RESUMO
Hypomagnesaemia (grass tetany) is a metabolic disorder of ruminants due to a reduced dietary intake of magnesium (primary deficiency), incorrect digestibility or associated metabolic factors reducing Mg intake (secondary deficiency). Grass tetany is a production disease responsible for important economic losses in beef herds from Argentina. Several factors influence the development of grass tetany in cattle, including physiological status, weather, soil and forage. This research described a retrospective analysis over the past 20 years, revising the cases of beef cattle clinical hypomagnesaemia registered at the Veterinary Diagnostic Service in INTA Balcarce, Argentina.
Hipomagnesemia é um distúrbio metabólico de ruminantes devido a uma redução na absorção de magnésio (deficiência primária), digestibilidade incorreta ou fatores metabólicos associados que reduzem a ingestão de Mg (deficiência secundária). Hipomagnesemia é uma doença de produção responsável por importantes perdas econômicas em rebanhos de corte da Argentina. Vários fatores influenciam o desenvolvimento da hipomagnesemia em bovinos, incluindo fatores fisiológicos, clima, solo e forragem. Este trabalho descreve uma análise retrospectiva dos últimos 20 anos, revisando os casos de hipomagnesemia clínica em bovinos de corte registrados no Serviço de Diagnóstico Veterinário do INTA Balcarce, Argentina.
Assuntos
Animais , Bovinos , Doenças dos Bovinos/sangue , Doenças dos Bovinos/epidemiologia , Deficiência de Minerais , Deficiência de Magnésio/metabolismo , Estudos RetrospectivosRESUMO
In dairy farming, cows display important metabolic changes during the transition period, particularly high-production cows, which need nutrients in greater quantity to meet the required demand. The aim of this study was to determine the prevalence of subclinical hypomagnesemia in pre- and post-partum dairy cows inserted in milk-production systems in the Sousa microregion and the district of São João do Rio do Peixe, both in the State of Paraíba, Brazil. As such, visits were made every two weeks to 34 rural properties, where the team collected 357 blood samples by venepuncture, 106 from pre-partum lactating cows and 251 from lactating cows in the post-partum period. It was found that the properties supplied three types of mineral supplement: a single supplement of NaCl, a supplement of NaCl + mineral base, and a commercial supplement. The cows receiving the commercial mineral supplement had the highest prevalence (10.53%) of the disorder, even showing a significant difference (P < .05) between the other types of supplement. In relation to reproductive period, it was found that the post-partum cows had a higher prevalence of subclinical hypomagnesemia (9.96%) than did the pre-partem cows (8.49%); there was, however, no significant difference (P > .05) between the two. Studies such as this are fundamental for alerting rural and technical producers to the occurrence of subclinical hypomagnesemia in the region, in addition to the damage caused by metabolic disorders.(AU)
Na bovinocultura leiteira, as vacas apresentam mudanças metabólicas importantes durante o período de transição, principalmente aquelas de alta produção, que necessitam de nutrientes em maior quantidade para suprir a demanda requerida. Este estudo teve como objetivo determinar a prevalência de hipomagnesemia subclínica no pré e pós-parto em vacas leiteiras inseridas em sistemas de produção de leite na microrregião de Sousa-PB e município de São João do Rio do Peixe-PB. Para isso foram realizadas visitas quinzenais a 34 propriedades rurais, onde a equipe coletou 357 amostras de sangue por meio de punção venosa, sendo 106 provenientes de vacas em lactação que se encontravam no período de pré-parto e 251 de vacas em lactação inseridas no período de pós-parto. Verificou-se que as propriedades forneciam três tipos de suplemento mineral: suplementação exclusiva com NaCl; suplementação com NaCl + núcleo mineral; e suplementação comercial. As vacas que recebiam a suplementação mineral do tipo comercial corresponderam aquelas com maior prevalência (10,53%) de ocorrência do distúrbio, apresentando ainda diferença significativa (P < 0,05) entre as demais formas de suplementação. Em relação ao período reprodutivo em que as vacas se encontravam, notou- se que aquelas do pós-parto apresentaram maior prevalência de hipomagnesemia subclínica (9,96%) em relação às vacas do pré-parto (8,49%). Porém não houve diferença significative (P > 0,05) entre ambas. Estudos como esse tornam-se fundamentais para alertar produtores rurais e técnicos sobre a ocorrência da hipomagnesemia subclínica na região, além dos prejuízos que os distúrbios metabólicos acarretam.(AU)
Assuntos
Animais , Feminino , Bovinos , Deficiência de Magnésio/epidemiologia , Deficiência de Magnésio/etiologia , Deficiência de Magnésio/metabolismo , Deficiência de Magnésio/veterinária , Magnésio , Minerais na Dieta , BrasilRESUMO
In dairy farming, cows display important metabolic changes during the transition period, particularly high-production cows, which need nutrients in greater quantity to meet the required demand. The aim of this study was to determine the prevalence of subclinical hypomagnesemia in pre- and post-partum dairy cows inserted in milk-production systems in the Sousa microregion and the district of São João do Rio do Peixe, both in the State of Paraíba, Brazil. As such, visits were made every two weeks to 34 rural properties, where the team collected 357 blood samples by venepuncture, 106 from pre-partum lactating cows and 251 from lactating cows in the post-partum period. It was found that the properties supplied three types of mineral supplement: a single supplement of NaCl, a supplement of NaCl + mineral base, and a commercial supplement. The cows receiving the commercial mineral supplement had the highest prevalence (10.53%) of the disorder, even showing a significant difference (P .05) between the two. Studies such as this are fundamental for alerting rural and technical producers to the occurrence of subclinical hypomagnesemia in the region, in addition to the damage caused by metabolic disorders.
Na bovinocultura leiteira, as vacas apresentam mudanças metabólicas importantes durante o período de transição, principalmente aquelas de alta produção, que necessitam de nutrientes em maior quantidade para suprir a demanda requerida. Este estudo teve como objetivo determinar a prevalência de hipomagnesemia subclínica no pré e pós-parto em vacas leiteiras inseridas em sistemas de produção de leite na microrregião de Sousa-PB e município de São João do Rio do Peixe-PB. Para isso foram realizadas visitas quinzenais a 34 propriedades rurais, onde a equipe coletou 357 amostras de sangue por meio de punção venosa, sendo 106 provenientes de vacas em lactação que se encontravam no período de pré-parto e 251 de vacas em lactação inseridas no período de pós-parto. Verificou-se que as propriedades forneciam três tipos de suplemento mineral: suplementação exclusiva com NaCl; suplementação com NaCl + núcleo mineral; e suplementação comercial. As vacas que recebiam a suplementação mineral do tipo comercial corresponderam aquelas com maior prevalência (10,53%) de ocorrência do distúrbio, apresentando ainda diferença significativa (P 0,05) entre ambas. Estudos como esse tornam-se fundamentais para alertar produtores rurais e técnicos sobre a ocorrência da hipomagnesemia subclínica na região, além dos prejuízos que os distúrbios metabólicos acarretam.
Assuntos
Feminino , Animais , Bovinos , Deficiência de Magnésio/epidemiologia , Deficiência de Magnésio/etiologia , Deficiência de Magnésio/metabolismo , Deficiência de Magnésio/veterinária , Magnésio , Brasil , Minerais na DietaRESUMO
We sought to evaluate the effects of magnesium (Mg) intake deficiency on bone metabolism in rats with induced periodontal disease (PD). Holtzman rats were randomly divided into two groups: Control - animals fed a standard diet and test - animals fed a diet with 90% Mg deficiency. After 60 days on the diets, all animals received ligature on the lower left first molars to induce PD. Animals were euthanized after 30 days following ligature placement. Blood and urine were collected for determination of serum concentrations of Mg, calcium, osteocalcin (OCN), alkaline phosphatase and parathyroid hormone (PTH) by enzyme-linked immunosorbent assay, and the urinary concentration of deoxypyridinoline (DPD). Systemic bone mineral density (BMD), bone volume and architectural bone parameters were evaluated by micro-CT in L4 lumbar vertebrae and mandible. Tartrate-resistant acid phosphatase staining and immunohistochemical (IHC) analysis of inducible nitric oxide synthase (iNOS), Runt-related transcription factor 2 (RUNX2), CD86, CD80, proliferating cell nuclear antigen, vascular endothelial growth factor, OCN and osteopontin were investigated. Reverse-transcription polymerase chain reaction was employed to assess mRNA expression of receptor-activator of nuclear factor-kB ligand, osteoprotegerin (OPG) and interleukin (IL)-6. Mg deficiency was associated with higher concentrations of PTH and DPD, and significant decrease on both systemic and mandibular BMD, as well as greater severity of alveolar and trabecular bone loss. Significant increase in osteoclasts was observed in the test group with PD. IHC analysis showed significant increase in the expression of iNOS and decreased expression of OCN and RUNX2. Increased IL-6 mRNA and decreased OPG mRNA expressions were evidenced in the test group with PD. Mg deficiency caused systemic effects indicative of altered bone metabolism in the vertebrae and affected both immune and stromal cells, aggravating inflammatory bone resorption in the ligature-induced model of periodontitis.
Assuntos
Densidade Óssea , Reabsorção Óssea , Inflamação/metabolismo , Deficiência de Magnésio/metabolismo , Fosfatase Alcalina/metabolismo , Animais , Biomarcadores/metabolismo , Cálcio/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Interleucina-6/metabolismo , Magnésio/metabolismo , Osteocalcina/metabolismo , Osteoclastos/metabolismo , Hormônio Paratireóideo/metabolismo , Periodontite/metabolismo , RNA Mensageiro/metabolismo , Ratos , Microtomografia por Raio-XRESUMO
Adipose tissue is considered an endocrine organ that promotes excessive production of reactive oxygen species when in excess, thus contributing to lipid peroxidation. Magnesium deficiency contributes to the development of oxidative stress in obese individuals, as this mineral plays a role as an antioxidant, participates as a cofactor of several enzymes, maintains cell membrane stability and mitigates the effects of oxidative stress. The objective of this review is to bring together updated information on the participation of magnesium in the oxidative stress present in obesity. We conducted a search of articles published in the PubMed, SciELO and LILACS databases, using the keywords 'magnesium', 'oxidative stress', 'malondialdehyde', 'superoxide dismutase', 'glutathione peroxidase', 'reactive oxygen species', 'inflammation' and 'obesity'. The studies show that obese subjects have low serum concentrations of magnesium, as well as high concentrations of oxidative stress marker in these individuals. Furthermore, it is evident that the adequate intake of magnesium contributes to its appropriate homeostasis in the body. Thus, this review of current research can help define the need for intervention with supplementation of this mineral for the prevention and treatment of disorders associated with this chronic disease.
Assuntos
Deficiência de Magnésio/fisiopatologia , Magnésio/fisiologia , Obesidade/fisiopatologia , Estresse Oxidativo/fisiologia , Suplementos Nutricionais , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Magnésio/administração & dosagem , Magnésio/metabolismo , Deficiência de Magnésio/metabolismo , Deficiência de Magnésio/prevenção & controle , Malondialdeído/metabolismo , Modelos Biológicos , Obesidade/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismoRESUMO
The objective, with this study, was to investigate the consequences of subclinical hypomagnesemia on the metabolic parameters of dairy cows. Blood samples were collected from 12 animals every two days, between -22 pre and 22 days postpartum, for blood analysis and determining the metabolic profile. The animals were grouped according to magnesium blood concentrations: Hypomagnesemia group (n=5), with blood levels below 1.8 mg/dL in at least two consecutive days, and Control group (n=7), with blood levels above 1.8 mg/dL during the period. The hypomagnesemia group had higher levels of glucagon on days 10, 18 and 20 as well as glucagon/insulin ratio was higher on 6, 8, 10, 12 and 16 days after calving. The blood concentrations of aspartate aminotransferase in the hypomagnesemia group were higher during days 0, 6, 8, 10, 12 and 14 after calving. The results indicate that the low blood levels of magnesium during peripartum may be associated with elevated levels of aspartate amino transferase and glucagon in the blood. In general, subclinical hypomagnesemia does not alter the levels of indicators of energy metabolism, but the results show that cows with hypomagnesemia have a higher rate of glucagon/insulin, demonstrating a greater challenge to maintain glucose blood concentration.(AU)
O objetivo, com este estudo, foi investigar as conseqüências da hipomagnesemia subclínica sobre parâmetros metabólicos de vacas leiteiras. Amostras de sangue foram coletadas de 12 animais, a cada dois dias, entre os dias 22 pré e 22 pós-parto, para a realização de análises sanguíneas e determinação do perfil metabólico. Os animais foram categorizados de acordo com os níveis séricos de magnésio: Grupo Hipomagnesêmicas (n=5), com níveis abaixo de 1,8 mg/dL em ao menos dois dias consecutivos, e o Grupo Controle (n=7), com níveis acima de 1,8 mg/dL em todo o período. O grupo hipomagnesêmicas apresentou níveis de glucagon maiores nos dias 10, 18 e 20, e a taxa Glucagon/Insulina foi maior nos dias 6, 8, 10, 12 e 16 após o parto. As concentrações de aspartato amino transferase foram maiores no grupo hipomagnesêmicas nos dias 0, 6, 8, 10, 12 e 14 pós-parto. Os resultados indicaram que níveis reduzidos de magnésio no periparto podem estar relacionados com níveis elevados de aspartato amino transferase e de glucagon. Em geral, a hipomagnesemia subclínica não altera os níveis dos indicadores do metabolismo energético, mas os resultados demonstraram que as vacas com hipomagnesemia apresentaram maior taxa de glucagon/insulina, demonstrando um maior desafio para manter os níveis glicêmicos.(AU)
Assuntos
Animais , Feminino , Bovinos , Deficiência de Magnésio/sangue , Deficiência de Magnésio/veterinária , Deficiência de Magnésio/metabolismo , Período Periparto , Aspartato AminotransferasesRESUMO
AIM: This study evaluated the efficacy of oral magnesium supplementation in the reduction of plasma glucose levels in adults with prediabetes and hypomagnesaemia. METHODS: A total of 116 men and non-pregnant women, aged 30 to 65 years with hypomagnesaemia and newly diagnosed with prediabetes, were enrolled into a randomized double-blind placebo-controlled trial to receive either 30 mL of MgCl2 5% solution (equivalent to 382 mg of magnesium) or an inert placebo solution once daily for four months. The primary trial endpoint was the efficacy of magnesium supplementation in reducing plasma glucose levels. RESULTS: At baseline, there were no significant statistical differences in terms of anthropometric and biochemical variables between individuals in the supplement and placebo groups. At the end of follow-up, fasting (86.9 ± 7.9 and 98.3 ± 4.6 mg/dL, respectively; P = 0.004) and post-load glucose (124.7 ± 33.4 and 136.7 ± 23.9 mg/dL, respectively; P = 0.03) levels, HOMA-IR indices (2.85 ± 1.0 and 4.1 ± 2.7, respectively; P = 0.04) and triglycerides (166.4 ± 90.6 and 227.0 ± 89.7, respectively; P = 0.009) were significantly decreased, whereas HDL cholesterol (45.6 ± 10.9 and 46.8 ± 9.2 mg/dL, respectively; P = 0.04) and serum magnesium (1.96 ± 0.27 and 1.60 ± 0.26 mg/dL, respectively; P = 0.005) levels were significantly increased in those taking MgCl2 compared with the controls. A total of 34 (29.4%) people improved their glucose status (50.8% and 7.0% in the magnesium and placebo groups, respectively; P < 0.0005). CONCLUSION: Our results show that magnesium supplementation reduces plasma glucose levels, and improves the glycaemic status of adults with prediabetes and hypomagnesaemia.
Assuntos
Glicemia/efeitos dos fármacos , Hipoglicemiantes/uso terapêutico , Cloreto de Magnésio/uso terapêutico , Deficiência de Magnésio/tratamento farmacológico , Estado Pré-Diabético/tratamento farmacológico , Adulto , Idoso , Feminino , Humanos , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/farmacologia , Cloreto de Magnésio/administração & dosagem , Cloreto de Magnésio/farmacologia , Deficiência de Magnésio/metabolismo , Masculino , Pessoa de Meia-Idade , Estado Pré-Diabético/metabolismoRESUMO
Minerals are essential nutrients for the body, are of inorganic nature which gives them the characteristic of being resistant to heat, are involved in a lot of chemical reactions in metabolism, regulating electrolyte balance, in maintaining bone, in the process of blood clotting and the transmission of nerve impulses, particularly its role as enzyme cofactors confers a key role in various physiological processes. Glucose homeostasis involves a fine coordination of events where hormonal control by insulin plays a key role. However, the role of minerals like magnesium, zinc, chromium, iron and selenium in the diabetes is less obvious and in some cases may be controversial. This review shows the knowledge of these five elements and their correlation with diabetes.
Los minerales son nutrientes esenciales para el organismo, de naturaleza inorgánica que les confiere, entre otras características, ser resistentes al calor, participan en diversas reacciones químicas del metabolismo en donde regulan el equilibrio hidroelectrolítico, el mantenimiento óseo, en la trasmisión de los impulsos nerviosos, y durante el proceso de coagulación sanguínea, particularmente por su función como cofactores enzimáticos, tienen un papel clave en varios procesos fisiológicos. La homeostasis de la glucosa involucra una fina coordinación de eventos en donde el control hormonal por la insulina tiene un papel primordial. Sin embargo, la función de los minerales, como el magnesio, el zinc, el cromo, el hierro y el selenio en la diabetes es menos evidente y puede ser, en algún caso, controversial. Esta revisión muestra el conocimiento acerca de estos cinco elementos y su correlación con la diabetes.
Assuntos
Diabetes Mellitus/metabolismo , Micronutrientes/fisiologia , Minerais/metabolismo , Animais , Cromo/deficiência , Cromo/fisiologia , Cromo/uso terapêutico , Diabetes Mellitus Experimental/metabolismo , Glucose/metabolismo , Homeostase , Humanos , Resistência à Insulina , Ferro/fisiologia , Ferro/uso terapêutico , Deficiências de Ferro , Magnésio/fisiologia , Magnésio/uso terapêutico , Deficiência de Magnésio/complicações , Deficiência de Magnésio/metabolismo , Síndrome Metabólica/metabolismo , Micronutrientes/uso terapêutico , Minerais/uso terapêutico , Estresse Oxidativo , Selênio/deficiência , Selênio/fisiologia , Selênio/uso terapêutico , Zinco/deficiência , Zinco/fisiologia , Zinco/uso terapêuticoRESUMO
Temporomandibular joint (TMJ) arthritis is a common cause of orofacial pain. In the present study, the modulatory effects of N-methyl-d-aspartate receptors (NMDA-Rs) and magnesium were investigated in TMJ arthritis hypernociception. Male Wistar rats received an intra-articular injection of carrageenan (Cg) in the TMJ, and mechanical hypernociception was measured. The NMDA-R antagonist, MK-801, and magnesium chloride (MgCl2 ) were administered before arthritis induction. Magnesium deficiency was promoted by feeding rats a synthetic magnesium-free diet for 9 d before injection of Cg. The Cg induced mechanical hypernociception that lasted for 120 h. MK-801 inhibited this hypernociceptive state. MgCl2 pretreatment prevented Cg-induced hypernociception and altered the nociceptive threshold in the absence of Cg. Magnesium deficiency increased hypernociception and induced spontaneous hypernociceptive behavior. TMJ arthritis increased the expression of mRNA for all NMDA-R subunits and immunostaining of phosphorylated NR1 (phospho-NR1). MgCl2 inhibited expression of NR2B mRNA and phospho-NR1 immunostaining and increased expression of NR3 mRNA. Magnesium deficiency increased expression of both NR1 and NR3 mRNAs and phospho-NR1 immunostaining in the trigeminal subnucleus caudalis. We found that magnesium modulates nociceptive behavior and induces NMDA-R subunit rearrangement in the subnucleus caudalis. The present results may lead to a better understanding of central processing in the nociceptive trigeminal pathway and the development of new approaches to treat orofacial pain with a TMJ origin.
Assuntos
Deficiência de Magnésio/metabolismo , Magnésio/farmacologia , Osteoartrite/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Transtornos da Articulação Temporomandibular/metabolismo , Núcleo Inferior Caudal do Nervo Trigêmeo/metabolismo , Nervo Trigêmeo/efeitos dos fármacos , Análise de Variância , Animais , Carragenina , Expressão Gênica , Magnésio/sangue , Deficiência de Magnésio/induzido quimicamente , Masculino , Dados de Sequência Molecular , Dor Nociceptiva/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transtornos da Articulação Temporomandibular/induzido quimicamente , Transtornos da Articulação Temporomandibular/tratamento farmacológico , Fatores de Tempo , Nervo Trigêmeo/metabolismoAssuntos
Diabetes Mellitus Tipo 2/metabolismo , Deficiência de Magnésio/complicações , Magnésio/fisiologia , Síndrome Metabólica/metabolismo , Animais , Glicemia/análise , Colesterol/metabolismo , Estudos de Coortes , Diabetes Mellitus Tipo 2/etiologia , Dieta , Feminino , Humanos , Hidroximetilglutaril-CoA Redutases/metabolismo , Hiperinsulinismo/urina , Hipertensão/metabolismo , Inflamação/metabolismo , Insulina/metabolismo , Resistência à Insulina/fisiologia , Transporte de Íons/fisiologia , Magnésio/urina , Deficiência de Magnésio/metabolismo , Masculino , Síndrome Metabólica/etiologia , Modelos Biológicos , Receptor de Insulina/metabolismoRESUMO
OBJECTIVES: This study evaluated the effect of magnesium dietary deficiency on bone metabolism and bone tissue around implants with established osseointegration. MATERIALS AND METHODS: For this, 30 rats received an implant in the right tibial metaphysis. After 60 days for healing of the implants, the animals were divided into groups according to the diet received. Control group (CTL) received a standard diet with adequate magnesium content, while test group (Mg) received the same diet except for a 90% reduction of magnesium. The animals were sacrificed after 90 days for evaluation of calcium, magnesium, osteocalcin and parathyroid hormone (PTH) serum levels and the deoxypyridinoline (DPD) level in the urine. The effect of magnesium deficiency on skeletal bone tissue was evaluated by densitometry of the lumbar vertebrae, while the effect of bone tissue around titanium implants was evaluated by radiographic measurement of cortical bone thickness and bone density. The effect on biomechanical characteristics was verified by implant removal torque testing. RESULTS: Magnesium dietary deficiency resulted in a decrease of the magnesium serum level and an increase of PTH and DPD levels (P ≤ 0.05). The Mg group also presented a loss of systemic bone mass, decreased cortical bone thickness and lower values of removal torque of the implants (P ≤ 0.01). CONCLUSIONS: The present study concluded that magnesium-deficient diet had a negative influence on bone metabolism as well as on the bone tissue around the implants.
Assuntos
Implantação Dentária Endóssea , Implantes Dentários , Implantes Experimentais , Deficiência de Magnésio/fisiopatologia , Tíbia/metabolismo , Absorciometria de Fóton , Animais , Fenômenos Biomecânicos , Densidade Óssea , Remoção de Dispositivo , Modelos Animais de Doenças , Deficiência de Magnésio/complicações , Deficiência de Magnésio/metabolismo , Osseointegração , Ratos , Estatísticas não Paramétricas , Tíbia/diagnóstico por imagem , Tíbia/cirurgia , TorqueRESUMO
PURPOSE: This study evaluated the effect of severe magnesium (Mg) dietary deficiency on systemic bone density and biomechanical resistance of bone tissue to the removal torque of osseointegrated implants. MATERIALS AND METHODS: The sample consisted of 45 rats; each received a titanium implant in their tibial metaphysis. After 60 days, the animals were divided into three groups (n = 15) according to their dietary Mg: the control group received the recommended content of Mg, group Mg1 received a 75% reduction in dietary Mg content, and group Mg2 was fed a diet with a 90% reduction in Mg content. Animals were sacrificed 150 days after implant placement. Serum concentrations of Mg were measured and the effect of Mg deficiency on systemic bone density was evaluated by densitometry of the lumbar vertebrae and femur. Biomechanical characteristics were measured by resistance of the bone tissue to removal of the implants. RESULTS: Lower Mg serum concentrations were found for the Mg1 and Mg2 groups; however, densitometric analysis and torque evaluations showed a statistically significant difference only in the Mg2 group (P < .05). There was a statistically significant difference in removal torque between the Mg2 group and the control group. CONCLUSIONS: This study showed that a severe deficiency of Mg decreased the systemic bone density and removal torque of osseointegrated implants.
Assuntos
Densidade Óssea , Implantes Dentários , Remoção de Dispositivo , Deficiência de Magnésio/fisiopatologia , Osseointegração , Ração Animal , Animais , Fenômenos Biomecânicos , Implantação Dentária Endóssea , Modelos Animais de Doenças , Magnésio/sangue , Deficiência de Magnésio/complicações , Deficiência de Magnésio/metabolismo , Distribuição Aleatória , Ratos , Índice de Gravidade de Doença , Tíbia/metabolismo , Tíbia/cirurgia , TorqueRESUMO
Magnesium (Mg) is the main intracellular divalent cation, and under basal conditions the small intestine absorbs 30-50% of its intake. Normal serum Mg ranges between 1.7-2.3 mg/dl (0.75-0.95 mmol/l), at any age. Even though eighty percent of serum Mg is filtered at the glomerulus, only 3% of it is finally excreted in the urine. Altered magnesium balance can be found in diabetes mellitus, chronic renal failure, nephrolithiasis, osteoporosis, aplastic osteopathy, and heart and vascular disease. Three physiopathologic mechanisms can induce Mg deficiency: reduced intestinal absorption, increased urinary losses, or intracellular shift of this cation. Intravenous or oral Mg repletion is the main treatment, and potassium-sparing diuretics may also induce renal Mg saving. Because the kidney has a very large capacity for Mg excretion, hypermagnesemia usually occurs in the setting of renal insufficiency and excessive Mg intake. Body excretion of Mg can be enhanced by use of saline diuresis, furosemide, or dialysis depending on the clinical situation.
Assuntos
Compostos de Magnésio/uso terapêutico , Deficiência de Magnésio/complicações , Magnésio/metabolismo , Insuficiência Renal/etiologia , Desequilíbrio Hidroeletrolítico/etiologia , Desequilíbrio Hidroeletrolítico/terapia , Humanos , Magnésio/farmacocinética , Compostos de Magnésio/sangue , Compostos de Magnésio/urina , Deficiência de Magnésio/metabolismo , Deficiência de Magnésio/terapia , Insuficiência Renal/metabolismo , Insuficiência Renal/terapia , Desequilíbrio Hidroeletrolítico/metabolismoRESUMO
Primary hypomagnesemia is a heterogeneous group of disorders characterized by renal or intestinal magnesium (Mg2+) wasting, resulting in tetany, cardiac arrhythmias, and seizures. The kidney plays an essential role in maintaining blood Mg2+ levels, with a prominent function for the Mg2+-transporting channel transient receptor potential cation channel, subfamily M, member 6 (TRPM6) in the distal convoluted tubule (DCT). In the DCT, Mg2+ reabsorption is an active transport process primarily driven by the negative potential across the luminal membrane. Here, we studied a family with isolated autosomal dominant hypomagnesemia and used a positional cloning approach to identify an N255D mutation in KCNA1, a gene encoding the voltage-gated potassium (K+) channel Kv1.1. Kv1.1 was found to be expressed in the kidney, where it colocalized with TRPM6 along the luminal membrane of the DCT. Upon overexpression in a human kidney cell line, patch clamp analysis revealed that the KCNA1 N255D mutation resulted in a nonfunctional channel, with a dominant negative effect on wild-type Kv1.1 channel function. These data suggest that Kv1.1 is a renal K+ channel that establishes a favorable luminal membrane potential in DCT cells to control TRPM6-mediated Mg2+ reabsorption.
Assuntos
Canal de Potássio Kv1.1/genética , Deficiência de Magnésio/genética , Mutação de Sentido Incorreto , Sequência de Aminoácidos , Sequência de Bases , Brasil , Linhagem Celular , Mapeamento Cromossômico , Análise Mutacional de DNA , Feminino , Genes Dominantes , Humanos , Rim/metabolismo , Canal de Potássio Kv1.1/química , Canal de Potássio Kv1.1/metabolismo , Deficiência de Magnésio/metabolismo , Masculino , Modelos Biológicos , Modelos Moleculares , Dados de Sequência Molecular , Linhagem , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Canais de Cátion TRPM/metabolismo , TransfecçãoRESUMO
This cross sectional study evaluated serum (SMg) and intramononuclear (MMg) magnesium in patients with metabolic syndrome without diabetes and correlated them with cardiovascular risk factors. 72 patients and 57 controls (blood donors) were studied. Hypomagnesemia (SMg<1.7 mg/dL) was seen in 23.2% and intracellular depletion in 36.1% of the patients. SMg and MMg means were significantly lower in patients than in controls: 1.80+/-0.18 mg/dL vs. 2.43+/-0.43 mg/dL and 0.98+/-0.55 microg/mg vs. 1.67+/-0.64 microg/mg of protein (P<0.001). Inverse correlation was observed between, SMg and MMg with BMI; SMg with systolic blood pressure and waist circumference in women. Patients with acanthosis nigricans had lower SMg (1.75+/-0.18 mg/dL vs. 1.85+/- 0.18 mg/dL, P<0.05). Non-white people had lower SMg (1.78+/-0.16 mg/dL vs. 1.92+/-0.24 mg/dL, P=0.007) and MMg (0.95+/-0.59 microg/mg vs. 1.13+/-0.42 microg/mg, P=0.03). Patients with IR showed lower MgM means (0.84+/-0.33 microg/mg vs. 1.14+/-0.69 microg/mg, P<0.05). The same occurred in patients with low HDL-c levels (0.92+/-0.46 microg/mg vs. 1.20+/-0.70 microg/mg, P=0.03), and those with moderate and severe hepatic steatosis (0.77+/-0.29 microg/mg vs. 1.21+/-0.80 microg/mg, P<0.05). In conclusion, magnesium depletion in serum and mononuclear cells is common in obese people with metabolic syndrome, and it is more evident in non-white people with insulin resistance. This depletion may contribute to a post-receptor insulin resistance.
Assuntos
Resistência à Insulina/fisiologia , Deficiência de Magnésio/epidemiologia , Síndrome Metabólica/epidemiologia , Adolescente , Adulto , Glicemia/metabolismo , Doenças Cardiovasculares/etiologia , Estudos Transversais , Complicações do Diabetes/sangue , Complicações do Diabetes/epidemiologia , Complicações do Diabetes/metabolismo , Feminino , Humanos , Espaço Intracelular/metabolismo , Magnésio/sangue , Magnésio/metabolismo , Deficiência de Magnésio/sangue , Deficiência de Magnésio/complicações , Deficiência de Magnésio/metabolismo , Masculino , Síndrome Metabólica/sangue , Síndrome Metabólica/metabolismo , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Adulto JovemRESUMO
Hipomagnesemia é, em geral, pouco diagnosticada na prática clínica diária. Niveis séricos normais podem ser visto mesmo na presenþa de grave depleþÒo (deplecion) intracelular. O magnésio é importante cofator (cofactor) metálico de mais de 300 reaþ§es enzimáticas, incluindo aquela de tirosina-cinase, na sub-unidade beta do receptor de insulina, fundamental para la sinalizaþÒo (señalización) intra-celular deste horm¶nio (hormona). Uma importante reduþÒo dos niveis de magnésio em paciente com diabetes mellitus, resistÛncia Ô insulina , hipertensÒo arterial e síndrome metabólica (SM). Entretanto, permanece controverso (controvertido) o potencial de benefício da reposiþÒo deste ion (ión) em pacientes com estas patologias. Este artigo revisa os principais trabalhos publicados relacionando os temas: magnésio, resistÛncia insulínica diabetes mellitus e síndrome metabólica, além (además) de tratar de dados ainda (datos todavía) nÒo publicados sobre a prevalÛncia de hipomagnesemia e deficiÛncia intra-celular do ion em pacientes com SM.(AU)
Assuntos
Humanos , Deficiência de Magnésio/metabolismo , Deficiência de Magnésio/fisiopatologia , Diabetes Mellitus , Resistência à InsulinaRESUMO
Hipomagnesemia é, em geral, pouco diagnosticada na prática clínica diária. Niveis séricos normais podem ser visto mesmo na presença de grave depleção (deplecion) intracelular. O magnésio é importante cofator (cofactor) metálico de mais de 300 reações enzimáticas, incluindo aquela de tirosina-cinase, na sub-unidade beta do receptor de insulina, fundamental para la sinalização (señalización) intra-celular deste hormônio (hormona). Uma importante redução dos niveis de magnésio em paciente com diabetes mellitus, resistência â insulina , hipertensão arterial e síndrome metabólica (SM). Entretanto, permanece controverso (controvertido) o potencial de benefício da reposição deste ion (ión) em pacientes com estas patologias. Este artigo revisa os principais trabalhos publicados relacionando os temas: magnésio, resistência insulínica diabetes mellitus e síndrome metabólica, além (además) de tratar de dados ainda (datos todavía) não publicados sobre a prevalência de hipomagnesemia e deficiência intra-celular do ion em pacientes com SM.
Assuntos
Humanos , Deficiência de Magnésio/fisiopatologia , Deficiência de Magnésio/metabolismo , Diabetes Mellitus , Resistência à InsulinaRESUMO
O magnésio é um íon predominantemente intra-celular, que participa como co-fator de mais de 300 reações enzimáticas, dentre elas na atividade da tirosino-cinase. Sua deficiência pode aumentar a resistência periférica à insulina, especialmente em pacientes com síndrome metabólica e diabetes mellitus tipo 2 (DM2). Este trabalho avaliou, em 27 pacientes com DM2 descompensado, o conteúdo intra-celular de magnésio, correlacionando-o com índices laboratoriais de resistência insulínica e controle glicêmico. Hipomagnesemia foi encontrada em 75 por cento dos pacientes e déficit intra-celular em 30,8 por cento. Houve correlação negativa do Mg intra-celular (Mg IC) com HbA1 e com IMC. 59,2 por cento dos pacientes apresentaram HOMA IR > 3,5, e tendência para correlação negativa com o Mg IC, porém sem significância estatística. Apesar do número pequeno de pacientes, ressalta-se que uma vez que deficiência de magnésio é comum em pacientes com diabetes, sua relação com resistência insulínica deve ser mais estudada.
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Resistência à Insulina , Deficiência de Magnésio , HDL-Colesterol , Deficiência de Magnésio/metabolismo , Deficiência de Magnésio/fisiopatologia , /metabolismo , /fisiopatologia , Glicemia/análise , Homeostase , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Magnésio/sangue , Magnésio/urina , Resistência à Insulina/fisiologiaRESUMO
The cause of keratoconus is unknown. However, an earlier report demonstrated magnesium deficiency in keratoconus patients, and suggested that magnesium deficiency could pathologically affect the mechanisms of the cornea. Experimental and clinical papers concerning a possible relationship between keratoconus and magnesium deficiency were reviewed. These studies have demonstrated molecular and cellular alterations specific to the keratoconic cornea, including: thinning and fragmentation of membranes, degenerated cells and collagen fibres, swelling of the mitochondria, and biochemical abnormalities in protein synthesis. Similar alterations have reportedly been induced by magnesium deficiency. This review suggests a possible relationship between the specific keratoconic disorders and the alteration induced by magnesium deficiency at the intracellular and extracellular levels. Although the etiology of keratoconus is still unknown, this paper may give some new ideas for further experimental and clinical studies on the etiology of keratoconus.
Assuntos
Ceratocone/etiologia , Deficiência de Magnésio/complicações , Apoptose , Proteínas do Olho/biossíntese , Humanos , Ceratocone/metabolismo , Ceratocone/patologia , Deficiência de Magnésio/metabolismo , Deficiência de Magnésio/patologiaRESUMO
Magnesium is a predominantly intracellular ion, and it is a cofactor in more than 300 enzymatic reactions, like tyrosinokinase activity. Its deficiency may increase insulin resistance, especially in patients with metabolic syndrome or type 2 diabetes. This study evaluated in 27 patients with poorly controlled type 2 diabetes if there was correlation between intracellular magnesium levels, laboratorial indexes of insulin resistance and glycemic control. Decreased serum and intracellular magnesium depletion were found in 75% and 30.8% of patients, respectively. A negative correlation between intracellular magnesium levels (ICMg) and BMI and HbA1 was found. The homeostasis model assessment for insulin resistance (HOMA-IR) was higher than 3.0 in 59.2% of patients and there was a tendency to negative correlation with ICMg levels, although without statistical significance. Despite the small number of patients, this study shows that magnesium deficiency is frequent in patients with diabetes and its correlation with insulin resistance should be more studied.