Intranasal vitamin B12 administration in elderly patients: A randomized controlled comparison of two dosage regimens.

AIM: Vitamin B12 deficiency is common in the elderly population. Standard treatment via intramuscular injections, however, has several disadvantages. Safer and more convenient dosage forms such as intranasal are therefore being explored. This study compares the effects of two intranasal vitamin B12 dosage regimens in elderly vitamin B12-deficient patients. METHODS: Sixty patients ≥65 years were randomly assigned to either a loading dose (daily administration for 14 days followed by weekly administration) or a no loading dose (administration every 3 days) regimen for 90 days. Each dose contained 1000 µg cobalamin. Total vitamin B12, holotranscoblamin (holoTC), methylmalonic acid (MMA) and total homocysteine (tHcy) levels in serum were measured on days 0, 7, 14, 30, 60 and 90. RESULTS: Both dosage regimens resulted in a rapid increase of vitamin B12 and holoTC concentrations and normalization of initial high, MMA and tHcy concentrations. The loading dose regimen resulted in the fastest and greatest increase to a median vitamin B12 of 1090 pmol/L (reference 350-650 pmol/L) concentration after 14 days. Following weekly administration, B12 rapidly decreased to a median concentration of 530 pmol/L after 90 days. The no loading dose regimen resulted in a steady increase to a median vitamin B12 of 717 pmol/L after 90 days. CONCLUSIONS: Intranasal vitamin B12 administration is an effective and suitable way to replenish and sustain vitamin B12 levels in elderly patients.

Homocysteine induces glyceraldehyde-3-phosphate dehydrogenase acetylation and apoptosis in the neuroblastoma cell line Neuro2a

High plasma levels of homocysteine (Hcy) promote the progression of neurodegenerative diseases. However, the mechanism by which Hcy mediates neurotoxicity has not been elucidated. We observed that upon incubation with Hcy, the viability of a neuroblastoma cell line Neuro2a declined in a dose-dependent manner, and apoptosis was induced within 48 h. The median effective concentration (EC50) of Hcy was approximately 5 mM. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) nuclear translocation and acylation has been implicated in the regulation of apoptosis. We found that nuclear translocation and acetylation of GAPDH increased in the presence of 5 mM Hcy and that higher levels of acetyltransferase p300/CBP were detected in Neuro2a cells. These findings implicate the involvement of GAPDH in the mechanism whereby Hcy induces apoptosis in neurons. This study highlights a potentially important pathway in neurodegenerative disorders, and a novel target pathway for neuroprotective therapy.

Hyperhomocysteinemia and primary antiphospholipid syndrome / Hiper-homocisteinemia e síndrome antifosfolípide primária

OBJETIVOS: Investigar a prevalência de hiper-homocisteinemia e suas possíveis associações clínicas e laboratoriais em pacientes com síndrome antifosfolípide primária (SAFP). PACIENTES E MÉTODOS: Estudo transversal de 27 pacientes (88% mulheres) com SAFP (critérios de Sapporo). Foram avaliados dados demográficos, clínicos, comorbidades, medicações, anticorpos antifosfolípides, colhendo-se uma amostra de sangue para dosagem da homocisteína, pela técnica de cromatografia líquida de alta resolução. RESULTADOS: Seis (22%) dos 27 pacientes apresentaram níveis de homocisteinemia acima dos valores normais (98,7 ± 8,9 versus 8,0 ± 2,9 »M, P = 0,0008). Comparando-se o grupo de pacientes com hiper-homocisteinemia com aquele que apresentava níveis normais, verificou-se que ambos os grupos de pacientes com SAFP não diferiram estatisticamente em relação aos dados demográficos (idade, cor branca, peso, altura e índice de massa corporal), bem como ao tempo de duração de doença (64 ± 39,6 versus 77,9 ± 61,3 meses, P = 0,32). Nenhum dos grupos apresentou diferenças quanto às manifestações da doença (eventos arteriais, venosos e obstétricos, trombose venosa profunda, tromboembolismo pulmonar, plaquetopenia, infarto agudo do miocárdio, angina e acidente vascular cerebral), comorbidades (hipertensão arterial e dislipidemia), ao estilo de vida (atividade física e tabagismos atual e pregresso), bem como ao uso de medicações (corticoide atual e pregresso, estatina, cloroquina e ácido acetilsalicílico). A prevalência e os títulos de anticorpos anticardiolipina foram semelhantes em ambos os grupos. CONCLUSÃO: A hiper-homocisteinemia pode ser detectada em cerca de um quarto da população com SAFP, sem associação com características distintivas clínicas e laboratoriais dessa doença.

OBJECTIVES: The objective of this study was to investigate the prevalence of hyperhomocysteinemia and its possible clinical and laboratorial associations in patients with primary antiphospholipid syndrome (PAPS). PATIENTS AND METHODS: This is a transversal study with 27 patients (88 percent women) with PAPS (Sapporo criteria). Demographic and clinical data, as well as comorbidities, medications, antiphospholipid antibodies, and blood concentrations of homocysteine, measured by high resolution liquid chromatography, were evaluated. RESULTS: Six (22 percent) out of 27 patients had high levels of homocysteine (98.7 ± 8.9 versus 8.0 ± 2.9 »M, P = 0.0008). Comparison between the group of patients with hyperhomocysteinemia and the group of patients with normal serum homocysteine levels did not show differences in the demographic data (age, white, weight, height, and body mass index) or in the duration of the disease (64 ± 39.6 versus 77.9 ± 61.3 months, P = 0.32). Differences in disease manifestations (arterial, venous, and obstetric events, deep venous thrombosis, pulmonary thromboembolism, thrombocytopenia, acute myocardial infarction, angina, and stroke), comorbidities (hypertension and hyperlipidemia), life style (physical activity, past and present smoking), as well as the use of medications (past and present use of corticosteroids, statins, chloroquine, and acetylsalicylic acid), were not observed between both groups. The prevalence and titers of anticardiolipin antibodies were similar in both groups of patients. CONCLUSION: Hyperhomocysteinemia can be detected in approximately one fourth of the PAPS patients, and it is not associated with distinct clinical and laboratorial characteristics of this disorder.

Administración parenteral de homocisteína y efecto del ácido fólico en la formación de ateromas en conejos / Effects of administering parenteral homocysteine and oral folic acid on the development of atheromas in rabbits

La homocisteína ha sido asociada con enfermedad vascular prematura, pudiendo actuar sinérgicamente con otros factores de riesgo como los niveles elevados de colesterol y triglicéridos, así como deficiencia de vitaminas. El presente trabajo se planteó establecer el efecto de la administración de homocisteína por vía parenteral y del ácido fólico por vía oral en la formación de ateromas en conejos. Para ello se estudiaron 15 conejos de raza Nueva Zelanda provenientes del Bioterio de la Universidad de Carabobo divididos en tres grupos, los cuales fueron alimentados con el siguiente esquema: grupo 1: conejarina Protinal tipo A; Grupo 2: homocisteína por vía parenteral subcutánea durante 40 días; Grupo 3: homocisteína de la misma forma que el grupo 2 y ácido fólico por vía oral. Se realizaron determinaciones de los niveles séricos de colesterol, HDL-C, LDL-C, triglicéridos, ácido fólico y homocisteína antes y después del período experimental. Los conejos fueron sacrificados y se les extrajo el corazón y la aorta, con la finalidad de realizar cortes histológicos de los mismos. Los resultados obtenidos revelan que los niveles de homocisteína fueron más altos en el grupo 2 que en los obtenidos en el grupo 1, siendo esta diferencia significativa entre los dos grupos P(0.000), observándose en el grupo 2 los ateromas más graves de grado IV y V; en el grupo 3 se aprecia que los niveles de homocisteína no aumentan; los niveles de ácido fólico en este grupo fueron más altos comparados con los otros; en este grupo se observaron ateromas menos graves de grado I y III. Se evidenció una correlación baja positiva entre la variable homocisteína y el ácido fólico del grupo 3 (R= 0,292) y una correlación alta entre los lípidos en el grupo 2 y 3