Thiamine pyrophosphate diminishes nitric oxide synthesis in endothelial cells.

Although thiamine pyrophosphate (TPP) is considered a protective agent for endothelial cells, it is still unknown if this is associated with nitric oxide (NO) synthesis. Our aim was to evaluate the synthesis of NO in endothelial cells incubated with TPP and high glucose concentrations. Endothelial cells from the umbilical cord vein from newborns (n = 20), were incubated with 5, 15 or 30 mmol/L glucose, in absence or presence of 0.625 mg/ml of TPP. Our results showed a significant increase in cell proliferation (> 40%; P < 0.05), and cell viability (> 90%; P < 0.001) after 48 h in endothelial cells cultured with glucose plus TPP. Likewise, in the presence of glucose and TPP an important rise in the consumption of glucose by the endothelial cells was observed after 24 h (> 7%; P < 0.001) and 48 h (> 10%; P < 0.05). Additionally, the levels of lactate after incubation with glucose and TPP showed only slight variations after 48 h (P < 0.05). However, these changes were clearly different from those observed in the absence of TPP. Interestingly, we found that the changes mentioned were linked with reduced levels of nitrites both at 24 h (< 171 pmol/µg protein; P < 0.001), and 48 h (< 250 pmol/µg protein; P < 0.05), which was associated with a reduced expression of mRNA of eNOS in endothelial cells incubated with TPP and high glucose. In conclusion, the presence of TPP regulates the consumption of glucose and the synthesis of NO, which would explain its protective effect in the endothelium of diabetic patients.

Thiamine deficiency contributes to synapse and neural circuit defects.

BACKGROUND: The previous studies have demonstrated the reduction of thiamine diphosphate is specific to Alzheimer's disease (AD) and causal factor of brain glucose hypometabolism, which is considered as a neurodegenerative index of AD and closely correlates with the degree of cognitive impairment. The reduction of thiamine diphosphate may contribute to the dysfunction of synapses and neural circuits, finally leading to cognitive decline. RESULTS: To demonstrate this hypothesis, we established abnormalities in the glucose metabolism utilizing thiamine deficiency in vitro and in vivo, and we found dramatically reduced dendrite spine density. We further detected lowered excitatory neurotransmission and impaired hippocampal long-term potentiation, which are induced by TPK RNAi in vitro. Importantly, via treatment with benfotiamine, Aß induced spines density decrease was considerably ameliorated. CONCLUSIONS: These results revealed that thiamine deficiency contributed to synaptic dysfunction which strongly related to AD pathogenesis. Our results provide new insights into pathogenesis of synaptic and neuronal dysfunction in AD.

Thiamine deficiency contributes to synapse and neural circuit defects

BACKGROUND: The previous studies have demonstrated the reduction of thiamine diphosphate is specific to Alzheimer's disease (AD) and causal factor of brain glucose hypometabolism, which is considered as a neurodegenerative index of AD and closely correlates with the degree of cognitive impairment. The reduction of thiamine diphosphate may contribute to the dysfunction of synapses and neural circuits, finally leading to cognitive decline. RESULTS: To demonstrate this hypothesis, we established abnormalities in the glucose metabolism utilizing thiamine deficiency in vitro and in vivo, and we found dramatically reduced dendrite spine density. We further detected lowered excitatory neurotransmission and impaired hippocampal long-term potentiation, which are induced by TPK RNAi in vitro. Importantly, via treatment with benfotiamine, Aß induced spines density decrease was considerably ameliorated. CONCLUSIONS: These results revealed that thiamine deficiency contributed to synaptic dysfunction which strongly related to AD pathogenesis. Our results provide new insights into pathogenesis of synaptic and neuronal dysfunction in AD.

Parámetros productivos y sanguíneos en pollos de carne suplementados con cocarboxilasa / Productive and blood performance of broiler supplemented with cocarboxylase

El objetivo de este estudio fue evaluar el efecto de la cocarboxilasa sobre los parámetros productivos y niveles sanguíneos de glucosa y lipídos en pollos de carne. Fueron utilizados 11004 pollos machos de 1 día de edad los cuales fueron distribuidos al azar en 3 tratamientos con 4 repeticiones (917 pollos por cada repetición) y criados de forma convencional por 42 días. Los grupos formados fueron T1 (Dieta convencional), T2 (Dieta modificada, reducción del porcentaje de aceite de soya y la adición de cocarboxilasa) y T3 (Dieta modificada, reducción del porcentaje de aceite de soya y sin cocarboxilasa). El grupo tratado con cocarboxilasa (T2) obtuvo mayor peso final y ganancia de peso comparado con los otros dos tratamientos. La inclusión de cocarboxilasa tuvo influencia positiva en el peso por lo que podria ser utilizada como reemplazo parcial del aceite de soya utilizado en la dieta de pollos de carne.(AU)

The aim of this study was to evaluate the effect of cocarboxylase on productive performance, blood glucose and lipid profile in broilers. A total of 11004 one-day-old male broiler chickens were randomly allocated into 1 of 3 treatments with 4 replicates per treatment (917 chickens per replicate) and conventionally reared until 42 days old. The treatments were T1 (Conventional diet), T2 (Modified diet, reducing a percentage soybean oil and the addition of cocarboxylase) and T3 (Modified diet, reducing a percentage soybean oil without cocarboxylase). Broilers supplemented with cocarboxylase (T2) resulted in higher final weight and weight gain compared with the others treatments. The inclusion of cocarboxylase had positive influence on weight, which suggests its usefulness as a partial replacement of the oil used in chicken diets.(AU)

Evaluation of the protective effect of thiamine pyrophosphate based on the biochemical analysis of rabbit foetuses at 30 days of gestation.

This study evaluated the effects of thiamine pyrophosphate (PPT) on the biochemical profiles of full-term rabbit foetuses that were subjected to experimental ischemia followed by 24h reperfusion. A total of 16 gestating rabbit dams were divided into two groups, one of which was treated by administering PPT and subjected to a process ischemia. During this interval, fetal blood samples were drawn from each dam (in the ischemia group) at 0, 15 and 45min. Ischemia for 15 and 45min was not associated with changes in lactate levels of the Ischemia group foetuses. However, in the foetuses in the reperfusion groups without PPT lactate levels were significantly higher after 15 and 45min of arterial occlusion compared to time zero. These results demonstrate that PTT alters some acute and some longer-term biochemical outcomes of uterine ischemia perhaps important in preserving energy metabolism under hypoxic conditions.

Parámetros productivos y sanguíneos en pollos de carne suplementados con cocarboxilasa / Productive and blood performance of broiler supplemented with cocarboxylase

El objetivo de este estudio fue evaluar el efecto de la cocarboxilasa sobre los parámetros productivos y niveles sanguíneos de glucosa y lipídos en pollos de carne. Fueron utilizados 11004 pollos machos de 1 día de edad los cuales fueron distribuidos al azar en 3 tratamientos con 4 repeticiones (917 pollos por cada repetición) y criados de forma convencional por 42 días. Los grupos formados fueron T1 (Dieta convencional), T2 (Dieta modificada, reducción del porcentaje de aceite de soya y la adición de cocarboxilasa) y T3 (Dieta modificada, reducción del porcentaje de aceite de soya y sin cocarboxilasa). El grupo tratado con cocarboxilasa (T2) obtuvo mayor peso final y ganancia de peso comparado con los otros dos tratamientos. La inclusión de cocarboxilasa tuvo influencia positiva en el peso por lo que podria ser utilizada como reemplazo parcial del aceite de soya utilizado en la dieta de pollos de carne.

The aim of this study was to evaluate the effect of cocarboxylase on productive performance, blood glucose and lipid profile in broilers. A total of 11004 one-day-old male broiler chickens were randomly allocated into 1 of 3 treatments with 4 replicates per treatment (917 chickens per replicate) and conventionally reared until 42 days old. The treatments were T1 (Conventional diet), T2 (Modified diet, reducing a percentage soybean oil and the addition of cocarboxylase) and T3 (Modified diet, reducing a percentage soybean oil without cocarboxylase). Broilers supplemented with cocarboxylase (T2) resulted in higher final weight and weight gain compared with the others treatments. The inclusion of cocarboxylase had positive influence on weight, which suggests its usefulness as a partial replacement of the oil used in chicken diets.

Can thiamine pyrophosphate prevent desflurane induced hepatotoxicity in rats?

PURPOSE: To investigate the effects of thiamine pyrophosphate (TPP) against desflurane induced hepatotoxicity. METHODS: Thirty experimental animals were divided into groups as healthy (HG), desflurane control (DCG) , TPP and desflurane group (TDG). 20 mg/kg TPP was injected to intraperitoneally TDG. After one hour of TPP administration, desflurane was applied for two hours. After 24 hours, liver tissues of the animals killed with decapitation were removed. The oxidant/antioxidant levels and ALT, AST and LDH activities were measured. The histopathological examinations were performed in the liver tissues for all rats. RESULTS: Notwithstanding the levels of oxidants and liver enzymes were significantly increased (p<0.0001), antioxidant levels were significantly decreased in DCG (p<0.0001). On contrary to the antioxidant parameters were increased (p<0.05) the oxidant parameters and liver enzymes were decreased in TDG (p<0.0001). Whereas multiple prominent, congestion, hemorrhage and dilatation were observed in sinusoids and lymphocyte-rich inflammation results in the centrilobular and portal areas of liver tissue in DCG, these findings were observed less frequently in TDG. CONCLUSION : Thiamine pyrophosphate prevented liver oxidative damage induced with desflurane and may be useful in prophylaxis of desflurane induced hepatotoxicity.

Can thiamine pyrophosphate prevent desflurane induced hepatotoxicity in rats?

PURPOSE: To investigate the effects of thiamine pyrophosphate (TPP) against desflurane induced hepatotoxicity.METHODS: Thirty experimental animals were divided into groups as healthy (HG), desflurane control (DCG) , TPP and desflurane group (TDG). 20 mg/kg TPP was injected to intraperitoneally TDG. After one hour of TPP administration, desflurane was applied for two hours. After 24 hours, liver tissues of the animals killed with decapitation were removed. The oxidant/antioxidant levels and ALT, AST and LDH activities were measured. The histopathological examinations were performed in the liver tissues for all rats.RESULTS: Notwithstanding the levels of oxidants and liver enzymes were significantly increased (p<0.0001), antioxidant levels were significantly decreased in DCG (p<0.0001). On contrary to the antioxidant parameters were increased (p<0.05) the oxidant parameters and liver enzymes were decreased in TDG (p<0.0001). Whereas multiple prominent, congestion, hemorrhage and dilatation were observed in sinusoids and lymphocyte-rich inflammation results in the centrilobular and portal areas of liver tissue in DCG, these findings were observed less frequently in TDG.CONCLUSİON: Thiamine pyrophosphate prevented liver oxidative damage induced with desflurane and may be useful in prophylaxis of desflurane induced hepatotoxicity.(AU)

Can thiamine pyrophosphate prevent desflurane induced hepatotoxicity in rats?

ABSTRACT PURPOSE : To investigate the effects of thiamine pyrophosphate (TPP) against desflurane induced hepatotoxicity. METHODS : Thirty experimental animals were divided into groups as healthy (HG), desflurane control (DCG) , TPP and desflurane group (TDG). 20 mg/kg TPP was injected to intraperitoneally TDG. After one hour of TPP administration, desflurane was applied for two hours. After 24 hours, liver tissues of the animals killed with decapitation were removed. The oxidant/antioxidant levels and ALT, AST and LDH activities were measured. The histopathological examinations were performed in the liver tissues for all rats. RESULTS : Notwithstanding the levels of oxidants and liver enzymes were significantly increased (p<0.0001), antioxidant levels were significantly decreased in DCG (p<0.0001). On contrary to the antioxidant parameters were increased (p<0.05) the oxidant parameters and liver enzymes were decreased in TDG (p<0.0001). Whereas multiple prominent, congestion, hemorrhage and dilatation were observed in sinusoids and lymphocyte-rich inflammation results in the centrilobular and portal areas of liver tissue in DCG, these findings were observed less frequently in TDG. CONCLUSİON : Thiamine pyrophosphate prevented liver oxidative damage induced with desflurane and may be useful in prophylaxis of desflurane induced hepatotoxicity.

Implantação de um método para determinação da atividade da transcetolase eritrocitária para avaliação indireta da tiamina / Implementation of a method for determining the erythrocyte transketolase activity for indirect evaluation of thiamin

O teste de ativação da transcetolase eritrocitária (TK-E) pelo pirofosfato de tiamina (TPP) exógeno é um método indireto para mensurar a tiamina (vitamina B1). A diminuição da atividade da transcetolase eritrocitária e o aumento da estimulação in vitro com o TPP maior do que 17 % indicam deficiência de tiamina. Este é um método plausível, pois são nos eritrócitos que estão concentradas a maior parte desta vitamina. Em virtude de surtos de beribéri que tem ocorrido no Brasil desde 2006, o Instituto Adolfo Lutz (IAL), como Laboratório Central de Saúde Pública, propôs a implantação desse método para auxiliar na investigação de novos surtos ou de casos isolados. Foram avaliados o teste de precisão, a linearidade, a estabilidade do hemolisado e da amostra, e estimados os limites de detecção e de quantificação. A atividade da TK-E sem ativação pelo TPP foi de 0,732 UI/gHb e com ativação foi de 0,827 UI/gHb. Todos os resultados dos parâmetros avaliados neste estudo apresentaram-se dentro dos critérios de aceitabilidade garantindo-se a confiabilidade do método. Fica, assim, disponível mais um ensaio bioquímico para a Rede Pública de Saúde, mas ainda necessário definir os valores de referência para estabelecer os limites clínicos da deficiência de tiamina.

Erythrocyte transketolase activation test (TK-E) by exogenous thiamine pyrophosphate (TPP) is an indirect method to measure thiamine (vitamin B1). The decrease in the erythrocyte transketolase activity and the increase of in vitro stimulation with TPP greater than 17 % indicate thiamine deficiency. It is a reasonable method as the major portion of this vitamin are concentrated in erithrocytes. Due to the beriberi outbreaks that have occurred in Brazil since 2006, the Adolfo Lutz Institute (IAL), as a Central Public Health Laboratory, proposed the implementation of this method to give support to the investigation on the new outbreaks or isolated cases. The evaluated parameters were precision, linearity, hemolysate and sample stability, and the limits of detection and quantification were estimated. The TK-E activity without activation by TPP was 0.732 UI/gHb, and with activation was 0.827 UI/gHb. All of the results obtained from the evaluated parameters showed to be within the eligibility criteria, ensuring the reliability of the proposed methods. Thus, this method showed to be adequate as biochemical assay for the Public Health Network. However, there is a need to define the reference values to establish the clinical limits of thiamine deficiency.

Implantação de um método para determinação da atividade da transcetolase eritrocitária para avaliação indireta da tiamina / Implementation of a method for determining the erythrocyte transketolase activity for indirect evaluation of thiamin

O teste de ativação da transcetolase eritrocitária (TK-E) pelo pirofosfato de tiamina (TPP) exógeno é um método indireto para mensurar a tiamina (vitamina B1). A diminuição da atividade da transcetolase eritrocitária e o aumento da estimulação in vitro com o TPP maior do que 17 % indicam deficiência de tiamina. Este é um método plausível, pois são nos eritrócitos que estão concentradas a maior parte desta vitamina. Em virtude de surtos de beribéri que tem ocorrido no Brasil desde 2006, o Instituto Adolfo Lutz (IAL), como Laboratório Central de Saúde Pública, propôs a implantação desse método para auxiliar na investigação de novos surtos ou de casos isolados. Foram avaliados o teste de precisão, a linearidade, a estabilidade do hemolisado e da amostra, e estimados os limites de detecção e de quantificação. A atividade da TK-E sem ativação pelo TPP foi de 0,732 UI/gHb e com ativação foi de 0,827 UI/gHb. Todos os resultados dos parâmetros avaliados neste estudo apresentaram-se dentro dos critérios de aceitabilidade garantindo-se a confiabilidade do método. Fica, assim, disponível mais um ensaio bioquímico para a Rede Pública de Saúde, mas ainda necessário definir os valores de referência para estabelecer os limites clínicos da deficiência de tiamina.(AU)

Erythrocyte transketolase activation test (TK-E) by exogenous thiamine pyrophosphate (TPP) is an indirect method to measure thiamine (vitamin B1). The decrease in the erythrocyte transketolase activity and the increase of in vitro stimulation with TPP greater than 17 % indicate thiamine deficiency. It is a reasonable method as the major portion of this vitamin are concentrated in erithrocytes. Due to the beriberi outbreaks that have occurred in Brazil since 2006, the Adolfo Lutz Institute (IAL), as a Central Public Health Laboratory, proposed the implementation of this method to give support to the investigation on the new outbreaks or isolated cases. The evaluated parameters were precision, linearity, hemolysate and sample stability, and the limits of detection and quantification were estimated. The TK-E activity without activation by TPP was 0.732 UI/gHb, and with activation was 0.827 UI/gHb. All of the results obtained from the evaluated parameters showed to be within the eligibility criteria, ensuring the reliability of the proposed methods. Thus, this method showed to be adequate as biochemical assay for the Public Health Network. However, there is a need to define the reference values to establish the clinical limits of thiamine deficiency.(AU)

New Insights on the Reaction Pathway Leading to Lactyl-ThDP: A Theoretical Approach.

In all ThDP-dependent enzymes, the catalytic cycle is initiated with the attack of the C2 atom of the ylide intermediate on the Cα atom of a pyruvate molecule to form the lactyl-ThDP (L-ThDP) intermediate. In this study, the reaction between the ylide intermediate and pyruvate leading to the formation of L-ThDP is addressed from a theoretical point of view. The study includes molecular dynamics, exploration of the potential energy surface by means of QM/MM calculations, and reactivity analysis on key centers. The results show that the reaction occurs via a concerted mechanism in which the carboligation and the proton transfers occur synchronically. It is also observed that during the reaction the protonation state of the N1' atom changes: the reaction starts with the ylide having the N1' atom deprotonated and reaches a transition state showing the N1' atom protonated. This conversion leads to the reaction path of minimum energy, with an activation energy of about 20 kcal mol(-1). On the other hand, it is also observed that the approaching distance between the pyruvate and the ylide, i.e., the Cα-C2 distance, plays a fundamental role in the reaction mechanism since it determines the nucleophilic character of key atoms of the ylide, which in turn trigger the elemental reactions of the mechanism.

Eficacia del pirofosfato de tiamina o cocarboxilasa en el rescate del pie diabético / Efficacy of thiamine pyrophosphate or carboxylase in the salvage of diabetic foot

El pie diabético representa una de las complicaciones más comunes en pacientes que han tenido una larga evolución. La etiología se circunscribe a la neuropatía, infecciones e isquemia, que actuando en conjunto contribuyen a la secuencia de necrosis tisular, ulceración y gangrena. Lo difícil que resulta su tratamiento hace necesaria la búsqueda de opciones que colaboren en la resolución de esta problemática, que se centra en la hiperglucemia crónica como detonante. El pirofosfato de tiamina o cocarboxilasa realiza múltiples actividades metabólicas y no metabólicas que han sido consideradas importantes en la solución de las alteraciones del diabético por lo que en el presente trabajo se muestran los resultados al emplearlo en pacientes con pie diabético. En un período comprendido entre Enero de 1998 y Julio de 2012 se trataron 29 pacientes con pie diabético: 19 Wagner tipo III y 12 Wagner tipo IV. El manejo consistió en administrar antibióticos, procedimientos quirúrgicos parciales y pirofosfato de tiamina. Se logró el control del proceso infeccioso, la aparición de tejido de granulación y cicatrización de la lesión en un período comprendido entre 2 y 6 meses de acuerdo a la gravedad del problema. Por los datos clínicos y la evolución de los pacientes, se concluye que la administración del pirofosfato de tiamina permitió el control de las disfunciones metabólicas y no metabólicas que conducen a las complicaciones del diabético, por lo que se debe considerar una herramienta para el tratamiento de los diabéticos en general y para el rescate del pie diabético en particular.

Diabetic foot represents one of the most common complications in patients with a long standing disease. The etiology is neuropathy, infections and ischemia that together contribute to the sequence of tissue necrosis, ulceration and gangrene. Since treatment is very difficult, we must look for several options to solve these problems caused by chronic hyperglycemia. Thiamine pyrophosphate or carboxylase perform multiple metabolic and non-metabolic activities that are considered important in the resolution of diabetic impairments, therefore, this work shows the results when using it in patients with diabetic foot. 29 patients with diabetic foot were treated between January 1998 and July 2012: 19 Wagner type III and 12 Wagner type IV. Management was the administration of antibiotics, partial surgical procedures and thiamine pyrophosphate. The infectious process was controlled, the appearance of granulation tissue and scarring of the lesion in a period of 2 to 6 months depending on the severity of the problem. Given the clinical data and evolution of the patients, we conclude that the administration of thiamine pyrophosphate was able to control metabolic and non-metabolic dysfunctions that lead to complications in diabetic patients, therefore we must consider it a tool in the treatment of diabetic patients in general and for diabetic foot salvage in particular.

El pirofosfato de tiamina reduce el daño celular inducido por hipoxia en el cerebro de ratas neonatas / Thiamine pyrophosphate reduces hypoxia-induced cellular damage in neonatal rat brain

La encefalopatía por hipoxia es causa de discapacidad y requiere de nuevas estrategias terapéuticas. El pirofosfato de tiamina (PPT) es un cofactor esencial de enzimas fundamentales en el metabolismo de la glucosa, cuya disminución puede conducir a la falla en la síntesis de ATP y a la muerte celular. El objetivo de este estudio fue determinar si la administración de PPT, puede reducir el daño celular en un modelo de hipoxia neonatal en ratas. Animales de 11 días de edad fueron tratados con PPT (130 mg/kg) en dosis única o solución salina, una hora antes del protocolo de hipoxia o al término de ésta. Los cerebros fueron colectados para la evaluación del daño celular. Además, se tomaron muestras sanguíneas para evaluar los indicadores gasométricos de presión de dióxido de carbono (PaCO2) y de oxígeno (PaO2) en sangre arterial y pH. Los resultados muestran que la administración de PPT previa a la inducción de hipoxia, reduce el daño celular y restablece los indicadores gasométricos. Estos datos indican que el uso de PPT reduce el daño inducido por la hipoxia en animales neonatos.

Hypoxic encephalopathy is a leading cause of disability and requires new therapeutic strategies. Thiamine pyrophosphate (TPP) is an essential cofactor of fundamental enzymes involved in glucose metabolism. TPP reduction may lead to ATP synthesis failure and cell death. The objective of this study was to determine if TPP administration can reduce cellular damage in a model of neonatal hypoxia in rats. Eleven day old animals were treated with TPP (130 mg/kg) as a single dose or with saline solution one hour before the hypoxia protocol or after ending the protocol. The brains were collected to evaluate cellular damage. Blood samples were also collected to evaluate arterial oxygen tension (PaO2), carbon dioxide tension (PaCO2) and acidity (pH). The results showed that TPP administration previous to hypoxia induction reduces cellular damage and reestablishes arterial blood gases. These data indicate that TPP use reduces the damage induced by hypoxia in neonatal animals.

Thiamine deficiency and cardiac dysfunction in Cambodian infants.

OBJECTIVES: To compare blood thiamine concentrations, echocardiography findings, and plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in infants with clinically diagnosed beriberi and healthy matched controls, and to evaluate changes after thiamine treatment. STUDY DESIGN: Sixty-two Cambodian infants (20 cases and 42 controls), aged 2-47 weeks, were enrolled in this prospective study. Echocardiography and phlebotomy were performed at baseline and after thiamine treatment. RESULTS: Both cases and controls were thiamine-deficient, with median blood thiamine diphosphate (TDP) concentrations of 47.6 and 55.1 nmol/L, respectively (P = .23). All subjects had normal left ventricular ejection fraction. The median NT-proBNP concentration in cases (340 pg/mL [40.1 pmol/L]) was higher than previously reported normal ranges, but not statistically significantly different from that in controls (175 pg/mL [20.7 pmol/L]) (P = .10), and was not correlated with TDP concentration (P = .13). Two cases with the lowest baseline TDP concentrations (24 and 21 nmol/L) had right ventricular enlargement and elevated NT-proBNP levels that improved dramatically by 48 hours after thiamine administration. CONCLUSION: Only a minority of thiamine-deficient Cambodian infants demonstrate abnormal echocardiography findings. Thiamine deficiency produces echocardiographic evidence of right ventricular dysfunction, but this evidence is not apparent until deficiency is severe. NT-proBNP concentrations are mildly elevated in sick infants with normal echocardiography findings, indicating possible physiological changes not yet associated with echocardiographic abnormalities.

[Efficacy of thiamine pyrophosphate or carboxylase in the salvage of diabetic foot]. / Eficacia del pirofosfato de tiamina o cocarboxilasa en el rescate del pie diabético.

Diabetic foot represents one of the most common complications in patients with a long standing disease. The etiology is neuropathy, infections and ischemia that together contribute to the sequence of tissue necrosis, ulceration and gangrene. Since treatment is very difficult, we must look for several options to solve these problems caused by chronic hyperglycemia. Thiamine pyrophosphate or carboxylase perform multiple metabolic and non-metabolic activities that are considered important in the resolution of diabetic impairments, therefore, this work shows the results when using it in patients with diabetic foot. 29 patients with diabetic foot were treated between January 1998 and July 2012: 19 Wagner type III and 12 Wagner type IV. Management was the administration of antibiotics, partial surgical procedures and thiamine pyrophosphate. The infectious process was controlled, the appearance of granulation tissue and scarring of the lesion in a period of 2 to 6 months depending on the severity of the problem. Given the clinical data and evolution of the patients, we conclude that the administration of thiamine pyrophosphate was able to control metabolic and non-metabolic dysfunctions that lead to complications in diabetic patients, therefore we must consider it a tool in the treatment of diabetic patients in general and for diabetic foot salvage in particular.

Pyruvate decarboxylase activity is regulated by the Ser/Thr protein phosphatase Sit4p in the yeast Saccharomyces cerevisiae.

Deletion of SIT4 phosphatase decreased the pyruvate decarboxylase activity, which is essential for directing the glucose flux to ethanol production. Concomitantly, a reduction in the fermentative capacity was observed. As pyruvate decarboxylase expression was not altered, its post-translational phosphorylation was studied. Immunoblot analyses using anti-phosphoserine antibodies against the affinity-purified Pdc1p showed that Pdc1p is a phosphoenzyme. Dephosphorylation of Pdc1p by alkaline phosphatase inhibited activity by 50%. Moreover, phosphorylation of Pdc1p was dependent on the growth phase, being hyperphosphorylated in the logarithmic phase, which showed to be dependent on the presence of SIT4. A comparison of the kinetic parameters of pyruvate decarboxylase in total protein extracts from WT yeast and the Δsit4 mutant revealed that the apparent K(m) values of the cofactor thiamin pyrophosphate (TPP) were 81 and 205 µM, respectively, with V(max) values of 0.294 and 0.173 µmol mg⁻¹ min⁻¹, respectively. Treatment of the purified enzyme with alkaline phosphatase increased the K(m) for TPP from 20 to 84 µM and for pyruvate from 2.3 to 4.6 mM, while the V(max) changed from 0.806 to 0.673 µmol mg⁻¹ min⁻¹. These results suggest that the Pdc1p phosphorylation dependent on SIT4 occurs at residues that change the apparent affinity for TPP and pyruvate.

Computer-assisted study on the reaction between pyruvate and ylide in the pathway leading to lactyl-ThDP.

In this study the formation of the lactyl-thiamin diphosphate intermediate (L-ThDP) is addressed using density functional theory calculations at X3LYP/6-31++G(d,p) level of theory. The study includes potential energy surface scans, transition state search, and intrinsic reaction coordinate calculations. Reactivity is analyzed in terms of Fukui functions. The results allow to conclude that the reaction leading to the formation of L-ThDP occurs via a concerted mechanism, and during the nucleophilic attack on the pyruvate molecule, the ylide is in its AP form. The calculated activation barrier for the reaction is 19.2 kcal/mol, in agreement with the experimental reported value.

Thiamine deficiency in Cambodian infants with and without beriberi.

OBJECTIVES: To test the hypothesis that heavy metal toxicity and consumption of thiaminase-containing foods predispose to symptomatic thiamine deficiency. STUDY DESIGN: In a case-control study, thiamine diphosphate (TDP) blood concentrations were measured in 27 infants diagnosed with beriberi at a rural clinic, as well as their mothers and healthy Cambodian and American controls. Blood and urine levels of lead, arsenic, cadmium, mercury, and thallium were measured. Local food samples were analyzed for thiaminase activity. RESULTS: Mean TDP level among cases and Cambodian controls was 48 and 56 nmol/L, respectively (P = .08) and was 132 nmol/L in American controls (P < .0001 compared with both Cambodian groups). Mean TDP level of mothers of cases and Cambodian controls was 57 and 57 nmol/L (P = .92), and was 126 nmol/L in American mothers (P < .0001 compared with both Cambodian groups). Cases (but not controls) had lower blood TDP levels than their mothers (P = .02). Infant TDP level decreased with infant age and was positively associated with maternal TDP level. Specific diagnostic criteria for beriberi did not correlate with TDP level. There was no correlation between heavy metal levels and either TDP level or case/control status. No thiaminase activity was observed in food samples. CONCLUSIONS: Thiamine deficiency is endemic among infants and nursing mothers in rural southeastern Cambodia and is often clinically inapparent. Neither heavy metal toxicity nor consumption of thiaminase-containing foods account for thiamine deficiency in this region.