Hemorrhagic Cerebrovascular Disease: An Unusual Presentation of Hyperhomocysteinemia / Accidente cerebrovascular hemorrágico: una inusual presentación de hiperhomocisteinemia / Acidente vascular cerebral hemorrágico: uma apresentação incomum da hiper-homocisteinemia

Introduction: Stroke is a major cause of morbidity and mortality worldwide, with hemorrhagic stroke being the deadliest form of acute stroke. Therefore, the cause of the event should be determined to direct the associated therapy and take preventive measures. Hyperhomocysteinemia has been described as a rare etiology of stroke. Although hyperhomocysteinemia has been associated with venous thrombotic events, altered endothelial function, and procoagulant states, its clinical role in stroke remains controversial. Case description: We present a case of a 60-year-old male patient with primary autoimmune hypothyroidism who presented with dysarthria, facial paresis, and left upper-limb monoparesis after sexual intercourse. A simple skull computed tomography scan showed hyperintensity in the right basal ganglion, indicating an acute hemorrhagic event. Etiological studies were performed, including ambulatory blood pressure monitoring, cerebral angiography, and transthoracic echocardiogram, which ruled out underlying vascular pathology. During follow-up, vitamin B12 deficiency and hyperhomocysteinemia were detected, without other blood biochemical profile alterations. Supplementation was initiated, and homocysteine levels gradually decreased, without new neurological deficits observed during follow-up. Conclusion: Quantification of homocysteine should be considered in patients with a cerebrovascular disease without apparent cause, as documenting hyperhomocysteinemia and correcting its underlying etiology are essential not only for providing appropriate management but also for preventing future events.

Introducción: el accidente cerebrovascular es una causa importante de morbilidad y mortalidad en todo el mundo, y el accidente cerebrovascular hemorrágico es la forma más mortífera de accidente cerebro- vascular agudo. La determinación de la causa del evento es esencial para dirigir la terapia asociada y poder tomar medidas preventivas. La hiperhomocisteinemia se ha descrito como una etiología poco frecuente de accidente cerebrovascular. Aunque esta se ha asociado con eventos trombóticos venosos, disfunción endotelial alterada y estados procoagulantes, sigue siendo controvertido su papel clínico en el accidente cerebrovascular. Descripción del caso: se presenta el caso de un hombre de 60 años con hipotiroidismo autoinmune primario que presentó disartria, paresia facial y monoparesia del miembro superior izquierdo después de un encuentro sexual. Una simple tomografía computarizada de cráneo mostró hipointensidad en la región del ganglio basal derecho, que indicaba un evento hemorrágico agudo. Se realizaron estudios etiológicos, incluyendo monitorización ambulatoria de la presión arterial, angiografía cerebral y ecocardiograma transtorácico, que descartaron patología vascular subyacente. Durante el seguimiento, se detectó deficiencia de vitamina B12 e hiperhomocisteinemia, sin otras alteraciones en el perfil bioquímico sanguíneo. Se inició la suplementación y los niveles de homocisteína disminuyeron gradualmente, sin observar nuevos déficits neurológicos durante el seguimiento. Conclusión: la cuantificación de homocisteína debe ser considerada en casos de enfermedad cerebrovascular sin causa aparente, dado que documentar la hiperhomocisteinemia y corregir su etiología subyacente es esencial no solo para proporcionar un manejo adecuado, sino también para prevenir eventos futuros.

Introdução: o acidente vascular cerebral (AVC) é uma das principais causas de morbidade e mortalidade em todo o mundo, sendo o AVC hemorrágico a forma mais letal de AVC agudo. A determinação da causa do evento é essencial para direcionar a terapia associada e poder tomar medidas preventivas. A hiperhomocisteinemia tem sido descrita como uma etiologia rara de acidente vascular cerebral. Embora a hiper-homocisteinemia tenha sido associada a eventos trombóticos venosos, disfunção endotelial alterada e estados pró-coagulantes, seu papel clínico no AVC permanece controverso. Descrição do caso: apresentamos o caso de um homem de 60 anos com hipotireoidismo autoimune primário que apresentou disartria, paresia facial e monoparesia do membro superior esquerdo após relação sexual. A tomografia computadorizada de crânio mostrou hipointensidade na região do gânglio da base direito, indicando evento hemorrágico agudo. Foram realizados estudos etiológicos, incluindo monitorização ambulatorial da pressão arterial, angiografia cerebral e ecocardiograma transtorácico, que descartaram patologia vascular subjacente. Durante o acompanhamento, foram detectados deficiência de vitamina B12 e hiper-homocistei- nemia, sem outras alterações no perfil bioquímico sanguíneo. A suplementação foi iniciada e os níveis de homocisteína diminuíram gradualmente, sem novos déficits neurológicos observados durante o acompanhamento. Conclusão: a quantificação da homocisteína deve ser considerada em casos de doença vascular cerebral sem causa aparente, pois documentar a hiper-homocisteinemia e corrigir sua etiologia subjacente é essencial não apenas para fornecer manejo adequado, mas também para prevenir eventos futuros.

Extraction-assisted voltammetric determination of homocysteine using magnetic nanoparticles modified with molecularly imprinted polymer.

A magnetic graphite-epoxy composite (m-GEC) electrochemical sensor is presented based on magnetic imprinted polymer (mag-MIP) to determine homocysteine (Hcy). Mag-MIP was synthesized via precipitation polymerization, using functionalized magnetic nanoparticles (Fe3O4) together with the template molecule (Hcy), the functional monomer 2-hydroxyethyl methacrylate (HEMA), and the structural monomer trimethylolpropane trimethacrylate (TRIM). For mag-NIP (magnetic non-imprinted polymer), the procedure was the same in the absence of Hcy. Morphological and structural properties of the resultant mag-MIP and mag-NIP were examined using TEM, FT-IR, and Vibrating Sample Magnetometer. Under optimized conditions, the m-GEC/mag-MIP sensor showed a linear range of 0.1-2 µmol L-1, with a limit of detection (LOD) of 0.030 µmol L-1. In addition, the proposed sensor responded selectively to Hcy compared to several interferents present in biological samples. The recovery values determined by differential pulse voltammetry (DPV) were close to 100% for natural and synthetic samples, indicating good method accuracy. The developed electrochemical sensor proves to be a suitable device for determining Hcy, with advantages related to magnetic separation and electrochemical analysis.

Nutritional Approaches to Modulate Cardiovascular Disease Risk in Systemic Lupus Erythematosus: A Literature Review.

Systemic lupus erythematosus (SLE) is a chronic pathology characterized by a bimodal mortality pattern attributed to clinical disease activity and cardiovascular disease (CVD). A complex interaction between traditional CVD risk factors such as obesity, dyslipidemia, smoking, insulin resistance, metabolic syndrome, and hypertension, as well as the presence of non-traditional CVD risk factors such as hyperhomocysteinemia, pro-inflammatory cytokines, and C-reactive protein levels, has been suggested as a cause of the high prevalence of CVD in SLE patients. On the other hand, environmental factors, such as nutritional status, could influence the disease's prognosis; several nutrients have immunomodulators, antioxidants, and anti-cardiometabolic risk properties which could reduce SLE severity and organ damage by decreasing the development of traditional and non-traditional CVD risk factors. Therefore, this critical literature review discusses the therapeutic potential of nutritional approaches that could modulate the development of the main comorbidities related to CVD risk in SLE patients.

Management of Hyperhomocysteinemia, Low Vitamin Levels, and Low Cortisol in Cannabis Users: A Report of 2 Cases.

Objective: The purpose of this study was to describe the management of 2 long-term users of cannabis with nutrition and psychotherapy. Clinical Features: A 28-year-old man presented with a medical history of asthma, depression, anxiety, and smoking, and was a long-term user of cannabis for 9 years (usually 3 times a week). A 39-year-old man presented with a medical history of anxiety and fatigue, and was a long-term user of cannabis for 14 years (usually twice a week). Laboratory tests showed altered blood levels of homocysteine, vitamins, and cortisol. Intervention and Outcome: Both patients were given supplements of vitamins (folic acid, methylcobalamin, and pyridoxine), vitamin D, Rhodiola rosea, and L-tyrosine. Psychotherapy also was provided to both patients. After 2 months of treatment, both patients improved and reduced their cannabis consumption. Conclusion: This study describes vitamin deficiencies, low cortisol levels, and hyperhomocysteinemia in 2 cannabis users who were managed with a combination of nutritional supplements and psychotherapy.

Rivastigmine Reverses the Decrease in Synapsin and Memory Caused by Homocysteine: Is There Relation to Inflammation?

Elevated levels of homocysteine (Hcy) in the blood, called hyperhomocysteinemia (HHcy), is a prevalent risk factor for it has been shown that Hcy induces oxidative stress and increases microglial activation and neuroinflammation, as well as causes cognitive impairment, which have been linked to the neurodegenerative process. This study aimed to evaluate the effect of mild hyperhomocysteinemia with or without ibuprofen and rivastigmine treatments on the behavior and neurochemical parameters in male rats. The chronic mild HHcy model was chemically induced in Wistar rats by subcutaneous administration of Hcy (4055 mg/kg body weight) twice daily for 30 days. Ibuprofen (40 mg/kg) and rivastigmine (0.5 mg/kg) were administered intraperitoneally once daily. Motor damage (open field, balance beam, rotarod, and vertical pole test), cognitive deficits (Y-maze), neurochemical parameters (oxidative status/antioxidant enzymatic defenses, presynaptic protein synapsin 1, inflammatory profile parameters, calcium binding adapter molecule 1 (Iba1), iNOS gene expression), and cholinergic anti-inflammatory pathway were investigated. Results showed that mild HHcy caused cognitive deficits in working memory, and impaired motor coordination reduced the amount of synapsin 1 protein, altered the neuroinflammatory picture, and caused changes in the activity of catalase and acetylcholinesterase enzymes. Both rivastigmine and ibuprofen treatments were able to mitigate this damage caused by mild HHcy. Together, these neurochemical changes may be associated with the mechanisms by which Hcy has been linked to a risk factor for AD. Treatments with rivastigmine and ibuprofen can effectively reduce the damage caused by increased Hcy levels.

The Role of High Concentrations of Homocysteine for the Development of Fetal Growth Restriction / O papel de altas concentrações de homocisteína para o desenvolvimento da restrição de crescimento fetal

Abstract Objective To assess homocysteine (Hcy) levels in the three trimesters of pregnancy in women with fetal growth restriction (FGR) and to evaluate the role of Hcy as a possible predictor of FGR. Methods A total of 315 singleton pregnant women were included in the present prospective cohort study and were monitored since the 1st trimester of pregnancy before delivery. Newborns were monitored for the first 7 days of life. Patients who had risk factors for FGR were excluded. Fetal growth restriction was defined according to uterine fundal height (< 10 percentile), ultrasound fetometry (< 5 percentile), and anthropometry of newborns (<5 percentile). The concentrations of Hcy were detected at between 10 and 14, between 20 and 24, and between 30 and 34 weeks of pregnancy by enzyme-linked immunosorbent assay (ELISA). Receiver operating characteristics (ROC) curve test and diagnostic odds ratio (DOR) were performed to evaluate the results of ELISA. Results The concentration of Hcy in patients with FGR was 19.65 umol/L at between 10 and 14 weeks, compared with 9.28 umol/L in patients with normal fetal growth (p<0.0001). The optimal cut-off level for Hcy in the 1st trimester of pregnancy was>13.9 umol/L with AUC 0.788, sensitivity of 75%, specificity of 83.6%, and DOR of 15.2. Conclusion Assessment of serum Hcy concentration may be used as a predictor of FGR, with the highest diagnostic utility in the 1st trimester of pregnancy.

Resumo Objetivo Avaliar os níveis de homocisteína (Hcy) em três trimestres da gravidez em mulheres com restrição de crescimento fetal (FGR, na sigla em inglês) e avaliar o papel da Hcy como possível preditor de FGR. Métodos Um total de 315 gestantes solteiras foram incluídas no presente estudo de coorte prospectivo e monitoradas desde o 1° trimestre de gravidez antes do parto. Os recém-nascidos foram acompanhados durante os primeiros 7 dias de vida. Pacientes que apresentam fatores de risco para FGR foram excluídos. A FGR foi definida de acordo com a altura do fundo do útero (< percentil 10), ultrassonografia fetometria (< percentil 5) e antropometria dos recém-nascidos (< percentil 5). As concentrações de Hcy foram detectadas entre 10 e 14, entre 20 e 24 e entre 30 e 34 semanas de gravidez por ensaio de imunoabsorção enzimática (ELISA, na sigla em inglês). O teste da curva das características de operação do receptor (ROC, na sigla em inglês) e a razão de chances de diagnóstico (DOR, na sigla em inglês) foram realizados para avaliar os resultados do ELISA. Resultados A concentração de Hcy em pacientes com FGR foi de 19,65 umol/L entre 10 e 14 semanas, em comparação com 9,28 umol/L em pacientes com crescimento fetal normal (p<0,0001). O nível de corte ideal para Hcy no 1° trimestre da gravidez foi>13,9 umol/L com AUC 0,788, sensibilidade de 75%, especificidade de 83,6%, e DOR 15,2. Conclusão A avaliação da concentração sérica de Hcy pode ser usada como um preditor de FGR, com maior utilidade diagnóstica no 1° trimestre de gravidez.

Anthropometric, biochemical, and haematological indicators associated with hyperhomocysteinemia and their relation to global DNA methylation in a young adult population.

Increased homocysteine (Hcy) levels have been associated with a higher risk of cardiovascular and neurodegenerative diseases. Passive DNA demethylation has been suggested as one of the mechanisms implicated in the development of these conditions, and most studies have investigated this relationship in older adult populations. Therefore, this study aimed to evaluate the relationship between corporal composition and biochemical and haematological indicators with plasma homocysteine levels and genome-wide methylation (Alu, LINE-1, and SAT2) in a population of healthy young adults (median age, 18 years). We showed that the prevalence of hyperhomocysteinemia was significantly higher in men (18.5%) than in women (6.6%) (P = 0.034). Increased Hcy level was substantially associated with higher levels of body mass index and visceral fat in females, whereas in males, it was significantly associated with reduced red cell distribution width and high-density lipoprotein (HDL) cholesterol (HDL-C) levels and increased low-density lipoprotein/HDL ratio. Hypomethylation of Alu was significantly associated with reduced levels of HDL-C (<40.0 mg dL-1), whereas hypomethylation of LINE-1 and SAT2 was significantly associated with higher levels of skeletal muscle (<39.3%) in males. These results highlight the participation of hormonal factors in regulating Hcy metabolism, primarily in the female population, whereas changes in DNA methylation observed in males might be associated with the consumption of a protein diet with high levels of methionine, independent of increased Hcy levels.

Mild Hyperhomocysteinemia Causes Anxiety-like Behavior and Brain Hyperactivity in Rodents: Are ATPase and Excitotoxicity by NMDA Receptor Overstimulation Involved in this Effect?

Mild hyperhomocysteinemia is a risk factor for psychiatric and neurodegenerative diseases, whose mechanisms between them are not well-known. In the present study, we evaluated the emotional behavior and neurochemical pathways (ATPases, glutamate homeostasis, and cell viability) in amygdala and prefrontal cortex rats subjected to mild hyperhomocysteinemia (in vivo studies). The ex vivo effect of homocysteine on ATPases and redox status, as well as on NMDAR antagonism by MK-801 in same structures slices were also performed. Wistar male rats received a subcutaneous injection of 0.03 µmol Homocysteine/g of body weight or saline, twice a day from 30 to 60th-67th days of life. Hyperhomocysteinemia increased anxiety-like behavior and tended to alter locomotion/exploration of rats, whereas sucrose preference and forced swimming tests were not altered. Glutamate uptake was not changed, but the activities of glutamine synthetase and ATPases were increased. Cell viability was not altered. Ex vivo studies (slices) showed that homocysteine altered ATPases and redox status and that MK801, an NMDAR antagonist, protected amygdala (partially) and prefrontal cortex (totally) effects. Taken together, data showed that mild hyperhomocysteinemia impairs the emotional behavior, which may be associated with changes in ATPase and glutamate homeostasis, including glutamine synthetase and NMDAR overstimulation that could lead to excitotoxicity. These findings may be associated with the homocysteine risk factor on psychiatric disorders development and neurodegeneration.

The Relationship of Circulating Homocysteine with Fibrinogen, Blood Pressure, and Other Cardiovascular Measures in African Adolescents.

OBJECTIVES: To evaluate the associations between homocysteine (Hcy) and cardiovascular health in South African adolescents. STUDY DESIGN: Circulating Hcy concentrations of 172 South African adolescents (105 girls, ages 13 to <18 years) were measured. Anthropometric and cardiovascular factors were also included and cross-sectionally analyzed through general linear models. RESULTS: Hcy correlated positively with body weight (P = .03; after adjusting for multiple testing, it was not regarded as significant) and muscle mass (P = .01), but negatively with fibrinogen concentrations (P = .001). Across Hcy tertiles, blood pressure produced approximating U-shaped curves, with differences between the middle and upper tertiles (all P < .02). Forty percent of the adolescents had elevated blood pressure, of whom 37% fell in the lowest and 38% in the highest Hcy tertiles. Hcy differed between the sexes (with boys having higher Hcy), but not between subgroups based on puberty, weight, stunting, smoking, or alcohol consumption. CONCLUSIONS: Both high and low Hcy could be early contributing risk factors to cardiovascular health. The associations between Hcy and blood pressure suggest that dietary and lifestyle manipulation, to achieve the optimal range of Hcy, may be beneficial in preventing Hcy-related hypertension in adulthood. The inverse relationship between Hcy and fibrinogen remains to be clarified.

Hyperhomocysteinemia alters cytokine gene expression, cytochrome c oxidase activity and oxidative stress in striatum and cerebellum of rodents.

AIMS: Homocysteine has been linked to neurodegeneration and motor function impairments. In the present study, we evaluate the effect of chronic mild hyperhomocysteinemia on the motor behavior (motor coordination, functional performance, and muscular force) and biochemical parameters (oxidative stress, energy metabolism, gene expression and/or protein abundance of cytokine related to the inflammatory pathways and acetylcholinesterase) in the striatum and cerebellum of Wistar male rats. MAIN METHODS: Rodents were submitted to one injection of homocysteine (0.03 µmol Hcy/g of body weight) between 30th and 60th postnatal days twice a day. After hyperhomocysteinemia induction, rats were submitted to horizontal ladder walking, beam balance, suspension, and vertical pole tests and/or euthanized to brain dissection for biochemical and molecular assays. KEY FINDINGS: Chronic mild hyperhomocysteinemia did not alter motor function, but induced oxidative stress and impaired mitochondrial complex IV activity in both structures. In the striatum, hyperhomocysteinemia decreased TNF-α gene expression and increased IL-1ß gene expression and acetylcholinesterase activity. In the cerebellum, hyperhomocysteinemia increased gene expression of TNF-α, IL-1ß, IL-10, and TGF-ß, while the acetylcholinesterase activity was decreased. In both structures, hyperhomocysteinemia decreased acetylcholinesterase protein abundance without altering total p-NF-κB, NF-κB, Nrf-2, and cleaved caspase-3. SIGNIFICANCE: Chronic mild hyperhomocysteinemia compromises several biochemical/molecular parameters, signaling pathways, oxidative stress, and chronic inflammation in the striatum and cerebellum of rats without impairing motor function. These alterations may be related to the mechanisms in which hyperhomocysteinemia has been linked to movement disorders later in life and neurodegeneration.

Homocysteine and Gliotoxicity.

Homocysteine is a sulfur amino acid that does not occur in the diet, but it is an essential intermediate in normal mammalian metabolism of methionine. Hyperhomocysteinemia results from dietary intakes of Met, folate, and vitamin B12 and lifestyle or from the deficiency of specific enzymes, leading to tissue accumulation of this amino acid and/or its metabolites. Severe hyperhomocysteinemic patients can present neurological symptoms and structural brain abnormalities, of which the pathogenesis is poorly understood. Moreover, a possible link between homocysteine (mild hyperhomocysteinemia) and neurodegenerative/neuropsychiatric disorders has been suggested. In recent years, increasing evidence has emerged suggesting that astrocyte dysfunction is involved in the neurotoxicity of homocysteine and possibly associated with the physiopathology of hyperhomocysteinemia. This review addresses some of the findings obtained from in vivo and in vitro experimental models, indicating high homocysteine levels as an important neurotoxin determinant of the neuropathophysiology of brain damage. Recent data show that this amino acid impairs glutamate uptake, redox/mitochondrial homeostasis, inflammatory response, and cell signaling pathways. Therefore, the discussion of this review focuses on homocysteine-induced gliotoxicity, and its impacts in the brain functions. Through understanding the Hcy-induced gliotoxicity, novel preventive/therapeutic strategies might emerge for these diseases.

Vitamin B12 Supplementation and NT-proBNP Levels in COPD Patients: A Secondary Analysis of a Randomized and Controlled Study in Rehabilitation.

PURPOSE: There is evidence of complex interaction between vitamin B12 (vB12) level, hyperhomocysteinemia (HyCy), and natriuretic peptide secretion. Exercise training could also modulate such interaction. In this secondary analysis of a Randomized Clinical Trial performed in a chronic obstructive pulmonary disease (COPD) rehabilitation setting, our primary objective was to investigate the interaction between vB12 supplementation, exercise training, and changes in NT-proBNP levels after 8 weeks of intervention. Secondary objectives were to explore the correlations between acute changes in NT-proBNP levels with (i) acute exercise and (ii) oxygen uptake (V'O2) kinetics during rest-to-exercise transition. METHODS: Thirty-two subjects with COPD were randomized into four groups: Rehabilitation+vB12 (n = 8), Rehabilitation (n = 8), vB12 (n = 8), or Maltodextrin(n = 8). They were evaluated at baseline and after 8 weeks, during resting and immediately after maximal exercise constant work-rate tests (CWTs, Tlim), for NT-proBNP plasmatic levels. RESULTS: After interaction analysis, the supplementation with vB12 significantly changed the time course of NT-proBNP responses during treatment (p = 0.048). However, the final analysis could not support a significant change in NT-proBNP levels owing to high-intensity constant work-rate exercise (p-value > 0.05). There was a statistically significant correlation between V'O2 time constant and ΔNT-proBNP values (Tlim - rest) at baseline (p = 0.049) and 2 months later (p = 0.015), considering all subjects (n = 32). CONCLUSION: We conclude that vB12 supplementation could modulate NT-proBNP secretion. Moreover, possibly, the slower the initial V'O2 adjustments toward a steady-state during rest-to-exercise transitions, the more severe the ventricular chamber volume/pressure stress recruitment, expressed through higher NT-proBNP secretion in subjects with larger V'O2 time constants, despite unchanged final acute exercise-induced neurohormone secretion.

Hormetic-Like Effects of L-Homocysteine on Synaptic Structure, Function, and Aß Aggregation.

Alzheimer's Disease (AD) is the primary cause of dementia among the elderly population. Elevated plasma levels of homocysteine (HCy), an amino acid derived from methionine metabolism, are considered a risk factor and biomarker of AD and other types of dementia. An increase in HCy is mostly a consequence of high methionine and/or low vitamin B intake in the diet. Here, we studied the effects of physiological and pathophysiological HCy concentrations on oxidative stress, synaptic protein levels, and synaptic activity in mice hippocampal slices. We also studied the in vitro effects of HCy on the aggregation kinetics of Aß40. We found that physiological cerebrospinal concentrations of HCy (0.5 µM) induce an increase in synaptic proteins, whereas higher doses of HCy (30-100 µM) decrease their levels, thereby increasing oxidative stress and causing excitatory transmission hyperactivity, which are all considered to be neurotoxic effects. We also observed that normal cerebrospinal concentrations of HCy slow the aggregation kinetic of Aß40, whereas high concentrations accelerate its aggregation. Finally, we studied the effects of HCy and HCy + Aß42 over long-term potentiation. Altogether, by studying an ample range of effects under different HCy concentrations, we report, for the first time, that HCy can exert beneficial or toxic effects over neurons, evidencing a hormetic-like effect. Therefore, we further encourage the use of HCy as a biomarker and modifiable risk factor with therapeutic use against AD and other types of dementia.

Deficiencia de cobalamina C de inicio temprano: presentación de caso clínico / Early onset cobalamin C deficiency: clinical case presentation

Cobalamin C (CblC) deficiency is an autosomal recessive disorder caused by mutations of the MMACHC gene that results in impaired synthesis of the methylcobalamin and adenosylcobalamin co-factors. This brings an impaired conversion of dietary cobalamin and therefore dysfunction of two key enzymes generating hyperhomocysteinemia, hypometionimemia and methylmalonic aciduria. It is the most common intracellular metabolism disorder of cobalamin. The early clinical form is the most frequent disorder and appears as a multisystemic disease with developmental delay, failure to thrive, and ocular, renal and hematological involvement during the first year of life. The thromboembolic events are associated with small vessel involvement, generating thrombotic microangiopathy responsible for renal involvement and pulmonary thromboembolism. The late-onset form is characterized by leukoencephalopathy, psychiatric disorders, subacute degeneration of the spinal cord, and thromboembolic events of medium to large vessels. The treatment currently available increases the survival of the patient and improves growth, neurological manifestations, biochemical, hematological profile and hydrocephalus. We present the neonatal debut of a case of CblC deficiency that appeared as a multisystem disease with initial neurological, ocular and hematological manifestations. The onset of symptoms was acute, a characteristic that is not frequent in CblC. The patient started treatment early, but in an unsatisfactory fashion, which led to increased neurological deterioration. Due to MRI images performed during the evolution of his condition, a superior and transverse sagittal sinus thrombosis, a rare manifestation of the disease, was observed.

La deficiencia de cobalamina C (CblC) es un defecto autosómico recesivo causado por la mutación del gen MMACHC, que resulta en la síntesis alterada de los cofactores metilcobalamina y adenosilcobalamina. Esto trae aparejado una disfunción de dos enzimas claves, lo cual genera hiperhomocisteinemia, hipometionimemia y aciduria metilmalónica. La presentación clínica de la deficiencia de CblC es heterogénea, y varía desde las formas de inicio temprano graves y potencialmente mortales, hasta los fenotipos más leves de inicio tardío. La forma clínica temprana es la más frecuente y se manifiesta como una enfermedad multisistémica, con restricción del desarrollo, restricción del crecimiento y alteraciones oculares, renales y hematológicas durante el primer año de vida. Las manifestaciones tromboembólicas están asociadas con el compromiso de pequeños vasos, lo que causa microangiopatía trombótica, responsable de compromiso renal y de tromboembolismo pulmonar. La forma tardía se caracteriza por leucoencefalopatía, trastornos psiquiátricos, degeneración subaguda de la médula espinal y eventos tromboembólicos de medianos o grandes vasos. El tratamiento disponible actualmente aumenta la supervivencia de la enfermedad y mejora el crecimiento, las manifestaciones neurológicas, el perfil bioquímico y hematológico y la hidrocefalia. Presentamos el debut neonatal de un caso de deficiencia de CblC que se manifestó con compromiso inicial neurológico, ocular y hematológico. El comienzo de los síntomas fue agudo, característica que no es frecuente en la deficiencia de CblC. El tratamiento se inició tempranamente, pero en forma insatisfactoria, con evolución de deterioro neurológico. En la evolución de su enfermedad en las imágenes de resonancia magnética, se puso de manifiesto trombosis de los senos sagital superior y transversos, una rara manifestación de la deficiencia de CblC.

Ly6C+ Inflammatory Monocyte Differentiation Partially Mediates Hyperhomocysteinemia-Induced Vascular Dysfunction in Type 2 Diabetic db/db Mice.

OBJECTIVE: Hyperhomocysteinemia (HHcy) is a potent risk factor for diabetic cardiovascular diseases. We have previously reported that hyperhomocysteinemia potentiates type 1 diabetes mellitus-induced inflammatory monocyte differentiation, vascular dysfunction, and atherosclerosis. However, the effects of hyperhomocysteinemia on vascular inflammation in type 2 diabetes mellitus (T2DM) and the underlying mechanism are unknown. Approach and Results: Here, we demonstrate that hyperhomocysteinemia was induced by a high methionine diet in control mice (homocysteine 129 µmol/L), which was further worsened in T2DM db/db mice (homocysteine 180 µmol/L) with aggravated insulin intolerance. Hyperhomocysteinemia potentiated T2DM-induced mononuclear cell, monocyte, inflammatory monocyte (CD11b+Ly6C+), and M1 macrophage differentiation in periphery and aorta, which were rescued by folic acid-based homocysteine-lowering therapy. Moreover, hyperhomocysteinemia exacerbated T2DM-impaired endothelial-dependent aortic relaxation to acetylcholine. Finally, transfusion of bone marrow cells depleted for Ly6C by Ly6c shRNA transduction improved insulin intolerance and endothelial-dependent aortic relaxation in hyperhomocysteinemia+T2DM mice. CONCLUSIONS: Hyperhomocysteinemia potentiated systemic and vessel wall inflammation and vascular dysfunction partially via inflammatory monocyte subset induction in T2DM. Inflammatory monocyte may be a novel therapeutic target for insulin resistance, inflammation, and cardiovascular complications in hyperhomocysteinemia+T2DM.

Exposure to homocysteine leads to cell cycle damage and reactive gliosis in the developing brain.

Studies that investigate the cellular effects of homocysteine (Hcy) on the differentiation of neural cells, and their involvement in establishment of cell layers in the developing brain are scarce. This study evaluated how Hcy affects the neural cell cycle and proteins involved in neuronal differentiation in the telencephalon and mesencephalon using the chicken embryo as a model. Embryos at embryonic day 2 (E2) received 20 µmol D-L Hcy/50 µl saline and analyzed at E6. The Hcy treatment induced an increase in the ventricular length of the telencephalon and also a reduction of the mantle layer thickness. We observed that Hcy induced impairments to the neural cell cycle and differentiation, which compromised the cell layers establishment in the developing brain. Hcy treatment also induced changes in gene and protein expression of astrocytes, characteristic of reactive gliosis. Our results point to new perspectives of evaluation of cellular targets of Hcy toxicity.

Chronic mild Hyperhomocysteinemia impairs energy metabolism, promotes DNA damage and induces a Nrf2 response to oxidative stress in rats brain.

Homocysteine (HCY) has been linked to oxidative stress and varied metabolic changes that are dependent on its concentration and affected tissues. In the present study we evaluate parameters of energy metabolism [succinate dehydrogenase (SDH), complex II and IV (cytochrome c oxidase), and ATP levels] and oxidative stress [DCFH oxidation, nitrite levels, antioxidant enzymes and lipid, protein and DNA damages, as well as nuclear factor erythroid 2-related (Nrf2) protein abundance] in amygdala and prefrontal cortex of HCY-treated rats. Wistar male rats were treated with a subcutaneous injection of HCY (0.03 µmol/g of body weight) from the 30th to 60th post-natal day, twice a day, to induce mild hyperhomocysteinemia (HHCY). The rats were euthanatized without anesthesia at 12 h after the last injection, and amygdala and prefrontal cortex were dissected for biochemical analyses. In the amygdala, mild HHCY increased activities of SDH and complex II and decreased complex IV and ATP level, as well as increased antioxidant enzymes activities (glutathione peroxidase and superoxide dismutase), nitrite levels, DNA damage, and Nrf 2 protein abundance. In the prefrontal cortex, mild HHCY did not alter energy metabolism, but increased glutathione peroxidase, catalase and DNA damage. Other analyzed parameters were not altered by HCY-treatment. Our findings suggested that chronic mild HHCY changes each brain structure, particularly and specifically. These changes may be associated with the mechanisms by which chronic mild HHCY has been linked to the risk factor of fear, mood disorders and depression, as well as in neurodegenerative diseases.

Impact of homocysteine on vasculogenic factors and bone formation in chicken embryos.

Developmental endochondral ossification requires constant blood supply, which is provided by the embryonic vascular network. High levels of homocysteine (Hcy) have vasculotoxic properties, but it remains unclear how Hcy disrupts blood vessel formation in endochondral ossification. Thus, we investigated the toxicity of Hcy on contents of vasculogenic factors (VEGF, VCAM-1, NOS3) and osteocalcin, using developing limbs as model. Chicken embryos were submitted to treatment with 20 µmol D-L Hcy at 12H&H and the analyses occur at 29H&H and 36H&H. We did not identify differences in the area of limb ossification in Hcy-treated (7.5 × 105 µm2 ± 3.9 × 104) and untreated embryos (7.6 × 105 µm2 ± 3.3 × 104) at 36H&H. In Hcy-treated embryos, we observed a significantly decrease of 46.8% at 29H&H and 26.0% at 36H&H in the number of VEGF-reactive cells. Also, treated embryos showed decrease of 98.7% in VCAM-1-reactive cells at 29H&H and 34.6% at 36H&H. The number of NOS3-reactive cells was reduced 54.0% at 29H&H and 91.5% at 36H&H, in the limbs of Hcy-treated embryos. Finally, in Hcy-treated embryos at 36H&H, we observed a reduction of 58.86% in the number of osteocalcin-reactive cells. Here, we demonstrated for the first time that the toxicity of Hcy is associated with a reduction in the contents of proteins involved in blood vessel formation and bone mineralization, which interferes with endochondral ossification of the limb during embryonic development. Graphical abstract.

Secondary hyperhomocysteinemia-related occlusive retinal vasculopathy: A case report.

PURPOSE: To report a case of occlusive retinal vasculopathy, secondary to hyperhomocysteinemia. OBSERVATIONS: A 43-year-old male was examined at the retina outpatient clinic due to complaints of bilateral decrease in visual acuity. The patient underwent a comprehensive ophthalmological examination, wide-field fundus photographs and fluorescein angiography, as well as spectral domain optical coherence tomography with enhanced-deep imaging. The patient had a significant medical history of chronic kidney disease and progressive bilateral vision loss over the last two years, which worsened in the left eye during the past 3 months. Fundus examination revealed a vitreous hemorrhage in the left eye and bilateral proliferative retinopathy. Blood glucose and systemic blood pressure were unremarkable. Plasma homocysteine was reported at >500 µmol/L, which is higher than the corrected reference range by age. CONCLUSION AND IMPORTANCE: Hyperhomocysteinemia is a rare but well-known disease, capable of accelerating atherosclerotic disease and generating a prothrombotic state that can lead to multiple systemic complications. Despite its low incidence, the disease should be part of the differential diagnosis in patients with bilateral proliferative retinopathy, in the absence of diabetes mellitus and systemic hypertension.

Modification of erythropoietin structure by N-homocysteinylation affects its antiapoptotic and proliferative functions.

Many patients under therapy with recombinant human erythropoietin (rhuEPO) show resistance to the treatment, an effect likely associated with the accumulation of tissue factors, especially in renal and cardiovascular diseases. Hyperhomocysteinemia due to high serum levels of homocysteine has been suggested among the risk factors in those pathologies. Its main effect is the N-homocysteinylation of proteins due to the interaction between the highly reactive homocysteine thiolactone (HTL) and lysine residues. The aim of this study was to evaluate the effect of N-homocysteinylation on the erythropoietic and antiapoptotic abilities of EPO, which can be a consequence of structural changes in the modified protein. We found that both cellular functions were altered in the presence of HTL-EPO. A decreased net positive charge of HTL-EPO was detected by capillary zone electrophoresis, while analysis of polyacrylamide gel electropherograms suggested formation of aggregates. Far-UV spectra, obtained by Circular Dichroism Spectroscopy, indicated a switch of the protein's secondary structure from α-helix to ß-sheet structures. Results of Congo red and Thioflavin T assays confirm the formation of repetitive ß-sheet structures, which may account for aggregates. Accordingly, Dynamic Light Scattering analysis showed a markedly larger radius of the HTL-EPO structures, supporting the formation of soluble oligomers. These structural changes might interfere with the conformational adaptations necessary for efficient ligand-receptor interaction, thus affecting the proliferative and antiapoptotic functions of EPO. The present findings may contribute to explain the resistance exhibited by patients with cardio-renal syndrome to treatment with rhuEPO, as a consequence of structural modifications due to protein N-homocysteinylation.