Family Medicine Resident Perspectives on Curricula in Herbal Medicine.

BACKGROUND AND OBJECTIVES: Despite widespread patient use, herbal and dietary supplement education is not required in US-accredited medical schools. Thus, physicians are unprepared to address supplement use with patients. Our objectives were to assess perceived adequacy of medical education on supplements, determine resident perspectives on appropriate placement of curricula in their longitudinal medical education, and evaluate the effects of an innovative workshop on family medicine resident knowledge about supplements and intentions to address this topic with patients. METHODS: Family medicine residents (N=65) participated in an hour-long workshop covering basic concepts about herbal and dietary supplements, including regulations, literature review techniques, and risk/benefit analysis. The participants completed pre/postworkshop surveys to assess need for increased education and evaluate efficacy of the workshop. RESULTS: Most participants (91.9%) thought they should have received more education than provided on supplements and perceived greater need for curricula in undergraduate medical education than in graduate medical education. Only 47.6% received required education on supplements, significantly less than the 72.6% who thought this education should be required (P<0.05). The workshop increased the proportion of residents planning to address patients' supplement use, increased the frequency residents intend to ask about supplements, and improved resident perceptions of the efficacy of some supplements when used with physician guidance. CONCLUSIONS: Residents perceived a lack of adequate medical education on the use of herbal and dietary supplements. Results showed a brief workshop increased resident intentions to discuss supplement use with patients. Further education on supplement use may be warranted.

FTY720 rescue therapy in the dark agouti rat model of experimental autoimmune encephalomyelitis: expression of central nervous system genes and reversal of blood-brain-barrier damage.

FTY720 (fingolimod) is an oral sphingosine-1 phosphate (S1P) receptor modulator in phase III development for the treatment of multiple sclerosis. To further investigate its mode of action, we analyzed gene expression in the central nervous system (CNS) during experimental autoimmune encephalomyelitis (EAE). FTY720 downregulated inflammatory genes in addition to vascular adhesion molecules. It decreased the matrix metalloproteinase gene MMP-9 and increased its counterregulator--tissue inhibitor of metalloproteinase, TIMP-1--resulting in a proteolytic balance that favors preservation of blood-brain-barrier (BBB) integrity. Furthermore, FTY720 reduced S1P lyase that increases the S1P concentration in the brain, in line with a marked reversal of neurological deficits and raising the possibility for enhanced triggering of S1P receptors on resident brain cells. This is accompanied by an increase in S1P(1) and S1P(5) in contrast with the attenuation of S1P(3) and S1P(4). Late-stage rescue therapy with FTY720, even up to 1 month after EAE onset, reversed BBB leakiness and reduced demyelination, along with normalization of neurologic function. Our results indicate rapid blockade of ongoing disease processes by FTY720, and structural restoration of the CNS parenchyma, which is likely caused by the inhibition of autoimmune T cell infiltration and direct modulation of microvascular and/or glial cells.

Ascomycete derivative to MS therapeutic: S1P receptor modulator FTY720.

Fingolimod (FTY720) represents the first in a new class of immune-modulators whose target is sphingosine-1-phosphate (S1P) receptors. It was first identified by researchers at Kyoto University and Yoshitomi Pharmaceutical as a chemical derivative of the ascomycete metabolite ISP-1 (myriocin). Unlike its natural product parent, FTY720 does not interfere with sphingolipid biosynthesis. Instead, its best characterized mechanism of action upon in vivo phosphorylation, leading to the active principle FTY720-P, is the rapid and reversible inhibition of lymphocyte egress from peripheral lymph nodes. As a consequence of S1P1 receptor internalization, tissue-damaging T-cells can not recirculate and infiltrate sites of inflammation such as the central nervous system (CNS). Furthermore, FTY720-P modulation of S1P receptor signaling also enhances endothelial barrier function. Due to its mode of action, FTY720 effectively prevents transplant rejection and is active in various autoimmune disease models. The most striking efficacy is in the multiple sclerosis (MS) model of experimental autoimmune encephalomyelitis, which has now been confirmed in the clinic. FTY720 demonstrated promising results in Phase II trials and recently entered Phase III in patients with relapsing MS. Emerging evidence suggests that its efficacy in the CNS extends beyond immunomodulation to encompass other aspects of MS pathophysiology, including an influence on the blood-brain-barrier and glial repair mechanisms that could ultimately contribute to restoration of nerve function. FTY720 may represent a potent new therapeutic modality in MS, combined with the benefit of oral administration.

FTY720 sustains and restores neuronal function in the DA rat model of MOG-induced experimental autoimmune encephalomyelitis.

FTY720 (fingolimod) is an oral sphingosine 1-phosphate (S1P) receptor modulator under development for the treatment of multiple sclerosis (MS). To elucidate its effects in the central nervous system (CNS), we compared functional parameters of nerve conductance in the DA rat model of myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) after preventive and therapeutic treatment. We demonstrate that prophylactic therapy protected against the emergence of EAE symptoms, neuropathology, and disturbances to visual and somatosensory evoked potentials (VEP, SEP). Moreover, therapeutic treatment from day 25 to 45 markedly reversed paralysis in established EAE and normalized the electrophysiological responses, correlating with decreased demyelination in the brain and spinal cord. The effectiveness of FTY720 in this model is likely due to several contributing factors. Evidence thus far supports its role in the reduction of inflammation and preservation of blood-brain-barrier integrity. FTY720 may also act via S1P receptors in glial cells to promote endogenous repair mechanisms that complement its immunomodulatory action.

Brain penetration of the oral immunomodulatory drug FTY720 and its phosphorylation in the central nervous system during experimental autoimmune encephalomyelitis: consequences for mode of action in multiple sclerosis.

FTY720 [2-amino-2-[2-(4-octylphenyl) ethyl]propane-1,3-diol hydrochloride] is an oral sphingosine-1-phosphate receptor modulator under development for the treatment of multiple sclerosis (MS). The drug is phosphorylated in vivo by sphingosine kinase 2 to its bioactive form, FTY720-P. Although treatment with FTY720 is accompanied by a reduction of the peripheral lymphocyte count, its efficacy in MS and experimental autoimmune encephalomyelitis (EAE) may be due to additional, direct effects in the central nervous system (CNS). We now show that FTY720 localizes to the CNS white matter, preferentially along myelin sheaths. Brain trough levels of FTY720 and FTY720-P in rat EAE are of the same magnitude and dose dependently increase; they are in the range of 40 to 540 ng/g in the brain tissue at efficacious doses and exceed blood concentrations severalfold. In a rat model of chronic EAE, prolonged treatment with 0.03 mg/kg was efficacious, but limiting the dosing period failed to prevent EAE despite a significant decrease in blood lymphocytes. FTY720 effectiveness is likely due to a culmination of mechanisms involving reduction of autoreactive T cells, neuroprotective influence of FTY720-P in the CNS, and inhibition of inflammatory mediators in the brain.

Selective inhibition of cotranslational translocation of vascular cell adhesion molecule 1.

Increased expression of vascular cell adhesion molecule 1 (VCAM1) is associated with a variety of chronic inflammatory conditions, making its expression and function a target for therapeutic intervention. We have recently identified CAM741, a derivative of a fungus-derived cyclopeptolide that acts as a selective inhibitor of VCAM1 synthesis in endothelial cells. Here we show that the compound represses the biosynthesis of VCAM1 in cells by blocking the process of cotranslational translocation, which is dependent on the signal peptide of VCAM1. CAM741 does not inhibit targeting of the VCAM1 nascent chains to the translocon channel but prevents translocation to the luminal side of the endoplasmic reticulum (ER), through a process that involves the translocon component Sec61beta. Consequently, the VCAM1 precursor protein is synthesized towards the cytosolic compartment of the cells, where it is degraded. Our results indicate that the inhibition of cotranslational translocation with low-molecular-mass compounds, using specificity conferred by signal peptides, can modulate the biosynthesis of certain secreted and/or membrane proteins. In addition, they highlight cotranslational translocation at the ER membrane as a potential target for drug discovery.

Synthesis of ether analogues derived from HUN-7293 and evaluation as inhibitors of VCAM-1 expression.

The cyclic depsipeptide HUN-7293 (1) and its D-lactate analogue 2 are highly potent inhibitors of inducible cell adhesion molecule expression. We report the synthesis of ether analogues varying in stereochemistry and side chain at the former hydroxyl acid position by employing a 'cut and paste chemistry' methodology starting from 1. As an additional fruit of this synthetic effort, a cyclodepsipeptide featuring a tertiary amine instead of a tertiary amide between PrLEU and MALA was obtained. Results on the inhibitory profile of these compounds in assays of VCAM-1 and ICAM-1 protein expression are discussed.

Predictability of FTY720 efficacy in experimental autoimmune encephalomyelitis by in vivo macrophage tracking: clinical implications for ultrasmall superparamagnetic iron oxide-enhanced magnetic resonance imaging.

PURPOSE: To examine the efficacy of FTY720 as a new agent to reduce inflammatory activity in an animal model of multiple sclerosis (MS) by in vivo macrophage tracking. MATERIAL AND METHODS: FTY720 was used for treatment of rats in a model of chronic relapsing experimental autoimmune encephalomyelitis (EAE) at an oral dose of 0.3 mg/kg/day. Magnetic resonance imaging (MRI) based on in vivo tracking of macrophages labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, immunohistological staining (IHC), and neurological readouts was used to study the burden of disease in treated and untreated animals. RESULTS: While untreated animals showed severe paralysis of the hind paws, intense accumulation of macrophages in brain tissue, and areas of blood-brain barrier (BBB) disruption, FTY720-treated animals displayed no signs of inflammatory activity or neurological impairment. These observations were made for both acute phase and first relapse. CONCLUSION: Tracking of macrophages by MRI provides direct evidence of the immunomodulatory efficacy of FTY720 in the EAE model and correlates well with neurological symptoms and histology.

Solution-phase parallel synthesis of a pharmacophore library of HUN-7293 analogues: a general chemical mutagenesis approach to defining structure-function properties of naturally occurring cyclic (depsi)peptides.

HUN-7293 (1), a naturally occurring cyclic heptadepsipeptide, is a potent inhibitor of cell adhesion molecule expression (VCAM-1, ICAM-1, E-selectin), the overexpression of which is characteristic of chronic inflammatory diseases. Representative of a general approach to defining structure-function relationships of such cyclic (depsi)peptides, the parallel synthesis and evaluation of a complete library of key HUN-7293 analogues are detailed enlisting solution-phase techniques and simple acid-base liquid-liquid extractions for isolation and purification of intermediates and final products. Significant to the design of the studies and unique to solution-phase techniques, the library was assembled superimposing a divergent synthetic strategy onto a convergent total synthesis. An alanine scan and N-methyl deletion of each residue of the cyclic heptadepsipeptide identified key sites responsible for or contributing to the biological properties. The simultaneous preparation of a complete set of individual residue analogues further simplifying the structure allowed an assessment of each structural feature of 1, providing a detailed account of the structure-function relationships in a single study. Within this pharmacophore library prepared by systematic chemical mutagenesis of the natural product structure, simplified analogues possessing comparable potency and, in some instances, improved selectivity were identified. One potent member of this library proved to be an additional natural product in its own right, which we have come to refer to as HUN-7293B (8), being isolated from the microbial strain F/94-499709.

The immune modulator FTY720 targets sphingosine 1-phosphate receptors.

Immunosuppressant drugs such as cyclosporin have allowed widespread organ transplantation, but their utility remains limited by toxicities, and they are ineffective in chronic management of autoimmune diseases such as multiple sclerosis. In contrast, the immune modulating drug FTY720 is efficacious in a variety of transplant and autoimmune models without inducing a generalized immunosuppressed state and is effective in human kidney transplantation. FTY720 elicits a lymphopenia resulting from a reversible redistribution of lymphocytes from circulation to secondary lymphoid tissues by unknown mechanisms. Using FTY720 and several analogs, we show now that FTY720 is phosphorylated by sphingosine kinase; the phosphorylated compound is a potent agonist at four sphingosine 1-phosphate receptors and represents the therapeutic principle in a rodent model of multiple sclerosis. Our results suggest that FTY720, after phosphorylation, acts through sphingosine 1-phosphate signaling pathways to modulate chemotactic responses and lymphocyte trafficking.