LDH Isoenzymes Research Articles

Persistent hypoxia promotes myofibroblast differentiation via GPR-81 and differential regulation of LDH isoenzymes in normal and idiopathic pulmonary fibrosis fibroblasts.

Hypoxia, a state of insufficient oxygen availability, promotes cellular lactate production. Lactate levels are increased in lungs from patients with idiopathic pulmonary fibrosis (IPF), a disease characterized by excessive scar formation, and lactate is implicated in the pathobiology of lung fibrosis. However, the mechanisms underlying the effects of hypoxia and lactate on fibroblast phenotype are poorly understood. We exposed normal and IPF lung fibroblasts to persistent hypoxia and found that increased lactate generation by IPF fibroblasts was driven by the FoxM1-dependent increase of lactate dehydrogenase A (LDHA) coupled with decreased LDHB that was not observed in normal lung fibroblasts. Importantly, hypoxia reduced α-smooth muscle actin (α-SMA) expression in normal fibroblasts but had no significant impact on this marker of differentiation in IPF fibroblasts. Treatment of control and IPF fibroblasts with TGF-β under hypoxic conditions did not significantly change LDHA or LDHB expression. Surprisingly, lactate directly induced the differentiation of normal, but not IPF fibroblasts under hypoxic conditions. Moreover, while expression of GPR-81, a G-protein-coupled receptor that binds extracellular lactate, was increased by hypoxia in both normal and IPF fibroblasts, its inhibition or silencing only suppressed lactate-mediated differentiation in normal fibroblasts. These studies show that hypoxia differentially affects normal and fibrotic fibroblasts, promoting increased lactate generation by IPF fibroblasts through regulation of the LDHA/LDHB ratio and promoting normal lung fibroblast responsiveness to lactate through GPR-81. This supports a novel paradigm in which lactate may serve as a paracrine intercellular signal in oxygen-deficient microenvironments.

Serum lactate dehydrogenase and its isoenzymes as predictors of clinical outcomes in acute exacerbation of chronic obstructive pulmonary disease: a retrospective analysis of a hospitalized cohort.

We aimed to test the relationship between serum lactate dehydrogenase (LDH) and its isoenzymes and treatment outcomes during hospitalization for acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Thirty-eight AECOPD patients were recruited from a tertiary hospital from December 2017 to June 2018. Serum LDH and LDH isoenzymes were measured on venous blood collected at admission. Treatment outcomes included duration of hospital stay, initiation of mechanical or non-invasive ventilation (NIV), initiation of antipseudomonal antibiotics, change in empirical antibiotic treatment, need for intravenous corticosteroids or methylxanthines, and percentage of change in C-reactive protein from admission to the third day. Multivariate linear and binary logistic regression analyses were used to test the study's objectives. We found that, after adjusting for age, gender, comorbidities, COPD severity, level of hypoxemia, and inflammation markers, each 10 U/L increase in serum LDH was associated with prolongation of the hospital stay by 0.25 (0.03, 0.46) days, 42% higher odds [odds ratio (OR) 1.42 (1.00, 2.03)] for need of NIV, and 25% higher odds [OR 1.25 (1.04, 1.49)] for initiation of antipseudomonal treatment. LDH1 and LDH2 were the LDH isoenzymes that mainly drove these relationships. LDH release in the context of an AECOPD could originate from lung, muscle, or heart tissue damage due to airway inflammation, respiratory muscle recruitment, and myocardial stress. Myocardial injury and aerobic adaptation in respiratory muscles may explain the predominance of LDH1 and LDH2 isoenzymes in these associations.

Лактатдегидрогеназа в условиях фармакологической блокады симпатического ганглия

The isoenzymes activity of LDH in the cranial cervical sympathetic ganglion (SCG) of rabbits was determined by disc- electrophoresis under conditions of pharmacological ganglion blockade by subcutaneous administration of the cholinolytic dimecoline. Pharmacological blockade causes significant rearrangements of the LDH isoenzyme spectrum in SCG. There is a complete reduction of M isoforms (LDH-4 and -5), H isoforms (LDH-1 and -2) only remain. It is assumed that a decrease in the activity of all LDH isoforms during pharmacological blockade occurs by allosteric inhibition and leads to a significant restructuring of metabolism and to hypofunction of SCG.

MALATHION INDUCED CHANGES IN LACTATE DEHYDROGENASE ISOENZYMES OF RED MUSCLE OF Heteropneustes fossilis (BLOCH)

Malathion, an organophosphate pesticide, is generally used in crop fields to reduce the loss of farm produce. However, its concomitant run-off from agricultural fields poses major threat to the aquatic fauna and especially fishes are exposed to such toxicity causing changes in various biochemical parameters involved in different metabolic pathways. The five isoenzymes of LDH identified electrophoretically, show conspicuous changes in terms of number and quantity with respect to different concentrations and exposure periods of malathion.

LDH-A-Modulation and the Variability of LDH Isoenzyme Profiles in Murine Gliomas: A Link with Metabolic and Growth Responses.

Simple SummaryThree different murine glioma cell lines were modified to downregulate the expression of the murine LDH-A gene using shRNA knock-down (KD), and compared to shRNA scrambled control (NC) cell lines. Successful LDH-A KD was confirmed by differences in the expression of LDH-A and LDH-B mRNA, protein and enzymatic activity, as well as their LDH isoenzyme profiles. mRNA expression data indicated that: (i) GL261 LDH-A KD cells may have an improved ability to metabolize lactate into the TCA cycle; and (ii) that GL261 LDH-A KD cells can upregulate lipid metabolism/fatty acid oxidation pathways, whereas the other glioma cell lines (CT2A, and ALTS1C1) do not have this capacity. The data suggest that GL261 LDH-A KD cells can develop/activate alternative metabolic pathways for enhanced survival in a nutrient-limited environment. Furthermore, LDH-A KD prolonged the doubling time of GL261 cells in culture and prevented the formation of subcutaneous flank tumors in immune-competent C57BL/6 mice. No differences between NC and KD cell proliferation (in vitro) or tumor growth in C57BL/6 mice (doubling time) were observed for CT2A and ALTS1C1 cells and tumors. Our results suggest that GL261 glioma cells (but not CT2A and ALTS1C1 cells) are pre-programmed with a capacity for activating different metabolic pathways with higher TCA cycle activity, and that this capacity is enhanced by LDH-A depletion, leading to a difference in growth and survival in an immune-competent environment.Three murine glioma cell lines (GL261, CT2A, and ALTS1C1) were modified to downregulate the expression of the murine LDH-A gene using shRNA, and compared to shRNA scrambled control (NC) cell lines. Differences in the expression of LDH-A and LDH-B mRNA, protein and enzymatic activity, as well as their LDH isoenzyme profiles, were observed in the six cell lines, and confirmed successful LDH-A KD. LDH-A KD (knock-down) resulted in metabolic changes in cells with a reduction in glycolysis (GlycoPER) and an increase in basal respiratory rate (mitoOCR). GL261 cells had a more limited ATP production capacity compared to CT2A and ALTS1C1 cells. An analysis of mRNA expression data indicated that: (i) GL261 LDH-A KD cells may have an improved ability to metabolize lactate into the TCA cycle; and (ii) that GL261 LDH-A KD cells can upregulate lipid metabolism/fatty acid oxidation pathways, whereas the other glioma cell lines do not have this capacity. These two observations suggest that GL261 LDH-A KD cells can develop/activate alternative metabolic pathways for enhanced survival in a nutrient-limited environment, and that specific nutrient limitations have a variable impact on tumor cell metabolism and proliferation. The phenotypic effects of LDH-A KD were compared to those in control (NC) cells and tumors. LDH-A KD prolonged the doubling time of GL261 cells in culture and prevented the formation of subcutaneous flank tumors in immune-competent C57BL/6 mice, whereas GL261 NC tumors had a prolonged growth delay in C57BL/6 mice. In nude mice, both LDH-A KD and NC GL261 tumors grew rapidly (more rapidly than GL261 NC tumors in C57BL/6 mice), demonstrating the impact of an intact immune system on GL261 tumor growth. No differences between NC and KD cell proliferation (in vitro) or tumor growth in C57BL/6 mice (doubling time) were observed for CT2A and ALTS1C1 cells and tumors, despite the small changes to their LDH isoenzyme profiles. These results suggest that GL261 glioma cells (but not CT2A and ALTS1C1 cells) are pre-programmed to have the capacity for activating different metabolic pathways with higher TCA cycle activity, and that this capacity is enhanced by LDH-A depletion. We observed that the combined impact of LDH-A depletion and the immune system had a significant impact on the growth of subcutaneous-located GL261 tumors.

Relationship between LDH and Mg in Monitoring of Hematological and Non-Hematological Malignant Diseases

Relationship between LDH and Mg in Monitoring of Hematological and Non-Hematological Malignant DiseaseAurelian Udristioiu,Titu Maiorescu University of Bucharest, Faculty of Medicine, Department of Molecular BiologyABSTRACTBackgroundMagnesium, which is the second most abundant into-cellular cation after potassium, plays a key role in regulating many cellular functions and enzymes, including ion channels, metabolic cycles, and signaling pathways.Aim of this study was to evaluate the correlation between the serum levels of lactate dehydrogenase (LDH) and magnesium (Mg) in patients diagnosed with hematological and non-hematological malignant diseases.MethodWe analyzed a cohort of patients (n = 75) comprising males (n = 36) and females (n =39) with a mean age of 57 years, who had cancer and were admitted to the oncology department. The biochemical parameters were measured running a Vitros 250 dry chemistry analyzer (Johnson & Johnson, USA) using the slides for multi-layer spectro-photometry measurements.These patients were closely monitored twice a week during treatment with specific cytostatic drugs and once a week during consolidation therapy, using specific tests for different types of cancer. In addition, with the cooperation of physicians and patients, they were performed along with hematological and biochemical tests, CBC with differential count and LDH and serum Mg levels, which can serve as markers for monitoring the progression of malignancies.Among the patients, 5 patients were diagnosed with lung cancer, 11 patients were diagnosed with breast cancer, 14 patients were diagnosed with colorectal cancer, 43 patients were diagnosed with chronic lymphocytic leukemia (CLL), 1 patient was diagnosed with acute promyelocytic leukemia (LAM-3) and 1 patient was diagnosed with chronic monocytic leukemia (CML).The CBC with the differential count, biochemistry samples, body radiography, ultrasound and computed tomography (CT) were used for the patient to establish the type of cancer diseases. An initial panel of monoclonal antibodies was used to determine the immune phenotypes of the subgroups of differentiated T cells and B cells. The diagnosis of LAM-3 was made based on blood smears, the examination of bone marrow (BM) aspirates, the evaluation of promyelocytes, (greater than 30% in BM), and the presence of a specific immune phenotype.ResultsThe results were interpreted for each patient based on medical history, clinical and para-clinical examinations and other signs of malignant diseases. Among the patients in this study, 55 patients (73%) exhibited normal serum levels of Mg (normal range value = 1.60-2.3 mg/dL; mean value = 2.2 mg/dL; SD = 0.2; p = 0.02) following cancer therapy. Six patients (8%) exhibited low levels of Mg (range = 0.60-1.50 mg/dL; mean value = 1.05 mg/dL). However, 12 patients (16%) displayed high levels of serum Mg (range =2.6-3.27 mg/dL; mean value = 2.89 mg/dL). The levels of serum lactic dehydrogenase (LDH) were also evaluated in patients newly diagnosed with cancer and in patients with unfavorable responses to the cancer therapy (range = 240-1330 U/L; mean value = 787 U/L; SD =1.33; p = 0.002; normal values 135-225 U/L), (Table 1).DiscussionsThe serum Mg level is increased via Mg²+ release from malignant tissues in patients with malignant disease prior to treatment with cytostatic drugs. In the different malignant diseases, the serum Mg values were high, normal or low, independent of the serum LDH values. The LDH levels remained elevated after initial cytostatic treatment until cancer remission.The number of chromosome copies in malignant tumors can be correlated with the total serum LDH values. LDH levels in cancer patients are elevated due to high levels of LDH-3 isoenzyme in patients with malignancies and high levels of LDH-4 and LDH-5 isoenzymes, elevated patients with cancer of liver, muscle, lung and tissue tissues. conjunctive. High concentrations of serum LDH damage the cell membrane. Thereafter, malignant cells become invasive and metastasizes.ConclusionsNormal levels of Mg with moderately increased LDH levels were observed in all patients who had cancer that was in the regression phase following good responses to a specific cancer therapy. Low levels of Mg with high levels of serum LDH were observed in all patients with poor prognosis and metastases. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Effet du stiripentol sur l’excrétion urinaire d’oxalate

Oxalate is a metabolite promoting the formation of calcium oxalate crystals in urine. Hyperoxaluria is a feature of genetic diseases, known as primary hyperoxaluria, leading to chronic kidney disease. Ethylene glycol poisoning induces the crystallization of calcium oxalate crystals in renal tubules, promoting acute renal failure. Urine oxalate results from glyoxylate transformation to oxalate in the liver, due to lactate dehydrogenase (LDH) activity, especially the LDH-5 isoenzyme. Genetic RNA interference therapy targeting lactate dehydrogenase lowers urine oxalate excretion in murine models. Stiripentol is a drug inhibiting neuronal LDH-5 isoenzyme activity. We hypothesized that stiripentol would also reduce hepatic oxalate production and urine oxalate excretion. In vitro Stiripentol decreases oxalate synthesis by hepatocytes. In vivo, stiripentol decreases urine oxalate excretion in rats and protects kidney tissue and function against ethylene glycol intoxication and hydroxyproline-induced calcium oxalate crystalline nephropathy. The use of stiripentol in clinical practice deserves further clinical studies.

Dietary flaxseed's protective effects on body tissues of mice after oral exposure to xylene.

Xylene is a common pollutant in the environment that enters the body of animals and humans in various ways, but most often through the respiratory tract and adversely affects their overall health. However, xylene effects after oral exposure have not been sufficiently studied. This study aimed to investigate the effects of xylene exposure on the mouse organism and to identify possible beneficial effects of flaxseed on such exposure. Eighty mice were divided into four groups: control group C (basal diet + no xylene exposure), group X (oral exposure by 400 mg/kg/day xylene), group F (10% flaxseed supplementation of basal diet), and group XF (10% dietary flaxseed + oral exposure by xylene). Experimental trial took 14 days. Clinical examination, spectroscopic analysis of tissue aminotransferases, total lactate dehydrogenase (TLDH), and acetylcholinesterase (AchE) activities, electrophoretic analysis of LDH isoenzymes, western blot and immunohistochemical analysis of apoptosis as well as routine histology of the kidneys and jejunum, and transmission electron microscopy of the liver were performed. Marked restlessness in group X and high weight losses in mice of all groups were recorded during the experiment. Xylene promoted apoptosis (caspase-3 expression) without causing marked structural changes in the liver and jejunum, although renal cortex structure was affected adversely. In the brain, liver, and kidney of mice, xylene increased levels of liver transaminases, LDH, and decreased AchE activities, reflecting cell membrane damage. Flaxseed feeding improved animal behaviour, leakage of enzymes and prevented selected tissue toxic damage induced by xylene by protecting cell membrane integrity and fluidity and by suppressing apoptosis. These results point at the protective effect of flaxseed consumption on mice.

Study of LDH Isoenzymes in Myocardial Infraction at Vidharbha Region (Central India)

Introduction: A significant cause of morbidity and mortality worldwide is myocardial infarction (MI).Within the first few hours of the beginning of MI, the greatest risk of death occurs. Thus, for the effectivetreatment of patients with MI, early detection of cardiac ischemia is essential. Inappropriate diagnosis ofpatients with chest pain sometimes leads to improper admission, and vice versa, of patients without MI.Physical examination, precise ECG results and evaluation of cardiac biomarkers play an important rolein the early diagnosis of acute ischemia, in addition to clinical history. In the present analysis, the cardiacbiomarker lactate dehydrogenase released during a MI event is discussed in depth.Aim: We conducted a cross sectional study to examine the different levels of LDH isoenzymes in myocardialinfarction patients those admitted in cardiac care unit in SMHRC Nagpur.Material and Methods: The present study included 100 subjects of age group 30-80 years. Patients admittedto the coronary care unit at SMHRC & AVBRH between January 2020 and June 2020 was consideredeligible for the study. These guidelines ensured that sufficient blood samples were available and the criteriafor diagnosis were consistent. Lactate dehydrogenase isoenzyme was fractionated by agarose gel electrophoresis as described by Cawley and Eberhard. The stained slides were scanned on Chromoscan at 520 mixand the percentages of the fractions were quantitated.Results: The results obtained in the present study indicate that serum lactate dehydrogenase enzyme activityincreases 4-5 folds in the first 24-72 hours after the onset of clinical infarction with a peak on the second day.It then declines gradually towards the normal within two weeks. Thus, determination of total serum LDHis valuable if patients present themselves for clinical check up even after a week from the day of infarct.Although the contribution of myocardium to total serum lactate dehydrogenase is large, its interpretationbecomes difficult if the diseases of other organs such as liver, kidney, etc.Conclusion: In conclusion, the present data strongly support the use of Lactate dehydrogenase for thediagnosis of MI. Such a strategy should boost both the precision and sensitivity for myocardial infarctiondiagnosis.

LACTATE DEHYDROGENASE ISOENZYMES IN TISSUES OF CARNIVOROUS MAMMALS DURING POSTNATAL ONTOGENY

The electrophoretic separation of isoenzymes of lactate dehydrogenase (LDH, EC 1.1.1.27) was performed in the kidneys, skeletal muscle, lungs and spleen in mink Neovison vison Schreber and blue fox Alopex lagopus L. pups at 15, 25, 60, 90, 120, 150, 180, and 210 days of age. Significant changes in the isoenzyme spectra of LDH in the tissues of mink and blue fox pups were observed in the initial period of the animals’ intensive growth and development –at the age of 15–0 days. In the skeletal muscles, lungs and spleen, the content of M-subunits of LDH during postnatal ontogeny was higher in mink than in foxes. The isozyme profile of renal LDH in 4‑onth-old pups of mink and blue foxes corresponded to that of 7‑onth-old animals. The tissue specificity of the LDH isoenzyme pattern reflects the metabolic profile of the tissues and is detectable already in early developmental stages.

Stiripentol identifies a therapeutic target to reduce oxaluria.

Oxalate is a metabolic end-product promoting the formation of calcium oxalate crystals in urine. Massive urine oxalate excretion occurs in genetic diseases, mainly primary hyperoxaluria type I and II, threatening renal function. Ethylene glycol poisoning may induce the precipitation of calcium oxalate crystals in renal tubules, leading to acute renal failure. In both cases, oxalate results from glyoxylate transformation to oxalate in the liver, by lactate dehydrogenase (LDH) enzymes, especially the LDH-5 isoenzyme. The purpose of the review is to highlight LDH as a potential therapeutic target according to recent publications. Genetic therapy targeting LDH metabolism decreases urine oxalate excretion in rodents. Stiripentol is an antiepileptic drug that has been shown recently to inhibit neuronal LDH-5 isoenzyme. Stiripentol was hypothesized to reduce hepatic oxalate production and urine oxalate excretion. In vitro, stiripentol decreases oxalate synthesis by hepatocytes. In vivo, stiripentol oral administration decreases urine oxalate excretion in rats and protects renal function and renal tissue against ethylene glycol intoxication and chronic calcium oxalate crystalline nephropathy. The use of stiripentol in-vitro and in-vivo highlights that targeting hepatic LDH by pharmacological or genetic tools may decrease oxalate synthesis, deserving clinical studies.

The influence of selenium deficiency on chosen biochemical parameters and histopathological changes in muscles of goat kids.

The research was conducted on 40 young alpine goats (kids) divided into two groups. First group consisted of 20 kids demonstrating clinical signs of muscular dystrophy. Second group was a control and consisted of 20 animals that received intramuscular injection (2ml per animal) of vitamin E and selenium preparation containing in 1ml 50 mg of tocopherol acetate, 0.5mg of sodium selenite and solvent on 2nd day of life. The kids were clinically examined and blood for laboratory analyses was sampled three times from day 5 of their life in 10 day intervals. In addition, six 24 days old kids demonstrating clinical signs of muscular dystrophy and six control kids were subjected to biceps femoris biopsy. Serum total protein, glucose, triglycerides, cholesterol as well as AST, CK and LDH were determined in all the animals. In addition, the activity of glutathione peroxidase (GSH-Px) was determined in whole blood and serum concentrations of selenium and vitamin E were deter-mined in 6 kids from each group. Total lactate dehydrogenase activity and its separation into isoenzymatic fractions were determined in the collected biopsy material. The muscle samples collected were additionally subjected to histopathological examination consisting of HE staining and HBFP staining to detect necrotic muscle fibers. Symptoms of muscular dystrophy began to appear in the first group between 17 and 23 days of age and included tremors of the limbs, poor posture, stilt gait and increased time of laying. The control animals did not show any symptoms of the disease during the experiment. Hypo-proteinemia, hypoglycemia, cholesterol reduction and elevated triglycerides level associated with lipolysis of adipose tissue have been found in the sick kids. A significant decrease in selenium, vitamin E and activity of glutathione peroxidase levels was observed in the kids with symptoms of muscular dystrophy. The activity of AST, CK and LDH was significantly higher in the animals with symptoms of the disease as well. Five isoenzymes were obtained in the electrophoretic separation of lactate dehydrogenase into isoenzymatic fractions in the muscle tissue. LDH4and LDH5 isoenzymes were dominating, and a significant increase in LDH5 fraction of the sick animals was also observed. Histopathological examination of muscle samples from sick animals revealed changes characteristic for the presence of Zenker necrosis.

Suppressed expression of LDHB promotes age-related hearing loss via aerobic glycolysis

Age-dependent decrease of mitochondrial energy production and cellular redox imbalance play significant roles in age-related hearing loss (ARHL). Lactate dehydrogenase B (LDHB) is a key glycolytic enzyme that catalyzes the interconversion of pyruvate and lactate. LDH activity and isoenzyme patterns are known to be changed with aging, but the role of LDHB in ARHL has not been studied yet. Here, we found that LDHB knockout mice showed hearing loss at high frequencies, which is the typical feature of ARHL. LDHB knockdown caused downregulation of mitochondrial functions in auditory cell line, University of Bristol/organ of Corti 1 (UB/OC1) with decreased NAD+ and increased hypoxia inducing factor-1α. LDHB knockdown also enhanced the death of UB/OC1 cells with ototoxic gentamicin treatment. On the contrary, the induction of LDHB expression caused enhanced mitochondrial functions, including changes in mitochondrial respiratory subunits, mitochondrial membrane potentials, ATP, and the NAD+/NADH ratio. Thus, we concluded that suppression of LDHB activity may be closely related with the early onset or progression of ARHL.

Functional and histological changes of the pancreas and the liver in the rats after the acute and subacute administration of diazinon

Background/Aim. Organophosphate pesticides (OPs) are used extensively worldwide in agriculture and forestry, and their application represents a major health problem for humans and animals. The aim of this study was to investigate the possibility of the adaptation of an organism to the pro-longed administration of a low dose of diazinon. Methods. The study was conducted on a total of 60 male Wistar rats. The first 30 rats were divided into four equal diazinon groups (n = 6) and the control one (corn oil). Diazinon was orally administered once at doses: 200, 400, 600, 800 mg/kg (one dose ? one group). The concentration of glucose, the activity of ?-amylase and the relative activity of LDH1-LDH5 isoenzymes in the blood were measured 24 hours after the application. The remaining 30 rats were divided into two equal diazinon groups (n = 10) and the control one (corn oil). The first group was treated during 7 days, and the second during 14 days with 55 mg/kg of diazinon (1/10 of previously determined LD50 value). The histopathology of the pancreas and the liver, as well as the relative activities of LDH isoenzymes in the blood, were determined after the completion of both time periods. Results. Single administration of increasing doses of diazinon resulted in a significant increase in the concentrations of glucose, activity of ?-amylase and LDH isoenzymes. Subacute application of a low diazinon dose induced histopathological changes in the pancreas manifested by acinar cell necrosis, and in the liver in the form of portal hepatitis and multifocal necrosis. The cumulative doses resulted in statistically significantly lower activities of LDH isoenzymes compared with the single administration of these doses, indicating a lower degree of the cells damage after the subacute diazinon administration. Conclusion. Subacute administration of a low dose of diazinon leads to a different adaptation degree of organs and organ systems to toxic effects caused by this organophosphate.

Evaluation of Tissue and Serum Expression Levels of Lactate Dehydrogenase Isoenzymes in Patients with Head and Neck Squamous Cell Carcinoma.

Head and Neck Squamous Cell Carcinoma (HNSCC) is a common malignancy that is associated with high morbidity and mortality all over the world. We explored the role of mRNA expression of both subunits of LDH in the early diagnosis of HNSCC. This was a case-control study on 62 healthy individuals and 62 patients with HNSCC. The expression of LDH in tumors and healthy tissue margins, and in the serum of both HNSCC patients and healthy individuals was evaluated using a quantitative real-time PCR method. Analysis of LDH-A and LDH-B expression and sensitivity-specificity analysis were carried out using SPSS software. mRNA expression levels of LDH-A (4.18±1.29) and LDH-B (2.85±1.07) isoenzymes in tumor tissues were significantly higher than the expressions in the corresponding healthy tissue margins (1.85±0.56 and 1.61±0.56 for LDH-A and LDH-B, respectively). A comparison of LDH-B expression between histological grade I tumor tissue (2.74±0.19) and marginal tissue (1.62±0.90) showed a significant difference (P=0.016). Patients with a positive history of alcohol consumption and cigarette smoking had significantly higher mRNA expression of LDH-A (P=0.024) and LDH-B (P=0.03) in the marginal tissue and blood, respectively. The highest sensitivity and specificity values pertained to the mRNA expression of LDH-A (90.9%) and LDH-B (85.5%) in the blood. This is the first study reporting LDH gene expression as a biomarker in blood and tumoral tissue of HNSCC patients. Given the highest sensitivity and specificity values for LDH-A and LDH-B in blood, we recommend the simultaneous evaluation of both LDH isoenzymes in blood samples as a potential diagnostic method.

Altered expression of lactate dehydrogenase and monocarboxylate transporter involved in lactate metabolism in broiler wooden breast

Wooden breast (WB) results in significant losses to the broiler industry due to reductions in meat quality. While the etiology of WB is unknown, it is believed to be associated with localized hypoxia and decreased lactate levels in skeletal muscles, indicating the presence of altered lactate metabolism in WB. We hypothesized that the expression levels of the major signaling molecules that control lactate metabolism, including lactate dehydrogenases (LDHA and LDHB) and monocarboxylate transporters (MCT1 and MCT4), were altered in WB. Therefore, the objectives of this study were to evaluate whether there were changes in mRNA and protein levels of LDHA, LDHB, MCT1, and MCT4 in WB compared to normal breast (NB) muscles. Biochemical analysis for LDH enzyme activity in NB and WB muscles was studied. MicroRNA375 (miR-375) expression, known to be inversely associated with LDHB protein expression in human cells, was also investigated. The level of LDHA mRNA was 1.7-fold lower in WB tissues than in NB tissues (P < 0.0001). However, the LDHA protein levels were similar in WB and NB tissues. In contrast, the levels of LDHB mRNA and protein were 8.4-fold higher (P < 0.002) and 13.6-fold higher (P < 0.02) in WB than in NB tissues, respectively. The level of miR-375 was not different between WB and NB muscles. The specific LDH isoenzyme activity that converted lactate to pyruvate was 1.8-fold lower in WB compared to NB tissues (P < 0.01). The level of MCT1 mRNA was 2.3-fold higher in WB than those in NB muscles (P < 0.02). However, this upregulation was not observed with MCT1 protein expression levels. The expression levels of MCT4 mRNA and protein were elevated 2.8-fold (P < 0.02) and 3.5-fold (P < 0.004) in WB compared to NB tissues, respectively. Our current findings suggest the potential roles of LDHB and MCT4 on lactate metabolism and provide a unique molecular elucidation for altered lactate homeostasis in WB muscles of broilers.

Evaluation of total LDH and its isoenzymes as markers in preeclampsia.

Preeclampsia, a rapidly progressing pregnancy-specific multi-systemic syndrome is globally the leading cause of maternal and neonatal morbidity and mortality. This study aims to evaluate the serum total Lactate dehydrogenase levels in women with preeclampsia when compared to normotensive pregnant women and assess the electrophoretic pattern of the LDH isoenzymes in normal pregnancy, preeclampsia and eclampsia. The study, carried out in the Department of Biochemistry of MVJ Medical College, included 30 patients of preeclampsia and 30 normotensive gestational age-matched pregnant women admitted to the Department of OBG. Serum total LDH was analysed by DGKC method. Serum and cord blood samples for isoenzyme distribution analysis were collected from a normal pregnant woman undergoing delivery, a woman with mild eclampsia, two women with eclampsia, and analysed by slab gel electrophoresis followed by activity staining. LDH was significantly elevated in cases as well as between the case (mild and severe) groups, showed a moderate positive statistically significant correlation with systolic, diastolic blood pressure and a sensitivity of 50% and a specificity of 80%. Further, the isoenzyme pattern showed a decreasing distribution of aerobic forms of LDH in preeclampsia-eclampsia. Serum total LDH may serve as a robust and affordable marker of preeclampsia. Serum total LDH, along with its isoenzyme profile, might serve as a predictor and a stronger marker of preeclampsia when compared to serum LDH analysis alone. It may also be used to assess the severity of preeclampsia and hence help in predicting and preventing adverse maternal and foetal outcomes.

LDH isoenzymes to hospital patients with exacerbation of chronic obstructive pulmonary disease (COPD)

Although average survival rates for lung cancer have improved, earlier and better diagnosis remains a priority. One promising approach to assisting earlier and safer diagnosis of lung lesions is bronchoalveolar lavage (BAL), which provides a sample of lung tissue as well as proteins and immune cells from the vicinity of the lesion, yet diagnostic sensitivity remains a challenge. Reproducible isolation of lung epithelia and multianalyte extraction have the potential to improve diagnostic sensitivity and provide new information for developing personalized therapeutic approaches. We present the use of a recently developed exclusion-based, solid-phase-extraction technique called SLIDE (Sliding Lid for Immobilized Droplet Extraction) to facilitate analysis of BAL samples. We developed a SLIDE protocol for lung epithelial cell extraction and biomarker staining of patient BALs, testing both EpCAM and Trop2 as capture antigens. We characterized captured cells using TTF1 and p40 as immunostaining biomarkers of adenocarcinoma and squamous cell carcinoma, respectively. We achieved up to 90% (EpCAM) and 84% (Trop2) extraction efficiency of representative tumor cell lines. We then used the platform to process two patient BAL samples in parallel within the same sample plate to demonstrate feasibility and observed that Trop2-based extraction potentially extracts more target cells than EpCAM-based extraction.

A more accurate method to interpret lactate dehydrogenase (LDH) isoenzymes’ results in patients with uterine masses

ObjectiveSince there are no approved reliable biomarkers for detecting preoperatively uterine sarcoma, lactate dehydrogenase (LDH) isoenzymes are usually required. We first evaluated the role of LDH isoenzymes in detecting uterine sarcoma risk, and then we tried to introduce a model to easily interpret the biochemical results. MethodsWe retrospectively retrieved records of patients who underwent surgical treatment for uterine masses from 2004 to 2016, and we compared data of 2211 patients with a definitive surgical diagnosis of uterine fibroids and 43 with uterine sarcomas. Quantitative relationships between serum LDH isoenzymes levels, as different single markers or in multiple assays, and the final diagnosis were investigated. ResultsLDH isoenzymes levels significantly differed between patients with benign uterine masses or sarcomas. LDH3 isoenzyme exhibited better predictive performances than the other four isoforms. Combining LDH3 with LDH1 isoenzymes into an inverse algebraic relationship, named Uterine mass Magna Graecia (U.M.G.) risk index, the accuracy of markers in discriminating between benign and suspicious malignant uterine masses was significantly enhanced, sensitivity at 100% and specificity at 99.6%, with nine false positive over 2211 benignant cases and no false negative over 43 sarcomas. ConclusionsThis retrospective analysis suggests to consider U.M.G. risk index as an inexpensive and accurate prognostic index that, once validated in a prospective study, may help clinicians in discriminating between benignant and suspicious malignant uterine masses.

Fructose-associated hepatotoxicity indexed by the lactate dehydrogenase isoenzyme LDH-5

Modern diets have become increasingly rich in fructose, for example through the addition of high-fructose corn syrup to many foods and drinks. It has been suggested that this might lead to hepatotoxicity, including the development of non-alcoholic fatty liver disease. After entering hepatocytes via insulin-independent glucose transporter 2 transmembrane carrier proteins, fructose is phosphorylated to fructose-1-phosphate in a reaction catalysed by fructokinase (ketohexokinase). In turn, fructose-1-phosphate is hydrolysed by aldolase B to glyceraldehydes. Glyceraldehydes may enter gluconeogenesis via fructose-1,6-bisphosphate and fructose-6-phosphate; glyceraldehydes may also enter glycogenolysis via pyruvate. The last pathway involves conversion of pyruvate to acetyl-CoA. Alternatively, pyruvate may be converted, via the action of the hepatic lactate dehydrogenase isoenzyme LDH-5, into lactate. In liver damage, the LDH-5 isoenzyme becomes elevated, predominantly in serum/plasma. We therefore hypothesised that if dietary fructose is associated with hepatotoxicity, there should be a positive correlation between erythrocyte fructose-6-phosphate and plasma LDH-5. This hypothesis was tested by assaying venous blood samples taken from 39 patients at rest, three hours after eating. Quantitative Fourier transform infrared spectrometry following gel electrophoresis was used to assay erythrocyte fructose-6-phosphate levels. Similarly, plasma LDH-5 concentrations were spectrophotometrically analysed, using the pyruvate-lactate reaction, following electrophoretic separation of the LDH isoenzymes. A significant positive correlation was found between the two variables (r = 0.44, p = 0.0047). This result, which supports our hypothesis, is evidence in favour of the possibility that dietary fructose is associated with hepatotoxicity. In addition to being a marker of hepatic damage, LDH-5 may play a more direct epigenetic role in causing liver damage; acute hepatic injury is associated with nuclear translocation of LDH, causing the production of lactate from pyruvate in the nucleus; in turn, the lactate inhibits histone deacetylase and is associated with upregulation of genes associated with the damage response, leading to cell death.