The relationship between glycemic control, beta2-microglobulin and inflammation in patients on maintenance dialysis treatment

Association of β 2-Microglobulin with Physical Performance in Chinese Hemodialysis Patients with and without Diabetes

KEY POINTS

In the patients on hemodialysis, β2-microglobulin was lower in those with worse physical performance than in those with better physical performance. A significant association of higher β2-microglobulin was discovered with better physical performance in the patients on hemodialysis without diabetes.

BACKGROUND

Higher β2-microglobulin (β2-MG) is associated with aging, stroke, and cognitive impairment, which are all connected with poor physical fitness. Poor physical function is ascribed to increasing mortality. However, there has been an academic dispute over the association of serum β2-MG with survival rate. Furthermore, diabetes mellitus (DM) has been well linked to poor physical function and a high level of β2-MG. We hypothesized that higher β2-MG could be associated with worse physical performance in patients on hemodialysis and that this association could vary with diabetes.

METHODS

We conducted a multicenter cross-sectional study at seven hemodialysis centers in Shanghai and Suzhou in China, where a collection was made of the clinical characteristics, laboratory indicators, physical performance, and DM assessment. Physical function was measured by the Short Physical Performance Battery (SPPB), and SPPB score ≤9 was considered as the cutoff for low physical performance. The patients were divided into two groups of low and high physical performance before being categorized into four subgroups on the basis of the absence of diabetes and SPPB scores. Logistic regression analyses were conducted to explore the association of β2-MG with physical performance.

RESULTS

The final analysis involved a total of 780 patients, 251 (32.2%) having diabetes. In the total population, β2-MG was lower in those with low SPPB scores than in those with high SPPB scores. Only in nondiabetic patients, β2-MG was lower in the low-SPPB group and positively associated with SPPB and its three component scores. Regardless of diabetes status, those who had low SPPB scores were prone to be older, accompanied by poor nutritional status. In addition, diabetic patients tended to have shorter hemodialysis duration and higher body mass index than the nondiabetic patients. Both before and after the covariates were adjusted, β2-MG was significantly associated with physical performance in patients on hemodialysis without diabetes.

CONCLUSIONS

Lower levels of β2-MG were significantly associated with poor physical performance in Chinese patients on hemodialysis without DM.

Utility of serum β2-microglobulin for prediction of kidney outcome among patients with biopsy-proven diabetic nephropathy

AIM

To examine whether serum β2-microglobulin (β2-MG) could improve the prediction performance for kidney failure with replacement therapy (KFRT) among patients with diabetic nephropathy (DN).

METHODS

Patients with biopsy-proven DN at Nara Medical University Hospital were included. The exposure of interest was log-transformed serum β2-MG levels measured at kidney biopsy. The outcome variable was KFRT. Multivariable Cox regression models and competing-risk regression models, with all-cause mortality as a competing event, were performed. Model fit by adding serum β2-MG levels was calculated using the Akaike information criterion (AIC). The net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indexes were used to evaluate the improvement of predictive performance for 5-year cumulative incidence of KFRT by serum β2-MG levels.

RESULTS

Among 408 patients, 99 developed KFRT during a median follow-up period of 6.7 years. A higher serum β2-MG level (1-unit increase in log-transformed serum β2-MG level) was associated with a higher incidence of KFRT, even after adjustments for previously known clinical and histological risk factors (hazard ratio [95% confidence interval {CI}]: 3.30 [1.57-6.94] and subdistribution hazard ratio [95% CI]: 3.07 [1.55-6.06]). The addition of log-transformed serum β2-MG level reduced AIC and improved the prediction of KFRT (NRI and IDI: 0.32 [0.09-0.54] and 0.03 [0.01-0.56], respectively).

CONCLUSIONS

Among patients with biopsy-proven DN, serum β2-MG was an independent predictor of KFRT and improved prediction performance. In addition to serum creatinine, serum β2-MG should probably be measured for DN.

β2-Microglobulin exacerbates neuroinflammation, brain damage, and cognitive impairment after stroke in rats

β2-Microglobulin (β2M), a component of the major histocompatibility complex class I molecule, is associated with aging-related cognitive impairment and Alzheimer's disease. Although upregulation of β2M is considered to be highly related to ischemic stroke, the specific role and underlying mechanistic action of β2M are poorly understood. In this study, we established a rat model of focal cerebral ischemia by occlusion of the middle cerebral artery. We found that β2M levels in the cerebral spinal fluid, serum, and brain tissue were significantly increased in the acute period but gradually decreased during the recovery period. RNA interference was used to inhibit β2M expression in the acute period of cerebral stroke. Tissue staining with 2,3,5-triphenyltetrazolium chloride and evaluation of cognitive function using the Morris water maze test demonstrated that decreased β2M expression in the ischemic penumbra reduced infarct volume and alleviated cognitive deficits, respectively. Notably, glial cell, caspase-1 (p20), and Nod-like receptor pyrin domain containing 3 (NLRP3) inflammasome activation as well as production of the inflammatory cytokines interleukin-1β, interleukin-6, and tumor necrosis factor-α were also effectively inhibited by β2M silencing. These findings suggest that β2M participates in brain injury and cognitive impairment in a rat model of ischemic stroke through activation of neuroinflammation associated with the NLRP3 inflammasome.

The Differences of N–Acetyl–β–Glucosaminidase and β2 Microglobulin levels in Patients with and without Early Diabetic Nephropathy

Diabetic Nephropathy (DN) is becoming the most serious microvascular complication, which be marked by the presence of persistent albuminuria. N–asetil–β–glucosaminidase is dominant lyzosom enzyme in the renal tubule epitel. β2 microglobulin is low molecular weight protein which produced by major histocompatibility complex class 1 (MHC-1) expressed cell in all nucleated cell. N–asetil–β–glucosaminidase and β2 microglobulin could be new usefull marker for early DN. Analytic observational study with cross sectional approach was conducted in May – July 2019 involving 27 non diabetic patients (K1), 27 diabetic patients without DN (K2) and 27 diabetic patients with early DN (K3) at the Clinical Pathology department of Faculty of Medicine, Diponegoro University and Diabetic Clinic. Data include age, gender, fasting blood glucose, blood preasure and urine albumin creatinine ratio. N–asetil–β–glucosaminidase level between groups were analyzed using Anova, β2 microglobulin level between groups using Kruskal Wallis, p<0.05 were considered significant. There are significant differences in levels of N–asetil–β–glucosaminidase between K1 and K2 (p =0.01), K1 and K3 (p =< 0.01), K2 and K3 (p = 0.03) and β2 microglobulin  between K1 and K2 (p = 0.02), K1 and K3 (p =< 0.01), K2 and K3 (p< 0.01). N-acetyl-β-glucosaminidase and β2 microglobulin levels were higher in K2 compared to K1 and increased higher in K3 compared to K1 and K2. N-acetyl-β-glucosaminidase and β2 microglobulin can be used as an alternative marker for early DN. 

Increased risk markers in women with polycystic ovary syndrome and gestational diabetes mellitus during mid-pregnancy

OBJECTIVE

This study aimed to investigate application of the urine albumin-to-creatinine ratio (ACR), serum beta 2-microglobulin (β2-MG), and cystatin C as risk markers in a cohort of women with polycystic ovary syndrome (PCOS) for the incidence of gestational diabetes mellitus (GDM).

METHODS

In this cross-sectional study, we analyzed 312 pregnant women with PCOS and classified them as those with and without GDM. For all participants, elbow venous blood and clean middle urine were collected in the morning after 8 hours of an empty stomach.

RESULTS

Logistic regression analysis showed that the ACR, urine β2-MG levels, and serum cystatin C levels were important markers for women with PCOS concomitant with GDM. Receiver operating characteristic curve analysis showed that the area under the curve of CysC was 0.81 with the threshold based on >0.93 and that of β2-MG was 0.72 with the threshold based on >1.25.

CONCLUSIONS

Increased levels of β2-MG and cystatin C and a high ACR might be risk factors for Chinese women with PCOS and GDM during mid-pregnancy.

Differential proteome analysis of diabetes mellitus type 2 and its pathophysiological complications

The prevalence of Diabetes Mellitus Type 2 (DM 2) is increasing every passing year due to some global changes in lifestyles of people. The exact underlying mechanisms of the progression of this disease are not yet known. However recent advances in the combined omics more particularly in proteomics and genomics have opened a gateway towards the understanding of predetermined genetic factors, progression, complications and treatment of this disease. Here we shall review the recent advances in proteomics that have led to an early and better diagnostic approaches in controlling DM 2 more importantly the comparison of structural and functional protein biomarkers that are modified in the diseased state. By applying these advanced and promising proteomic strategies with bioinformatics applications and bio-statistical tools the prevalence of DM 2 and its associated disorders i-e nephropathy and retinopathy are expected to be controlled.

Hippocampal β2‑microglobulin mediates sepsis‑induced cognitive impairment

Acute brain dysfunction is a frequent complication in sepsis patients and is associated with long‑term neurocognitive consequences and increased mortality, yet the underlying mechanism remains unclear. Emerging evidence has suggested that β2‑microglobulin [a component of major histocompatibility complex (MHC) class I molecules] is involved in cognitive dysfunction in various neurological diseases. Therefore, the present study tested the hypothesis that β2‑microglobulin in the brain also mediates sepsis‑induced cognitive impairment. In the present study, wild‑type and antigen processing 1 (Tap1)‑deficient mice (Tap1‑/‑) were subjected to cecal ligation and puncture (CLP). Survival rate, cognitive function, and biochemical analysis were performed at the indicated time points. The data revealed that CLP induced anxiety‑like behavior and impaired hippocampal‑dependent contextual memory in wild‑type mice, which was accompanied by hippocampal microglial activation, increased level of interleukin‑1β, and decreased concentrations of brain derived neurotrophic factor and postsynaptic density protein 95. Notably, it was demonstrated that Tap1‑/‑ mice with reduced cell surface expression of MHC I protected mice from anxiety‑like behavior and impaired hippocampal‑dependent contextual memory and reversed most of these biochemical parameters following sepsis development. In summary, the results of the present study suggest that β2‑microglobulin negatively regulates cognitive impairment in an animal model of sepsis induced by CLP.

Aldosterone and Insulin Resistance: Vicious Combination in Patients on Maintenance Hemodialysis

Recently, we demonstrated that plasma aldosterone contributed to insulin resistance in chronic kidney disease. The aim of this study is the clinical impact of this relationship in hemodialysis patients. In a cross section study using a total of 128 hemodialysis patients, multiple regression analysis revealed that plasma aldosterone levels were independently associated with HOMA-IR, insulin resistance index. This association was found to be more stringent in diabetic patients than in non-diabetic patients. Aldosterone levels were associated with cardiac hypertrophy and carotid artery stenosis. HOMA-IR was associated with cardiac hypertrophy. The patients whose aldosterone and HOMA-IR were above the top tertile of each parameter in this cohort showed more severe cardiac hypertrophy and lower contractile function as compared with the patients whose aldosterone levels and HOMA-IR are below the lowest tertile of each parameter. In conclusion, in hemodialysis patients, aldosterone levels and insulin resistance are closely interrelated and the constellation of the two is related to severe cardiovascular tissue damages.

Differentiation of type 2 diabetes mellitus with different complications by proteomic analysis of plasma low abundance proteins

BACKGROUND

Few biomarkers of type 2 diabetes mellitus (T2DM) are replicable in the differentiation of T2DM with different complications. We aimed to identify proteomic biomarkers among T2DM patients with nephropathy or retinopathy.

METHODS

Plasma low abundance proteins were enriched by depletion of 14 high abundance proteins using an affinity removal system, and subjected to nanoflow liquid chromatography electrospray ionization (nano LC-ESI) mass spectrometry after a gel electrophoresis with in-gel digestion. The plasma differential proteomes between normal adults and diabetic patients were validated by another cohort of 149 T2DM patients.

RESULTS

A total of 826 proteins in plasma were consistently identified from 8 plasma samples of normal adults, and 817 proteins were consistently identified in 8 plasma samples of T2DM patients. Using the MetaCore analysis, low abundance proteins in plasma between normal adults and T2DM patients were significantly different in 5 functional pathways. Moreover, plasma prolactin-induced protein (PIP), thrombospondin-2 (THBS2), L1 cell adhesion molecule (L1CAM) and neutrophil gelatinase-associated lipocalin (NGAL) levels were higher in T2DM patients. Further, PIP, THBS2 and NGAL were significantly higher in T2DM patients with nephropathy (albuminuria) but not in those with retinopathy, while L1CAM levels were higher in T2DM patients with retinopathy.

CONCLUSIONS

This study identified that higher PIP, THBS2 and/or NGAL levels were significantly associated with nephropathy of T2DM, and higher L1CAM but normal PIP, THBS2 or NGAL was significantly associated with retinopathy of T2DM.

Label-Free Quantitative Proteomics Reveals Differences in Molecular Mechanism of Atherosclerosis Related and Non-Related to Chronic Kidney Disease

The major cause of mortality in patients with chronic kidney disease (CKD) is atherosclerosis related to traditional and non-traditional risk factors. However, the understanding of the molecular specificity that distinguishes the risk factors for classical cardiovascular disease (CVD) and CKD-related atherosclerosis (CKD-A) is far from complete. In this study we investigated the disease-related differences in the proteomes of patients with atherosclerosis related and non-related to CKD. Plasma collected from patients in various stages of CKD, CVD patients without symptoms of kidney dysfunction, and healthy volunteers (HVs), were analyzed by a coupled label-free and mass spectrometry approach. Dysregulated proteins were confirmed by an enzyme-linked immunosorbent assay (ELISA). All proteomic data were correlated with kidney disease development and were subjected to bioinformatics analysis. One hundred sixty-two differentially expressed proteins were identified. By directly comparing the plasma proteomes from HVs, CKD, and CVD patients in one study, we demonstrated that proteins involved in inflammation, blood coagulation, oxidative stress, vascular damage, and calcification process exhibited greater alterations in patients with atherosclerosis related with CKD. These data indicate that the above nontraditional risk factors are strongly specific for CKD-A and appear to be less essential for the development of "classical" CVD.