Glycated albumin is associated with body mass index in euglycemic adults but is not predictive of postprandial blood glucose response

Glycated Albumin to Predict Adverse Neonatal Outcomes among Women with Diabetes and Overweight or Obese Body Mass Index

BACKGROUND

Glycated albumin (GA) has shown promise in predicting risk of adverse neonatal outcomes (ANO) in pregnant women with type 2 diabetes (T2DM) and gestational diabetes (GDM). However, previous studies showing a negative correlation between GA and body mass index (BMI) suggest that lower predictive cutoffs may be needed in populations with elevated BMI.

METHODS

We performed a case-control study of prospectively enrolled pregnant women with T2DM or GDM and BMI ≥25 kg/m2 matched to biobanked controls without diabetes. Serum collected during the second and/or third trimesters was used to measure the percentage of GA (% GA). Receiver operating characteristic (ROC) curves were used to examine % GA to predict an ANO composite, including macrosomia, hypoglycemia, respiratory distress syndrome, and/or hyperbilirubinemia for the second and third trimesters.

RESULTS

The median BMIs for cases and controls were 34.0 and 31.0 kg/m2, respectively. The area under the ROC curve to predict the ANO composite was significant for second trimester values but ambiguous for third trimester due to its wide 95% CI. A cutoff of 12.3% GA during second trimester showed 100% sensitivity and 73% specificity. Transference of previously published reference ranges did not validate, suggesting lower ranges are needed for women with overweight/obesity.

CONCLUSIONS

In this pilot study, % GA shows promise to stratify pregnant patients with diabetes and obesity into risk categories for ANO with excellent predictive ability in the second trimester. If this holds in larger studies, using second trimester % GA could allow additional intervention to improve blood glucose control and minimize ANO.

Antiglycating Effects of Spirulina platensis Aqueous Extract on Glucose-Induced Glycation of Bovine Serum Albumin

Glucose, the predominant carbohydrate in the human body, initiates nonenzymatic reactions in hyperglycemia, potentially leading to adverse biochemical interactions. This study investigates the interaction between glucose and Bovine Serum Albumin (BSA), along with the protective effects of Spirulina platensis PCC 7345 aqueous extract. Phycobiliproteins (phycocyanin, phycoerythrin, and allophycocyanin) in the extract were quantified using spectrophotometry. The extract's anti-glycation potential was assessed by analyzing its effects on albumin glycation, fluorescent advanced glycation end products (AGEs), thiol group oxidation, and β-amyloid structure generation. Additionally, its antidiabetic potential was evaluated by measuring α-amylase and α-glucosidase enzyme inhibition. Results indicate that the Spirulina extract significantly mitigated ketoamine levels, fluorescence, and protein-carbonyl production induced by glucose, demonstrating a 67.81 % suppression of AGE formation after 28 days. Moreover, it effectively inhibited amyloid formation in BSA cross-linkages. These findings suggest the potential of S. platensis as an anti-glycation and antidiabetic agent, supporting its consideration for dietary inclusion to manage diabetes and associated complications.

Glycated serum proteins and albumin but not glycated albumin show negative correlation with BMI in an overweight/obese, diabetic population from the United States

BACKGROUND AND AIMS

Multiple previously published studies have shown a weak to medium, negative correlation between BMI and glycated albumin (GA). However, many of these studies were in populations with a narrow range of BMI. It is unknown whether this trend exists if a wider BMI range is used. This is an important question for proper interpretation of GA levels in obese populations.

MATERIALS AND METHODS

A retrospective analysis of clinical trial data (NCT02519309) was performed. After appropriate exclusions, 334 subjects remained. These included 73.7% with type 2 diabetes (T2D) diagnosis and 26.3% with prediabetes. BMI ranged from 24.8-86.9 kg/m2. Laboratory data were measured in a CLIA-certified laboratory using commercially available, automated methods.

RESULTS

No significant, negative correlation was seen between GA and BMI. However, individual components (glycated serum proteins and albumin) as well as the GA/HbA1c ratio show a weak, negative correlation with BMI for all subjects and those with T2D. The strongest negative correlation was with albumin. Examination by traditional BMI subgroups also showed statistically significant differences for those with T2D, but not for the prediabetic cohort. Correlations between BMI and C-reactive protein were similar in those with diabetes and prediabetes; however, correlation between BMI and insulin was stronger in those with diabetes.

CONCLUSION

Negative correlations between BMI and albumin or BMI and glycated serum proteins persist in diabetic populations that are obese and overweight, even when a statistically significant negative correlation is not observed between BMI and GA. Inflammation or insulin-mediated changes in protein synthesis could be contributors to these negative correlations, but BMI-related changes to the glomerulus could also affect clearance of albumin or glycated proteins and should be examined.

D-Ribose-Induced Glycation and Its Attenuation by the Aqueous Extract of Nigella sativa Seeds

Background and Objectives: Glycation and oxidative stress are the major contributing factors responsible for diabetes and its secondary complications. Aminoguanidine, a hydrazine derivative, is the only approved drug that reduces glycation with its known side effects. As a result, research into medicinal plants with antioxidant and antiglycation properties is beneficial in treating diabetes and its consequences. This investigation aimed to examine the efficacy of the aqueous extract of Nigella sativa seeds against the D-ribose-induced glycation system. Materials and Methods: The suppression of α-amylase and α-glucosidase enzymes were used to assess the antidiabetic capacity. UV-Visible, fluorescence, and FTIR spectroscopy were used to characterize the Nigella sativa seed extract and its efficacy in preventing glycation. The inhibition of albumin glycation, fluorescent advanced glycation end products (AGEs) formation, thiol oxidation, and amyloid formation were used to evaluate the extracts' antiglycation activity. In addition, the extent of glycoxidative DNA damage was analyzed using agarose gel electrophoresis. Results: The IC₅₀ for the extract in the α-amylase and α-glucosidase enzyme inhibition assays were approximately 1.39 ± 0.016 and 1.01 ± 0.022 mg/mL, respectively. Throughout the investigation, it was found that the aqueous extract of Nigella sativa seeds (NSAE) inhibited the level of ketoamine, exerted a considerable drop in fluorescence intensity, and reduced carbonyl production and thiol modification when added to the D-ribose-induced glycation system. In addition, a reduction in the BSA-cross amyloid formation was seen in the Congo red, thioflavin T assay, and electrophoretic techniques. NSAE also exhibited a strong capability for DNA damage protection. Conclusion: It can be concluded that Nigella sativa could be used as a natural antidiabetic, antiglycation treatment and a cost-effective and environmentally friendly source of powerful bioactive chemicals.

Serum glycated albumin as a predictive biomarker for renal involvement of antineutrophil cytoplasmic antibody-associated vasculitis in non-diabetic patients

Background

Glycated albumin (GA) is known to reflect the current inflammatory burden in non-diabetes mellitus (DM) patients. In this study, we investigated whether GA at diagnosis could reflect the cross-sectional activity and predict poor outcomes during follow-up in non-DM patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

Methods

The medical records of 118 immunosuppressive drug-naïve AAV patients were retrospectively reviewed, and 76 patients who had both GA and glycated haemoglobin (HbA1c) results but not DM were included in this study. Demographic, clinical, and laboratory data at diagnosis were assessed.

Results

The median age of AAV patients was 61 years, and 31 patients were male. GA was positively correlated with five-factor score (r = 0.282), Birmingham vasculitis activity score (BVAS) assigned to renal manifestation (r = 0.315), and blood urea nitrogen (r = 0.382), whereas negatively correlated with haemoglobin (r = -0.345). AAV patients with end-stage renal disease (ESRD) exhibited significantly higher GA than those without ESRD (15.8% vs. 13.6%). When the cut-off of GA at diagnosis for ESRD was set at GA ≥ 14.25%, AAV patients with GA ≥ 14.25% had a significantly higher risk for ESRD development than those without (relative risk 12.040). In addition, AAV patients with GA ≥ 14.25% exhibited significantly lower cumulative ESRD-free survival rates than those without (P = 0.020).

Conclusion

In conclusion, GA at diagnosis can reflect the cross-sectional BVAS assigned to renal manifestation of AAV and predict ESRD development during follow-up better than HbA1c or GA/HbA1c in AAV patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02913-5.

Factors associated with glycated albumin in adults without diabetes

Background and aims

Glycated albumin is a glycemic marker useful in short-term monitoring and in situations when a glycated hemoglobin test is not reliable. This study aims to evaluate glycated albumin levels and its associated factors in normoglycemic adults from Southern Brazil.

Method

136 individuals, without diabetes or pre-diabetes, were included in this cross-sectional study. Levels of glycated albumin, glycated hemoglobin, and other biochemical markers were measured.

Results

Glycated albumin levels ranged from 11.1% to 17.5% (2.5^th and 97.5^th percentiles). Glycated albumin/glycated hemoglobin ratio was 2.8±0.2. Glycated albumin did not differ according to gender and age groups. However, in overweight individuals, levels of glycated albumin and glycated albumin/glycated hemoglobin ratio were lower and weakly and negatively correlated with body mass index.

Conclusions

Glycated albumin levels in Brazilians were similar to those previously described in other populations. Glycated albumin seems to be irrespective of gender or age, but weakly correlated with weight. These aspects should be taken into account in the interpretation of glycated albumin results.

Influence of Sex Hormones on the Relationship Between Body Fat and Glycated Albumin Levels

BACKGROUND

Previous studies have reported that glycated albumin (GA) is affected by body fat distribution. Sex hormones are reported to play an important role in fat metabolism.

AIM

This study aimed to explore the influence of sex hormones on the relationship between body fat and GA in a community population.

METHODS

We recruited 763 middle-aged and elderly subjects with normal glucose tolerance from communities. GA was determined using the enzyme method, and serum estradiol (E₂), total testosterone, and sex hormone-binding globulin (SHBG) were detected using chemiluminescent microparticle immunoassays.

OUTCOME

There was a statistically significant association between SHBG and GA remained after adjusting for body fat in both men and women.

RESULTS

The average serum GA levels were 13.40 ± 1.10% in the 298 men and 465 postmenopausal women included in this study. GA presented a significant downward trend with increasing quartiles of total fat mass (FM), limb FM, and trunk FM in both men and women (all P for trend < .01). In men, total testosterone, free testosterone, and SHBG were positively correlated with GA (both P < .01), and the correlation between SHBG and GA remained after adjusting for body fat (P < .01). In women, E2, free testosterone, bioactive testosterone, and SHBG were correlated with GA (all P < .01); furthermore, the positive correlation between SHBG and GA and the inverse correlation between E2 and GA remained after adjusting for body fat (both P < .05). Multivariate linear regression analyses showed that in addition to trunk FM, SHBG was positively correlated with GA in both men and women (standardized β = 0.136, P = .035; standardized β = 0.101, P = .033); however, E2 was not independently correlated with GA in women.

CLINICAL IMPLICATIONS

SHBG may contribute to the influence of body fat, especially trunk fat on GA levels.

STRENGTHS & IMPLICATIONS

This study used an automated bioelectrical impedance analyzer to measure segmental body composition including limb FM and trunk FM and further investigated the role of segmental body fat in the correlation between SHBG and GA. Sex hormones may explain in part why body fat content and distribution can alter GA levels.

CONCLUSION

SHBG is positively correlated with serum GA levels, and this correlation is independent of total or segmental body fat. Xu Y, Ma X, Shen Y, et al. Influence of Sex Hormones on the Relationship Between Body Fat and Glycated Albumin Levels. J Sex Med 2020;17:903-910.

Glycated albumin in pregnancy: reference intervals establishment and its predictive value in adverse pregnancy outcomes

Background

Many efforts have been focused on the alternative glycemic marker glycated albumin (GlyA) and its application in pregnancy during which profound physiological changes take place. Our objective was to determine the reference intervals (RIs) of GlyA in healthy Chinese pregnant women and to assess the predictive value of serum GlyA in adverse pregnancy outcomes.

Methods

Totally 421 healthy subjects including 137 in the first trimester, 152 in the second trimester, and 132 in the third trimester were enrolled from March to July 2019, for the purpose of establishing the trimester-specific RIs of GlyA. In addition, 67 pregnant women diagnosed with GDM were enrolled at 24–28 weeks of gestation. The diagnostic value of GlyA for GDM patients was evaluated and compared with that of fasting plasma glucose (FPG) at 24–28 weeks of gestation. The association between GlyA in the late pregnancy and the adverse pregnancy outcomes was analyzed with the data collected from January to June 2018 at our hospital.

Results

The estimated RIs of GlyA in present study were 11.26–15.10%, 10.04–13.50%, and 9.76–13.09% in the first, second, and third trimesters respectively. The areas under receiver operating characteristic (ROC) curves were 0.503 for GlyA and 0.705 for FPG. More importantly, the GlyA level in the third trimester was not more elevated in the patients with adverse pregnancy outcomes including large for gestational age (LGA), preterm delivery, hypertension and preeclampsia (PE). The exception was made with the GDM patients who suffered from postpartum hemorrhage and had significantly higher GlyA levels than the control group.

Conclusions

Our results showed that the GlyA was continuously decreased as the gestational age went up. The GlyA testing has limited value in diagnosing GDM and predicting adverse pregnancy outcomes.

Associations Between Thyroid Hormones and Glycated Albumin in Euthyroid and Subclinical Hypothyroid Individuals: Results of an Observational Study

PURPOSE

Although overt thyroid dysfunction has been found to influence the level of glycated albumin (GA), the associations between thyroid hormones and GA in individuals with euthyroidism and subclinical hypothyroidism (SHypo) are still unknown. The present study aimed to investigate whether thyroid hormones were related to GA in euthyroid and SHypo individuals.

METHODS

We recruited 685 euthyroid and 103 SHypo subjects with normal weight from communities in Shanghai. Electrochemiluminescence immunoassay was used to detect the serum levels of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone. GA was detected by the enzymatic method. Glycated hemoglobin (HbA_1c) was detected by high-performance liquid chromatography.

RESULTS

Among the 788 subjects (age range 31-81 years old), 307 were men and 481 were women. In the Spearman correlation analysis and multiple stepwise regression analysis, FT3 was negatively correlated with both GA and GA/HbA_1c in euthyroid subjects (all P < 0.05). The values of GA and GA/HbA_1c were reduced by approximately 0.30 and 0.05, respectively, for each 0.50 pmol/L increment in FT3. In SHypo subjects, FT4 was negatively associated with both GA and GA/HbA_1c (all P < 0.05). The values of GA and GA/HbA_1c were reduced by approximately 0.23 and 0.03, respectively, for each 1.00 pmol/L increment in FT4.

CONCLUSION

In euthyroid and SHypo subjects, more attention should be paid to the potential effects of individual differences in thyroid hormones on GA.

d-Ribose contributes to the glycation of serum protein

d-Ribose is active in glycation and rapidly produces advanced glycation end products, leading to cell death and to cognitive impairment in mice. Glycated serum protein (GSP) is a relatively short-term biomarker for glycemic control in diabetes mellitus. However, whether d-ribose is related to GSP is unclear. The aim of this work was to identify the contribution of d-ribose to GSP compared to d-glucose. Here, we showed that the yield of glycated human serum albumin with d-ribose was at least two-fold higher than that with d-glucose in a 2-week incubation. The glycation of human serum albumin (HSA) with d-ribose was much faster than that with d-glucose, as determined by monitoring changes in the fluorescent intensity of glycation products with time. Liquid chromatography-mass spectrometry/mass spectrometry revealed that 17 and 7 lysine residues on HSA were glycated in the presence of d-ribose and d-glucose, respectively, even when the concentration ratio [d-ribose]/[d-glucose] was 1/50. The intraperitoneal injection of d-ribose significantly increased the GSP levels in Sprague Dawley rats, but the injection of d-glucose did not. The level of d-ribose was more positively associated with GSP than the level of d-glucose in streptozotocin-treated rats. In diabetic patients, the levels of both d-ribose and d-glucose were closely related to the level of GSP. Together, these in vitro and in vivo findings indicated that d-ribose is an important contributor to the glycation of serum protein, compared to d-glucose. To assess GSP levels in diabetes mellitus, we should consider the contribution from d-ribose, which plays a nonnegligible role.

Increasing waist circumference is associated with decreased levels of glycated albumin

BACKGROUND

Glycated albumin (GA) levels are affected by body fat and its distribution. We explored the association of waist circumference (WC) with GA and to assess the extent to which WC influences GA.

METHODS

We recruited 1799 subjects (age 26-82 y) from communities. GA was determined using the enzyme method, and glycated hemoglobin A_1c (HbA_1c) was detected using high-performance liquid chromatography.

RESULTS

Subjects with central obesity had lower GA and GA/HbA_1c than those without (both P < .01). GA and GA/HbA_1c were negatively correlated with central obesity (both P < .01), whereas HbA_1c was not correlated (P = .833). In the euglycemic and hyperglycemic subpopulations, GA and GA/HbA_1c showed decreasing trends as WC levels increased (both P for trends <0.01). WC was a significant negative determinant of GA (P < .05). In the hyperglycemic subpopulation, the GA value decreased by approximately 0.15% for each 5 cm increment in WC regardless of the presence of central obesity.

CONCLUSIONS

The GA value was reduced by approximately 0.15% for each 5 cm increment in WC, suggesting that more attention should be paid to actual blood glucose underestimated by GA in obese people.

Role of the Soluble Receptor for Advanced Glycation End Products (sRAGE) as a Prognostic Factor for Mortality in Hemodialysis and Peritoneal Dialysis Patients

End-stage renal disease patients on dialysis (CKD-G5D) have a high mortality rate due to cardiovascular diseases (CVD). In these patients, inflammation, oxidative stress, and uremia increase the production of glycation products (AGEs) which in turn accelerate CVD onset and progression. Recently, attention has been given to the soluble receptor for AGEs (sRAGE) as a marker of inflammation, oxidative stress, atherosclerosis, and heart failure in CKD-G5D. However, its association with patient outcomes is still under debate. Our aim is to explore whether sRAGE may be a predictor of mortality in CKD-G5D. We studied 123 CKD-G5D for 24 months. Of these patients, 56 were on hemodialysis (HD) and 67 on peritoneal dialysis (PD). Demographic, anthropometric, biochemical, and clinical data were recorded. sRAGE was quantified by enzyme-linked immunosorbent assay. sRAGE was a predictor of mortality at 2-year follow-up. Each increase of 100 pg/mL in sRAGE levels was associated with an approximately 7% increased risk of mortality. Furthermore, in the entire study group, as well as in PD and HD patient subgroups, sRAGE was positively correlated with brain natriuretic peptide (BNP) levels. Mortality rates as well as sRAGE levels in patients who died did not differ between PD and HD patients. In conclusion, the positive association observed with BNP levels suggests a role for sRAGE as a prognostic factor for mortality in CKD-G5D patients displaying an active process of cardiac remodeling.

Haemoglobin A1c or Glycated Albumin for Diagnosis and Monitoring Diabetes: An African Perspective

Diabetes mellitus (DM) has reached epidemic proportions across the globe with the largest increases seen in sub-Saharan Africa. Those that are diagnosed are largely poorly controlled. This review summarizes the limitations of the use of glycated haemoglobin (HBA1c) in Africa and current knowledge on the utility of glycated albumin and fructosamine in African patients. The diagnosis and monitoring of DM in African patients may be compromised by associated conditions like sickle cell anaemia, chronic kidney disease and HIV infection. Glycated albumin reflects short term glycaemia and is not affected by many conditions that alter HbA1c. It can be measured enzymatically, and this review discusses methods for analysis, and discusses the advantages and limitations in specific situations with an emphasis on conditions that also affect HbA1c.

Glycated albumin is stable in plasma when exposed to common laboratory conditions and comparable when drawn from venous or capillary sites

BACKGROUND

Circulating glycated albumin is a marker of blood glucose reflecting the previous 2 weeks. However, the effects of storage conditions and draw site on glycated albumin values are not fully understood.

METHODS

Fifteen plasma samples from people with type 2 diabetes were assessed during repeated freeze-thaw rounds for 10 cycles. A further 15 samples were stored at 4°C and assessed over 3 days. Another 40 samples drawn concurrently from capillary and venous sites had their glycated albumin content compared.

RESULTS

Glycated albumin concentration did not alter over 10 freeze-thaw cycles (P=.856), or after 72 hours at 4°C (P=.962). Capillary and venous samples did not differ in their percentage of glycated albumin (P=.379), although lower concentrations of albumin and glycated albumin (g/dL) were observed in the capillary sample (P<.001).

CONCLUSION

Glycated albumin in plasma appears relatively stable when exposed to common laboratory conditions, reducing a potential confounder to its use as a marker of blood glucose control. The glycated albumin (%) in samples from capillary and venous sites was comparable, suggesting the potential of rapid or portable assessment devices that require a finger prick.