Triple Isozyme Lactic Acid Dehydrogenase Inhibition in Fully Viable MDA-MB-231 Cells Induces Cytostatic Effects That Are Not Reversed by Exogenous Lactic Acid

A number of aggressive human malignant tumors are characterized by an intensified glycolytic rate, over-expression of lactic acid dehydrogenase A (LDHA), and subsequent lactate accumulation, all of which contribute toward an acidic peri-cellular immunosuppressive tumor microenvironment (TME). While recent focus has been directed at how to inhibit LDHA, it is now becoming clear that multiple isozymes of LDH must be simultaneously inhibited in order to fully suppress lactic acid and halt glycolysis. In this work we explore the biochemical and genomic consequences of an applied triple LDH isozyme inhibitor (A, B, and C) (GNE-140) in MDA-MB-231 triple-negative breast cancer cells (TNBC) cells. The findings confirm that GNE-140 does in fact, fully block the production of lactic acid, which also results in a block of glucose utilization and severe impedance of the glycolytic pathway. Without a fully functional glycolytic pathway, breast cancer cells continue to thrive, sustain viability, produce ample energy, and maintain mitochondrial potential (ΔΨM). The only observable negative consequence of GNE-140 in this work, was the attenuation of cell division, evident in both 2D and 3D cultures and occurring in fully viable cells. Of important note, the cytostatic effects were not reversed by the addition of exogenous (+) lactic acid. While the effects of GNE-140 on the whole transcriptome were mild (12 up-regulated differential expressed genes (DEGs); 77 down-regulated DEGs) out of the 48,226 evaluated, the down-regulated DEGS collectively centered around a loss of genes related to mitosis, cell cycle, GO/G1–G1/S transition, and DNA replication. These data were also observed with digital florescence cytometry and flow cytometry, both corroborating a G0/G1 phase blockage. In conclusion, the findings in this work suggest there is an unknown element linking LDH enzyme activity to cell cycle progression, and this factor is completely independent of lactic acid. The data also establish that complete inhibition of LDH in cancer cells is not a detriment to cell viability or basic production of energy.

DIAGNOSTIC UTILITY OF SERUM LACTATE DEHYDROGENASE LEVELS (LDL) IN DIFFERENTIATING MEGALOBLASTIC ANEMIA FROM MYELODYSPLASTIC SYNDROMES IN PAKISTAN

Objective: To study the diagnostic utility of lactate dehydrogenase levels in differentiating megaloblastic anemia from myelodysplastic anemia in Pakistan. Study Design: Comparative cross-sectional study. Place and Duration of Study: Department of Hematology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan from Feb, 2019 to Aug, 2019. Methodology: In this study, total 240 patients (18-75 years of age) males and females were selected by consecutive sampling technique and were equally divided into 3 groups; patients with megaloblastic anemia, patients with myelodysplastic syndromes and healthy control group. The clinical history and duration of anemia were recorded on special designed proforma. The laboratory investigations including lactate dehydrogenase levels were also noted. Both types of anemia were compared on basis of Lactate Dehydrogenase Levels. Results: The lactate dehydrogenase levels in megaloblastic group were more than 3000 IU/L in 58 out of 80 patients (72.5%). On other hand, myelodysplastic group had 79 out of 80 patients with lactic acid dehydrogenase levels below 450 IU/L (98.75%). The difference in lactic acid dehydrogenase levels between both groups was found to be statistically significant. Conclusion: Serum lactate dehydrogenase levels can be used to differentiate megaloblastic anemia from other anemia especially myelodysplastic syndromes before doing a bone marrow examination. High lactate dehydrogenase levels above 3000 IU/L in megaloblastic anemia can differentiate it from other anemia.

Incidence of intravascular hemolysis after transcatheter mitral valve repair

Background Chronic subclinical intravascular hemolysis is a common complication after valve replacement associated with worse prognosis, occurring in up to 80% of patients after mitral valve surgery. While serious intravascular hemolysis after MitraClip implantation has been reported anecdotally, data on the impact of transcatheter mitral valve repair on the prevalence of subclinical hemolysis are lacking. Methods and results From August 2017 to November 2019, 77 patients with high perioperative risk and moderate-to-severe or severe mitral regurgitation were prospectively enrolled in a single-center trial. All participants were treated with transcatheter edge-to-edge mitral valve repair using the MitraClip NT, NTR or XTR system. Before and three months after the procedure, all patients underwent comprehensive clinical assessment including laboratory measurement of hemoglobin, haptoglobin and lactic acid dehydrogenase in venous blood samples. Presence of subclinical intravascular hemolysis was defined as hemoglobin <13.8 g/dl for males or <12.4 g/dl for females, haptoglobin <65 mg/dl and lactic acid dehydrogenase >250 U/l. Levels of the hemolysis marker haptoglobin significantly decreased three months after the intervention (127±71 mg/dl at three months vs. 158±73 mg/dl at baseline, p<0.001), accompanied by an increase in lactic acid dehydrogenase (251±88 U/l vs. 222±55 U/l, p<0.01), implying the induction of intravascular hemolysis by transcatheter mitral valve repair. Higher residual mitral regurgitation was associated with lower haptoglobin levels three months after mitral valve repair (p<0.05), hinting that shear stress caused by regurgitation flow is the primary mechanism for hemolysis after MitraClip implantation. Concurrently, we observed a trend towards an increase in the presence of subclinical intravascular hemolysis (9.1% at three months vs. 3.9% at baseline, p=0.289). Hemoglobin levels remained unchanged (12.1±1.5 g/dl at three months vs 12.3±1.8 g/dl at baseline, p=0.107). No patient needed treatment for intravascular hemolysis. Conclusion Transcatheter edge-to-edge mitral valve repair in a high-risk collective is associated with the induction of hemolysis. Yet, prevalence of subclinical intravascular hemolysis is low when compared to mitral valve surgery, emphasizing the good safety profile of minimal-invasive mitral valve therapy. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): ReForM-B research grant, University of Regensburg

Relationship between various maternal conditions and lactic acid dehydrogenase activity in umbilical cord blood at birth

Background: Lactic acid dehydrogenase (LDH) is a valuable marker for some of the most important diseases in newborns and the plasma LDH activity in newborns correlates well with conditions such as asphyxia. If LDH should be considered as a useful tool also in obstetric care, key factors associated with maternal health before and during pregnancy which could affect umbilical cord LDH activity need to be known. The aims of this study were to explore relationships between selected maternal conditions and arterial lactic acid dehydrogenase activity (aLDH) in umbilical cord blood at delivery. Methods: A prospective observational study was conducted at Sodersjukhuset, Stockholm, Sweden. Included in the study were 1247 deliveries, and cord blood samples from each were analyzed for aLDH. Background, delivery and neonatal data were collected from the medical records. Results: Higher median values of aLDH were found (P=0.001) among women with chronic disorders not related to pregnancy but there was no increased frequency of high aLDH levels (>612 μ/L, P=0.30). No difference in aLDH was identified between infants born to women with pregnancy-related disorders compared with healthy women, neither in median values, nor in high values (>612 μ/L, P=0.95). Conclusion: Newborn infants born to women with non-pregnancy-related chronic disorders had a somewhat higher median value of aLDH in cord blood at delivery. The influence of common maternal conditions and diseases on umbilical cord arterial LDH levels is small compared to the increase reported in fetal distress and several other critical conditions in the newborn.

Low expression of dendritic cell-specific intercellular adhesion molecule-grabbing nonintegrin-related protein in non-Hodgkin lymphoma and significant correlations with lactic acid dehydrogenase and β2-microglobulin

Dendritic cell-specific intercellular adhesion molecule-grabbing nonintegrin-related protein (DC-SIGNR), a type II integral membrane protein and a member of the C-type lectins, has been reported to bind various strains of HIV-1, HIV-2, and simian immunodeficiency virus. Serum DC-SIGNR is not currently available for the detection of non-Hodgkin lymphoma (NHL). Using an enzyme-linked immunosorbent assay (ELISA), we assessed the serum levels of DC-SIGNR in 70 cancer patients and 100 healthy controls. Additionally, using immunohistochemistry, we determined the expression of DC-SIGNR in the lymph nodes. Using the ELISA, low serum levels of DC-SIGNR were detected in the patients (median, 4.513 ng·L−1; range, 1.066–9.232 ng·L−1; p = 0.0003). Serum concentrations of DC-SIGNR correlated significantly with age (p = 0.0077) and lactic acid dehydrogenase (p = 0.0046) and β2-microglobulin (p = 0.0491) levels. However, we found no statistically significant correlation between serum DC-SIGNR levels and clinical data such as sex, Ann Arbor stage, B symptoms, and histologic subtypes. Moreover, NHL patients with a lower level of serum DC-SIGNR expression in lymphatic endothelial cells also showed negative immunostaining levels. These results suggest that DC-SIGNR is a biological molecule that may be potentially useful in NHL clinical settings.