitution syndrome

It has become evident that while a robust inflammatory response plays a critical role in eradicating invading microbes, dysregulated immunity can be detrimental to the host if an optimal balance between the inflammatory and anti-inflammatory reactions is disrupted. Opportunistic infection-associated immune reconstitution syndrome is characterized by an aggressive inflammatory immune response and its management remains challenging and largely unknown. Statins, in addition to their lipid lower effects have anti-inflammatory attributes and there is precedence for the use of these agents as a therapeutic modality for autoimmune inflammatory disorders which have similar underlying pathogenesis as immune reconstitution syndrome. We hypothesize that statins may have a potential role for the management of immune reconstitution syndrome. Our proposal has biologic and translational implications for optimizing outcomes in patients with immune reconstitution syndrome.

New drug therapies for multiple sclerosis

PURPOSE OF REVIEW

Multiple sclerosis (MS) is an autoimmune and inflammatory disease of the central nervous system (CNS) that causes neurological disability in young adults and that to date has no cure. Until now, expensive and only partially efficacious therapies have become available. For this reason, researchers, clinicians and pharmaceutical companies are currently investigating new drugs for the treatment of MS. Here, we review the most recent data on drug candidates for MS.

RECENT FINDINGS

In the preclinical phase, such drug candidates have shown a beneficial effect on the onset of experimental autoimmune encephalomyelitis (microtubule-stabilizing drugs, MS14, Lithium, GEMSP...), a decrease in CNS cell infiltrates (recombinant T cell receptor ligand, lovastatin-rolipram, ribavirin, GEMSP...), prevention of demyelination (lovastatin-rolipram, calpain inhibitor, lithium...); and a reduction of axonal loss (phenytoin, lovastatin-rolipram, calpain inhibitor). In clinical trials, drug candidates against MS have shown safety (rituximab, ustekinumab, intravenous immunoglobulin, laquinimod, BHT-3009, fumarate, chaperonin 10, GEMSP...), an improvement of gadolinium-enhanced lesions (protiramer, fingolimod, laquinimod, BHT-3009, fumarate, daclizumab...), and an improvement of the relapse rate (fingolimod, fumarate...).

SUMMARY

Future research into MS should focus on a combination of therapies and on the development of drugs directed against the remitting and progressive phases of the disease. In this sense, MS is a very complex multifactorial disease that requires treatment able to cover all the aspects of MS and not only the anti-inflammatory aspect.

Simvastatin protects bladder and renal functions following spinal cord injury in rats

BACKGROUND

Urinary bladder and renal dysfunction are secondary events associated with spinal cord injury (SCI) in humans. These secondary events not only compromise quality of life but also delay overall recovery from SCI pathophysiology. Furthermore, in experimental models the effects of SCI therapy on bladder and renal functions are generally not evaluated. In this study, we tested whether simvastatin improves bladder and renal functions in a rat model of experimental SCI.

METHODS

SCI was induced by controlled contusion of T9-T10 in adult female rats. Simvastatin (5 mg/Kg body weight) was administered at two hours after SCI and repeated every 24 hours until the end point. Simvastatin-treated SCI animals (simvastatin group) were compared with vehicle-treated SCI animals (vehicle group) in terms of the Basso Beattie Bresnahan score, tissue morphology, cell death, and bladder/renal functions.

RESULTS

The urinary bladder of vehicle animals showed a 4.3-fold increase in size and a 9-fold increase in wet weight compared to sham animals. Following SCI, the urine to plasma osmolality ratio increased initially but decreased 1 week after SCI. Hematoxylin and eosin staining of bladder tissue showed transitional epithelial hyperplasia, degeneration of lamina propria, and enlargement of tunica adventia in addition to detrusor muscle hypertrophy. Rats treated with simvastatin for 14 days displayed remarkable recovery by showing decreased bladder size and maintenance of a normal urine/plasma osmolality ratio, in addition to improved locomotion. The muscularis layer of the bladder also regained its compact nature in simvastatin animals. Moreover, SCI-induced renal caspase-3 activity was significantly decreased in the simvastatin group indicating the ability of simvastatin to reduce the renal tubular apoptosis.

CONCLUSION

Post-injury administration of simvastatin ameliorates bladder and renal dysfunction associated with SCI in rats.

Phosphodiesterase inhibitors in the management of autoimmune disease

Phophodiesterases inhibitors (PDEis) act by inhibiting the catabolism of cyclic nucleotides, cAMP and cGMP, which are ubiquitously expressed in cells of the immune system. Increased levels of cAMP and/or cGMP have been reported to decrease the activity of pro-inflammatory TH1 cells, attenuate experimental autoimmune encephalomyelitis and experimental arthritis. PDE5i like Sildenafil improves endothelial dysfunction and vascular remodelling in patients with pulmonary artery hypertension and refractory secondary Raynaud's phenomenon, with a potential to cause disease modification in the former. Studies in animal models of fibrosis suggest that these drugs have anti-fibrotic effect and may be potentially useful in conditions like scleroderma. They also have been shown to have renoprotective effect in animal models. The emerging trends make it necessary to exploit the full therapeutic potential of this class of drugs in various autoimmune diseases like rheumatoid arthritis, scleroderma, profibrotic conditions and PAH.

Animal models of multiple sclerosis for the development and validation of novel therapies - potential and limitations

Various types of experimental autoimmune encephalomyelitis (EAE) reflect some of the pathogenetic, clinical, and therapeutic features of the different forms of multiple sclerosis (MS), thereby, providing some, albeit limited, insight into the molecular and cellular basis of the human disease. Specific questions of MS therapy including the search for new therapeutic targets and strategies and their validation require investigations in different available EAE models. A survey is given of experimental therapeutic approaches that are currently under study with the most promising examples of monoclonal antibodies, gene therapy, stem cell transplantation and orally applied small molecular weight disease-modifying drugs. Reasons for therapy failure and adverse side-effects of some experimental trials are discussed. Precaution is advised, if results of new experimental approaches are translated into clinical practice.