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1.
Pain Physician ; 24(2): 175-184, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33740353

RESUMO

BACKGROUND: Insulin resistance (IR) is a pathological condition in which cells fail to respond normally to insulin. IR has been associated with multiple conditions, including chronic pain. Fibromyalgia (FM) is one of the common generalized chronic painful conditions with an incidence rate affecting 3% to 6% of the population. Substantial interest and investigation into FM continue to generate  many hypotheses.The relationship between IR and FM has not been explored. IR is known to cause abnormalities in the cerebral microvasculature, leading to focal hypoperfusion. IR also has been shown to cause cognitive impairment in FM patients, as in parkinsonism. As demonstrated by advanced imaging methods, similar brain perfusion abnormalities occur in the brain of patients with FM as with IR. OBJECTIVES: To determine the potential association between FM and IR. SETTING: Subspecialty pain medicine clinics. STUDY DESIGN: Observational cross-sectional study. METHODS: Laboratory data was extracted through a retrospective review of medical records from patients who had met the American College of Rheumatology (ACR) criteria for FM. The Hemoglobin A1c (HbA1c) values from 33 patients with FM were compared with the means of the glycated HbA1c levels of 2 control populations. In addition, established indices of IR [Quantitative Insulin Sensitivity Check Index (QUICKI) and the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR)] were calculated in a subgroup of patients in whom the analytes necessary for these calculations were available. To assess for confounding factors, the associations between HbA1c, QUICKI, HOMA-IR, fasting insulin levels, and glucose, after controlling for age, were explored by multiple analyses of variance with relation to gender and ethnicity. RESULTS: We found an association between IR and FM that was independent of age, gender, and ethnicity. We found that patients with FM belong to a distinct population that can be segregated from the control groups by their HbA1c levels, a surrogate marker of IR. This was demonstrated by analyzing the data after introducing an age correction into a linear regression model. This strategy showed significant differences between patients with FM and control subjects (P < 0.0001 and P  = 0.0002, for 2 separate control populations, respectively). A subgroup analysis using the QUICKI and HOMA-IR showed that all patients with FM in this subgroup (100%) exhibited laboratory abnormalities pointing to IR. LIMITATIONS: Small observational cross-sectional study. There are also intrinsic limitations that are attributed to cross-sectional studies. CONCLUSION: The association demonstrated in this study warrant further investigation, including the pursuit of randomized, double-blind clinical trials to determine the effect of improving insulin sensitivity in FM related pain scores. Such studies could unveil a potential pathogenetic relationship between FM, central pain, and IR. Based on these initial findings, we present the hypothesis that IR may underlie pathological mechanisms leading to central pain. If confirmed, this may lead to a paradigm shift in the management of central pain.

2.
Pain Physician ; 24(S1): S1-S26, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33492917

RESUMO

BACKGROUND: The re-engineered definition of clinical guidelines in 2011 from the IOM (Institute of Medicine) states, "clinical practice guidelines are statements that include recommendations intended to optimize patient care that is informed by a systematic review of evidence and an assessment of the benefit and harms of alternative care options." The revised definition distinguishes between the term "clinical practice guideline" and other forms of clinical guidance derived from widely disparate development processes, such as consensus statements, expert advice, and appropriate use criteria. OBJECTIVE: To assess the literature and develop methodology for evidence synthesis and development of comprehensive evidence-based guidelines for interventional techniques in chronic spinal pain. METHODS: A systematic review of the literature including methodology of guideline development encompassing GRADE approach for guidance on evidence synthesis with recommendations. RESULTS: Some of the many factors described in 2011 continue as of 2020 and impede the development of clinical practice guidelines. These impediments include biases due to a variety of conflicts and confluence of interest, inappropriate and poor methodological quality, poor writing and ambiguous presentation, projecting a view that these are not applicable to individual patients or too restrictive with the elimination of clinician autonomy, and overzealous and inappropriate recommendations, either positive, negative, or non-committal. Thus, ideally, a knowledgeable, multidisciplinary panel of experts with true lack of bias and confluence of interest must develop guidelines based on a systematic review of the existing evidence. This manuscript describes evidence synthesis from observational studies, various types of randomized controlled trials (RCTs), and, finally, methodological and reporting quality of systematic reviews. The manuscript also describes various methods utilized in the assessment of the quality of observational studies, diagnostic accuracy studies, RCTs, and systematic reviews. LIMITATIONS: Paucity of publications with appropriate evidence synthesis methodology in reference to interventional techniques. CONCLUSION: This review described comprehensive evidence synthesis derived from systematic reviews, including methodologic quality and bias measurement. The manuscript described various methods utilized in the assessment of the quality of the systematic reviews, RCTs, diagnostic accuracy studies, and observational studies.

3.
PLoS One ; 14(5): e0216079, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31059525

RESUMO

Fibromyalgia (FM) is one of the most frequent generalized pain disorders with poorly understood neurobiological mechanisms. This condition accounts for an enormous proportion of healthcare costs. Despite extensive research, the etiology of FM is unknown and thus, there is no disease modifying therapy available for this condition. We show that most (if not all) patients with FM belong to a distinct population that can be segregated from a control group by their glycated hemoglobin A1c (HbA1c) levels, a surrogate marker of insulin resistance (IR). This was demonstrated by analyzing the data after introducing an age stratification correction into a linear regression model. This strategy showed highly significant differences between FM patients and control subjects (p < 0.0001 and p = 0.0002, for two separate control populations, respectively). A subgroup of patients meeting criteria for pre-diabetes or diabetes (patients with HbA1c values of 5.7% or greater) who had undergone treatment with metformin showed dramatic improvements of their widespread myofascial pain, as shown by their scores using a pre and post-treatment numerical pain rating scale (NPRS) for evaluation. Although preliminary, these findings suggest a pathogenetic relationship between FM and IR, which may lead to a radical paradigm shift in the management of this disorder.

4.
Pain Physician ; 21(6): 515-540, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30508983

RESUMO

BACKGROUND: Several cell-based therapies have been proposed in recent years the management of low back pain, including the injection of medicinal signaling cells or mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP). However, there is only emerging clinical evidence to support their use at this time. OBJECTIVE: To assess the effectiveness of MSCs or PRP injections in the treatment of low back and lower extremity pain. STUDY DESIGN: A systematic review and metaanalysis of the effectiveness of PRP and MSCs injections in managing low back and lower extremity pain. DATA SOURCES: PubMed, Cochrane Library, US National Guideline Clearinghouse, prior systematic reviews, and reference lists. The literature search was performed from 1966 through June 2018. STUDY SELECTION: Randomized trials, observational studies, and case reports of injections of biologics into the disc, epidural space, facet joints, or sacroiliac joints. DATA EXTRACTION: Data extraction and methodological quality assessment were performed utilizing Cochrane review methodologic quality assessment and Interventional Pain Management Techniques - Quality Appraisal of Reliability and Risk of Bias Assessment (IPM-QRB) and Interventional Pain Management Techniques - Quality Appraisal of Reliability and Risk of Bias Assessment for Nonrandomized Studies (IPM-QRBNR). The evidence was summarized utilizing principles of best evidence synthesis on a scale of 1 to 5. DATA SYNTHESIS: Twenty-one injection studies met inclusion criteria. There were 12 lumbar disc injections, 5 epidural, 3 lumbar facet joint, and 3 sacroiliac joint studies RESULTS: Evidence synthesis based on a single-arm metaanalysis, randomized controlled trials (RCTs), and observational studies, disc injections of PRP and MSCs showed Level 3 evidence (on a scale of Level I through V). Evidence for epidural injections based on single-arm metaanalysis, a single randomized controlled trial and other available studies demonstrated Level 4 (on a scale of Level I through V) evidence. Similarly, evidence for lumbar facet joint injections and sacroiliac joint injections without metaanalysis demonstrated Level 4 evidence (on a scale of Level I through V). LIMITATIONS: Lack of high quality RCTs. CONCLUSION: The findings of this systematic review and single-arm metaanalysis shows that MSCs and PRP may be effective in managing discogenic low back pain, radicular pain, facet joint pain, and sacroiliac joint pain, with variable levels of evidence in favor of these techniques. KEY WORDS: Chronic low back pain, regenerative therapy, medicinal signaling or mesenchymal stem cells, platelet-rich plasma, disc injection, lumbar facet joint injections, sacroiliac joint injections.


Assuntos
Dor Lombar/terapia , Transplante de Células-Tronco Mesenquimais/métodos , Manejo da Dor/métodos , Plasma Rico em Plaquetas , Medicina Regenerativa/métodos , Dor Crônica/tratamento farmacológico , Humanos
5.
Curr Alzheimer Res ; 12(1): 32-46, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25523424

RESUMO

Amyloid-ß proteins (Aß) of 42 (Aß42) and 40 aa (Aß40) accumulate as senile plaques (SP) and cerebrovascular amyloid protein deposits that are defining diagnostic features of Alzheimer's disease (AD). A number of rare mutations linked to familial AD (FAD) on the Aß precursor protein (APP), Presenilin-1 (PS1), Presenilin- 2 (PS2), Adamalysin10, and other genetic risk factors for sporadic AD such as the ε4 allele of Apolipoprotein E (ApoE-ε4) foster the accumulation of Aß and also induce the entire spectrum of pathology associated with the disease. Aß accumulation is therefore a key pathological event and a prime target for the prevention and treatment of AD. APP is sequentially processed by ß-site APP cleaving enzyme (BACE1) and γ-secretase, a multisubunit PS1/PS2-containing integral membrane protease, to generate Aß. Although Aß accumulates in all forms of AD, the only pathways known to be affected in FAD increase Aß production by APP gene duplication or via base substitutions on APP and γ-secretase subunits PS1 and PS2 that either specifically increase the yield of the longer Aß42 or both Aß40 and Aß42. However, the vast majority of AD patients accumulate Aß without these known mutations. This led to proposals that impairment of Aß degradation or clearance may play a key role in AD pathogenesis. Several candidate enzymes, including Insulin-degrading enzyme (IDE), Neprilysin (NEP), Endothelin-converting enzyme (ECE), Angiotensin converting enzyme (ACE), Plasmin, and Matrix metalloproteinases (MMPs) have been identified and some have even been successfully evaluated in animal models. Several studies also have demonstrated the capacity of γ-secretase inhibitors to paradoxically increase the yield of Aß and we have recently established that the mechanism is by skirting Aß degradation. This review outlines major cellular pathways of Aß degradation to provide a basis for future efforts to fully characterize the panel of pathways responsible for Aß turnover.


Assuntos
Doença de Alzheimer/metabolismo , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/genética , Animais , Apolipoproteínas E/genética , Humanos , Modelos Biológicos , Mutação , Placa Amiloide/patologia , Presenilina-1/metabolismo , Presenilina-2/metabolismo , Transdução de Sinais/genética
6.
PLoS One ; 9(3): e91531, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24658363

RESUMO

BACE1 (ß-secretase) and α-secretase cleave the Alzheimer's amyloid ß protein (Aß) precursor (APP) to C-terminal fragments of 99 aa (CTFß) and 83 aa (CTFα), respectively, which are further cleaved by γ-secretase to eventually secrete Aß and Aα (a.k.a. P3) that terminate predominantly at residues 40 and 42. A number of γ-secretase inhibitors (GSIs), such as N-[N-(3,5-Difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT), have been developed with the goal of reducing Aß to treat Alzheimer's disease (AD). Although most studies show that DAPT inhibits Aß in a dose-dependent manner several studies have also detected a biphasic effect with an unexpected increase at low doses of DAPT in cell cultures, animal models and clinical trials. In this article, we confirm the increase in Aß40 and Aß42 in SH-SY5Y human neuroblastoma cells treated with low doses of DAPT and identify one of the mechanisms for this paradox. We studied the pathway by first demonstrating that stimulation of Aß, a product of γ-secretase, was accompanied by a parallel increase of its substrate CTFß, thereby demonstrating that the inhibitor was not anomalously stimulating enzyme activity at low levels. Secondly, we have demonstrated that inhibition of an Aß degrading activity, endothelin converting enzyme (ECE), yielded more Aß, but abolished the DAPT-induced stimulation. Finally, we have demonstrated that Aα, which is generated in the secretory pathway before endocytosis, is not subject to the DAPT-mediated stimulation. We therefore conclude that impairment of γ-secretase can paradoxically increase Aß by transiently skirting Aß degradation in the endosome. This study adds to the growing body of literature suggesting that preserving γ-secretase activity, rather than inhibiting it, is important for prevention of neurodegeneration.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/metabolismo , Células Cultivadas , Endossomos/fisiologia , Enzimas Conversoras de Endotelina , Humanos , Metaloendopeptidases/antagonistas & inibidores , Metaloendopeptidases/metabolismo , Modelos Biológicos , Proteólise
7.
Am J Geriatr Psychiatry ; 21(5): 474-83, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23570890

RESUMO

OBJECTIVES: To understand the cleavage of the amyloid ß protein (Aß) precursor (APP) by γ-secretase and to determine its changes in a representative familial Alzheimer disease (FAD) mutation. METHODS: Transfected cells expressing wild-type and FAD mutant APP were analyzed for changes in the levels of the major secreted Aß species and of the corresponding intracellular C-terminal APP fragments (APP intracellular domain, AICD) generated by γ-secretase, whereas radio-sequencing was used to precisely identify the resulting cleavage site(s). RESULTS: The AICD fragment(s) generated by γ-secretase cleavage comigrated in gels with a 50-residue synthetic peptide used as control, which is smaller than the 59 and 57 residues predicted from Aß ending at positions 40 (Aß40) and 42 (Aß42), respectively. In agreement with previous findings, an FAD mutant form of presenilin 1 (PS1-M139V) significantly increased the longer Aß42 while showing trends toward reducing Aß40. AICD levels were reduced by the mutation, suggesting that γ-secretase activity may be actually impaired by the mutation. Radiosequence analysis in cells expressing wild-type PS1 detected γ-secretase cleavage sites at the Aß peptide bond L(49)-V(50) to generate a 50-amino acid (aa) AICD fragment (AICD50) and the Aß peptide bond T(48)-L(49), generating an AICD of 51 aa (AICD51). No other cleavage sites were reliably detected. CONCLUSIONS: Based on findings that the FAD mutation that increases Aß42 also reduces AICD, we propose that γ-secretase activity is impaired by FAD mutations and predict that physiologic and environmental agents that inhibit γ-secretase will actually induce AD pathogenesis rather that prevent it. Furthermore, we propose that the cleavage site to generate AICD is naturally ragged and occurs predominantly at two sites 48 and 49 aa from the start of the Aß sequence. Thus, end specific antibodies to these two sites will need to be generated to study the quantitative relationships between these two cleavages in sporadic AD and FAD.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/química , Precursor de Proteína beta-Amiloide/metabolismo , Fragmentos de Peptídeos/química , Sequência de Aminoácidos , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animais , Células CHO , Cricetulus , Dados de Sequência Molecular , Mutação , Fragmentos de Peptídeos/metabolismo , Presenilina-1/genética , Presenilina-1/metabolismo
8.
J Neurochem ; 117(3): 359-74, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21320126

RESUMO

Current evidence suggests that Alzheimer's disease (AD) is a multi-factorial disease that starts with accumulation of multiple proteins. We have previously proposed that inhibition of γ-secretase may impair membrane recycling causing neurodegeneration starting at synapses (Sambamurti K., Suram A., Venugopal C., Prakasam A., Zhou Y., Lahiri D. K. and Greig N. H. A partial failure of membrane protein turnover may cause Alzheimer's disease: a new hypothesis. Curr. Alzheimer Res., 3, 2006, 81). We also proposed familal AD mutations increase Aß42 by inhibiting γ-secretase. Herein, we discuss the failure of Eli Lilly's γ-secretase inhibitor, semagacestat, in clinical trials in the light of our hypothesis, which extends the problem beyond toxicity of Aß aggregates. We elaborate that γ-secretase inhibitors lead to accumulation of amyloid precursor protein C-terminal fragments that can later be processed by γ-secretase to yields bursts of Aß to facilitate aggregation. Although we do not exclude a role for toxic Aß aggregates, inhibition of γ-secretase can affect numerous substrates other than amyloid precursor protein to affect multiple pathways and the combined accumulation of multiple peptides in the membrane may impair its function and turnover. Taken together, protein processing and turnover pathways play an important role in maintaining cellular homeostasis and unless we clearly see consistent disease-related increase in their levels or activity, we need to focus on preserving their function rather than inhibiting them for treatment of AD and similar diseases.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Inibidores Enzimáticos/uso terapêutico , Animais , Humanos
9.
J Med Chem ; 53(13): 4849-61, 2010 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-20527971

RESUMO

Our group has demonstrated that the amphiphilic character of alpha-phenyl-N-tert-butyl nitrone based agents is a key feature in determining their bioactivity and protection against oxidative toxicity. In this work, we report the synthesis of a new class of amphiphilic amide nitrones. Their hydroxyl radical scavenging activity and radical reducing potency were shown using ABTS competition and ABTS(+) reduction assays, respectively. Cyclic voltammetry was used to investigate their redox behavior, and the effects of the substitution of the PBN on the charge density of the nitronyl atoms, the electron affinity, and the ionization potential were computationally rationalized. The protective effects of amphiphilic amide nitrones in cell cultures exposed to oxidotoxins greatly exceeded those exerted by the parent compound PBN. They decreased electron and proton leakage as well as hydrogen peroxide formation in isolated rat brain mitochondria at nanomolar concentration. They also significantly enhanced mitochondrial membrane potential. Finally, dopamine-induced inhibition of complex I activity was antagonized by pretreatment with these agents. These findings indicate that amphiphilic amide nitrones are much more than just radical scavenging antioxidants but may act as a new class of bioenergetic agents directly on mitochondrial electron and proton transport.


Assuntos
Encéfalo/metabolismo , Mitocôndrias/metabolismo , Óxidos de Nitrogênio/química , Óxidos de Nitrogênio/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Tensoativos/farmacologia , Animais , Benzotiazóis/química , Encéfalo/efeitos dos fármacos , Depuradores de Radicais Livres/síntese química , Depuradores de Radicais Livres/química , Depuradores de Radicais Livres/farmacologia , Peróxido de Hidrogênio/química , Espectroscopia de Ressonância Magnética , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Óxidos de Nitrogênio/síntese química , Rotação Ocular , Oxirredução , Ratos , Ratos Sprague-Dawley , Espectrometria de Massas por Ionização por Electrospray , Ácidos Sulfônicos/química , Tensoativos/síntese química , Tensoativos/química
10.
PLoS One ; 5(4): e10206, 2010 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-20421998

RESUMO

Aging is a multi-factorial process, however, it is generally accepted that reactive oxygen species (ROS) are significant contributors. Mitochondria are important players in the aging process because they produce most of the cellular ROS. Despite the strength of the free-radical hypothesis, the use of free radical scavengers to delay aging has generated mixed results in vertebrate models, and clinical evidence of efficacy is lacking. This is in part due to the production of pro-oxidant metabolites by many antioxidants while scavenging ROS, which counteract their potentially beneficial effects. As such, a more effective approach is to enhance mitochondrial metabolism by reducing electron leakage with attendant reduction of ROS generation. Here, we report on the actions of a novel endogenous indole derivative, indolepropionamide (IPAM), which is similar in structure to melatonin. Our results suggest that IPAM binds to the rate-limiting component of oxidative phosphorylation in complex I of the respiratory chain and acts as a stabilizer of energy metabolism, thereby reducing ROS production. IPAM reversed the age-dependent decline of mitochondrial energetic capacity and increased rotifer lifespan, and it may, in fact, constitute a novel endogenous anti-aging substance of physiological importance.


Assuntos
Indóis/farmacologia , Longevidade/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Envelhecimento , Animais , Transporte de Elétrons , Metabolismo Energético , Fosforilação Oxidativa , Substâncias Protetoras , Espécies Reativas de Oxigênio , Roedores
11.
J Alzheimers Dis ; 20(4): 1243-53, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20413851

RESUMO

Amyloid-beta (Abeta) accumulates in several types of retinal degeneration and in Alzheimer's disease (AD), but its source has been unclear. We detected the neuronal 695 amino acid form of amyloid-beta protein precursor (AbetaPP) in the normal retina and AbetaPP751 in the retinal pigment epithelium (RPE) and anterior eye tissues. Similar to the brain, alpha- and beta-secretases cleaved AbetaPP to soluble derivatives (sAbetaPP) alpha or beta and membrane-bound C-terminal fragments alpha or beta in the retina and RPE. Levels of sAbetaPP were particularly high in the vitreous and low in aqueous humor revealing a molecular barrier for AbetaPP. In contrast, Abeta40 and Abeta42 levels were only 50% lower in the aqueous than the vitreous humor, indicating relatively barrier-free movement of Abeta. These studies demonstrated a relatively high yield of AbetaPP and Abeta in the ocular fluids, which may serve as a trackable marker for AD. In addition, failure of free clearance from the eye may trigger retina degeneration in a manner similar to Abeta-related neurodegeneration in AD.


Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Olho/metabolismo , Sequência de Aminoácidos , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Humor Aquoso/química , Humor Aquoso/metabolismo , Líquidos Corporais/metabolismo , Química Encefálica/fisiologia , Bovinos , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Cicloeximida/farmacologia , Ensaio de Imunoadsorção Enzimática , Olho/anatomia & histologia , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Inibidores da Síntese de Proteínas/farmacologia , Retina/metabolismo , Retina/patologia , Epitélio Pigmentado da Retina/efeitos dos fármacos , Epitélio Pigmentado da Retina/metabolismo , Corpo Vítreo/metabolismo
12.
Am J Med ; 123(3): 267-74, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20193836

RESUMO

OBJECTIVE: Hypercholesterolemia is an early risk factor for Alzheimer's disease. Low-density lipoprotein (LDL) receptors might be involved in this disorder. Our objective was to determine the risk of mild cognitive impairment in a population of patients with heterozygous familial hypercholesterolemia, a condition involving LDL receptor dysfunction and lifelong hypercholesterolemia. METHODS: By using a cohort study design, patients with familial hypercholesterolemia (N=47) meeting inclusion criteria and comparison patients without familial hypercholesterolemia (N=70) were consecutively selected from academic specialty and primary care clinics, respectively. All patients were older than 50 years. Those with disorders that could affect cognition, including history of stroke or transient ischemic attacks, were excluded from both groups. Thirteen standardized neuropsychologic tests were performed in all subjects. Mutational analysis was performed in patients with familial hypercholesterolemia, and brain imaging was obtained in those with familial hypercholesterolemia and mild cognitive impairment. RESULTS: Patients with familial hypercholesterolemia showed a high incidence of mild cognitive impairment compared with those without familial hypercholesterolemia (21.3% vs 2.9%; P=.00). This diagnosis was unrelated to structural pathology or white matter disease. There were significant differences, independent of apolipoprotein E4 or E2 status, between those with familial hypercholesterolemia and those with no familial hypercholesterolemia in several cognitive measures, all in the direction of worse performance for those with familial hypercholesterolemia. CONCLUSION: Because prior studies have shown that older patients with sporadic hypercholesterolemia do not show a higher incidence of mild cognitive impairment, the findings presented suggest that early exposure to elevated cholesterol or LDL receptor dysfunction may be risk factors for mild cognitive impairment.


Assuntos
Transtornos Cognitivos/epidemiologia , Hiperlipoproteinemia Tipo II/complicações , LDL-Colesterol/sangue , Cognição/fisiologia , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/etiologia , Feminino , Seguimentos , Humanos , Hiperlipoproteinemia Tipo II/sangue , Hiperlipoproteinemia Tipo II/epidemiologia , Incidência , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Receptores de Lipoproteínas/sangue , Estudos Retrospectivos , Fatores de Risco , Espanha/epidemiologia
13.
Exp Dermatol ; 19(1): 12-8, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19601981

RESUMO

Here, we examine the currently available information which supports that the adipokine, leptin, is a major player in the biology and pathology of mammalian skin and its appendages. Specifically, the potent metabolic effects of leptin and its mimetics may be utilized to improve, preserve and restore skin regeneration and hair cycle progression, and may halt or even partially reverse some aspects of skin ageing. Since leptin can enhance mitochondrial activity and biogenesis, this may contribute to the wound healing-promoting and hair growth-modulatory effects of leptin. Leptin dependent intracellular signalling by the Janus kinase 2 dependent signal transducer and activator of transcription 3, adenosine monophosphate kinase, and peroxisome proliferator-activated receptor (PPAR) gamma coactivator/PPAR converges to mediate mitochondrial metabolic activation and enhanced cell proliferation which may orchestrate the potent developmental, trophic and protective effects of leptin. Since leptin and leptin mimetics have already been clinically tested, investigative dermatology is well-advised to place greater emphasis on the systematic exploration of the cutaneous dimensions and dermatological potential of this pleiotropic hormone.


Assuntos
Cabelo/metabolismo , Leptina/metabolismo , Pele/metabolismo , Animais , Humanos , Transdução de Sinais , Neoplasias Cutâneas/metabolismo , Cicatrização
14.
Free Radic Res ; 43(2): 156-64, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19160110

RESUMO

Oxidative modifications are a hallmark of oxidative imbalance in the brains of individuals with Alzheimer's, Parkinson's and prion diseases and their respective animal models. While the causes of oxidative stress are relatively well-documented, the effects of chronically reducing oxidative stress on cognition, pathology and biochemistry require further clarification. To address this, young and aged control and amyloid-beta protein precursor-over-expressing mice were fed a diet with added R-alpha lipoic acid for 10 months to determine the effect of chronic antioxidant administration on the cognition and neuropathology and biochemistry of the brain. Both wild type and transgenic mice treated with R-alpha lipoic acid displayed significant reductions in markers of oxidative modifications. On the other hand, R-alpha lipoic acid had little effect on Y-maze performance throughout the study and did not decrease end-point amyloid-beta load. These results suggest that, despite the clear role of oxidative stress in mediating amyloid pathology and cognitive decline in ageing and AbetaPP-transgenic mice, long-term antioxidant therapy, at levels within tolerable nutritional guidelines and which reduce oxidative modifications, have limited benefit.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Antioxidantes/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Ácido Tióctico/farmacologia , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/biossíntese , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Análise de Variância , Animais , Cognição/efeitos dos fármacos , Modelos Animais de Doenças , Imuno-Histoquímica , Aprendizagem em Labirinto/efeitos dos fármacos , Camundongos , Camundongos Transgênicos
15.
Indian J Psychiatry ; 51 Suppl 1: S56-60, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21416019

RESUMO

Alzheimer's disease (AD) is characterized by progressive dementia and brain deposits of the amyloid ß protein (Aß) as senile plaques and the microtubule-associated protein, Tau, as neurofibrillary tangles (NFT). The current treatment of AD is limited to drugs that attempt to correct deficits in the cholinergic pathway or glutamate toxicity. These drugs show some improvement over a short period of time but the disease ultimately requires treatment to prevent and stop the neurodegeneration that affects multiple pathways. The currently favored hypothesis is that Aß aggregates to toxic forms that induce neurodegeneration. Drugs that reduce Aß successfully treat transgenic mouse models of AD, but the most promising anti-Aß vaccination approach did not successfully treat AD in a clinical trial. These studies suggest that AD pathogenesis is a complex phenomenon and requires a more broad-based approach to identify mechanisms of neurodegeneration. Multiple hypotheses have been proposed and the field is ready for a new generation of ideas to develop early diagnostic approaches and develop successful treatment plans.

17.
CNS Neurol Disord Drug Targets ; 7(3): 278-94, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18673212

RESUMO

The most popular current hypothesis is that Alzheimer's disease (AD) is caused by aggregates of the amyloid peptide (Abeta), which is generated by cleavage of the Abeta protein precursor (APP) by beta-secretase (BACE-1) followed by gamma-secretase. BACE-1 cleavage is limiting for the production of Abeta, making it a particularly good drug target for the generation of inhibitors that lower Abeta. A landmark discovery in AD was the identification of BACE-1 (a.k.a. Memapsin-2) as a novel class of type I transmembrane aspartic protease. Although BACE-2, a homologue of BACE-1, was quickly identified, follow up studies using knockout mice demonstrated that BACE-1 was necessary and sufficient for most neuronal Abeta generation. Despite the importance of BACE-1 as a drug target, development has been slow due to the incomplete understanding of its function and regulation and the difficulties in developing a brain penetrant drug that can specifically block its large catalytic pocket. This review summarizes the biological properties of BACE-1 and attempts to use phylogenetic perspectives to understand its function. The article also addresses the challenges in discovering a selective drug-like molecule targeting novel mechanisms of BACE-1 regulation.


Assuntos
Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/fisiologia , Ácido Aspártico Endopeptidases/química , Ácido Aspártico Endopeptidases/fisiologia , Evolução Biológica , Doença de Alzheimer/enzimologia , Secretases da Proteína Precursora do Amiloide/genética , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Ácido Aspártico Endopeptidases/genética , Humanos , Modelos Biológicos
19.
Neurochem Res ; 32(12): 2225-34, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17701350

RESUMO

The amyloid peptide (Abeta) deposited in Alzheimer's disease (AD) is generated by beta- and gamma-secretase processing of a larger integral membrane protein precursor (APP). Intramembrane processing of APP by gamma-secretase also yields an intracellular fragment, CTFgamma (a.k.a. AICD), which is highly conserved and is believed to regulate the transcription of several genes including KAI-1 and GSK3beta. The intracellular domain of APP is also processed by caspase to a 31 aa fragment that was shown to induce apoptosis by several groups. Although large quantities of CTFgamma are generated continuously by neurons, little if any is normally detected in cell lysates, which suggests that it is very rapidly turned over in vivo. Previous studies demonstrated that insulysin (IDE), an Abeta-degrading enzyme, is responsible for cytosol-mediated CTFgamma degradation in vitro. Consistent with this finding, knockout mice lacking IDE accumulate CTFgamma to detectable levels in the brain, although its levels remain lower than its precursor, suggesting that it continues to be turned over in the brain. Moreover, when we treated cultured cells with IDE inhibitors, we did not observe an increase in CTFgamma in cell lysates, suggesting that pathways other than IDE are also involved in CTFgamma turnover. To understand CTFgamma turnover further, we have mapped the IDE cleavage sites with the intention of mutating them to examine alternative pathways in future studies. Edman degradation revealed that IDE cleaves CTFgamma at multiple sites to small peptides ranging from 5 to 14 aa. The cleavage sites do not reveal the existence of any sequence specificity for IDE cleavage. Understanding the turnover mechanisms of CTFgamma is critical to the understanding of the signaling function of APP mediated by this fragment. The current study presents the interesting specificity of CTFgamma turnover by IDE, which has been previously identified as the major degrading enzyme for Abeta as well as CTFgamma. In addition, the study provides evidence for the presence of alternative CTFgamma-degrading pathways in the cell.


Assuntos
Precursor de Proteína beta-Amiloide/química , Citoplasma/química , Insulisina/química , Sequência de Aminoácidos , Animais , Células CHO , Cricetinae , Cricetulus , Feminino , Fluoresceínas , Corantes Fluorescentes , Camundongos , Dados de Sequência Molecular , Inibidores de Proteases/farmacologia , Coloração pela Prata , Especificidade por Substrato
20.
J Med Chem ; 50(17): 3976-9, 2007 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-17649989

RESUMO

A new series of hydrophilic, lipophilic, and amphiphilic alpha-phenyl-N-tert-butylnitrone (PBN) derivatives were synthesized to explore the relationship between their hydrophilic-lipophilic properties and antioxidant potency. Very potent protective effects of amphiphilic lactobionamide and tris(hydroxymethyl)aminomethane PBN derivatives were observed in mitochondrial preparations, in cell cultures, and in rotifers exposed to unspecific and mitochondria targeted oxidotoxins.


Assuntos
Antioxidantes/síntese química , Óxidos N-Cíclicos/química , Óxidos de Nitrogênio/síntese química , Animais , Antioxidantes/química , Antioxidantes/farmacologia , Células Cultivadas , Dissacarídeos/síntese química , Dissacarídeos/química , Dissacarídeos/farmacologia , Desenho de Fármacos , Complexo I de Transporte de Elétrons/metabolismo , Técnicas In Vitro , Óxidos de Nitrogênio/química , Óxidos de Nitrogênio/farmacologia , Ratos , Rotíferos/efeitos dos fármacos , Relação Estrutura-Atividade , Partículas Submitocôndricas/efeitos dos fármacos , Partículas Submitocôndricas/metabolismo , Trometamina/análogos & derivados , Trometamina/síntese química , Trometamina/química , Trometamina/farmacologia
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