The Oxidative Status and Na+/K+-ATPase Activity in Obsessive-Compulsive Disorder: A Case Control Study

Background

Oxidative stress is involved in pathogenesis of some psychiatric disorders. To examine the role of oxidative stress in the etiopathogenesis of obsessive-compulsive disorder (OCD), we aimed to determine oxidative stress indices, including malondialdehyde (MDA) levels in serum and red blood cells (RBC) membrane, total antioxidant capacity (TAC), serum glutathione (GSH) levels, serum antioxidant vitamins (A and E), and Na+/K+-ATPase activity, in patients with the mentioned disorder vs. healthy controls.

Method

39 OCD patients diagnosed based on Diagnostic and Statistical Manual of Mental Disorders (DSM-V) and 39 volunteer healthy subjects were included in this study. MDA levels in serum and RBC membrane were measured using fluorometric method. Serum TAC level, serum GSH level, and Na+/K+-ATPase activity were also measured using spectrophotometric methods. Serum levels of vitamins were calculated by reversed-phase high-performance liquid chromatography (RP-HPLC).

Result

There was a significantly higher MDA level in serum (p < 0.0001) and RBC membrane (p = 0.002) of OCD patients compared with those in controls. A significant reduction in vitamin A (p = 0.001) and vitamin E (p = 0.024) levels was found in OCD patients vs. controls. There was significantly lower activity of erythrocyte membrane Na+/K+-ATPase in RBC membrane of OCD patients vs. controls (p < 0.0001).

Conclusion

Our findings indicate significantly higher levels MDA in both serum and RBC membrane, lower levels of serum vitamins A and E, and lower activity of membrane Na+/K+-ATPase in OCD patients compared to controls. These suggest an imbalance between oxidant and antioxidant factors in OCD patients that might play a fundamental role in the etiopathogenesis of OCD.

Liver Disorders Caused by Inborn Errors of Metabolism

Inborn errors of metabolism (IEMs) are a vast array of inherited/congenital disorders, affecting a wide variety of metabolic pathways and/or biochemical processes inside the cells. Although IEMs are usually rare, they can be represented as serious health problems. During the neonatal period, these inherited defects can give rise to almost all key signs of liver malfunction, including jaundice, coagulopathy, hepato- and splenomegaly, ascites, etc. Since the liver is a vital organ with multiple synthetic, metabolic, and excretory functions, IEM-related hepatic dysfunction could seriously be considered life-threatening. In this context, the identification of those hepatic manifestations and their associated characteristics may promote the differential diagnosis of IEMs immediately after birth, making therapeutic strategies more successful in preventing the occurrence of subsequent events. Among all possible liver defects caused by IEMs, cholestatic jaundice, hepatosplenomegaly, and liver failure have been shown to be manifested more frequently. Therefore, the current study aims to review substantial IEMs that mostly result in the aforementioned hepatic disorders, relying on clinical principles, especially through the first years of life. In this article, a group of uncommon hepatic manifestations linked to IEMs is also discussed in brief.

Effect of Omega-3 Fatty Acids Supplementation on Homocysteine Level in Patients Undergoing Continuous Ambulatory Peritoneal Dialysis

Objective

One of the most common diseases with high morbidity and mortality rates is chronic kidney disease. Cardiovascular disease affects most patients with chronic kidney disorders, particularly patients undergoing dialysis; hence, appropriate prevention and management approaches are essential. This study aimed to evaluate the reduction of inflammatory biomarkers, especially homocysteine, by omega-3 fatty acids in peritoneal dialysis patients.

Methods

This study enrolled 60 peritoneal dialysis patients who met specified inclusion and exclusion criteria and were randomized to intervention or placebo groups. Omega-3 capsules were given at a dose of 3 g/d for 8 weeks. Inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP), homocysteine, albumin, and lipid profile measured before and after the study.

Findings

Results of this trial revealed that the levels of homocysteine, hs-CRP, and albumin did not change significantly during the study. Analysis of lipid profiles before and after intervention showed omega-3 has no significant effect on the level of total cholesterol or low-density lipoprotein cholesterol; However, the level of triglyceride reduced remarkably (P = 0.002). In addition, serum levels of high-density lipoprotein cholesterol increased at the end of the study (P < 0.001).

Conclusion

Omega-3 does not seem to be able to change the inflammatory markers significantly, particularly homocysteine. More extensive trials must be conducted to better understand the impact of omega-3 on inflammatory and nutritional markers, particularly in peritoneal dialysis patients.

Effect of Selenium Supplementation on Lipid Profile, Anemia, and Inflammation Indices in Hemodialysis Patients

Objective

Trace elements deficiency is common among end-stage renal disease (ESRD) patients due to excessive loss during dialysis and the lower intake secondary to loss of appetite. Selenium (Se) is a trace element that plays an important role in the radical scavenging system and helps the body defend against oxidative stress. This study aims to evaluate the effects of Se supplementation on lipid profile, anemia, and inflammation indices in ESRD patients.

Methods

Fifty-nine hemodialysis patients enrolled and were randomly divided into two groups. Two hundred microgram Se capsules once daily for the case group and matching placebo for the control group were administered for three months. Demographic data were collected at the study beginning. Uric acid (UA), anemia and inflammation indices, and lipid profiles were recorded at the beginning and the end of the study.

Findings

UA and UA-to-HDL (high-density lipoprotein) ratio decreased significantly in the case group (P < 0.001). The changes in lipid profile were not significant among both groups. Hemoglobin slightly increased in the case group, however, it decreased significantly in the control group (P = 0.031). High-sensitivity C-reactive protein (hs-CRP) decreased in the case group and increased in the control group, however, none of these changes were significant.

Conclusion

According to the results of this study, selenium supplementation in ESRD patients could reduce some risk factors related to their mortality, such as the ratio of uric acid to HDL. However, the changes related to lipid profile, hemoglobin level and hs-CRP biomarker were not significant.

Determination of plasma and erythrocyte levels of copper, magnesium and zinc by atomic absorption spectrometry in type-2 diabetes mellitus patients with metabolic syndrome

BACKGROUND AND PURPOSE

Imbalance in blood levels of trace elements is independent risk factor for metabolic syndrome (MetS), type 2 diabetes mellitus (T2DM), and its complications. This study investigated plasma and erythrocyte levels of copper, magnesium, zinc, and their correlations with biochemical components of the MetS in T2DM patients compared to the healthy controls.

EXPERIMENTAL APPROACH

Forty men recently diagnosed T2DM with MetS without complications and thirty six age-matched healthy controls were enrolled in this cross-sectional study. Plasma and erythrocyte levels of selected elements were measured by graphite furnace atomic absorption spectroscopy.

FINDINGS/RESULTS

The results of the present study showed significantly lower plasma levels of copper, magnesium, and zinc and lower erythrocytes copper in the patients' group compared to the controls; while erythrocyte levels of magnesium and zinc were not significantly different between the two groups. Significant negative correlations were observed between plasma levels of copper with waist and hip circumferences, waist to hip ratio, systolic and diastolic blood pressures, fasting blood glucose, and glycated hemoglobin levels in all subjects; while erythrocyte copper levels showed significant negative correlation with triglyceride, and erythrocyte zinc was positively correlated with diastolic blood pressure and negatively with triglyceride.

CONCLUSION AND IMPLICATIONS

Alterations of trace elements may have a significant role in the pathogenesis of MetS and T2DM patients. It is suggested that the body status of copper, magnesium, and zinc might be significantly correlated with components of MetS in T2DM patients; and plasma copper levels may be correlated with complications of type 2 diabetes mellitus.

Investigation of the relationship between miR-33a, miR-122, erythrocyte membrane fatty acids profile, and serum lipids with components of metabolic syndrome in type 2 diabetic patients

Background and purpose:

MicroRNAs (miRNAs) are small non-coding RNA molecules acting as critical regulators of post-transcriptional gene expression. MiR-33a and miR-122 have a crucial role in cholesterol and lipid metabolism. Therefore, their dysregulation may contribute to metabolic abnormality and their inhibition may be a useful therapeutic strategy. The objective of the present study was to investigate the relationship between miR-33a, miR-122, erythrocyte membrane fatty acids profile, and serum lipids with components of metabolic syndrome in an Iranian population suffering from type 2 diabetes mellitus (T2DM).

Experimental approach:

Expression of miR-33a and miR-122 was measured by real-time polymerase chain reaction and erythrocyte membrane fatty acid profiles were analyzed by gas chromatography-mass spectrometry.

Findings/Results:

T2DM patients with and without metabolic syndrome had significantly higher miR-33a and miR-122 levels compared to controls. MiRNAs were significantly correlated with saturated fatty acid (SFAs), total SFAs/total polyunsaturated fatty acids (PUFAs) ratio, fasting plasma glucose, triacylglycerols, insulin and homeostatic model assessment of insulin resistance. In addition, there was a significant negative correlation between miR-33a and miR-122 levels and PUFAs, total PUFAs/total SFAs ratio and omega 6 fatty acids.

Conclusion and implications:

Considering the roles of miR-33a and miR-122 in cholesterol and lipids metabolism, it may be concluded that the measurement of their expression may be useful as a potential additional biomarker for cardiometabolic derangement in T2DM patients. In addition, these findings may suggest that the inhibition of these miRNAs by anti-miRNA therapies may be explored as a potential therapeutic strategy.

Homocysteine-Lowering Interventions in Chronic Kidney Disease

The incidence of cardiovascular events and mortality is higher in patients with chronic kidney disease (CKD) compared to the general population. Homocysteine (Hcy) appears to be an independent risk factor for cardiovascular diseases in general populations and patients with CKD. Further, hyperhomocysteinemia can cause endothelial damage and increase the activity and production of coagulation factors, and its prevalence among patients with end-stage renal disease is approximately 85%-100%. Most treatments, which lower Hcy levels and have been considered in previous studies, include folic acid, B vitamins, omega-3 fatty acids, and N-acetylcysteine. However, the effect of therapies that can decrease Hcy levels and thus cardiovascular events in these patients is still unclear. The results are conflicting and require further investigation. To guide treatment decisions and improve patient outcomes, multiple databases were searched, including Web of Science, PubMed, and Medline to summarize the available evidence (i.e., clinical trial and meta-analyses) on Hcy-lowering interventions and cardiovascular events.

Oxidant/antioxidant status in Type-2 diabetes mellitus patients with metabolic syndrome

Background

The concurrence of metabolic syndrome (MS) and diabetes mellitus (DM) is increasing worldwide. The long-term complications of these chronic diseases are a threat to patients' well-being. Oxidative stress is involved in the pathogenesis of several diseases. To understand the basic pathophysiological mechanisms of Type-2 DM (T2DM) and its related complications, we aimed to investigate the oxidant/antioxidant status and Na⁺-K⁺ ATPase activity in T2DM with MS.

Materials and Methods

A population of ninety individuals including fifty patients diagnosed with T2DM and MS, but without overt diabetes complications, and forty individuals without T2DM or MS as control group participated in this study. Plasma malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) activities, total antioxidant capacity (TAC), and Na⁺-K⁺ ATPase activity were assessed by standard laboratory methods.

Results

Plasma MDA in patients group was statistically significantly higher than that of controls (P ≤ 0.05). Whereas, Na⁺-K⁺ ATPase activity was statistically significantly lower in patient group (P ≤ 0.05). TAC, CAT, SOD, and GPx enzyme activities were not statistically significantly different between two groups (P > 0.05). Results from the patient group showed positive correlations between CAT activity and triglyceride and positive correlations between GPx activity and weight, body mass index (BMI), and waist circumference. In addition, there was a positive correlation between MDA results with high-density lipoprotein-cholesterol (HDL-C) and total cholesterol and a negative correlation with TAC, BMI, and weight (P ≤ 0.05) in controls.

Conclusion

Because T2DM patients were without any vascular complications, antioxidant defense results may reflect the lack of progression of diabetes complications in these patients. These results emphasize the need for initial and continued assessment of cardiovascular disease risks in diabetic individuals. Implementation of timely interventions may improve the management of diabetes and prevent the progression of diabetes complications.

Association of the serum apelin, but not ghrelin, with the presence and severity of coronary artery disease

Increasing evidence suggests that apelin and ghrelin may participate in atherogenesis. We sought to investigate whether the serum levels of apelin and ghrelin are significantly different in patients with coronary artery disease (CAD) compared to patients with nonsignificant coronary stenosis and determine the correlation between these adipokines and the severity of coronary stenosis. The study population included 31 stable CAD patients, 38 unstable CAD patients, and 39 non-CAD subjects. Serum levels of apelin and ghrelin, fasting blood glucose, lipid parameters, hs-CRP and hematological indices were determined in all groups using routine standard laboratory procedures. Serum apelin levels were significantly lower in patient with unstable CAD (0.354 ± 0.063 ng/mL) compared to stable CAD patients (0.401 ± 0.045 ng/mL, p = 0.003) and non-CAD subjects (0.415 ± 0.055 ng/mL, p<0.001). In addition, serum apelin levels were inversely correlated with the severity of coronary stenosis in CAD patients (p<0.05). However, there was no significant difference in ghrelin levels among the 3 groups. This data may suggest that the presence of unstable CAD may be associated with lower serum apelin which may indicate the potential role of this peptide in the progression and destabilization of coronary plaques.

Potential benefits of selenium supplementation in patients with kidney disease

Trace element deficiency is common among patients with end-stage renal disease (ESRD); the reason is that since these patients undergo dialysis, they lose these elements more than healthy people, and also the use of trace elements is restricted due to loss of appetite. Selenium (Se) is a trace element that is essential for the oxidative stress defense system. Se deficiency leads to some complications similar to those often seen in ESRD patients, such as all-cause mortality due to cardiovascular diseases, bone loss, uric acid elevation, and anemia. This article aims to review the evidence on consequences of Se deficiency in ESRD patients, as well as effects of Se supplementation in hemodialysis patients. Multiple databases were searched to summarize the available evidence on selenium's role in kidney diseases. Since the complications of ESRD and those of Se deficiency are mostly similar, this triggers the idea that Se deficiency may be considered as a cause of these problems, but it needs to be more assessed that Se deficiency is a single factor or there are other factors participated in. Also the role of Se supplementation on resolving the mentioned complications, needs to be more studied through welldesigned clinical studies.

Investigation of Supercharging as A Strategy to Enhance the Solubility and Plasminogen Cleavage Activity of Reteplase

Background

Reteplase, the recombinant form of tissue plasminogen activator, is a thrombolytic drug with outstanding characteristics, while demonstrating limited solubility and reduced plasminogen activation. Previously, we in silico designed a variant of Reteplase with positively supercharged surface, which showed promising stability, solubility and activity. This study was devoted to evaluation of the utility of supercharging technique for enhancing these characteristics in Reteplase.

Objective

To test the hypothesis that reinforced surface charge of a rationally-designed Reteplase variant will not compromise its stability, will increase its solubility, and will enhance its plasminogen cleavage activity.

Materials and Methods

Supercharged Reteplase coding sequence was cloned in pDest527 vector and expressed in E. coli BL21 (DE3). The expressed protein was extracted by cell disruption. Inclusion bodies were solubilized using guanidine hydrochloride, followed by dialysis for protein refolding. After confirmation with SDS-PAGE and western blotting, extracted proteins were assayed for solubility and tested for bioactivity.

Results

SDS-PAGE and western blot analysis confirmed the successful expression of Reteplase. Western blot experiments showed most of Reteplase expressed in the insoluble form. Plasminogen cleavage assay showed significantly higher activity of the supercharged variant than the wild type protein (P < 0.001). The stability of the supercharged variant was also comparable to the wild type.

Conclusion

Our findings, i.e. the contribution of the surface supercharging technique to retained stability, enhanced plasminogen cleavage activity, while inefficiently changed solubility of Reteplase, contain implications for future designs of soluble variants of this fibrinolytic protein drug.

A review of strategies for untargeted urinary metabolomic analysis using gas chromatography-mass spectrometry

BACKGROUND

Human urine gives evidence of the metabolism in the body and contains different metabolites at various concentrations. A number of analytical techniques including mass spectrometry (MS) and nuclear magnetic resonance (NMR) have been used to obtain metabolites levels in urine samples. However, gas chromatography-mass spectrometry (GC-MS) is one of the most widely used techniques for urinary metabolomics studies due to its higher sensitivity, resolution, reproducibility, reliability, relatively low cost and ease of operation compared to liquid chromatography-mass spectrometry and NMR.

AIM OF REVIEW

This review looks at various aspects of urine preparation prior to analysis by GC-MS including sample storage, urease pretreatment, derivatization, use of internal standard and quality control samples for data correction. In addition, most common types of inlet liners, ionization techniques and columns are discussed and a summary of mass analyzers are also highlighted. Lastly, the role of retention index in metabolite identification and data normalization methods are presented.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The purpose of this review is summarizing methods of sample storage, pretreatment, and GC-MS analysis that are mostly used in urine metabolomics studies. Specific emphasis is given to the critical steps within the GC-MS urine metabolomics that those new to this field need to be aware of and the remaining challenges that require further attention and studies.

Evaluation of long-chain acyl-coenzyme A synthetase 4 (ACSL4) expression in human breast cancer

Background and purpose:

Breast cancer (BC) is one of the major causes of female cancer-related death. It has recently been demonstrated that metabolic reprogramming including alteration in lipid metabolism is indicated in various types of cancer. The enzymes of the acyl-coenzyme A synthetase long-chain family (ACSLs) are responsible for converting fatty acids to their corresponding fatty acyl-coenzyme A esters which are essential for some lipid metabolism pathways. ACSL4 is one of the isoforms of ACSLs and has a marked preference for arachidonic and eicosapentaenoic acids. The objective of this study was to evaluate ACSL4 expression, its prognostic significance, and its correlation with p53 tumor suppressor in BC patients.

Experimental approach:

In this study 55 pairs of fresh samples of BC and adjacent non-cancerous tissue were used to analyze ACSL4 expression, using real-time polymerase chain reaction and immunohistochemistry (IHC) staining. The expression of other studied variables was also examined using the IHC technique.

Findings / Results:

ACSL4 expression was significantly higher in BC tissues compared to the adjacent normal tissue. This upregulation was negatively correlated with Ki-67 and age, and positively correlated with p53 status. The correlation between ACSL4 and p53 may indicate the role of p53 in the regulation of lipid metabolism in cancer cells, in addition to its role in the regulation of ferroptosis cell death.

Conclusion and implications:

Our results indicated that the expression of ACSL4 may be considered as a prognostic indicator and potential therapeutic target in BC. However, further studies are needed to confirm the significance of these findings.

Expression and clinicopathological significance of lipin-1 in human breast cancer and its association with p53 tumor suppressor gene

Breast cancer (BC) is an important cause of female cancer-related death. It has recently been demonstrated that metabolic disorders including lipid metabolism are a hallmark of cancer cells. Lipin-1 is an enzyme that displays phosphatidate phosphatase activity and regulates the rate-limiting step in the pathway of triglycerides and phospholipids synthesis. The objective of this study was to evaluate lipin-1 expression, its prognostic significance, and its correlation with p53 tumor suppressor in patients with BC. In this study, 55 pairs of fresh samples of BC and adjacent noncancerous tissue were used to analyze lipin-1, using quantitative real-time polymerase chain reaction and immunohistochemistry (IHC) staining. The expression of other clinicopathological variables and p53 was also examined using IHC technique. The cell migration was studied in MCF-7 and MDA-MB231 cells following the inhibition of lipin-1 by propranolol. Our results show that the relative expression of lipin-1 messenger RNA was significantly higher in BC tissues compared with the adjacent normal tissue and its inhibition reduced cell migration in cancer cells. This upregulation was negatively correlated with histological grade of tumor and p53 status (p = .001 and p = .034) respectively and positively correlated with the tumor size (p = .006). Our results also seem to indicate that the high lipin-1 expression is related to a good prognosis in patients with BC. The expression of lipin-1 may be considered as a novel independent prognostic factor. The inhibition of lipin-1 may also have therapeutic significance for patients with BC. The correlation between lipin-1 and p53 confirms the role of p53 in the regulation of lipid metabolism in cancer cells.

Improving the solubility, activity, and stability of reteplase using in silico design of new variants

Reteplase (recombinant plasminogen activator, r-PA) is a thrombolytic agent recombined from tissue-type plasminogen activator (t-PA), which has several prominent features such as strong thrombolytic ability and E. coli expressibility. Despite these outstanding features, it demonstrates reduced fibrin binding affinity, reduced stimulation of protease activity, and lower solubility, hence higher aggregation propensity, compared to t-PA. The present study was devoted to design r-PA variants with comparable structural stability, enhanced biological activity, and high solubility. For this purpose, computational molecular modeling techniques were utilized. The supercharging technique was applied for r-PA to designing new species of the protein. Based on the results from in silico evaluation of selected mutations in comparison to the wild-type r-PA, the designed supercharged mutant (S7 variant) exhibited augmented stability, decreased solvation energy, as well as enhanced binding affinity to fibrin. The data also implied increased plasminogen cleavage activity of the new variant. These findings have implications to therapies which involve removal of intravascular blood clots, including the treatment of acute myocardial infarction.

Decreased Na+/K+-ATPase Activity and Altered Susceptibility to Peroxidation and Lipid Composition in the Erythrocytes of Metabolic Syndrome Patients with Coronary Artery Disease

Background: The increased generation of reactive oxygen species that occurs in the case of a metabolic syndrome (MetS) may be responsible for the increased oxidative injury to erythrocyte membranes in coronary artery disease (CAD). Therefore, we studied the effects of MetS on both indexes of oxidative damage and biochemical properties of erythrocyte membranes in CAD patients. Methods: We analyzed the markers of oxidative stress, Na+/K+-ATPase activity, total cholesterol content of erythrocyte membranes (CEM), and fatty acid compositions of the erythrocyte membrane in 82 patients with stable CAD and 39 non-CAD subjects. Results: The CAD patients had higher levels of CEM, membrane lipid peroxidation, erythrocyte superoxide dismutase (SOD) activity, and Na+/K+-ATPase activity compared with non-CAD subjects. The Na+/K+-ATPase activity was correlated negatively with membrane lipid peroxidation, and positively with the CEM. In CAD patients with MetS compared with those without MetS, we found that the membrane lipid peroxidation and CEM were increased, whereas the n-3 fatty acids content, SOD activity, Na+/K+-ATPase activity were decreased. Conclusion: These findings suggest an impairment of erythrocyte membrane biochemical properties in stable CAD patients as a consequence of oxidative injury that may contribute to the development of CAD. In addition, MetS may be related to increased oxidative injury to erythrocyte membranes.

The effect of FADS2 gene rs174583 polymorphism on desaturase activities, fatty acid profile, insulin resistance, biochemical indices, and incidence of type 2 diabetes

Background:

In this study, we investigated the associations of erythrocytes fatty acid composition, activities of delta-5 desaturase (D5D) and delta-6 desaturase (D6D), and other metabolic risk factors, with type 2 diabetes (T2D) risk to determine if rs174583 polymorphism of FADS2 gene had any effect on these associations.

Materials and Methods:

Fatty acid profile of erythrocytes was determined using gas chromatography-mass spectrometry in 95 T2D patients and 95 apparently healthy participants. The genotypes of single-nucleotide polymorphism (SNP) of FADS2 gene were determined using the polymerase chain reaction-restriction fragment length polymorphism technique. Other biochemical parameters were measured in the serum using standard analytical procedures.

Results:

D6D activity was increased (P < 0.001) and D5D activity was decreased in T2D patients (P < 0.001) compared to controls. Homeostatic model assessment insulin resistance (HOMA-IR) index was positively correlated with D6D (r = 0.34, P < 0.001) and negatively correlated with D5D (r = −0.19, P = 0.02). Palmitic acid (P < 0.001) and dihomo-gamma-linolenic acid (P = 0.03) were higher and linoleic acid (P < 0.001) and arachidonic acid (AA) (P < 0.001) were lower in T2D patients. The distribution of rs174583 genotypes which includes C/T, C/C, and T/T was not different in the two groups (P = 0.63).

Conclusion:

In the population studied, there was a strong association in the erythrocytes fatty acid composition, D5D and D6D activities and other metabolic risk factors between non-T2D and T2D patients. In addition, there was a strong association in erythrocytes DGLA and AA contents and D5D activities between rs174583 genotypes in all participants. However, the distribution of rs174583 genotypes did not differ significantly between T2D patient and controls, and it did not appear to be an association between rs174583 SNP and incident of T2D.

The difference in correlation between insulin resistance index and chronic inflammation in type 2 diabetes with and without metabolic syndrome

BACKGROUND

Insulin resistance (IR) is associated with low-grade systemic inflammation. It plays an important role in the pathogenesis of type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) in patients with metabolic syndrome (MetS). It is unclear whether diabetic patients with MetS confer elevated CVD risk and outcomes beyond the impact of individual's components of MetS. The aim of this study is to highlight the central role of IR, inflammation, triglyceride/high-density lipoprotein- cholesterol (TG/HDL-C) ratio, and atherogenic index of plasma (AIP) in T2DM with MetS.

MATERIALS AND METHODS

This cross-sectional study comprised 130 men distributed into three groups, namely Controls: 40 nondiabetic healthy volunteers; Group I: 40 T2DM patients without MetS, and Group II: 50 T2DM patients with MetS. Fasting blood samples were collected for the measurement of blood lipid profile, glucose, insulin, hemoglobin A1c, and high-sensitivity C-reactive protein (hs-CRP). TG/HDL-C ratio, AIP, and homeostasis model assessment of insulin resistance (HOMA-IR) were calculated.

RESULTS

Significant positive association was observed between HOMA-IR and hs-CRP only in Group II and between HOMA-IR and TG/HDL-C ratio in all subjects. Significant differences were seen in waist and hip circumferences, waist/hip ratio, body mass index, systolic blood pressure, fasting blood glucose, TGs, HDL-C, insulin, hs-CRP, HOMA-IR, TG/HDL ratio, and AIP between Controls and Group I with Group II.

CONCLUSIONS

In T2DM with MetS, coexistence of elevated atherogenic indices, systemic inflammation, and association between HOMA-IR and TG/HDL-C ratio were seen. These factors are considered having important role in elevated CVD risk beyond MetS components in these patients.

In vitro and in silico studies of the inhibitory effects of some novel kojic acid derivatives on tyrosinase enzyme

OBJECTIVES

Tyrosinase is a key enzyme in pigment synthesis. Overproduction of melanin in parts of the skin results in hyperpigmentation diseases. This enzyme is also responsible for the enzymatic browning in fruits and vegetables. Thus, its inhibitors are of great importance in the medical, cosmetic and agricultural fields.

MATERIALS AND METHODS

A series of twelve kojic acid derivatives were designed to be evaluated as tyrosinase activity inhibitors. The potential inhibitory activity of these compounds was investigated in silico using molecular docking simulation method. Four compounds with a range of predicted tyrosinase inhibitory activities were prepared and their inhibitory effect on tyrosinase activity was evaluated. The antioxidant properties of these compounds were also investigated by in vitro DPPH (2,2-diphenyl-1-picrylhydrazyl) and hydrogen peroxide scavenging assays.

RESULTS

Compound IIId exhibited the highest tyrosinase inhibitory activity with an IC50 value of 0.216 ± 0.009 mM which was in accordance with the in silico ΔGbind results (-13.24 Kcal/mol).

CONCLUSION

Based on the docking studies, from the twelve compounds studied, one (IIId) appeared to have the highest inhibition on tyrosinase activity. This was confirmed by enzyme activity measurements. Compound IIId has an NO2 group which binds to both of Cu(2+) ions located inside the active site of the enzyme. This compound appeared to be even stronger than kojic acid in inhibiting tyrosinase activity. The DPPH free radical scavenging ability of all the studied compounds was more than that of BHT. However, they were not as strong as BHT or gallic acid in scavenging hydrogen peroxide.

Biochemical changes in blood of type 2 diabetes with and without metabolic syndrome and their association with metabolic syndrome components

Background:

Multiple factors are involved in the development and progression of type 2 diabetes mellitus (DMII) to DMII with metabolic syndrome (MetS) and cardiovascular complications. To identify some of these factors, we aim to investigate the changes in erythrocyte membrane Na⁺/K⁺-ATPase activity, serum glucose, insulin, lipid profile, hemoglobin A1C (HbA1c), high-sensitivity C-reactive protein (hs-CRP), anthropometric measurements, and blood pressure in DMII with and without MetS.

Materials and Methods:

This cross-sectional study comprised 155 male subjects distributed into three groups as healthy controls (50 non-DMII volunteers), Group I (50 DMII without MetS), and Group II (55 DMII with MetS). Fasting blood samples were taken for the measurement of glucose, insulin, HbA1c, hs-CRP and lipid profile. Na⁺/K⁺-ATPase activity was determined in erythrocyte ghost.

Results:

Na⁺/K⁺-ATPase activity was significantly decreased in DMII groups compared with controls. No significant difference was shown in Na⁺/K⁺-ATPase activity between DMII groups. Total ATPase activity, total cholesterol and low-density lipoprotein-cholesterol levels were similar in the three groups. Levels of insulin, hs-CRP, triacylglycerols, systolic blood pressure, weight, waist and hip circumference, waist/hip ratio, and body mass index were significantly elevated and high-density lipoprotein-cholesterol significantly decreased only in Group II. Significant differences in serum glucose and hip circumference were seen between the groups. No significant differences in HbA1c levels were observed between DMII groups.

Conclusion:

Changes in many of the measured risk factors that occurred only in Group II compared with controls and Group I may provide an explanation of how DMII progresses to DMII with MetS and future cardiovascular complications.

The influence of BsmI and TaqI vitamin D receptor gene polymorphisms on the intensity of hyperparathyroidism in Iranian hemodialysis patients

Background:

The influence of vitamin D receptor (VDR) gene polymorphisms on the regulation of the parathyroid hormone is important in end-stage renal disease (ESRD) patients. We analyzed rs1544410 (BsmI) and rs731236 (TaqI) polymorphisms of VDR gene in hemodialysis patients to determine their relationship with serum intact parathyroid hormone (iPTH).

Materials and Methods:

Ninety hemodialysis patients were included in this study. Patients were classified into four groups according to their serum iPTH level. Polymorphisms of VDR gene were surveyed using polymerase chain reaction-restriction fragment length polymorphism method with BsmI and TaqI enzymes in all the patients.

Results:

Patients age ranged between 30 and 60 years (mean ± SD: 36.0 ± 11.4) and period undergoing hemodialysis 80 ± 71 months. Patients were divided into four groups based on the serum concentration of iPTH. The distribution of VDR gene allelic variation for BsmI and TaqI polymorphisms was different between the four groups of uremic patients. Analysis of data revealed a significant correlation between the TaqI variants and serum iPTH level. There was also a correlation between the BsmI variants and serum iPTH level in that patients with the BB genotype were more likely to have a higher serum iPTH level. However, the latter was not statistically significant.

Conclusions:

Genotype of the TaqI and BsmI VDR gene polymorphisms is reported in Iranian patients with ESRD. Those with tt or BB genotypes may develop more severe secondary hyperparathyroidism.

The associations between high-density lipoprotein mean particle size and its fatty acid composition

AIM

High-density lipoprotein (HDL) particles are heterogeneous in their composition, structure and size and may differ in conferring protection against coronary artery disease. The aim of this study is to investigate the associations between HDL size and its fatty acid composition.

PATIENTS & METHODS

HDL mean particle size from 140 healthy men was detected by dynamic light scattering methodology and fatty acid composition of HDL was determined by gas chromatography.

RESULTS

HDL with smaller size had a higher proportion of saturated fatty acids and lower proportion of unsaturated fatty acids. HDL mean size indicated a negative correlation with palmitic acid (r = -0.17; p < 0.05) and a positive correlation with palmitoleic acid (r = 0.17; p < 0.05), oleic acid (r = 0.23; p < 0.01), arachidonic acid (r = 0.17; p < 0.05) and dihomogamalinoleic acid (r = -0.18; p < 0.05).

CONCLUSION

Saturated fatty acids of HDL are inversely assocaited and unsaturated fatty acids are directly associated with HDL mean size.

Synthesis and tyrosinase inhibitory properties of some novel derivatives of kojic acid

Tyrosinase is a multifunctional oxidase that is widely distributed in nature. It is a key enzyme in melanin biosynthesis and is involved in determining the color of mammalian skin and hair. In addition it is responsible for the undesirable enzymatic browning that occurs in plant-derived foods, limiting the shelf-life of fresh-cut products with the resultant economic loss. In recent years there has been considerable interest to study the inhibitory activity of tyrosinase and a number of inhibitory compounds derived from natural sources or partly/fully synthetic have been described. However, the current conventional methods to control tyrosinase action are inadequate. Considering the significant industrial and economic impact of the inhibitors of tyrosinase, this study was set to seek new potent inhibitors of this enzyme. A series of 3-hydroxypyridine-4-one derivatives were prepared in high yield and evaluated for their inhibitory activity on tyrosinase enzyme using dopachrome method. Our results show that all synthesized compounds have inhibitory effect on tyrosinase activity for the oxidation of L-DOPA. Among compounds studied those containing two free hydroxyl group (ie Va and V'a) were more potent than their analogues with one hydroxyl group (ie Vb and V'b). Also substitution of a methyl group on position N(1) of the hydroxypyridinone ring seems to confer more inhibitory potency.

Associations between high density lipoprotein mean particle size and serum paraoxonase-1 activity

BACKGROUND

High density lipoprotein (HDL) particles are heterogeneous in composition, structure, size, and may differ in conferring protection against cardiovascular disease. HDL associated enzyme, paraoxonase-1 (PON1), has an important role in attenuation of atherogenic low density lipoprotein (LDL) oxidation. The aim of this study was to investigate the associations between HDL particle size and PON1 activity in relation to serum HDL cholesterol (HDL-C) levels.

MATERIALS AND METHODS

One hundred and forty healthy subjects contributed to this study. HDL was separated by sequential ultracentrifugation and its size was estimated by dynamic light scattering. Paraoxonase activity was measured spectrophotometrically using paraoxon as substrate.

RESULTS

Results of this study showed that PON1 activity had negative correlations with HDL mean particle size (r = -0.22, P < 01), HDL2/HDL3 ratio, and serum HDL-C levels (r = -0.25, P < 0.01). HDL mean particle size and HDL2/HDL3 ratio had negative correlation with body mass index (BMI), waist hip ratio (WHR), and serum triglyceride (TG) levels, and positive correlation with serum HDL-C levels. Serum HDL-C levels had significant positive correlations with age, total cholesterol (TC), and apolipoprotein A-I (apo A-I) and significant negative correlation with BMI, WHR, and TG.

CONCLUSION

Based on the results of this study, determination of HDL mean particle size beside the serum PON1 activity may help to better understand the CAD risks, pathogenesis, and prognosis, and may also help to design therapeutic protocols toward beneficial modifications of HDL characteristics.

Elevated plasma myeloperoxidase levels in relation to circulating inflammatory markers in coronary artery disease

Aims: Elevation of the leukocyte enzyme myeloperoxidase (MPO) in stable coronary artery disease (CAD) is controversial and its relationship with oxidized low-density lipoprotein (ox-LDL) and nitrite/nitrate (NOx) levels in CAD patients has not been evaluated. Therefore, we sought to evaluate these relationships. Materials & methods: This study included 50 stable CAD patients, 50 unstable CAD patients and 50 control subjects. Plasma MPO and ox-LDL levels were determined using enzyme immunoassay. Plasma NOx and other risk factors were also measured in the patients. Results: Plasma MPO levels were higher in unstable CAD patients (71.2 ± 19.6 ng/ml) than in stable CAD patients (34.5 ± 6.8 ng/ml) and control subjects (23.0 ± 3.6 ng/ml) (p < 0.001). Furthermore, plasma MPO was positively correlated with ox-LDL and negatively correlated with NOx levels (p < 0.05). Conclusion: Plasma MPO levels were elevated in CAD patients and its relation to CAD may be through the oxidation of LDL and reduction of NO levels.

Elevated plasma platelet-activating factor acetylhydrolase activity and its relationship to the presence of coronary artery disease

BACKGROUND

Platelet-activating factor acetylhydrolase (PAF-AH) is a circulating enzyme that has an important role in the development of coronary artery disease (CAD). The correlations between PAF-AH and CAD are controversial. Furthermore, the differences of the enzyme levels between patients with stable and unstable CAD are not fully determined. The purpose of this study was to evaluate plasma PAF-AH levels and its association with the presence of CAD and some clinical risk factors in the patients.

METHODS

This case-control study included 50 control subjects without CAD, 50 stable CAD patients and 50 unstable CAD patients with angiographically documented CAD. Plasma PAF-AH activity was determined by a commercial kit. The inflammatory markers, high sensitivity C-reactive protein (hsCRP) and oxidized low density lipoprotein (ox-LDL), and lipid profile were also measured. Comparisons of biochemical risk factors among all groups were performed by one way ANOVA. The association of PAF-AH activity with the presence of CAD was analyzed by multiple logistic regression.

RESULTS

Plasma PAF-AH activity levels were higher in unstable CAD patients (0.040 ± 0.012 μmol/min/ml) than in stable CAD patients (0.032 ± 0.010 μmol/min/ml) and control subjects (0.026 ± 0.009 μmol/min/ml) (p < 0.01). Plasma PAF-AH activity was also independently associated with the presence of CAD (p< 0.01).

CONCLUSIONS

Plasma PAF-AH activity levels were highly increased in unstable and stable CAD patients as compared to control subjects and may be a useful biomarker for CAD prediction.

Levels of carnitine and acylcarnitines in reconstituted red blood cell samples washed with different concentrations of saline solutions

Objective: To evaluate the percentage of carnitine and acylcarnitines remaining in red blood cells after washing them with different concentrations of saline solution. Materials and methods: Human blood samples were centrifuged and the blood cells were washed with different saline solutions. The final pellet was resuspended in PBS for card preparation and tandem mass spectrometry analysis. Results: It was found that carnitine, as well as short-chain, medium-chain, and long-chain acylcarnitines remain in red blood cells at average percentages of 19.3; 34; 34; and 32%, respectively. Significant differences were found for carnitine and acylcarnitine levels in blood washed with an isotonic solution compared to their levels using several hypotonic solutions (p<0.05). Conclusion: Because carnitine and acylcarnitines remained associated with the blood cells, we recommend using whole blood to measure these metabolites.

Reduced plasma adiponectin levels relative to oxidized low density lipoprotein and nitric oxide in coronary artery disease patients

INTRODUCTION

Adiponectin is a circulating hormone that is produced exclusively by adipocytes and has antiinflammatory and anti-atherogenic properties. The hypothesis that there are differences in adiponectin levels between stable and unstable coronary-artery disease patients remains controversial. Furthermore, the potential relationships between the plasma adiponectin level and the inflammatory and non-inflammatory markers (oxidized low density lipoprotein and nitric oxide) in patients with stable and unstable coronary-artery disease relative to normal subjects have not been assessed.

OBJECTIVES

To assess whether plasma adiponectin levels differ among patients with stable and unstable coronary-artery disease and among control subjects, and to correlate plasma adiponectin level with inflammatory and clinical risk factors (such as oxidized-LDL and nitric oxide) in these patients.

METHODS

This study included 50 control subjects, 50 stable angina patients and 50 unstable angina patients with angiographically documented coronary-artery disease. Plasma adiponectin and oxidized-LDL levels were determined using an enzyme immunoassay. Plasma nitric oxide, high sensitivity C-reactive protein and lipid profile levels were also measured.

RESULTS

Plasma adiponectin levels were lower in the unstable angina patients (4.9 ± 1.30 µg/mL) than in the stable angina patients (6.34 ± 1.0 µg/mL) or in the controls (9.25 ± 1.8 µg/mL); these levels were also significantly lower in stable angina patients versus controls (p<0.001). Plasma adiponectin levels were negatively correlated with oxidized-LDL, high sensitivity C-reactive protein, lipid profile and other clinical risk factors but positively correlated with nitric oxide.

CONCLUSION

Plasma adiponectin levels were found to be lower in both stable and unstable angina patients relative to control subjects, and the correlation between plasma adiponectin and cardiovascular markers is weakened in these patients.

Are antioxidants helpful for disease prevention?

Free radicals are produced continuously in the cells as part of normal cellular function, however excess production might play a role in pathophysiology of many disease conditions, including cancer, Alzheimer's disease, atherosclerosis and some of the drug-induced toxicity. Many basic research studies and observational epidemiologic studies in human suggest that antioxidants can prevent oxidative damage. However, this is still a controversial issue because the results of clinical trials have been inconsistent. This article provides a brief overview of some of the diseases which are associated with free radicals, then discusses the roles of some of dietary antioxidant supplements in disease prevention, with particular reference to the findings of latest clinical trials.

Methylmalonic acidaemia: examination of genotype and biochemical data in 32 patients belonging to mut, cblA or cblB complementation group

Methylmalonic acidaemia (MMA) is a genetic disorder caused by defects in methylmalonyl-CoA mutase or in any of the different proteins involved in the synthesis of adenosylcobalamin. The aim of this work was to examine the biochemical and clinical phenotype of 32 MMA patients according to their genotype, and to study the mutant mRNA stability by real-time PCR analysis. Using cellular and biochemical methods, we classified our patient cohort as having the MMA forms mut (n = 19), cblA (n = 9) and cblB (n = 4). All the mut (0) and some of the cblB patients had the most severe clinical and biochemical manifestations, displaying non-inducible propionate incorporation in the presence of hydroxocobalamin (OHCbl) in vitro and high plasma odd-numbered long-chain fatty acid (OLCFA) concentrations under dietary therapy. In contrast, mut (-) and cblA patients exhibited a milder phenotype with propionate incorporation enhanced by OHCbl and normal OLCFA levels under dietary therapy. No missense mutations identified in the MUT gene, including mut (0) and mut (-) changes, affected mRNA stability. A new sequence variation (c.562G>C) in the MMAA gene was identified. Most of the cblA patients carried premature termination codons (PTC) in both alleles. Interestingly, the transcripts containing the PTC mutations were insensitive to nonsense-mediated decay (NMD).

[Determination of normal acylcarnitine levels in a healthy pediatric population as a diagnostic tool in inherited errors of mitochondrial fatty acid beta-oxidation]

INTRODUCTION

Acylcarnitine measurement in blood is a useful test for the diagnosis of inherited errors of mitochondrial fatty acid beta-oxidation. However, there are few data in the literature on the reference ranges of the various acylcarnitines and on whether these reference ranges are age- or sex-dependent.

OBJECTIVES

To draw attention to inherited errors of mitochondrial fatty acid beta-oxidation and to establish reference acylcarnitine values in children.

PATIENTS AND METHODS

A total of 309 blood samples from healthy children divided into four age groups (group A: <1 month; group B: 1-12 months; group C: 1-7 years; group D: 7-18 years) were obtained and analyzed using tandem mass spectrometry.

RESULTS AND CONCLUSION

Reference acylcarnitine values in children are provided. No significant differences were found in relation to age or sex. Our results differ from those reported in the literature reviewed. Importantly, hydroxyacylcarnitines and glutaryl carnitine are absent when normal samples are processed. We review the literature on the main clinical and laboratory findings in mitochondrial fatty acid beta-oxidation deficiencies.

ETFDH mutations as a major cause of riboflavin-responsive multiple acyl-CoA dehydrogenation deficiency

Multiple acyl-CoA dehydrogenation deficiency (MADD) is a disorder of fatty acid, amino acid and choline metabolism that can result from defects in two flavoproteins, electron transfer flavoprotein (ETF) or ETF: ubiquinone oxidoreductase (ETF:QO). Some patients respond to pharmacological doses of riboflavin. It is unknown whether these patients have defects in the flavoproteins themselves or defects in the formation of the cofactor, FAD, from riboflavin. We report 15 patients from 11 pedigrees. All the index cases presented with encephalopathy or muscle weakness or a combination of these symptoms; several had previously suffered cyclical vomiting. Urine organic acid and plasma acyl-carnitine profiles indicated MADD. Clinical and biochemical parameters were either totally or partly corrected after riboflavin treatment. All patients had mutations in the gene for ETF:QO. In one patient, we show that the ETF:QO mutations are associated with a riboflavin-sensitive impairment of ETF:QO activity. This patient also had partial deficiencies of flavin-dependent acyl-CoA dehydrogenases and respiratory chain complexes, most of which were restored to control levels after riboflavin treatment. Low activities of mitochondrial flavoproteins or respiratory chain complexes have been reported previously in two of our patients with ETF:QO mutations. We postulate that riboflavin-responsive MADD may result from defects of ETF:QO combined with general mitochondrial dysfunction. This is the largest collection of riboflavin-responsive MADD patients ever reported, and the first demonstration of the molecular genetic basis for the disorder.

So doctor, what exactly is wrong with my muscles? Glutaric aciduria type II presenting in a teenager

Late-onset glutaric aciduria type II (GAII) is a rare but treatable cause of profound proximal myopathy. GAII is caused by defects in intra-mitochondrial acyl-CoA dehydrogenation due to deficiency in one of three molecules: the alpha or beta subunits of the electron transport flavoprotein (ETFA; OMIM 231680, ETFB; OMIM 130410), or ETF-dehydrogenase (ETFDH; OMIM 231675). This case report illustrates that GAII may present in the teenage years and may not be associated with hypoglycaemia. It outlines some important diagnostic conundrums faced in diagnosing and managing juvenile onset myopathies. Mutational analysis from this patient revealed two mutations of the ETF-DH gene: EFTDH-334C>T/His122Tyr and EFTDH-1366C>A/Pro456Thr (OMIM 231675). An outline of this rare but important disease, its clinical characteristics and diagnostic methodology are given.

Biochemical, clinical and molecular findings in LCHAD and general mitochondrial trifunctional protein deficiency

General mitochondrial trifunctional protein (TFP) deficiency leads to a wide clinical spectrum of disease ranging from severe neonatal/infantile cardiomyopathy and early death to mild chronic progressive sensorimotor poly-neuropathy with episodic rhabdomyolysis. Isolated long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency resulting from the common Glu510Gln mutation usually gives rise to a moderately severe phenotype with multiorgan involvement with high morbidity and mortality. However, isolated LCHAD deficiency can also be consistent with long-term survival in patients identified and treated from an early age. We present biochemical, clinical and mutation data in 9 patients spanning the full spectrum of disease. Fibroblast acylcarnitine profiling shows good correlation with clinical phenotype using the ratio C18(OH)/(C14(OH)+C12(OH)). This ratio shows a gradation of values, from high in four patients with severe neonatal disease (2.5+/-0.8), to low in two neuromyopathic patients (0.35, 0.2). Fibroblast fatty acid oxidation flux assays also show correlation with the patient phenotype, when expressed either as percentage residual activity with palmitate or as a ratio of percentage activity of myristate/oleate (M/O ratio). Fibroblasts from four patients with severe neonatal disease gave an M/O ratio of 4.0+/-0.6 compared to 1.97 and 1.62 in two neuromyopathic patients. Specific enzyme assay of LCHAD and long-chain 3-ketothiolase activity in patient cells shows lack of correlation with phenotype. These results show that measurements in intact cells, which allow all determinative and modifying cellular factors to be present, better reflect patient phenotype. Mutation analysis reveals a number of alpha- and beta-subunit mutations. Peripheral sensorimotor polyneuropathy, often as the initial major presenting feature but usually later accompanied by episodic rhabdomyolysis, is a manifestation of mild TFP protein deficiency. The mild clinical presentation and relative difficulty in diagnosis suggest that this form of TFP is probably underdiagnosed.

[Early diagnosis of neurometabolic diseases by tandem mass spectrometry. Acylcarnitine profile from cord blood]

INTRODUCTION

Tandem mass spectrometry (MS/MS) provides a multi-analyte technology for the detection of disorders characterised by the presence of abnormal concentrations of metabolites related to neurological deterioration. It has been recently recommended the use of this technique for early diagnosis of inherited metabolic diseases using cord blood.

AIMS

To draw the attention to the inherited metabolic diseases detected by tandem mass spectrometry and to establish reference values for acylcarnitines in cord blood.

PATIENTS AND METHODS

One hundred and thirty cord blood specimens from full-term and normal birth weight children (78 males and 52 females) were analysed by MS/MS.

RESULTS AND CONCLUSION

Reference values for acylcarnitines from cord blood by MS/MS as a tool for the diagnosis of some neurometabolic diseases are provided. No statistical significant difference between sexes was found. We reviewed the literature related to the diagnosis of inherited metabolic diseases, with emphasis in fatty acid mitochondrial beta-oxidation using MS/MS.

Lipid-storage myopathy and respiratory insufficiency due to ETFQO mutations in a patient with late-onset multiple acyl-CoA dehydrogenation deficiency

We report a patient with lipid-storage myopathy due to multiple acyl-CoA dehydrogenation deficiency (MADD). Molecular genetic analysis showed that she was compound heterozygous for mutations in the gene for electron transfer flavoprotein:ubiquinone oxidoreductase (ETFQO). Despite a good initial response to treatment, she developed respiratory insufficiency at age 14 years and has required long-term overnight ventilation. Thus, MADD is one of the few conditions that can cause a myopathy with weakness of the respiratory muscles out of proportion to the limb muscles.

Glutaryl-CoA dehydrogenase deficiency: region-specific analysis of organic acids and acylcarnitines in post mortem brain predicts vulnerability of the putamen

The neurometabolic disorder glutaryl-CoA dehydrogenase (GCDH) deficiency is biochemically characterised by an accumulation of the marker metabolites 3-hydroxyglutaric acid, glutaric acid, and glutarylcarnitine. If untreated, the disease is complicated by acute encephalopathic crises, resulting in neurodegeneration of vulnerable brain regions, in particular the putamen. 3-hydroxyglutaric acid is considered the major neurotoxin in this disease. There are only preliminary data concerning glutaric acid concentrations in the brains of affected children and the distribution of 3-hydroxyglutaric acid and glutarylcarnitine has not been described. In the present study, we investigated post mortem the distribution of 3-hydroxyglutaric and glutaric acids as well as glutarylcarnitine in 14 different brain regions, internal organs, and body fluids (urine, plasma, cerebrospinal fluid) in a 14-year-old boy. 3-Hydroxyglutaric acid showed the highest concentration (62 nmol/g protein) in the putamen among all brain areas investigated. The glutarylcarnitine concentration was also highest in the putamen (7.1 nmol/g protein). We suggest that the regional-specific differences in the relative concentrations of 3-hydroxyglutaric acid contribute to the pattern of neuronal damage in this disease. These results provide an explanatory basis for the high vulnerability of the putamen in this disease, adding to the strong corticostriatal glutamatergic input into the putamen and the high excitotoxic susceptibility of neostriatal medium spiny neurons.

A splice junction mutation in muscle carnitine palmitoyltransferase II deficiency

We report the first splice junction mutation to be described in the carnitine palmitoyltransferase (CPT) 2 gene in a patient with the muscle form of CPT II deficiency. The patient, a 25-year-old man, suffered from attacks of myalgia and muscle weakness in early adult life. There was biochemical evidence of CPT II deficiency. Molecular genetic analysis revealed the common S113L mutation on one allele whilst a novel mutation at the splice donor junction in intron 3 was identified on the other allele. Sequencing of reverse transcription polymerase chain reaction (RT-PCR) products clearly demonstrated that this mutation causes the skipping of exon 3, thus establishing its pathogenic role.

Mutation and biochemical analysis in carnitine palmitoyltransferase type II (CPT II) deficiency

Carnitine palmitoyltransferase type II (CPT II) deficiency has three basic phenotypes, late-onset muscular (mild), infantile/juvenile hepatic (intermediate) and severe neonatal. We have measured fatty acid oxidation and CPT II activity and performed mutation studies in 24 symptomatic patients representing the full clinical spectrum of disease. Severe and intermediate phenotypes show a clear correlation with biochemical indices and genetic analysis revealed causative mutations in most patients. Studies of mild phenotypes suggest a more complex interaction, with higher residual fatty acid oxidation, a wider range of CPT II activity (10-60%) but little evidence of genotype-phenotype correlation. Residual CPT II mutant protein from myopathic patients shows thermal instability at 41 degrees C. The common 'polymorphisms' V3681 and M647V are strikingly overrepresented in the myopathic patients, the implication being that they may significantly influence the manifestation of clinical disease and could therefore potentially be considered as a susceptibility variants. Among myopathic individuals, males comprised 88% of patients, suggesting increased susceptibility to clinical disease. A small number of symptomatic patients appear to have significant residual CPT II activity (42-60%) The synergistic interaction of partial deficiencies of CPT II, muscle adenosine monophosphate deaminase and possibly other enzymes of muscle energy metabolism in the aetiology of episodic myopathy deserves wider consideration.

Plasma free and total carnitine measured in children by tandem mass spectrometry

Free and total carnitine quantification is important as a complementary test for the diagnosis of unusual metabolic diseases, including fatty acid degradation disorders. The present study reports a new method for the quantification of free and total carnitine in dried plasma specimens by isotope dilution electrospray tandem mass spectrometry with sample derivatization. Carnitine is determined by looking for the precursor of ions of m/z = 103 of N-butylester derivative, and the method is validated by comparison with radioenzymatic assay. We obtained an inter- and intra-day assay coefficient of variation of 4.3 and 2.3, respectively. Free and total carnitine was analyzed in 309 dried plasma spot samples from children ranging in age from newborn to 14 years using the new method, which was found to be suitable for calculating reference age-related values for free and total carnitine (less than one month: 19.3 +/- 2.4 and 23.5 +/- 2.9; one to twelve months: 28.8 +/- 10.2 and 35.9 +/- 11.4; one to seven years: 30.7 +/- 10.3 and 38.1 +/- 11.9; seven to 14 years: 33.7 +/- 11.6, and 43.1 +/- 13.8 micro M, respectively). No difference was found between males and females. A significant difference was observed between neonates and the other age groups. We compare our data with reference values in the literature, most of them obtained by radioenzymatic assay. However, this method is laborious and time consuming. The electrospray tandem mass spectrometry method presented here is a reliable, rapid and automated procedure for carnitine quantitation.

Mitochondrial fatty acid beta-oxidation in the retinal pigment epithelium

Pigmentary retinopathy is an important feature of long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, a disorder of mitochondrial fatty acid beta-oxidation. Pathogenesis of this complication remains unknown. The retinal pigment epithelium (RPE) is affected early in this retinopathy. We wanted to determine whether there is evidence of mitochondrial fatty acid beta-oxidation in the RPE cells. Fatty acid oxidation was measured from cultured porcine RPE cells by incubating them with [U-13C]-hexadecanoic acid. Acylcarnitine esters were analyzed by tandem mass spectrometry. The activity of LCHAD and carnitine uptake capacity were measured from the cultured cells. Antibodies to the human mitochondrial trifunctional protein (MTP) containing LCHAD activity were used to analyze the expression of the MTP in the cultured RPE cell lysate and in human retinal sections by immunoblotting and immunohistochemistry. Fatty acid oxidation analysis showed normal chain shortening of hexadecanoic acid and production of acetylcarnitine in cultured RPE cells. Immunoblotting revealed expression of the MTP and enzyme assay showed the activity of LCHAD in the RPE cells. RPE cells were also capable of carnitine uptake. Positive labeling to the MTP antibodies was detected in the RPE, photoreceptors, and ganglion cells. The results give strong in vitro evidence for the presence of mitochondrial fatty acid beta-oxidation in RPE cells and the expression of the MTP in the RPE and other layers of the retina. Further studies are required to clarify whether this pathway acts also in vivo in the retina.

Analysis of mitochondrial fatty acid oxidation intermediates by tandem mass spectrometry from intact mitochondria prepared from homogenates of cultured fibroblasts, skeletal muscle cells, and fresh muscle

Defects of mitochondrial fatty acid beta-oxidation are an important group of inherited metabolic disorders in children. Despite improved screening opportunities, diagnosis of these disorders is not often straightforward and requires enzyme analyses. Because therapy is effective in many of these disorders, rapid diagnosis is essential. We report a technique that allows analysis of fatty acid oxidation not only in cultured cells (fibroblasts, myoblasts, and myotubes) but also in fresh muscle homogenate. Fatty acid oxidation analysis was performed by incubating fresh muscle homogenate or harvested cultured cells with stable isotopically labeled palmitate. The intermediates generated were analyzed by tandem mass spectrometry. Results of patients with seven different beta-oxidation disorders were compared with controls. Acylcarnitine intermediates in patient samples could be easily differentiated from the control samples. The acylcarnitine profile of each beta-oxidation defect was compatible with localization of the enzyme defect. Both in patient and control samples, the same pattern of intermediates could be detected in fibroblasts, muscle cells, and fresh muscle homogenate. The procedure described allowed correct diagnosis of all the beta-oxidation defects studied. Utilization of fresh muscle samples reduces the delay in diagnosis related to tissue culture and is useful in diagnostic of patients with neuromuscular phenotype. Measurement of fatty acid oxidation intermediates from myoblasts or myotubes is an additional tool in investigating pathogenetic mechanisms of myopathy in beta-oxidation defects.

Neonatal screening for medium-chain acyl-CoA dehydrogenase deficiency

Neonatal screening for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency has not yet been introduced in the UK, primarily because of uncertainty about the natural history of the disorder and concerns about the specificity of the screening test. To obtain data on these issues, we did a retrospective study in which we analysed the concentrations of acylcarnitines in stored neonatal blood spots, and reviewed patients with high octanoylcarnitine concentrations at age 7-9 years. The high morbidity and mortality associated with the disorder, and the specificity of acylcarnitine analysis seen in our study support the introduction of screening for MCAD deficiency.