Is the level of serum lactate dehydrogenase a potential biomarker for glucose monitoring with type 2 diabetes mellitus?

Evaluation of the toxicity potential of exercise and atorvastatin/metformin combination therapy on STZ-diabetic rats

Exercise is recommended for individuals with diabetes, and metformin and atorvastatin are commonly prescribed to diabetic patients. However, these two drugs have potential effects that may lead to toxicity in the skeletal muscle system. Therefore, the effects and potential interactions of combining these two drugs on skeletal muscle performance and structure were investigated in vivo in an experimental diabetes model. Male Wistar rats were divided into six groups: a sedentary control group (N) and five treatment groups-exercise (C), diabetes (D), diabetes with metformin (MET), diabetes with atorvastatin (ATO), and diabetes with metformin and atorvastatin (MET + ATO). In the diabetes model experimentally created with streptozotocin (STZ; 45 mg/kg, i.p.) and metformin (300 mg/kg/day), atorvastatin (10 mg/kg/day) was administered to drug groups by gavage during the 4-week study period. The rats were allowed to run (at moderate level) for 30 min, 5 days a week, on the treadmill. At the end of the study, blood samples and gastrocnemius muscle tissues of the rats were obtained under ketamine anesthesia (100 mg/kg; i.p). The effects of combining exercise and medication on skeletal muscle were assessed by examining the levels of significant biomarkers including PGC-1α, UCP-3, and MyHCs, as well as analyzing oxidative stress/antioxidant capacity parameters in muscle tissue samples. Additionally, relevant biochemical indicators were determined in serum samples. The quantity and morphology of mitochondria in muscle tissue were assessed using transmission electron microscopy. It was observed in the study that some toxic effects associated with the use of drugs alone were reduced by combination therapy. It is thought that this study will contribute to the literature in the evaluation of the effects of drugs and their combined use in Type 1 diabetes under exercise conditions.

Role of lactate dehydrogenase A in the regulation of podocyte metabolism and glucose uptake under hyperglycemic conditions

Lactate is a cellular product of glycolytic metabolism, serving as both an additional oxidative energy substrate and a signaling molecule in metabolic regulation. Plasma lactate levels are elevated in diabetes, and chronic extracellular lactic acidosis is recognized as a negative prognostic marker for the disease. The development of diabetic kidney disease is closely associated with podocyte injury, which forms a crucial layer of the glomerular filtration barrier. Given that high extracellular glucose concentrations also induce lactate production and excretion in podocytes, we hypothesize that an appropriate LDH expression pattern is crucial for maintaining proper podocyte metabolism and function. Our research shows that hyperglycemia significantly decreases lactate dehydrogenase activity in podocytes. Specifically, reduced LDHA expression under hyperglycemic conditions contributes to metabolic disturbances in these cells. Lower LDH activity results in decreased glycolytic activity, altered expression of monocarboxylate transporters, reduced insulin-dependent glucose uptake, and a decrease in the number of podocyte foot processes. These findings underscore the essential role of LDHA in the metabolic adaptation of podocytes to elevated glucose levels typical of diabetes. By elucidating the molecular mechanisms underlying podocyte injury, our study provides new insights into potential therapeutic targets for preventing or mitigating diabetic kidney disease.

Integrated analysis of long non‑coding RNA megacluster, microRNA‑132 and microRNA‑133a and their implications for cardiovascular risk and kidney failure progression in diabetic patients

Inefficient control of elevated blood sugar levels can lead to certain health complications such as diabetic nephropathy (DN) and cardiovascular disease (CVD). The identification of effective biomarkers for monitoring diabetes was performed in the present study. The present study aimed to investigate the implications of long non-coding RNA megacluster (lnc-MGC), microRNA (miR)-132 and miR-133a, and their correlation with lactate dehydrogenase (LDH) activity and glycated hemoglobin (HbA1C) levels to identify biomarkers for the early diagnosis of diabetes mellitus, induced DN and CVD. The present study included a total of 200 patients with type 2 diabetes, as well as 40 healthy subjects as controls. The diabetic patients were classified into six groups based on their estimated HbA1c level, glomerular filtration rate and LDH activity, while the healthy controls constituted the seventh group. Diabetic patients exhibited significant increases in parameters related to diabetes as fasting blood sugar, HbA1c levels, cardiac injury and kidney failure. Furthermore, the expression levels of TNF-α were significantly increased in the diabetic groups compared with healthy controls. Diabetic patients with cardiovascular dysfunction showed significantly increased expression levels of miR-132, miR-133a and lnc-MGC, compared with the healthy group. The expression of circulating miR-132 in blood was low in the groups of diabetic patients compared with the healthy controls, and demonstrated a negative correlation with LDH and HbA1C levels. Expression levels of miR-132, miR-133a and lnc-MGC, along with their correlations with LDH and HbA1C levels, could be used to distinguish diabetic patients with reduced CVD from those at early stage diabetes, which indicated their potential as biomarkers for CV complications associated with diabetes mellitus in the future.

Factors related to type 2 diabetic retinopathy and their clinical application value

Objective

To compare the differences in clinical-related factors between patients with type 2 diabetes (T2DM) and those without diabetic retinopathy (DR) and to explore the risk factors or protective factors affecting DR in T2DM patients.

Methods

We performed a retrospective analysis of 380 patients with type 2 diabetes admitted to Handan Central Hospital from June 2023 to May 2024. Clinical data collected included baseline characteristics, hematological tests, metabolic indicators, and information on diabetic complications and comorbidities.

Results

Our findings identified intervention, neck vascular disease, bilateral lower limb venous thrombosis, high creatinine, high glomerular filtration rate, high chloride, high fasting C-peptide, and high lactate dehydrogenase as risk factors for DR. In contrast, High 2-hour postprandial C-peptide is a protective factor for diabetic retinopathy. A logistic regression model was constructed using stepwise regression to predict DR occurrence, achieving an accuracy of 0.80 and an AUC of 0.83.

The Effect of Diabetic Ketoacidosis and Hyperosmolar Hyperglycemic on the Metabolic Tumor Markers: A Real-World Retrospective Study

Objective

Serum tumor markers have been discovered to be elevated in individuals with diabetes mellitus (DM); however, their significance in diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemia (HHS) is unknown. We evaluated these indicators in the patients with DKA and HHS.

Materials and Methods

We retrospectively collected the laboratory data of 565 diabetic patients from Shanghai Pudong Hospital between Jan, 2019 and May, 2023, including 300 patients with type 2 diabetes mellitus (T2DM), 206 with DKA, and 59 with HHS. Serum tumor biomarkers and further clinical laboratory tests were compared among the three groups. Patients with conspicuous tumor evidence were excluded from the study.

Results

We found significantly higher levels of carbohydrate antigen 199 (CA199) in DKA (p<0.01), carcinoembryonic antigen (CEA), complex prostate specific antigen (CPSA) (p<0.01), prostate specific antigen (PSA) (p<0.05) in HHS, as well as the plasma lipid profile, iron, and electrolytes, in addition to decreased thyroid function, hepatic and renal function, and cardiac function (p<0.05). A Spearman correlational study revealed that osmolar levels were significantly positively correlated with myoglobin (MYO) and cardiac troponin I (cTNI), whereas serum iron concentration (r=0.520) was positively correlated with CEA levels in HHS. pH was negatively correlated with CA199 (r=-0.195), while HbA1c (r=0.22), globin (r=0.341), and total cholesterol (TC) (r=0.191) were positively correlated with elevated CA199 levels. Moreover, the multilinear regression investigation identified osmolarity as a significant determinant for CEA, as well as other parameters, and all proved to be proper predictors for CEA in HHS via ROC curve establishment.

Conclusion

Elevated CA199 levels in DKA were associated with acidosis, whereas HHS with elevated CEA levels may be related to iron homeostasis and could be predicted via the osmolar degree and other predictors.

Development and validation of nomograms for predicting cardiovascular disease risk in patients with prediabetes and diabetes

This study aimed to develop and validate distinct nomogram models for assessing CVD risk in individuals with prediabetes and diabetes. In a cross-sectional study design, we examined data from 2294 prediabetes and 1037 diabetics who participated in the National Health and Nutrition Examination Survey, which was conducted in the United States of America between 2007 and 2018. The dataset was randomly divided into training and validation cohorts at a ratio of 0.75-0.25. The Boruta feature selection method was used in the training cohort to identify optimal predictors for CVD diagnosis. A web-based dynamic nomogram was developed using the selected features, which were validated in the validation cohort. The Hosmer-Lemeshow test was performed to assess the nomogram's stability and performance. Receiver operating characteristics and calibration curves were used to assess the effectiveness of the nomogram. The clinical applicability of the nomogram was evaluated using decision curve analysis and clinical impact curves. In the prediabetes cohort, the CVD risk prediction nomogram included nine risk factors: age, smoking status, platelet/lymphocyte ratio, platelet count, white blood cell count, red cell distribution width, lactate dehydrogenase level, sleep disorder, and hypertension. In the diabetes cohort, the CVD risk prediction nomogram included eleven risk factors: age, material status, smoking status, systemic inflammatory response index, neutrophil-to-lymphocyte ratio, red cell distribution width, lactate dehydrogenase, high-density lipoprotein cholesterol, sleep disorder, hypertension, and physical activity. The nomogram models developed in this study have good predictive and discriminant utility for predicting CVD risk in patients with prediabetes and diabetes.

Enhanced mitochondrial function in B cells from elderly type-2 diabetes mellitus patients supports intrinsic inflammation

In this paper, we measured B cell function in elderly healthy individuals (EH) and in elderly patients with Type-2 Diabetes Mellitus (T2DM, ET2DM), which are treatment-naive, as compared to healthy young (YH) individuals. Results show a higher serum inflammatory status of elderly versus young individuals, and especially of ET2DM versus EH. This status is associated with a reduced response to the seasonal influenza vaccine and with increased frequencies of the circulating pro-inflammatory B cell subset called Double Negative (DN) B cells. B cells from ET2DM patients are not only more inflammatory but also hyper-metabolic as compared to those from EH controls. The results herein are to our knowledge the first to show that T2DM superimposed on aging further increases systemic and B cell intrinsic inflammation, as well as dysfunctional humoral immunity. Our findings confirm and extend our previously published findings showing that inflammatory B cells are metabolically supported.

Association between lactate dehydrogenase and the risk of diabetic kidney disease in patients with type 2 diabetes

Objective

This study aims to investigate the association between lactate dehydrogenase (LDH) and the risk of diabetic kidney disease (DKD) in patients with type 2 diabetes (T2D).

Methods

The study enrolled patients with diagnosis of T2D between 2009 and 2018 from the National Nutrition and Health Examination Survey (NHANES) database. Demographic information, laboratory test, and diagnostic data were collected. Restricted cubic spline (RCS) plots were used to assess the dose-effect relationship between LDH levels and the risk of DKD in patients with T2D. Based on LDH levels, individuals were divided into higher and lower groups using dichotomy, and multivariate logistic regression analysis was conducted to explore the relationship between different LDH levels and the risk of DKD in T2D patients. Stratified analysis was performed to assess the consistency of the result.

Results

A total of 4888 patients were included in the study, with 2976 (60.9%) patients without DKD and 1912 (39.1%) patients with DKD. RCS plots showed that the risk of DKD increased with increasing LDH levels. Multifactorial logistic regression analysis revealed that T2D patients with higher LDH levels had a 45% increased risk of DKD compared to those with lower LDH levels (OR=1.45; 95% CI: 1.11-1.89). Furthermore, each standard deviation increase in LDH level was associated with a 24% increase in DKD incidence among T2D patients (OR=1.24; 95% CI: 1.07-1.44). Stratified analysis consistently supported these findings.

Conclusions

LDH can serve as a valuable biomarker for screening DKD in patients with T2D.

Characterization of genetic and molecular tools for studying the endogenous expression of Lactate dehydrogenase in Drosophila melanogaster

Drosophila melanogaster larval development relies on a specialized metabolic state that utilizes carbohydrates and other dietary nutrients to promote rapid growth. One unique feature of the larval metabolic program is that Lactate Dehydrogenase (Ldh) activity is highly elevated during this growth phase when compared to other stages of the fly life cycle, indicating that Ldh serves a key role in promoting juvenile development. Previous studies of larval Ldh activity have largely focused on the function of this enzyme at the whole animal level, however, Ldh expression varies significantly among larval tissues, raising the question of how this enzyme promotes tissue-specific growth programs. Here we characterize two transgene reporters and an antibody that can be used to study Ldh expression in vivo. We find that all three tools produce similar Ldh expression patterns. Moreover, these reagents demonstrate that the larval Ldh expression pattern is complex, suggesting the purpose of this enzyme varies across cell types. Overall, our studies validate a series of genetic and molecular reagents that can be used to study glycolytic metabolism in the fly.

Association of lactate dehydrogenase and diabetic retinopathy in US adults with diabetes mellitus

OBJECTIVES

The purpose of our investigation is to evaluate the level of relationship between lactate dehydrogenase (LDH) and the occurrence of diabetic retinopathy (DR) in adults with diabetes mellitus (DM).

METHODS

The investigation involved an analysis of five sectional data cycles acquired from the National Health and Nutrition Examination Survey from 2009 to 2018. The present study involved the selection of DM samples from a complex multistage probability sample. These samples were subsequently classified into two distinct groups, namely the No DR (NDR) and DR groups. The present study comprehensively investigated the biological and social risk factors associated with DR. The biological factors examined in this investigation included blood pressure, blood routine, hemoglobin A1c, blood glucose, and comorbidities. The social dimensions encompass education and sex.

RESULTS

After considering all factors, multivariate regression models indicated a significant relationship between DR and increased LDH (adjusted odds ratio = 1.007, 95% confidence interval: 1.003-1.011). The subgroup analysis revealed that the effect size of LDH on the existence of DR in the subgroups remained consistent, as indicated by all p values greater than .05. A statistically significant relationship was identified between elevated LDH levels > 134 U/L and a raised risk of DR in people with DM.

CONCLUSION

LDH concentrations were connected with an increased prevalence of DR in participants with DM. Our study highlights that patients with LDH > 134 U/L are distinguishably related to DM complicated by DR. DR is more common in diabetic individuals with coronary heart disease.

The effect of hormones insulin and glucagon on ubiquitin modifications elucidated by proteomics in liver cells

AIMS

Insulin action is intertwined with changing levels of glucose and counter-regulatory hormone glucagon. While insulin lowers blood sugar level, glucagon raises it by promoting the breakdown of the stored glycogen in liver and releases glucose into the bloodstream. The hormones insulin and glucagon are key in the pathogenesis of type 2 diabetes (T2D). Insulin resistance is a primary predisposing factor for diabetes. Phosphorylation of insulin signaling molecules is altered in the insulin-resistant state. However, ubiquitin (Ub) modifications in insulin-resistant state are relatively understudied. To dissect the underlying mechanisms, we performed a proteomics study on hepatoma cells to study the regulation of ubiquitination by insulin and glucagon.

MATERIALS AND METHODS

We performed western blotting, immunoprecipitations, and affinity pull down using tandem Ub binding entities (TUBE) reagents on hepatoma cells treated with insulin or glucagon. Next, we performed MS/MS analysis on Ub-linkage specific affinity pull down samples. Gene ontology analysis and protein-protein interaction network analysis was performed using DAVID GO and STRING db, respectively.

KEY FINDINGS

The ubiquitination pattern of total Ub, K48-linked Ub, and K63-linked Ub was altered with the treatment of hormones insulin and glucagon. Ubiquitination in immunoprecipitated samples showed enrichment with total Ub and K48-linked Ub but not with K63-linked Ub. Ubiquitination by treatment with hormones mainly enriched key signaling pathways MAPK, Akt, oxidative stress etc. SIGNIFICANCE: Our study identified key altered proteins and signal transduction pathways which aids in understanding the mechanisms of hormonal action on ubiquitination and identify new therapeutic targets for T2D.

Cancer and Diabetes: Predictive Factors in Patients with Metabolic Syndrome

BACKGROUND AND OBJECTIVES

A growing number of epidemiological studies have suggested that diabetes mellitus may increase cancer risk and is implicated in numerous other metabolic and inflammatory disorders. The increase in proinflammatory cytokines plays a major role in insulin resistance and leads to hypoalbuminemia and micro- and macrovascular diabetes complications, including kidney disease and anemia. This study aimed to investigate the utility of carcinoembryonic antigen (CEA), C-reactive protein (CRP), serum albumin level, hemoglobin, and lactate dehydrogenase (LDH) as biomarkers for cancer risk, and the biological implications of diabetes on the evolution and prognosis of oncological patients.

MATERIAL AND METHODS

We conducted a retrospective, longitudinal, observational study on a total group of 434 patients, of which 217 were diagnosed with a form of cancer and type two diabetes as a comorbidity, and the other 217 were a control group without diabetes. These patients were admitted to the oncology clinic. In subgroups, the same number of patients was considered, depending on the location of the oncological pathology. Anemia, hypoalbuminemia, elevated lactate dehydrogenase, glycated hemoglobin, and C-reactive protein levels are more pronounced in subjects with type two diabetes and cancer.

CONCLUSIONS

The presence of diabetes negatively affects the clinical and biological prognosis of cancer patients.

Characterization of genetic and molecular tools for studying the endogenous expression of Lactate dehydrogenase in Drosophila melanogaster

Drosophila melanogaster larval development relies on a specialized metabolic state that utilizes carbohydrates and other dietary nutrients to promote rapid growth. One unique feature of the larval metabolic program is that Lactate Dehydrogenase (Ldh) activity is highly elevated during this growth phase when compared to other stages of the fly life cycle, indicating that Ldh serves a key role in promoting juvenile development. Previous studies of larval Ldh activity have largely focused on the function of this enzyme at the whole animal level, however, Ldh expression varies significantly among larval tissues, raising the question of how this enzyme promotes tissue-specific growth programs. Here we characterize two transgene reporters and an antibody that can be used to study Ldh expression in vivo . We find that all three tools produce similar Ldh expression patterns. Moreover, these reagents demonstrate that the larval Ldh expression pattern is complex, suggesting the purpose of this enzyme varies across cell types. Overall, our studies validate a series of genetic and molecular reagents that can be used to study glycolytic metabolism in the fly.