Serum fructosamine, serum glycated albumin and serum glycated β-lipoprotein in type 2 diabetes mellitus patients with and without microvascular complications

Protein glycation in diabetes mellitus

Diabetes mellitus is the ninth leading cause of mortality worldwide. It is a complex disease that manifests as chronic hyperglycemia. Glucose exposure causes biochemical changes at the proteome level as reflected in accumulation of glycated proteins. A prominent example is hemoglobin A1c (HbA1c), a glycated protein widely accepted as a diabetic indicator. Another emerging biomarker is glycated albumin which has demonstrated utility in situations where HbA1c cannot be used. Other proteins undergo glycation as well thus impacting cellular function, transport and immune response. Accordingly, these glycated counterparts may serve as predictors for diabetic complications and thus warrant further inquiry. Fortunately, modern proteomics has provided unique analytic capability to enable improved and more comprehensive exploration of glycating agents and glycated proteins. This review broadly covers topics from epidemiology of diabetes to modern analytical tools such as mass spectrometry to facilitate a better understanding of diabetes pathophysiology. This serves as an attempt to connect clinically relevant questions with findings of recent proteomic studies to suggest future avenues of diabetes research.

FRUCTOSAMINE VALUES IN MONITORING COMPENSATION AND EFFICACY OF DIABETES MELLITUS TREATMENT

OBJECTIVE

Aim: The relevance of the study is determined by the objective of finding an optimal type of diagnostics of carbohydrate metabolism, that would assess the condition of a diabetic patient undergoing treatment. The purpose of the study is to create a model for monitoring the efficacy of diabetes mellitus treatment by determining the fructosamine levels.

PATIENTS AND METHODS

Materials and Methods: The methods for investigating the highlighted issue are clinical examination and laboratory diagnosis of diabetic patients to measure the state of carbon metabolism using ion-exchange chromatography to determine glycated haemoglobin levels and an automatic colorimetric method to determine fructosamine levels.

RESULTS

Results: The study presents certain values of fructosamine over the level of changes in the state of patients with diabetes mellitus, reflecting the progress from the treatment in the compensation of carbohydrate metabolism, which allows creating a model of diagnostic values of the fructosamine levels, according to which the efficacy of treatment of diabetes mellitus, the state of progress of the disease in its compensation or decompensation are determined at a qualitative level.

CONCLUSION

Conclusions: This allows for the timely adaptive corrective therapeutic and preventive measures to be carried out by medical personnel, who, using values, will monitor the efficacy of treatment in each patient once every three weeks, as this will determine the influence of the type of conducted treatment or other factors aimed at compensating for pathogenetic and clinical manifestations of the disease, which makes the identified fructosamine criteria an important component in the treatment of diabetes mellitus, and indirectly allows to improve the life quality of this patient population, thus bringing a practical solution to the challenge facing the healthcare sector.

Glycated albumin stimulates expression of inflammatory cytokines in muscle cells

The effects of glycated albumin on the expression of inflammatory cytokines in differentiated myotubes were investigated. Glycated albumin stimulates the expression of TNF α, IL-1β, IL-6 and CCL-2 both at the mRNA and protein levels via the receptor of AGEs. Various cytokines demonstrated different kinetics of stimulation by glycated albumin. At a high glucose concentration, the stimulation effect was more pronounced than at a low one. At physiological concentrations of albumin and fructosamine, the stimulation effect of glycated albumin on inflammatory cytokine expression in myotubes was also observed. The induction of expression of all studied cytokines was sensitive to the inhibitors of JNK, p38 MAPK, MEK1/2, Src family protein kinases and NF-κB. At the same time, the induction of TNFα and IL-1β was diminished by the Ca²⁺/calmodulin-dependent protein kinase inhibitor, whereas the induction of IL-6 and CCL-2 was reduced by the inhibitor of phosphoinositide 3-kinase. Possible implications of observed stimulation of cytokine expression by glycated albumin in the development of diabetes mellitus symptoms are discussed.

Influence of Glycemic Control on Coagulation and Lipid Metabolism in Pregnancies Complicated by Pregestational and Gestational Diabetes Mellitus

Hypercoagulability and altered lipid metabolism, which are observed in normal pregnancy, can be enhanced in diabetes mellitus. The aim of the study was to evaluate the influence of glycemic control on coagulation and lipid metabolism in women with pregestational (PGDM) and gestational (GDM) diabetes treated with insulin. There were 50 patients with PGDM and 101 patients with GDM enrolled into the study. Serum lipid and coagulation parameters were assessed at 18-22, 25-28, and 31-34 weeks of pregnancy and were compared within the diabetic groups with reference to the effectiveness of glycemia control. We found that poor glycemic control was associated with shortened activated partial thromboplastin time (APTT) and increased activity of antithrombin III (ATIII) in both diabetic groups and with a higher plasminogen activator inhibitor (PAI-1) content level in the GDM group. Poorly controlled PGDM was associated with higher levels of total cholesterol and high-density cholesterol (HDL) in the second trimester and triglycerides in the third trimester. In patients with poorly controlled GDM, a higher concentration of HDL was observed in third trimester, whereas a higher triglyceride level was found in both second and third trimesters. Positive correlations between total cholesterol and APTT and between triglyceride and APTT and ATIII were found in the poorly controlled PGDM group. We conclude that poor glycemic control of diabetic pregnancy impacts both lipid metabolism and the blood coagulation system.

Significance of glycated LDL in different stages of diabetic nephropathy

AIM

The aim of this study was to investigate the role of elevated glycated LDL (low-density lipoprotein) in the progression of diabetic kidney disease among type 2 diabetes (T2D) subjects.

MATERIALS AND METHODS

This case-control observational study is a part of Saudi Diabetes Kidney Disease (SAUDI-DKD) study conducted during the period from April 2014 to June 2015. This study cohort is divided into two groups; the first group was T2D patients without diabetic nephropathy (DN) (n = 24) and the second group was T2D with DN (n = 45). Serum glycated LDL levels were determined by ELISA. Pearson's correlation analysis was performed, and the diagnostic accuracy was assessed using the area under the ROC curve.

RESULTS

There was a threefold increase of serum glycated LDL level among diabetic subjects when compared with non-diabetic subjects and this level progressively increased with the progression of DN. The glycated LDL was found to have a significant diagnostic accuracy with AUC of 0.685 and 0.775 for cases with microalbuminuria and macroalbuminuria respectively.

CONCLUSION

The glycated LDL could play a significant role in predicting diabetic patients who are susceptible to develop DN among T2D patients.

Methylglyoxal: A newly detected and potentially harmful metabolite in the blood of ketotic dairy cows

Ketosis causes serious economic losses for the modern dairy industry because it is a highly prevalent metabolic disease among cows in high-producing herds during the transition period. Due to some striking similarities between diabetes in humans and ketosis in dairy cows, there is potential for the use of methylglyoxal (MGO)-commonly used in human diabetics-as a biomarker in dairy cattle. However, currently no data are available about the presence of MGO in the serum of dairy cattle or about the characteristics of its production or its potential contribution in the pathogenesis of ketosis. To determine the potential origin and pathway of formation of MGO, cows in different metabolic conditions [i.e., non-subclinically ketotic dairy cows in early lactation (n = 7), subclinically ketotic dairy cows in early lactation (n = 8), overconditioned dry cows (BCS >4.25, n = 6), and nonlactating heifers (n = 6)] were selected. Serum MGO concentrations were determined and correlated with indicators of the glucose and lipid metabolism and with haptoglobin (Hp) as an inflammatory marker. The serum MGO concentrations in subclinically ketotic cows (712.60 ± 278.77 nmol/L) were significantly greater than in nonlactating heifers (113.35 ± 38.90 nmol/L), overconditioned dry cows (259.71 ± 117.97 nmol/L), and non-subclinically ketotic cows (347.83 ± 63.56 nmol/L). In serum of lactating cows, concentrations of glucose and fructosamine were lower than in heifers and were negatively correlated with MGO concentrations. Even so, concentrations of metabolic and inflammatory markers such as dihydroxyacetone phosphate, nonesterified fatty acids, β-hydroxybutyrate, acetone, and Hp were remarkably higher in subclinically ketotic cows compared with nonlactating heifers; these metabolites were also positively correlated with MGO. In human diabetics elevated MGO concentrations are stated to originate from both hyperglycemia and the enhanced lipid metabolism, whereas higher MGO concentrations in subclinically ketotic cows were not associated with hyperglycemia. Therefore, our data suggest MGO in dairy cows to be a metabolite produced from the metabolization of acetone within the lipid metabolization pathway and from the metabolization of dihydroxyacetone phosphate. Furthermore, the highly positive correlation between MGO and Hp suggests that this reactive compound might be involved in the proinflammatory state of subclinical ketosis in dairy cows. However, more research is needed to determine the potential use of MGO as a biomarker for metabolic failure in dairy cows.