Cardiac oxidative stress is involved in heart failure induced by thiamine deprivation in rats

The relationship between thiamin, folic acid and cognitive function in a rat model of uremia

End-stage renal disease is a worldwide health burden, but the pathogenesis of uremia-associated cognitive impairment (CI) is poorly recognized. We hypothesized that uremia brings about deficiency of thiamin and folic acid and causes CI by inducing oxidative stress. Therefore, 24 Sprague-Dawley rats were randomly divided into two groups: a 5/6 nephrectomy group (n = 12) and a sham-operated group (n = 12). The Morris water maze was used to assess the cognitive function eight weeks post-surgery, and serum levels of thiamin, folic acid and homocysteine were detected subsequently. Brain and kidney tissues were collected for pathological examination and 8-Hydroxy-2'-deoxyguanosine (8-OHdG) immunochemistry staining. Results showed that the escape latency on training days 1-2 was longer, and the time in quadrant IV on experimental day 6 was significantly shorter in 5/6 nephrectomy group. Meanwhile, the uremic rats showed decreased thiamin, folic acid and increased homocysteine. We also found the time in quadrant IV was positively correlated with thiamin and folic acid level, while negatively correlated with the blood urea nitrogen and 8-OHdG positive cell proportion. Furthermore, in 5/6 nephrectomy group, the hippocampal neuron count was significantly reduced, and a greater proportion of 8-OHdG positive cells were detected. Pretreating LPS-stimulated rat microglial cells with thiamin or folic acid in vitro alleviated the inflammatory impairment in terms of cell viability and oxidative stress. In summary, we applied a uremic rat model and proved that uremia causes serum thiamin and folic acid deficiency, homocysteine elevation, along with neuron reduction and severe oxidative stress in hippocampus, finally leading to CI.

Melatonin prevents overproduction of reactive oxygen species and vascular dysfunction induced by cyclophosphamide

AIMS

Overproduction of reactive oxygen species (ROS) is a pathologic hallmark of cyclophosphamide toxicity. For this reason, antioxidant compounds emerge as promising tools for preventing tissue damage induced by cyclophosphamide. We hypothesized that melatonin would display cytoprotective action in the vasculature by preventing cyclophosphamide-induced oxidative stress.

MATERIALS AND METHODS

Male C57BL/6 mice (22-25 g) were injected with a single dose of cyclophosphamide (300 mg/kg; i.p.). Mice were pretreated or not with melatonin (10 mg/kg/day, i.p.), given during 4 days before cyclophosphamide injection. Functional (vascular reactivity) and oxidative/inflammatory patterns were evaluated at 24 h in resistance arteries. The antioxidant action of melatonin was assessed in vitro in cultured vascular smooth muscle cells (VSMCs) of mesenteric arteries.

KEY FINDINGS

Cyclophosphamide induced ROS generation in both mesenteric arterial bed (MAB) and cultured VSMCs, and this was normalized by melatonin. Cyclophosphamide-induced ROS generation and lipoperoxidation in the bladder and kidney was also prevented by melatonin. Increased levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 were detected in the MAB of cyclophosphamide-treated mice, all of which were prevented by melatonin. Functional assays using second-order mesenteric arteries of cyclophosphamide-treated mice revealed a decrease in vascular contractility. Melatonin prevented vascular hypocontractility in the cyclophosphamide group. Melatonin partially prevented the decrease in myeloperoxidase (MPO) and N-acetyl-beta-D-glucosaminidase (NAG) activities in the MAB of the cyclophosphamide group.

SIGNIFICANCE

Melatonin may constitute a novel and promising therapeutic approach for management of the toxic effects induced by cyclophosphamide in the vasculature.

Metabolic resuscitation therapy in critically ill patients with sepsis and septic shock: A pilot prospective randomized controlled trial

The main purpose of our research was to further clarify the effectiveness and potential pathophysiological principles of metabolic resuscitation therapy in critically ill patients with sepsis and septic shock. We found that metabolic resuscitation therapy is beneficial for patients with sepsis and septic shock, shortening the length of intensive care unit (ICU) stay, reducing the duration of vasopressor use, and reducing the ICU mortality rate of patients with sepsis and septic shock, but it does not reduce the hospital mortality rate.

S-limonene protects the heart in an experimental model of myocardial infarction induced by isoproterenol: Possible involvement of mitochondrial reactive oxygen species

BACKGROUND

Myocardial infarction (MI) is associated with high mortality rates, despite the fact that there are therapies available. Importantly, excessive oxidative stress may contribute to ischemia/reperfusion injury leading to death related to MI. In this scenario, naturally occurring antioxidant compounds are an important source of possible therapeutic intervention. Thus, this study sought to elucidate the mechanisms of cardioprotection of s-limonene in an isoproterenol-induced MI animal model.

METHODS

Wistar rats were treated with 1 mg/kg s-limonene (SL) or 100 mg/kg N-acetylcysteine (NAC, positive control) once, 30 min after isoproterenol-induced MI (applied in two doses with a 24 h interval). The protective effects of SL in the heart were examined via the serum level of creatine kinase myocardial band (CK-MB), electrocardiographic profile, infarct size and histological parameters. Using isolated cardiomyocytes, we also assessed calcium transient amplitude, cytosolic and mitochondrial oxidative stress and the expression of proteins related to oxidative stress.

RESULTS

SL at a concentration of 1 mg/kg attenuated isoproterenol-induced MI injury, by preventing ST-segment elevation and QTc prolongation in the ECG. SL reduced the infarct size and collagen content in cardiac tissue. At the cellular level, SL prevented increased Ca²⁺, associated with attenuation of cytosolic and mitochondrial oxidative stress. These changes resulted in a reduction of the oxidized form of Ca²⁺ Calmodulin-Dependent Kinase II (CaMKII) and restored superoxide dismutase and glutathione peroxidase activity.

CONCLUSION

Our data show that s-limonene promotes cardioprotection against MI injury, probably through inhibition of increased Ca²⁺ and attenuation of oxidative stress via CaMKII.

Inhibition of Mammalian Target of Rapamycin Attenuates Recurrent Seizures Associated Cardiac Damage in a Zebrafish Kindling Model of Chronic Epilepsy

Sudden Unexpected Death in Epilepsy (SUDEP) is primarily linked with the cardiac irregularities that occur due to recurrent seizures. Our previous studies found a role of mTOR pathway activation in seizures-linked cardiac damage in a rat model. In continuation to the earlier work, the present study was devised to explore the role of rapamycin (mTOR inhibitor and clinically used immunosuppressive agent) in a zebrafish kindling model and associated cardiac damage. Adult zebrafish were incubated with increasing concentrations of rapamycin (1, 2 and, 4 μM), followed by pentylenetetrazole (PTZ) exposure to record seizure latency and severity. In another experiment, zebrafish were subjected to a standardized PTZ kindling protocol. The kindled fish were treated daily with rapamycin for up to 25 days, along with PTZ to record seizure severity. At the end, zebrafish heart was excised for carbonylation assay, gene expression, and protein quantification studies. In the acute PTZ convulsion test, treatment with rapamycin showed a significant increase in seizure latency and decreased seizure severity without any change in seizure incidence. Treatment with rapamycin also reduced the severity of seizures in kindled fish. The cardiac expressions of gpx, nppb, kcnh2, scn5a, mapk8, stat3, rps6 and ddit were decreased, whereas the levels of trxr2 and beclin 1 were increased following rapamycin treatment in kindled fish. Furthermore, rapamycin treatment also decreased p-mTOR expression and protein carbonyls level in the fish cardiac tissue. The present study concluded that rapamycin reduces seizures and associated cardiac damage by inhibiting mTOR activation in the zebrafish kindling model.

Andrographolide protects against isoproterenol-induced myocardial infarction in rats through inhibition of L-type Ca2+ and increase of cardiac transient outward K+ currents

Myocardial infarction (MI) is the irreversible injury of the myocardium caused by prolonged myocardial ischemia and is a major cause of heart failure and eventual death among ischemic patients. The present study assessed the protective potentials of andrographolide against isoproterenol-induced myocardial infarction in rats. Animals were randomly divided into four groups: Control (Ctr) group received 0.9% saline solution once daily for 21 days, Isoproterenol (Iso) group received 0.9% saline solution once daily for 19 days followed by 80 mg/kg/day of isoproterenol hydrochloride solution on day 20 and 21, Andrographolide (Andro) group received 20 mg/kg/day of andrographolide for 21 days, and Andrographolide plus Isoproterenol (Andro + Iso) group received 20 mg/kg/day of andrographolide for 21 days with co-administration of 80 mg/kg/day of isoproterenol hydrochloride solution on day 20 and 21. After all treatments, cardiac-specific parameters that define cardiac health and early subacute MI were measured in all groups using both biophysical and pharmacological assay methods. Isoproterenol administration significantly (P < 0.05) increased cardiac mass indexes, systemic cardiac biomarkers, infarct size and caused cardiac histological alterations; significantly (P < 0.05) increased heart rate, QRS & QTc intervals and caused ST-segment elevation; significantly (P < 0.05) increased myocytes shortening, action potential duration (APD), L-type Ca²⁺ current (I_Ca,L) density and significantly (P < 0.05) decreased transient outward K⁺ current (I_to) density typical of the early subacute MI. Interestingly, pretreatment with andrographolide prevented and or minimized these anomalies, notably, by reducing I_Ca,L density and increasing I_to density significantly. Therefore, andrographolide could be seen as a promising therapeutic agent capable of making the heart resistant to early subacute infarction and it could be used as template for the development of semisynthetic drug(s) for cardiac protection against MI.

Protection of clozapine-induced oxidative stress and mitochondrial dysfunction by kaempferol in rat cardiomyocytes

Clozapine (CLZ) is unusually efficient in psychotic diseases. Nonetheless, its use is confined due to potentially life-threatening adverse events, including cardiotoxicity. Since the cardiotoxicity of CLZ is mediated through the generation of active metabolites, free radical, and inflammation. Here, we tested this hypothesis that kaempferol (KP) as antioxidant and anti-inflammatory agent could attenuate CLZ-induced mitochondrial/lysosomal and oxidative damages in rat ventricular cardiomyocytes. Rat ventricular cardiomyocytes were isolated by collagenase perfusion. Then isolated cardiomyocytes were simultaneously treated with different concentrations of KP (10, 20, and 50 μM) and CLZ (50 μM) for 4 h at 37°C. After 4 h of incubation, using by flow cytometry and biochemical evaluations, the parameters of cellular toxicity including: cell viability, reactive oxygen species (ROS) formation, mitochondria membrane potential (ΔΨm) collapse, lysosomal membrane integrity, malondialdehyde, and oxidized/reduced glutathione were analyzed. The results showed that CLZ (50 μM) induced a significant increase in cytotoxicity, ROS formation, mitochondrial membrane potential collapse, lipid peroxidation, and oxidative stress while KP reverted the above toxic effect of CLZ on isolated cardiomyocytes. Our data suggest that KP prevents and reverses CLZ-induced oxidative and mitochondrial/lysosomal damages in isolated cardiomyocytes, providing an experimental basis for clinical treatment on CLZ-induced cardiotoxicity.

Ellagic acid alleviates clozapine‑induced oxidative stress and mitochondrial dysfunction in cardiomyocytes

Clozapine (CLZ) as an antipsychotic agent is very effective in treating of psychosis disorders and resistant schizophrenia, but the risk of severe cardiac toxicity effects restricts its clinical use. There are several interrelated hypotheses to explain clozapine-induced cardiotoxicity which all of them may be related to oxidative stress. Therefore, the current study investigated the harmful effects of clozapine on cardiomyocytes and assessed the cytoprotective effect of ellagic acid (EA). Freshly isolated adult rat ventricular cardiomyocytes were incubated for 4 h at 37 °C with 00.05% ethanol as control, CLZ (50 µM), CLZ (50 µM) + a series of EA concentrations (10, 20 and 50 µM) and EA (50 µM). To evaluate the protective effect of EA, the markers of cell viability, reactive oxygen species (ROS) formation, mitochondria membrane potential (ΔΨm) collapse, lysosomal membrane integrity, malondialdehyde (MDA) and oxidized/reduced glutathione (GSH/GSSG) content were checked by biochemical and flowcytometry techniques. Our results demonstrated that EA (10, 20 and 50 µM) effectively inhibited CLZ-induced cytotoxicity which is associated with ROS overproduction and amelioration of mitochondrial and lysosomal damages. In addition, EA (10, 20 and 50 µM) in the presence of CLZ reduced the production of MDA as a specific marker lipid peroxidation and GSSG. Collectively, these findings suggested that EA protects cardiomyocytes from oxidative injury through inhibiting ROS formation, mitochondria dysfunction, and lysosomal damages, which suggest a potential therapeutic strategy of EA for CLZ-induced oxidative stress and cardiotoxicity.

Effects of thiamine on vasopressor requirements in patients with septic shock: a prospective randomized controlled trial

Background

Thiamine, an essential vitamin for aerobic metabolism and glutathione cycling, may decrease the effects of critical illnesses. The objective of this study was to determine whether intravenous thiamine administration can reduce vasopressor requirements in patients with septic shock.

Methods

This study was a prospective randomized double-blind placebo-controlled trial. We included adult patients with septic shock who required a vasopressor within 1–24 h after admission between March 2018 and January 2019 at a tertiary hospital in Thailand. Patients were divided into two groups: those who received 200 mg thiamine or those receiving a placebo every 12 h for 7 days or until hospital discharge. The primary outcome was the number of vasopressor-free days over 7 days. The pre-defined sample size was 31 patients per group, and the study was terminated early due to difficult recruitment.

Results

Sixty-two patients were screened and 50 patients were finally enrolled in the study, 25 in each group. There was no difference in the primary outcome of vasopressor-free days within the 7-day period between the thiamine and placebo groups (mean: 4.9 days (1.9) vs. 4.0 days (2.7), p = 0.197, mean difference − 0.9, 95% CI (− 2.9 to 0.5)). However, the reductions in lactate (p = 0.024) and in the vasopressor dependency index (p = 0.02) at 24 h were greater among subjects who received thiamine repletion vs. the placebo. No statistically significant difference was observed in SOFA scores within 7 days, vasopressor dependency index within 4 days and 7 days, or 28-day mortality.

Conclusions

Thiamine was not associated to a significant reduction in vasopressor-free days over 7-days in comparison to placebo in patients with septic shock. Administration of thiamine could be associated with a reduction in vasopressor dependency index and lactate level within 24 h. The study is limited by early stopping and low sample size.

Trial registration

TCTR, TCTR20180310001. Registered 8 March 2018, http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trialsearch&smenu=fulltext&task=search&task2=view1&id=3330.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s12871-020-01195-4.

Thiamine (vitamin B1) in septic shock: a targeted therapy

Thiamine (vitamin B1) is a water-soluble vitamin essential for human health. Thiamine deficiency is causal and/or contributory in a number of debilitating diseases including beri-beri, the Wernicke-Korsakoff syndrome, optic neuropathy, and others. While thiamine deficiency is relatively rare in developed nations as a result of dietary supplementation, thiamine deficiency is more common in nutritionally compromised populations. Thiamine pyrophosphate, a thiamine derivative, is essential to the citric acid cycle and thiamine deficiency can result in impaired aerobic respiration and cellular energy production. Thiamine also plays an important role in the pentose phosphate pathway and other key metabolic processes. Although thiamine deficiency is a known cause of lactic acidosis, it has been recently evaluated as a potential contributor to refractory lactic acidosis and organ injury in septic shock and other shock states. In this article, we review the epidemiology of thiamine deficiency in septic shock and the existing evidence base supporting thiamine supplementation. We conclude that specific sepsis phenotypes may stand to benefit the most from thiamine supplementation, and efforts might be made to identify and supplement these patients early in their hospital course.

Ascorbic Acid, Thiamine, and Steroids in Septic Shock: Propensity Matched Analysis

INTRODUCTION

We aimed to study the use of ascorbic acid, thiamine, and steroids (ATS) in patients with septic shock (SS).

METHODS

Data on 62 patients with SS were collected from Acute Physiologic and Chronic Health Evaluation (APACHE) Outcome database and medical records. The ATS group received full doses of intravenous (IV) ATS (ascorbic acid [1.5 g every 6 hours for 4 days], hydrocortisone [50 mg every 6 hours for 7 days], and thiamine [200 mg every 12 hours for 4 days]). Data included age, gender, APACHE III, acute physiologic score (APS), mechanical ventilation (MV), lactic acid (LA), serum creatinine (Cr), duration of vasopressors (VP, days, median: interquartile ranges [IQR]: [Q1, Q3]), MV-free days (median: IQR [Q1-Q3]), percentage of patients requiring renal replacement therapy (RRT) for acute kidney injury (AKI), and mortality. Propensity analysis was used to match patients on age, gender, MV, APACHE III, APS, LA, and Cr.

RESULTS

The ATS group had longer duration of VP (4.5: 4.0-6.0 vs 2.0: 1.0-2.0, P = .001), similar RRT for AKI (26% vs 29%, P = .8), similar MV-free days (10.2: 5.0-15.0 vs 10.2: 1.6-18.0, P > .9), lower intensive care unit mortality (9.6% vs 42%, P = .004), and a trend toward lower hospital mortality (29% vs 45%, P = .2) compared to the NO ATS group.

CONCLUSIONS

The use of IV ascorbic acid, thiamine, and hydrocortisone might be beneficial in patients with SS.

Benfotiamine supplementation prevents oxidative stress in anterior tibialis muscle and heart

OBJECTIVE

This study aimed to evaluate the influence of oral supplementation with benfotiamine on oxidative stress in the liver, heart and muscles of endurance-trained mice.

METHODS

Twenty-five male BALB/c mice were allocated to the following treatment groups: standard diet and sedentary activity (Sta-Sed), benfotiamine-supplemented diet and sedentary activity (Ben-Sed), standard diet and training activity (Sta-Tr) and benfotiamine-supplemented diet and training activity (Ben-Tr). The training comprised 6 weeks of endurance swimming training. The concentration of thiobarbituric acid reactive substances (TBARS), carbonylated proteins, total thiols and non-protein thiols was analyzed in the liver, heart and tibialis anterior muscle.

RESULTS

In the muscle, TBARS concentration in the Sta-Sed group was higher than that in other groups; in the heart, TBARS concentration in the Sta-Sed and Ben-Tr groups was higher than that in the Ben-Sed group. The carbonyl content of the muscle tissues was higher in the Sta-Sed group than in both supplemented groups. In liver, the carbonyl content was lower in the Ben-Sed group than in the Sta-Sed group. The level of total thiols was lower in the Ben-Sed group than in the Sta-Tr group. In the heart, the level of total thiols was higher in the Ben-Sed group than in the Ben-Tr group. The concentration of non-protein thiols in the muscle was higher in the Ben-Sed group than in the Ben-Tr group, whereas in the heart, concentration of non-protein thiols of Sta-Tr group was lower than that of Sta-Sed group.

CONCLUSION

The results show that benfotiamine is an efficient antioxidant for the anterior tibialis muscle and heart; however, swimming training did not alter redox status.

Increased oxidative stress and CaMKII activity contribute to electro-mechanical defects in cardiomyocytes from a murine model of Huntington's disease

Huntington's disease (HD) is a neurodegenerative genetic disorder. Although described as a brain pathology, there is evidence suggesting that defects in other systems can contribute to disease progression. In line with this, cardiovascular defects are a major cause of death in HD. To date, relatively little is known about the peripheral abnormalities associated with the disease. Here, we applied a range of assays to evaluate cardiac electro-mechanical properties in vivo, using a previously characterized mouse model of HD (BACHD), and in vitro, using cardiomyocytes isolated from the same mice. We observed conduction disturbances including QT interval prolongation in BACHD mice, indicative of cardiac dysfunction. Cardiomyocytes from these mice demonstrated cellular electro-mechanical abnormalities, including a prolonged action potential, arrhythmic contractions, and relaxation disturbances. Cellular arrhythmia was accompanied by an increase in calcium waves and increased Ca²⁺ /calmodulin-dependent protein kinase II activity, suggesting that disruption of calcium homeostasis plays a key part. We also described structural abnormalities in the mitochondria of BACHD-derived cardiomyocytes, indicative of oxidative stress. Consistent with this, imbalances in superoxide dismutase and glutathione peroxidase activities were detected. Our data provide an in vivo demonstration of cardiac abnormalities in HD together with new insights into the cellular mechanistic basis, providing a possible explanation for the higher cardiovascular risk in HD.

Hydrocortisone, Ascorbic Acid and Thiamine (HAT Therapy) for the Treatment of Sepsis. Focus on Ascorbic Acid

Sepsis is a devastating disease that carries an enormous toll in terms of human suffering and lives lost. Over 100 novel pharmacologic agents that targeted specific molecules or pathways have failed to improve the outcome of sepsis. Preliminary data suggests that the combination of Hydrocortisone, Ascorbic Acid and Thiamine (HAT therapy) may reduce organ failure and mortality in patients with sepsis and septic shock. HAT therapy is based on the concept that a combination of readily available, safe and cheap agents, which target multiple components of the host’s response to an infectious agent, will synergistically restore the dysregulated immune response and thereby prevent organ failure and death. This paper reviews the rationale for HAT therapy with a focus on vitamin C.

Ascorbic acid, corticosteroids, and thiamine in sepsis: a review of the biologic rationale and the present state of clinical evaluation

The combination of thiamine, ascorbic acid, and hydrocortisone has recently emerged as a potential adjunctive therapy to antibiotics, infectious source control, and supportive care for patients with sepsis and septic shock. In the present manuscript, we provide a comprehensive review of the pathophysiologic basis and supporting research for each element of the thiamine, ascorbic acid, and hydrocortisone drug combination in sepsis. In addition, we describe potential areas of synergy between these therapies and discuss the strengths/weaknesses of the two studies to date which have evaluated the drug combination in patients with severe infection. Finally, we describe the current state of current clinical practice as it relates to the thiamine, ascorbic acid, and hydrocortisone combination and present an overview of the randomized, placebo-controlled, multi-center Ascorbic acid, Corticosteroids, and Thiamine in Sepsis (ACTS) trial and other planned/ongoing randomized clinical trials.

Oxidative Stress Upregulates the Transcription of Genes Involved in Thiamine Metabolism

Thiamine is a major vitamin that acts as a cofactor in energy metabolism in all organisms, as well as in lipid and amino acid metabolisms, and is associated with many diseases. It is known that glucose starvation decreases the intracellular thiamine pool while increasing oxidative stress tolerance. Earlier, in whole genome analysis, we detected major differences in the expression of genes related to thiamine pathway against oxidative stress in Schizosaccharomyces pombe. We investigated the effects of oxidative stress and glucose repression to thiamine pathway in S. pombe by comparing some genes encoding key enzymes of each related pathway at the transcription level. In the present study, we found that the expression of genes related to thiamine biosynthesis and transport (thi2, thi3, and pho1) increased in wild type and ird11 cells grown in thiamine-rich media under oxidative stress induced by H2O2. Based on our findings, we suggested that there might be an important effect of oxidative stress on thiamine biosynthesis and transport.

Clozapine, ziprasidone, and sertindole-induced morphological changes in the rat heart and their relationship to antioxidant enzymes function

Atypical antipsychotics produce severe side effects including myocarditis that may be attributed to oxidative stress. The aim of this study was to investigate the influence of clozapine, ziprasidone, and sertindole on rat heart morphology and determine whether redox imbalane plays a role in development of histopathological changes. Adult 3-month-old male Wistar rats were treated with recommended daily dose for selected drugs. After 4 week treatment histopathological analysis of the heart was performed and expression and activity of antioxidant enzymes determined. All examined drugs induced histopathological changes that were characterized as toxic myocarditis. Degenerative changes in cardiomyocytes were accompanied by lymphocytic infiltration as well as pericardial histopathological alterations in all treated groups. The least prominent changes were observed in sertindole-treated animals, and most severe with clozapine. Clozapine increased superoxide dismutase 1 (SOD1) activity while ziprasidone reduced glutathione reductase (GR) activity. Sertindole exerted no marked effect on antioxidant enzyme function in the heart even though myocardial degeneration was noted. In conclusion, treatment with clozapine or ziprasidone induced pathophysiological alterations in rat heart, which appeared to be associated disturbances in antioxidant capacity. Abbreviation: AAP, Atypical antipsychotics; ROS, reactive oxygen species; SOD1, Copper-zinc superoxide dismutase; SOD2, Manganese superoxide dismutase; CAT, Catalase; GPx, Glutathione peroxidase; GR, Glutathione reductase; H&E, hematoxylin and eosin stain; TNF- α, tumor necrosis factor alpha.

Thiamine as a Renal Protective Agent in Septic Shock. A Secondary Analysis of a Randomized, Double-Blind, Placebo-controlled Trial

RATIONALE

Acute kidney injury (AKI) is common in patients with sepsis and has been associated with high mortality rates. The provision of thiamine to patients with sepsis may reduce the incidence and severity of sepsis-related AKI and thereby prevent renal failure requiring renal replacement therapy (RRT).

OBJECTIVES

To test the hypothesis that thiamine supplementation mitigates kidney injury in septic shock.

METHODS

This was a secondary analysis of a single-center, randomized, double-blind trial comparing thiamine to placebo in patients with septic shock. Renal function, need for RRT, timing of hemodialysis catheter placement, and timing of RRT initiation were abstracted. The baseline creatinine and worst creatinine values between 3 and 24 hours, 24 and 48 hours, and 48 and 72 hours were likewise abstracted.

RESULTS

There were 70 patients eligible for analysis after excluding 10 patients in whom hemodialysis was initiated before study drug administration. Baseline serum creatinine in the thiamine group was 1.2 mg/dl (interquartile range, 0.8-2.5) as compared with 1.8 mg/dl (interquartile range, 1.3-2.7) in the placebo group (P = 0.3). After initiation of the study drug, more patients in the placebo group than in the thiamine group were started on RRT (eight [21%] vs. one [3%]; P = 0.04). In the repeated measures analysis adjusting for the baseline creatinine level, the worst creatinine levels were higher in the placebo group than in the thiamine group (P = 0.05).

CONCLUSIONS

In this post hoc analysis of a randomized controlled trial, patients with septic shock randomized to receive thiamine had lower serum creatinine levels and a lower rate of progression to RRT than patients randomized to placebo. These findings should be considered hypothesis generating and can be used as a foundation for further, prospective investigation in this area.

Effect of blood thiamine concentrations on mortality: Influence of nutritional status

OBJECTIVE

To test the hypothesis that low blood thiamine concentrations in malnourished critically ill children are associated with higher risk of 30-d mortality.

METHODS

Prospective cohort study in 202 consecutively admitted children who had whole blood thiamine concentrations assessed on admission and on days 5 and 10 of intensive care unit (ICU) stay. The primary outcome variable was 30-d mortality. Mean blood thiamine concentrations within the first 10 d of ICU stay, age, sex, malnutrition, C-reactive protein concentration, Pediatric Index of Mortality 2 score, and severe sepsis/septic shock were the main potential exposure variables for outcome.

RESULTS

Thiamine deficiency was detected in 61 patients within the first 10 d of ICU stay, 57 cases being diagnosed on admission and 4 new cases on the 5th d. C-reactive protein concentration during ICU stay was independently associated with decreased blood thiamine concentrations (P = 0.003). There was a significant statistical interaction between mean blood thiamine concentrations and malnutrition on the risk of 30-d mortality (P = 0.002). In an adjusted analysis, mean blood thiamine concentrations were associated with a decrease in the mortality risk in malnourished patients (odds ratio = 0.85; 95% confidence interval [CI]: 0.73-0.98; P = 0.029), whereas no effect was noted for well-nourished patients (odds ratio: 1.03; 95% CI: 0.94-1.13; P = 0.46).

CONCLUSIONS

Blood thiamine concentration probably has a protective effect on the risk of 30-d mortality in malnourished patients but not in those who were well nourished.

Thiamine Deficiency Induced Dietary Disparity Promotes Oxidative Stress and Neurodegeneration

Thiamine or vitamin B1 is a well known coenzyme and nutrient necessary for the assembly and right functioning of several enzymes involved in the energy metabolism. The present study evaluates oxidative stress and prevalence of neurodegenerative conditions in the brain following TD. The study was carried out on mice (Musmusculus) in three groups, namely control and thiamine-deficient group for 8 (TD 8) and 10 (TD 10) days. Lipid peroxidation was determined in terms of reduced glutathione (GSH) and thiobarbituric acid reactive substance (TBARS). The level of antioxidant enzymes such as catalase (CAT), glutathione reductase, glutathione peroxidase (GPx), superoxide dismutase (SOD) and glutathione transferase (GST) were measured along with histopathological studies in all the groups. There was significant increase in the TBARS levels in group II (TD 8) and group III (TD 10) animals in comparison to controls (Group I). The GSH levels were found to be lower in both the treated groups. The level of antioxidant enzymes CAT (p < 0.001), glutathione reductase (p < 0.001), GPx (p < 0.001), SOD (p < 0.0001) were found to be significantly reduced in group III (TD 10) in comparison to controls. Histopathological studies showed moderated to extensive neuronal loss in group II and group III in comparison to control group. The increase in LPO and reduction in enzymes CAT, glutathione reductase, GPx, SOD, and GST following TD suggests mitochondrial dysfunction, neuronal loss acute oxidative stress that may impair the functioning of the brain along with the rise of neurodegenerative conditions in the affected animals.

HDAC2 is required by the physiological concentration of glucocorticoid to inhibit inflammation in cardiac fibroblasts

We previously suggested that endogenous glucocorticoids (GCs) may inhibit myocardial inflammation induced by lipopolysaccharide (LPS) in vivo. However, the possible cellular and molecular mechanisms were poorly understood. In this study, we investigated the role of physiological concentration of GCs in inflammation induced by LPS in cardiac fibroblasts and explored the possible mechanisms. The results showed that hydrocortisone at the dose of 127 ng/mL (equivalent to endogenous basal level of GCs) inhibited LPS (100 ng/mL)-induced productions of TNF-α and IL-1β in cardiac fibroblasts. Xanthine oxidase/xanthine (XO/X) system impaired the anti-inflammatory action of GCs through downregulating HDAC2 activity and expression. Knockdown of HDAC2 restrained the anti-inflammatory effects of physiological level of hydrocortisone, and blunted the ability of XO/X system to downregulate the inhibitory action of physiological level of hydrocortisone on cytokines. These results suggested that HDAC2 was required by the physiological concentration of GC to inhibit inflammatory response. The dysfunction of HDAC2 induced by oxidative stress might be account for GC resistance and chronic inflammatory disorders during the cardiac diseases.

Maternal low-protein diet in female rat heart: possible protective effect of estradiol

Several studies have shown that maternal low-protein (LP) diet induces detrimental effects in cardiovascular system and oxidative stress in male animals. Additional studies suggested that female has lower incidence of cardiovascular disease. However until present data, the possible effects of estradiol on the undernutrition during gestational and lactation periods are not discussed. The present study was conducted to evaluate the effects of a maternal LP diet during gestational and lactation period on oxidative balance in the female rat hearts ventricles at two ages. Dams were fed with normal protein (NP) or a LP diet during the gestational and lactation period, and their female offspring were divided into age groups (22 or 122 days, corresponding to a low or high estrogen level) composing four experimental groups. Evaluating the nutritional effect showed an increase in oxidative stress biomarkers and decrease in enzymatic defense in LP-22D compared with NP-22D. In contrast, no changes were observed in malondialdehyde and carbonyls, but an increase in glutathione-S-transferase (GST) activity in the LP-122D compared with NP-122D. The global oxy-score in the LP-22D group indicated a predominance of oxidative damage when compared with NP-22D, while in LP-122D group the global oxy-score was restored to NP-122D levels. Evaluating the estradiol effect, our data show a significant decrease in oxidative stress with increase in CAT and GST activity, associated with increase in intracellular thiols. Our data suggest that in situation with low levels of estradiol, hypoproteic diet during gestation and lactation period has detrimental effects on heart, however when estradiol levels raise, the detrimental effects induced are mitigated.

Electrical properties of isolated cardiomyocytes in a rat model of thiamine deficiency

In modern society, thiamine deficiency (TD) remains an important medical condition linked to altered cardiac function. There have been contradictory reports about the impact of TD on heart physiology, especially in the context of cardiac excitability. In order to address this particular question, we used a TD rat model and patch-clamp technique to investigate the electrical properties of isolated cardiomyocytes from epicardium and endocardium. Neither cell type showed substantial differences on the action potential waveform and transient outward potassium current. Based on our results we can conclude that TD does not induce major electrical remodeling in isolated cardiac myocytes in either endocardium or epicardium cells.

Clozapine-induced cardiotoxicity in rats: Involvement of tumour necrosis factor alpha, NF-κβ and caspase-3

Clozapine, an ideal antipsychotic drug for the treatment of resistant schizophrenia, is considered the most underutilised treatment for schizophrenia. However, safety concerns have been raised about clozapine-induced cardiotoxicity, which may lead to sudden death, particularly in young patients. The exact mechanism of clozapine cardiotoxicity has not yet been thoroughly studied. This study aimed to investigate the possible mechanisms of clozapine-induced cardiotoxicity in a rat model. Young male Wistar rats were treated with clozapine (10, 15 and 25 mg/kg/day, i.p.) for 21 days. Haemodynamic and echocardiographic studies were performed for assessment of cardiac functions. Heart sections were studied histopathologically and immunohistochemically. Serum and cardiac markers of cardiotoxicity, oxidative stress, inflammation and apoptosis were evaluated. Heart sections of CLZ-treated animals showed increased cardiac inflammation that correlated with the clozapine dose. Serum levels of CK-MB and LDH levels increased, as did cardiac levels of TNF-α, MDA, NO, myeloperoxidase (MPO), 8-OHdG, caspase-3 and NF-κB p65. In contrast, GSH levels and GSH-Px activity decreased. Furthermore, immunohistochemical examination of the heart sections showed positive immunostaining for both 3-nitrotyrosine and caspase-3 in all clozapine-treated groups. Clozapine, particularly in relatively high doses, has a clear cardiotoxic effect. This cardiotoxicity is accompanied by increased myocardial oxidative stress, inflammatory cytokines, DNA damage and apoptosis with attenuation in antioxidant defences, thus explaining the previously reported myocarditis and pericarditis during clozapine therapy in clinical studies.

A potential link among antioxidant enzymes, histopathology and trace elements in canine visceral leishmaniasis

Canine visceral leishmaniasis (CVL) is a severe and fatal systemic chronic inflammatory disease. We investigated the alterations in, and potential associations among, antioxidant enzymes, trace elements and histopathology in CVL. Blood and tissue levels of Cu-Zn superoxide dismutase, catalase and glutathione peroxidase were measured in mixed-breed dogs naturally infected with Leishmania infantum chagasi, symptomatic (n = 19) and asymptomatic (n = 11). Serum levels of copper, iron, zinc, selenium and nitric oxide, and plasma lipid peroxidation were measured. Histological and morphometric analyses were conducted of lesions in liver, spleen and lymph nodes. We found lower blood catalase and glutathione peroxidase activity to be correlated with lower iron and selenium respectively. However, higher activity of Cu-Zn superoxide dismutase was not correlated with the increase in copper and decreased in zinc observed in infected animals compared to controls. Organ tissue was characterized by lower enzyme activity in infected dogs than in controls, but this was not correlated with trace elements. Lipid peroxidation was higher in symptomatic than in asymptomatic and control dogs and was associated with lesions such as chronic inflammatory reaction, congestion, haemosiderin and fibrosis. Systemic iron deposition was observed primarily in the symptomatic dogs showing a higher tissue parasite load. Dogs with symptomatic CVL displayed enhanced LPO and Fe tissue deposition associated with decreased levels of antioxidant enzymes. These results showed new points in the pathology of CVL and might open new treatment perspectives associated with antioxidants and the role of iron in the pathogenesis of CVL.

The effect of thiamine deficiency on inflammation, oxidative stress and cellular migration in an experimental model of sepsis

Background

Sepsis is a prevalent condition in critically ill patients and may be associated with thiamine deficiency (TD). The aim of this study was to evaluate the effect of TD on inflammation, oxidative stress and cellular recruitment in a sepsis model.

Methods

The experimental sepsis model, cecal ligation and puncture (CLP), was utilized on mice in comparison with a sham procedure. The following four groups were compared against each other: SHAM with AIN93G complete chow, SHAM with thiamine deficient (TD) chow, CLP with AIN93G complete chow, and CLP with TD chow. Thiamine pyrophosphate (TPP) blood concentrations were determined, and blood and peritoneal fluid were evaluated for differences in TNF-alpha, IL-1, IL-6, KC and MCP-1/CCL2 levels. In addition, the levels of 4-HNE adducts in liver proteins were evaluated by Western Blot.

Results

The mean TPP blood concentration from the mice fed with the complete chow was 303.3 ± 42.6 nmol/L, and TD occurred within 10 days. TNF-α and MCP-1 concentrations in the peritoneal fluid were significantly greater in the CLP with TD chow group when compared with the other groups. The blood IL-1β level, however, was lower in the CLP with TD chow group. Liver 4-HNE levels were highest in the TD chow groups. Blood mononuclear cell numbers, as well as peritoneal total leukocyte, mononuclear cell and neutrophil numbers were greater in the CLP with TD chow group. Peritoneal bacterial colony forming units (CFU) were significantly lower in the CLP with TD chow group.

Conclusion

TD was associated with greater bacterial clearance, oxidative stress and inflammatory response changes.

Thiamine deficiency leads to reduced nitric oxide production and vascular dysfunction in rats

BACKGROUND AND AIMS

Thiamine deficiency is a condition that is known to cause damage to the nervous and cardiovascular systems because it interferes with cellular metabolism. It is well known that the control of vascular function is highly dependent on the production of nitric oxide (NO) by NO synthases. Studies exploring the physiological relevance of NO signaling under conditions of thiamine deficiency are scarce. The present study sought to investigate whether chronic metabolic changes would cause alterations in vascular responsiveness.

METHODS AND RESULTS

By removing thiamine from the diet, we observed a reduced acetylcholine-mediated relaxation and an increased phenylephrine-mediated vasoconstriction in the aortas containing functional endothelium. Removal of the endothelium or the pre-treatment of vessels with l-NAME restored the contractile responses to the level of controls. Conversely, indomethacin did not modify phenylephrine-mediated contractions. We also used carbon microsensors to continually measure NO production in situ while simultaneously measuring the vascular tone. The results revealed a significant decrease in NO production. Western blot analysis showed a decreased expression of the total eNOS in the thiamine-deficient aorta compared to the control. Concentration-response curves for phenylephrine indicated no difference between the control and deficient groups in the presence and absence of SOD or Tyron. The NO donor DEA-NONOate produced a concentration-dependent relaxation response in the endothelium-denuded vessels that did not differ between the control and thiamine-deficient rats.

CONCLUSION

Thiamine deficiency modulates eNOS-dependent NO production, leading to a decreased vasorelaxation and an increased contractile response in the rat aorta.

Current aspects of thiamine deficiency on heart function

Beriberi is a disease caused by thiamine deficiency (TD), which may lead to heart problems, including heart failure. Despite the fact that thiamine prevalence is reduced in the industrialized world, it remains a health hazard especially due to chronic alcohol consumption. Diagnosing the presence of TD based on both electrocardiogram and echocardiogram exams is particularly challenging because of its non-specific symptoms. TD diagnosis is unique, which then leads to determination of its severity. If thiamine infusion abrogates its symptomology, only then can the case be definitely diagnosed as TD. Another condition eliciting increased likelihood of developing TD in humans is furosemide administration to heart failure patients. Furosemide administration worsens heart failure due to heightened TD. However, literature data provided are contradictory and require clarification. Up until now, the rat has been the preferred TD animal model. However, the results are even more contradictory than those in humans. It seems that if the rat TD models are separated into two distinct groups, according to animal age, the results appear to be more consistent: younger rats are more prone to develop TD signs similar to those found in humans. Their symptoms stem from changes in cardiac myocyte function that are reversed after thiamine supplementation. However, it remains an open question as to why only younger rats are able to develop human-like symptoms and deserve further investigation.

Thiamin concentration in geriatric hospitalized patients using frusemide

AIM

To assess the association between thiamin concentration, frusemide use, and renal function in older adults.

METHOD

Thiamin concentration was measured in 73 consecutive admissions of patients aged over 65 years in a secondary care hospital. The patients were assigned to the study or control group based on frusemide use. A two-sample t test estimated the association between frusemide use and thiamin concentration and regression between thiamin concentration and EGFR.

RESULTS

The mean (SD) thiamin concentration was 181.7 (64.6) nmol/L in those using frusemide and 169.3 (46.8) in non-users, P =0.35. There was a weak linear relationship between thiamin concentration and EGFR, with thiamin concentration being 17.0 nmol/L lower per 30 ml/min greater EGFR, P=0.076. Thiamin concentration was below the reference range in 20/73 (27.4%) of the participants.

CONCLUSION

We found no association between frusemide use and thiamin concentration, but showed a significant prevalence of lower thiamin concentration in the study population of older adults.

Serum thiamine concentration and oxidative stress as predictors of mortality in patients with septic shock

PURPOSE

The purpose of the study is to determine the influence of serum thiamine, glutathione peroxidase (GPx) activity, and serum protein carbonyl concentrations in hospital mortality in patients with septic shock.

MATERIALS AND METHODS

This prospective study included all patients with septic shock on admission or during intensive care unit (ICU) stay, older than 18 years, admitted to 1 of the 3 ICUs of the Botucatu Medical School, from January to August 2012. Demographic information, clinical evaluation, and blood sample were taken within the first 72 hours of the patient's admission or within 72 hours after septic shock diagnosis for serum thiamine, GPx activity, and protein carbonyl determination.

RESULTS

One hundred eight consecutive patients were evaluated. The mean age was 57.5 ± 16.0 years, 63% were male, 54.6% died in the ICU, and 71.3% had thiamine deficiency. Thiamine was not associated with oxidative stress. Neither vitamin B1 levels nor the GPx activity was associated with outcomes in these patients. However, protein carbonyl concentration was associated with increased mortality.

CONCLUSIONS

In patients with septic shock, oxidative stress was associated with mortality. On the other hand, thiamine was not associated with oxidative stress or mortality in these patients.

The role of thiamine in HIV infection

Patients infected with HIV have a high prevalence of thiamine deficiency. Genetic studies have provided the opportunity to determine which proteins link thiamine to HIV pathology, i.e., renin-angiotensin system, poly(ADP-ribosyl) polymerase 1, Sp1 promoter gene, transcription factor p53, apoptotic factor caspase 3, and glycogen synthetase kinase 3β. Thiamine also affects HIV through non-genomic factors, i.e., matrix metalloproteinase, vascular endothelial growth factor, heme oxygenase 1, the prostaglandins, cyclooxygenase 2, reactive oxygen species, and nitric oxide. In conclusion, thiamine may benefit HIV patients, but further investigation of the role of thiamine in HIV infection is needed.

Effects of endurance training on apoptotic susceptibility in striated muscle

An increase in the production of reactive oxygen species occurs with muscle disuse, ischemic cardiomyopathy, and conditions that arise with senescence. The resulting oxidative stress is associated with apoptosis-related myopathies. Recent research has suggested that chronic exercise is protective against mitochondrially mediated programmed cell death. To further investigate this, we compared soleus (Sol) and cardiac muscles of voluntary wheel-trained (T; 10 wk) and untrained (C) animals. Training produced a 52% increase in muscle cytochrome c oxidase (COX) activity. Sol and left ventricle (LV) strips were isolated and incubated in vitro with H2O2 for 4 h. Strips were then fractionated into cytosolic and mitochondrial fractions. Whole muscle apoptosis-inducing factor (AIF) and Bax/Bcl-2 levels were reduced in both the Sol and LV from T animals. H2O2 treatment induced increases in JNK phosphorylation, cofilin-2 localization to the mitochondria, as well as cytosolic AIF in both Sol and LV of T and C animals, respectively. Mitochondrial Bax and cytosolic cytochrome c were augmented under oxidative stress in the LV only. The H2O2-induced increases in P-JNK, mitochondrial Bax, and cytosolic AIF were ablated in the LV of T animals. These data suggest that short-term oxidative stress can induce apoptotic signaling in striated muscles in vitro. In addition, training can attenuate oxidative stress-induced apoptotic signaling in a tissue-specific manner, with an effect that is most prominent in cardiac muscle.

Cardiac beriberi: morphological findings in two fatal cases

Cardiovascular beriberi is categorized into two main groups, according to its cause: alcoholic and non-alcoholic (dietary). Cardiovascular beriberi can also be divided into a fulminant form (Shoshin beriberi) and a chronic form. Shoshin beriberi is characterized by hypotension, tachycardia, and lactic acidosis and is mainly encountered in non-alcoholic patients in Asian countries, although it has also been seen in alcoholics in Western countries. Due to the complex clinical presentation and to the lack of diagnostic tests, thiamine deficiency is still being missed, especially among non-alcoholics patients. We present two fatal cases of non - alcohol associated cardiac beriberi. An acute myocardial infarction was observed in one case; extensive colliquative myocytolisis (grade 2) was described in the second case respectively. Morphologically, myocardial necrosis and colliquative myocytolysis are the histologic hallmarks of this acute, rare clinical entity. An increase in apoptotic myocytes was demonstrated probably sustaining the cardiogenic shock.

Effect of chronic kidney disease on the expression of thiamin and folic acid transporters

BACKGROUND

Chronic kidney disease (CKD) is associated with significant cardiovascular, neurological and metabolic complications. Thiamin and folate are essential for growth, development and normal cellular function, and their uptake is mediated by regulated transport systems. While plasma folate and thiamin levels are generally normal in patients with CKD, they commonly exhibit features resembling vitamin deficiency states. Earlier studies have documented impaired intestinal absorption of several B vitamins in experimental CKD. In this study, we explored the effect of CKD on expression of folate and thiamin transporters in the key organs and tissues.

METHODS

Sprague-Dawley rats were randomized to undergo 5/6 nephrectomy or sham operation and observed for 12 weeks. Plasma folate and thiamin concentrations and gene expression of folate (RFC, PCFT) and thiamin transporters (THTR-1 and THTR-2) were determined in the liver, brain, heart and intestinal tissues using real-time PCR. Hepatic protein abundance of these transporters was determined using western blot analysis.

RESULTS

Plasma folate and thiamin levels were similar between the CKD and the control groups. However, expressions of both folate (RFC and PCFT) and thiamin (THTR-1, THTR-2) transporters were markedly reduced in the small intestine, heart, liver and brain of the CKD animals. Liver protein abundance of folate and thiamin transporters was significantly reduced in the CKD animals when compared with the sham-operated controls. Furthermore, we found a significant reduction in mitochondrial folate and thiamin transporters in the CKD animals.

CONCLUSIONS

CKD results in marked down-regulation in the expression of folate and thiamin transporters in the intestine, heart, liver and brain. These events can lead to reduced intestinal absorption and impaired cellular homeostasis of these essential micronutrients despite their normal plasma levels.

Thiamine status in humans and content of phosphorylated thiamine derivatives in biopsies and cultured cells

Background

Thiamine (vitamin B1) is an essential molecule for all life forms because thiamine diphosphate (ThDP) is an indispensable cofactor for oxidative energy metabolism. The less abundant thiamine monophosphate (ThMP), thiamine triphosphate (ThTP) and adenosine thiamine triphosphate (AThTP), present in many organisms, may have still unidentified physiological functions. Diseases linked to thiamine deficiency (polyneuritis, Wernicke-Korsakoff syndrome) remain frequent among alcohol abusers and other risk populations. This is the first comprehensive study on the distribution of thiamine derivatives in human biopsies, body fluids and cell lines.

Methodology and Principal Findings

Thiamine derivatives were determined by HPLC. In human tissues, the total thiamine content is lower than in other animal species. ThDP is the major thiamine compound and tissue levels decrease at high age. In semen, ThDP content correlates with the concentration of spermatozoa but not with their motility. The proportion of ThTP is higher in humans than in rodents, probably because of a lower 25-kDa ThTPase activity. The expression and activity of this enzyme seems to correlate with the degree of cell differentiation. ThTP was present in nearly all brain and muscle samples and in ∼60% of other tissue samples, in particular fetal tissue and cultured cells. A low ([ThTP]+[ThMP])/([Thiamine]+[ThMP]) ratio was found in cardiovascular tissues of patients with cardiac insufficiency. AThTP was detected only sporadically in adult tissues but was found more consistently in fetal tissues and cell lines.

Conclusions and Significance

The high sensitivity of humans to thiamine deficiency is probably linked to low circulating thiamine concentrations and low ThDP tissue contents. ThTP levels are relatively high in many human tissues, as a result of low expression of the 25-kDa ThTPase. Another novel finding is the presence of ThTP and AThTP in poorly differentiated fast-growing cells, suggesting a hitherto unsuspected link between these compounds and cell division or differentiation.