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| Men's Health Forum: This is a discussion on Interesting article on Finasteride (Propecia) and Brain Fog within the Anabolic Steroids forums, part of the extensive steroid information at MESO-Rx; http://www.bio.net/bionet/mm/neur-sc...st/058929.html Allopregnenolone (synthesized from 5AR) may prevent neurodegeneration Kofi kofi at anon.un Wed Aug 11 19:26:31 EST 2004 The latest ... |
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| http://www.bio.net/bionet/mm/neur-sc...st/058929.html Allopregnenolone (synthesized from 5AR) may prevent neurodegeneration Kofi kofi at anon.un Wed Aug 11 19:26:31 EST 2004 The latest research in mice raises a disturbing question about the safety of FDA approved 5AR inhibitors like finasteride (Proscar/Propecia) and especially dutasteride (Avodart) when it comes to managing long-term risk for neurodegenerative diseases like Alzheimer's. This is because these drugs not only reduce levels of DHT but also wound allopregnanolone production in the process. To summarize the new findings on allopregnanolone (see attached below), Niemann-Pick type C is a rare lysosomal storage disorder/childhood neurodegenerative disease in which brain cells accumulate fat and die due in part to severely disrupted neurosteroidogenesis. A mutant gene for lysosomal acid sphingomyelinase disturbs cholesterol synthesis throughout the body and results in the accumulation of sphingomyelin. Progressive loss of neurosteroid synthesis may contribute to neurodegeneration. Replacing lost allopregnanolone substantially increases the survival of mice with this type of disease by mitigating the damage and delaying the onset of symptoms. Results were best when administered as early as possible in the animalıs life. Allopregnanolone may be effective with managing other neurodegenerative disorders. Other important neurosteroids like pregnenolone are also diminished in Niemann-Pick type C but what's interesting here is how valuable allopregnanolone is by itself. model mice may have amyloid-beta accumulations similar to those in Alzheimer's [PMID 14982851, 14982829] and may represent a good model for studying general aspects of neurodegeneration. 5 alpha reductase (5AR) is an enzyme which comes in two forms, type I and type II. It not only converts testosterone (T) to dihydrotestosterone (DHT, a ketone), it also converts progesterone to allopregnanolone and deoxycorticosterone (DOC) to tetrahydroDOC (THDOC), both allosteric enhancers of the GABA(a) receptor (e.g., they increase the effectiveness of inhibition signals relayed along GABA channels in nerves). The second stage of this conversion is performed by 3alpha-hydroxysteroid oxidoreductase. This pathway has widespread influence in the body. Progesterone is the precursor to allopregnanolone. Monthly drops in womenıs progesterone prior to their periods is a factor in PMS and epileptic seizure. Progesterone lozenges ameliorate seizures. Both estrogen and progesterone are important for TMJ remodeling [PMID 10670598]. Men with epilepsy can benefit from aromatase inhibitors which block the conversion of testosterone to estrogen via aromatase [PMID 15123030]. Allopregnanolone can block cocaine induced seizures [PMID 12921865]. Complete 5AR inhibition shortens inhibitory currents in GABA(A) channels both via allopregnanolone [PMID 12559121] and 5alpha-dihydrocoticosterone (THDOC) [PMID 11978855]. SSRIs (antidepressants like Zoloft) have been shown to upregulate levels of progesterone and allopregnanolone (THP) [PMID 12957330] as well as neurogenesis [PMID 14872203, 15001810, 14512209]. In animal models itıs the hippocampal neurogenesis that accounts for the behavioral effects of SSRIs [PMID 12907793]. Conversely, inescapable stress which reduces hippocampal neurogenesis also causes depression [PMID 12838272]. Levels of allopregnanolone can also be regulated by 3alpha-HSDs (3alpha-hydroxysteroid dehydrogenase) - enzymes which are identical in function to 5AR, except they convert T back from DHT instead of the other way around. 3alpha-HSDs are responsible for downregulating levels of DHT in the prostate and unusual inhibition of 3alpha-HSD would increase DHT levels, decrease allopregnanolone and incline a male toward impaired GABA functioning, acne, baldness, BHP and prostate cancer. Stimulating 3alpha-HSD might be more effective than 5AR inhibition for treating androgen disorders (although elevated exposure to either progesterone or allopregnanolone can become anxiety-provoking instead of calming; there are gender differences to this effect [PMID 12606703]). Certain synthetic progesterones may interfere with allopregnanolone synthesis. Medroxyprogesterone acetate (MPA), an ingredient in some birth control pills and hormone replacement therapies, doesnıt convert into allopregnanolone and causes anxiety, aggression and depressed sex drive in mice compared to combinations of natural hormones This overview should drive home just how important allopregnanolone may be to human health. Finasteride is a 5AR type II inhibitor which reduces DHT levels by up to 70%. Dutasteride inhibits both type I and type II 5AR achieving a reduction of up to 94% of DHT. Type I is the only 5AR expressed in the brain. Its long term inhibition was never studied when dutasteride was approved by the FDA. Blocking DHT synthesis in the brain like this also blocks allopregnanolone production there. While other tissues like bone also express 5AR, finasteride has been specifically studied on bone growth and has had no effect. Will this also be true for neurodegenerative disorders which take decades to develop? Will 5AR inhibitors be safe for individuals with epilepsy, TMJ, neuropathy, alcoholism, tinnitus, metals poisoning or other GABAergic illnesses? If it's true that dramatic 5AR inhibition contributes to long term neurodegeneration then what other therapeutic agents are available for dealing with excessive DHT? Understanding why male hormonal disorders like BHP, prostate cancer and baldness have become common in "advanced" economies is important to answering this question. One contributing factor is the bad mix of fats consumed in the American diet (high in trans-fats, hydrogenated oils, bad omega-6 and -9's and low in omega-3). Another factor is high glycemic index diets which contribute to insulin resistance and androgen signaling disorders like polycystic ovarian syndrome. High levels of insulin lower levels of sex hormone-binding globulin, a substance which binds to testosterone and lowers the amount of "free" androgens available to bind to the receptor (see [PMID 14527633], <http://www.thepaleodiet.com/articles/acne vulgaris.pdf>). These androgen driven disorders are all complex genetic disorders which can develop from many different angles. For instance, in a small study, prematurely balding men could be divided into two groups: the first group (about a third of the men) had a hormonal/insulin profile similar to women with polycycstic ovarian syndrome (low SHBG, hyperinsulemia, high free androgens and insulin resistance) whereas the second group had no similarities or only lower SHBG [PMID 15209536]. How you react to pathologically elevated levels of DHT is determined by your genetic risk and your environment. While dietary factors like fat and sugar consumption are important , the major actor on DHT throughout our evolutionary history has been a substance called equol. Equol is a derivative of the soy metabolite daidzein produced by bifidus bacteria in the gut. It directly binds to dihydrotestosterone and deactivates it [PMID 14681200]. Most male mammals produce ample amounts of equol to regulate excessive DHT production. High levels of equol in men lowers the risk for prostate cancer [PMID 14681200, 14720329] and improves blood cholesterol [PMID 14679315]. By taking antibiotics, you usually increase your risk for chronic inflammatory disorders. In this case, killing your gut bacteria leaves abnormally high levels of free DHT floating around in your blood stimulating your androgen receptors beyond what your body is used to. Over a lifetime, this brings out your genetic risk for androgen-driven disorders like the ones I keep mentioning. Destroying your gut bacteria with antibiotics probably also increases the risk for allergies, asthma, arthritis and other inflammatory disorders (see 15120189) - not to mention it can give you a bad yeast infection like you see in chronic sinusitis. How can you obtain equol if you no longer make your own? That's the problem. You can't. The only versions manufactured and sold today are racemic - meaning both the left and right isomers of the molecule are produced in a mixture. Only one form is naturally made and used in the human body. The other is not well studied. Another limiting factor is that finasteride and dutasteride are patented while equol can't be - it's a natural product which has been around too long. Contact manufacturers and let them know there is a market for this therapeutic substance and that it's worth conducting clinical trials. If 5AR inhibitors do pose long term risks and you absolutely have to take them, it may be possible to lessen the neurological damage with things like acetyl-l-carnitine, minocycline, l-theanine, taurine, curcumin, green tea (EGCG), CoQ10, nicotinamide/niacinamide, creatine, ketogenic diets, so on and so forth (each of which carries with it its own complicating factors). If this information has in any way improved your medical care, please consider voting for John Kerry. - Your amazing one and only crime-fighting/medical-spelunking UN secretary general Kofi Anon (Relevant NIH abstracts are denoted by PMID ### reference. To look it up, type <http://www.ncbi.nlm.nih.gov/entrez/q...&db=PubMed&lis t_uids=###&dopt=Abstract> in your browser or simply type the abstract ID into the NIH search engine.) http://www.sciencedaily.com/releases...0713082347.htm Source: University Of California, San Francisco Date: 2004-07-13 Print this page Email to friend Neurodegenerative Disease In Children Might Respond To Neurosteroids Scientists studying mice have identified a possible strategy for slowing a rare, fatal childhood neurodegenerative disease known as Niemann-Pick type C, in which brain cells accumulate fat and die. The finding could also have implications for treating other neurodegenerative disease, they say. In their study, published in the July issue of Nature Medicine, the team discovered that the synthesis of neurosteroid hormones in the brain -- a process known as neurosteroidogenesis -- is severely disrupted in mice that naturally develop the disease. They then determined that replenishing the depleted neurosteroid hormone allopregnanolone, the prime casualty of the disruption, significantly delayed the onset of some of the animals' neurological deficits, and doubled their lifespan. The treatment was particularly potent when administered early in the animals' life. "The results were astounding," says senior author Synthia Mellon, PhD, professor of obstetrics, gynecology and reproductive sciences at University of California, San Francisco. While the treatment did not target the cause of the disease -- a mutation in one of two genes that disrupts the transport of cholesterol within all cells of the body -- nor cure it, the therapy substantially delayed the onset of weight loss, motor coordination, mobility -- and death. It also significantly delayed the accumulation of fats in cortical cells, and the death of some neurons in the cortex and cerebellum. The study was not designed to test intellectual function, another component of the disease. LOSS OF NEUROSTEROIDS IN NEURODEGENERATION "The finding suggests that the progressive loss of neurosteroids contributes to neuronal degeneration in NP-C mice," says Mellon. "We didn't cure the problem. There's still a big clog in the cell, but we've circumvented it. We've treated downstream consequences of that clog." Scientists do not know if neurosteroid synthesis is disrupted in children with the disease, so the potential efficacy of allopregnanolone in children with NP-C cannot be predicted, says Mellon. However, allopregnanolone is produced naturally in humans, and provoked no evident side effects when administered to the NP-C mice. Thus, if the neurosteroid hormone is depleted in patients, it could prove a tactic for delaying the onset or progression of some symptoms of the disease. To determine neurosteroidogenesis activity in children with NP-C, scientists could compare brain tissue from autopsied NP-C patients with that from children who died from unrelated causes. Mellon says she and colleagues hope to be able to initiate pre-clinical studies aimed at determining safety, safe dosage and any possible side effects of allopregnanolone, with an eye to optimizing dosage and carrying out a clinical trial. If the therapy worked, it would signify a major advance, as scientists have not made headway in repairing the culprit gene, discovered in 1997, or the protein it synthesizes. Although clinical manifestations are varied and can present at any time from intrauterine life to adulthood, patients often begin demonstrating motor and intellectual decline during late childhood, and die between the ages of eight and eighteen. The disease, which also causes enlargement of the liver, occurs in about 1 in 150,000 children. ILLUMINATING THE ROLE OF NEUROSTEROIDS The finding, in broader terms, provides some of the strongest evidence to date that neurosteroids may play an important role in neurological function in humans, says Mellon. If synthesis of these steroid hormones is found to be disrupted in other neurodegenerative diseases -- a question that has just begun to be investigated -- neurosteroid therapy could prove effective in stalling them, she says. Like most other steroid hormones, neurosteroids are derived from cholesterol, a lipid that plays an important role in the formation of cell membranes. But while much is known about the role of other steroid hormones, such as testosterone, scientists are only beginning to understand the role of those that function in the brain. Neurosteroids are known to affect neuronal growth and differentiation and to modulate various moods and reactions via neurotransmitter receptors, including GABA. However, says Mellon, scientists generally have presumed that neurosteroids play a supportive, rather than an essential, role in neurological function. The research team, whose scientific interest is illuminating the role of neurosteroids, suspected that neurosteroid synthesis would be disturbed in NP-C, due to disruption of cholesterol transport within cells, which leads to the accumulation of cholesterol and other lipids in cellular compartments. Their theory was bolstered by the fact that mice with NP-C have below normal concentrations of testosterone and underdeveloped reproductive organs, suggesting that, at least, the synthesis of sex steroid hormones in the testes is disrupted in the disease. To test their hypothesis, the scientists compared the brains of normal, so-called "wild type," mice, with those of animals with NP-C. The results were dramatic. While neurosteroidogenesis was not affected in NP-C mice prenatally, the impact began at birth and increased over time. The quantity of pregnenolone, the first steroid produced from cholesterol, was significantly decreased. The quantity of allopregnanolone, which is converted from pregnenolone, was diminished even further. Supporting this finding, the two enzymes that synthesize allopregnanolone, 3a-hydroxysteroid dehydrogenase and 5a-reductase, were significantly depleted in all principal brain regions (the cortex, the midbrain and the hindbrain) by birth, and were reduced to irrelevant quantities by 10 weeks. The team then examined the impact of administering allopregnanolone to the brains of NP-C mice. The effect was equally pronounced. In a series of experiments, the drug was given progressively early in the animals' lives, at 21 to 23 days of age in the first mice examined, at 7 days of age in the last mice evaluated. The response, in terms of stalled neurological deficits, cellular damage and death, was greater the earlier the administration of the neurosteroid. DRAMATIC RESULTS The most dramatic results reported were in mice treated with a single injection at seven days of age. They gained weight steadily until age 86 days, and lived to a mean age of 124 days. In contrast, untreated NP-C mice had a mean survival of 67 days. In still more notable results, the researchers cited, but did not report, in their published paper that several treatments beginning at day seven in the animals' lives extended their lifespan and delayed the onset of neurological impairment even further. "The finding suggests that allopregnanolone may be involved in a neurodevelopmental process that occurs within or before the first week of life," says Mellon. NP-C is an autosomal recessive disease, meaning both parents must contribute a copy of the mutated gene to cause the disease, and that there is a 25 percent chance their offspring will develop it. As infants suspected of having the disease can be tested to see if they carry the mutated gene, the disease can be detected early. Thus, if allopregnanolone proves effective in humans, it could be used to stall the disease from the outset. The obvious next challenge for the researchers, however, will be determining how brain development of the mouse compares to that of the human. Co-authors of the study were Lisa D. Griffin, MD, PhD, formerly UCSF assistant professor of neurology, Wenhui Gong, MD, PhD, a postdoctoral fellow in the Mellon lab, and Lucie Verot, PhD, graduate student in the laboratory of Marie T. Vanier, MD, PhD, of INSERM, U189 and Laboratoire Foundation Gillet-Merieux, Lyon-Sud Medical School and Hospital, Pierre-Benite, France. The study was funded by the National Institutes of Health, the National Niemann Pick Disease Foundation, the March of Dimes Birth Defects Foundation, the Ara Parsaeghian Medical Research Foundation and Vaincre les Maladies Lyosomales. Editor's Note: The original news release can be found here. Semin Cell Dev Biol. 2004 Aug;15(4):445-54. Related Articles, Links Click here to read Cellular pathology of Niemann-Pick type C disease. Ikonen E, Holtta-Vuori M. Institute of Biotechnology, University of Helsinki, Helsinki, Finland. Niemann-Pick type C (NPC) is a lysosomal storage disorder that results in the accumulation of cholesterol and sphingolipids. Mutations in the NPC1 or NPC2 gene are responsible for the disease but the precise functions of the encoded proteins remain unresolved. Recent observations have challenged the traditional concept of NPC as a primary cholesterol transport defect. This review updates the recent NPC literature, summarizing the increasing insight into the cholesterol trafficking circuits and also addressing the contribution of other lipids in the cellular pathogenesis. The importance of NPC as a model for subcellular lipid imbalance in studying more common diseases, such as Alzheimer's and cardiovascular diseases, is discussed. PMID: 15207834 [PubMed - in process] Am J Respir Cell Mol Biol. 2004 Jul 15 [Epub ahead of print] Related Articles, Links Click here to read Mechanistic similarities between cultured cell models of cystic fibrosis and Niemann-Pick type C. White NM, Corey DA, Kelley TJ. Recent data demonstrate that inhibition of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase restores normal signal transducer and activator of transcription-1 (STAT1) and inducible nitric oxide synthase expression (NOS2) regulation in CF cells through the modulation of RhoA function. These findings lead to the hypothesis that alterations in the cholesterol synthesis pathway may be an initiating factor in CF-related cell signaling regulation. A disease with a known lesion in the cholesterol synthesis pathway is Niemann-Pick type C (NPC). The hypothesis of this study is that CF cells and NPC fibroblasts share a common mechanistic lesion and should exhibit similar cell signaling alterations. NPC fibroblasts exhibit similar alterations in STAT1, RhoA, SMAD3, and NOS2 protein expression that characterize CF. Further comparison reveals NPC-like accumulation of free cholesterol in two cultured models of CF epithelial cells. These data identify novel signaling changes in NPC, demonstrate the cholesterol-synthesis pathway is a likely source of CF-related cell signaling changes, and that cultured CF cells exhibit impaired cholesterol processing. PMID: 15256387 [PubMed - as supplied by publisher] Nat Med. 2004 Jul;10(7):704-11. Epub 2004 Jun 20. Related Articles, Links Click here to read Niemann-Pick type C disease involves disrupted neurosteroidogenesis and responds to allopregnanolone. Griffin LD, Gong W, Verot L, Mellon SH. Department of Neurology, Center for Reproductive Sciences, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, California 94143-0556, USA. Niemann-Pick type C (NP-C) disease is a fatal, autosomal recessive, childhood neurodegenerative disease. The NP-C mouse recapitulates the cholesterol and sphingolipid storage, onset of neurological deficits, histopathological lesions, Purkinje cell loss and early death typical of the most severe form of human NP-C. Neurosteroids, steroids made in the brain, affect neuronal growth and differentiation, and modulate neurotransmitter receptors. Disordered cholesterol trafficking might disrupt neurosteroidogenesis, thereby contributing to the NP-C phenotype. Here we show that NP-C mouse brain contains substantially less neurosteroid than wild-type brain and has an age-related decrease in the ability to synthesize 5alpha-dihydroprogesterone and allopregnanolone. Immunohistochemical assessment confirms a decrease in expression of 5alpha-reductase and 3alpha-hydroxysteroid dehydrogenase, especially in cerebellum. Neonatal administration of allopregnanolone delays the onset of neurological symptoms, increases Purkinje and granule cell survival, reduces cortical GM2 and GM3 ganglioside accumulation and doubles the lifespan of NP-C mice. Earlier administration increases effectiveness of treatment. Decreased production of allopregnanolone apparently contributes to the pathology of NP-C; thus, neurosteroid treatment may be useful in ameliorating progression of the disease. PMID: 15208706 [PubMed - in process] Biochem Biophys Res Commun. 2004 Mar 5;315(2):408-17. Related Articles, Links Click here to read Chronic exposure to U18666A induces apoptosis in cultured murine cortical neurons. Cheung NS, Koh CH, Bay BH, Qi RZ, Choy MS, Li QT, Wong KP, Whiteman M. Department of Biochemistry, Faculty of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore. Niemann-Pick disease type C (NPC) is a juvenile neurodegenerative disorder characterized by premature neuronal loss and altered cholesterol metabolism. Previous reports applying an 8-h exposure of U18666A, a cholesterol transport-inhibiting agent, demonstrated a dose-dependent reduction in beta-amyloid (Abeta) deposition and secretion in cortical neurons, with no significant cell injury. In the current study, we examined the chronic effect of 24-72h of U18666A treatment on primary cortical neurons and several cell lines. Our results showed caspase-3 activation and cellular injury in U18666A-treated cortical neurons but not in the cell lines, suggesting cell death by apoptosis only occurred in cortical neurons after chronic exposure to U18666A. We also demonstrated through filipin staining the accumulation of intracellular cholesterol in cortical neurons treated with U18666A, indicating the phenotypic mimic of NPC by U18666A. However, additions of 10 and 25microM pravastatin with 0.5microg/ml U18666A significantly attenuated toxicity. Taken together, these data showed for the first time that U18666A induces cell death by apoptosis and suggested an important in vitro model system to study NPC. PMID: 14766223 [PubMed - indexed for MEDLINE] Exp Neurol. 2003 Dec;184(2):887-903. Related Articles, Links Click here to read Postnatal development of inflammation in a murine model of Niemann-Pick type C disease: immunohistochemical observations of microglia and astroglia. Baudry M, Yao Y, Simmons D, Liu J, Bi X. Department of Psychiatry & Human Behavior, University of California Irvine, Irvine, CA 92612, USA. Niemann-Pick type C (NPC) is a rare and fatal neurovisceral storage disorder that is currently untreatable. In most cases, NPC is caused by mutations of the NPC1 gene, which encodes a glycoprotein playing an important role in cholesterol transport. Mice lacking the NPC1 gene exhibit several pathological features of NPC patients and have been widely used to provide insights into the mechanisms of the disease. In the present study, we analyzed the postnatal development of pathological manifestations of inflammation in several brain regions of NPC1-/- mice. Brain sections from NPC1-/- and wild-type (NPC1+/+) mice were immunostained with the MAC1 antibody, which recognizes microglia, with antibodies against glial fibrillary acidic protein (GFAP), which recognize astrocytes, and with antibodies against the cytokine interleukin-1beta (IL-1beta). Numbers of MAC1 immunopositive cells were markedly increased in several brain regions of NPC1-/- mice as early as 2 weeks of age. This effect was particularly evident in globus pallidus, ventral lateral thalamus, medial geniculate nucleus, and cerebellum. MAC1-immunopositive cells had enlarged cell bodies and shorter processes, suggesting they were in an active state. By 4 weeks, most brain structures exhibited enhanced microglial activation in NPC1-/- mice, and this was maintained at 12 weeks. At 2 weeks, reactive astrocytes were only observed in the ventral lateral thalamus while they were present throughout the brain of NPC1-/- mice at 4 weeks of age. Moreover, the astroglial reaction coincided with up-regulation of the cytokine, interleukin-1beta, in most, but not all brain regions. In particular, no interleukin-1beta up-regulation was observed in regions devoid of neuronal degeneration. These results suggest that microglial activation precedes and might be causally related to neuronal degeneration, while astrocyte activation might be a consequence of neuronal degeneration. PMID: 14769381 [PubMed - indexed for MEDLINE] Last edited by jasonshadow; 09-23-2006 at 01:15 PM. |
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