Serum β-2 microglobulin predicts mortality in people with diabetes

Evidence Linking Cadmium Exposure and β2-Microglobulin to Increased Risk of Hypertension in Diabetes Type 2

The most common causes of chronic kidney disease, diabetes, and hypertension are significant public health issues worldwide. Exposure to the heavy metal pollutant, cadmium (Cd), which is particularly damaging to the kidney, has been associated with both risk factors. Increased levels of urinary β₂-microglobulin (β₂M) have been used to signify Cd-induced kidney damage and circulating levels have been linked to blood pressure control. In this study we investigated the pressor effects of Cd and β₂M in 88 diabetics and 88 non-diabetic controls, matched by age, gender and locality. The overall mean serum β₂M was 5.98 mg/L, while mean blood Cd and Cd excretion normalized to creatinine clearance (C_cr) as E_Cd/C_cr were 0.59 µg/L and 0.0084 µg/L of filtrate (0.95 µg/g creatinine), respectively. The prevalence odds ratio for hypertension rose by 79% per every ten-fold increase in blood Cd concentration. In all subjects, systolic blood pressure (SBP) showed positive associations with age (β = 0.247), serum β₂M (β = 0.230), and E_Cd/C_cr (β = 0.167). In subgroup analysis, SBP showed a strong positive association with E_Cd/C_cr (β = 0.303) only in the diabetic group. The covariate-adjusted mean SBP in the diabetics of the highest E_Cd/C_cr tertile was 13.8 mmHg higher, compared to the lowest tertile (p = 0.027). An increase in SBP associated with Cd exposure was insignificant in non-diabetics. Thus, for the first time, we have demonstrated an independent effect of Cd and β₂M on blood pressure, thereby implicating both Cd exposure and β₂M in the development of hypertension, especially in diabetics.

Geriatric Nutrition Risk Index as a predictor of cardiovascular and all-cause mortality in older Americans with diabetes

BACKGROUND AND AIMS

Few studies have examined the relationship between malnutrition, as defined by the Geriatric Nutrition Risk Index (GNRI), and all-cause mortality and cardiovascular mortality events, particularly in persons with diabetes. The study aimed at the association between GNRI and all-cause mortality and cardiovascular mortality in older Americans with diabetes.

METHODS

Data from this retrospective study were obtained from the National Health and Nutrition Examination (NHANES) 1999-2016. Using data from The NHANES Public-Use Linked Mortality Files to assess all-cause mortality (ACM) and cardiovascular mortality (CVM). After excluding participants younger than 60 years and without diabetes, and with missing follow-up data, 4400 cases were left in this study. Persons with diabetes were divided by GNRI into 3 groups: GNRI ≥ 98; 92 ≤ GNRI < 98; and GNRI < 92; (No; Low; Moderate/Severe (M/S) group). We used Cox proportional hazard regression model to explore the predictive role of GNRI on ACM and CVM in elderly persons with diabetes. Restricted cubic splines to investigate the existence of a dose-response linear relationship between them.

RESULT

During a median follow-up period of 89 months, a total of 538 (12.23%) cardiovascular deaths occurred and 1890 (42.95%) all-cause deaths occurred. Multifactorial COX regression analysis showed all-cause mortality (hazard ratio [HR]: 2.58, 95% CI: 1.672-3.994, p < 0.001) and cardiovascular mortality (HR: 2.29, 95% CI: 1.063-4.936, p = 0.034) associated with M/S group risk of malnutrition in GNRI compared to no group. A negative association between GNRI and all-cause mortality was observed across gender and ethnicity. However, the same negative association between GNRI and cardiovascular mortality was observed only for males (HR:0.94, 95% CI:0.905-0.974, p < 0.001) and other races (HR:0.92, 95% CI:0.861-0.976, p = 0.007). And there was no significant correlation between low malnutrition and cardiovascular mortality (p = 0.076). Restricted cubic splines showed a nonlinear relationship between GNRI and all-cause mortality and cardiovascular mortality (non-linear p < 0.001, non-linear p = 0.019).

CONCLUSIONS

Lower GNRI levels are associated with mortality in older patients with diabetes. GNRI may be a predictor of all-cause mortality and cardiovascular mortality risk in older patients with diabetes.

Association of beta-2-microglobulin with cardiovascular and all-cause mortality in the general and non-CKD population

β-2 microglobulin, a light chain in the major histocompatibility complex Class 1 molecule, is associated with mortality in dialysis or uremic patients. Current evidence on the relationship between beta-2-microglobulin (B2M) and mortality in the general and non-chronic kidney disease (CKD) population are limited and controversial. Data from the nutrition and health examination survey database and the nutrition and health examination survey linked mortality file were used. In total, 10,388 adults who had complete data for B2M were included. Weighted multivariable Cox proportional hazards regression models and regression splines were employed to evaluate the relationship between B2M with mortality. Moreover, subgroup and sensitivity analyses were performed. During a median follow up of 17.9 years (interquartile range 15.2-18.7), 2780 people died, 902 (32%) from cardiovascular disease. Restricted cubic splines showed that B2M is J-shaped nonlinear positively associated with all-cause mortality and cardiovascular disease mortality in the non-CKD and general population. Based on the multivariable adjustment model, the adjusted hazard ratios comparing the highest versus lowest quartile of the distribution of B2M were 2.50 (95% confidence interval: 1.90, 3.28) for all-cause mortality in the general population, 2.58 (95% confidence interval: 1.52, 4.37) for cardiovascular disease mortality in the general population, 2.58 (1.91, 3.49) for all-cause mortality in the non-CKD population and 2.62 (1.52, 4.53) for cardiovascular disease mortality in the non-CKD population. The positive associations between B2M and outcomes remained broadly significant across subgroups and sensitivity analyses. Higher B2M levels were associated with cardiovascular and all-cause mortality in the general and non-CKD population.

DIA-PRM Proteomic Analysis of Phlegm-Dampness Constitution with Glucolipid Metabolic Disorders by the Intervention of Hua Tan Qu Shi Recipe

Background

Phlegm-dampness constitution as one of nine constitutions in traditional Chinese medicine (TCM) has been a high risk factor for glucolipid metabolic disorders (GLMD). Based on our previous findings, Hua Tan Qu Shi recipe (HTQSR) could effectively improve metabolic indicators of GLMD by targeting on phlegm-dampness constitution. However, the proteomic mechanisms of GLMD with the treatment of HTQSR targeting on phlegm-dampness constitution remain unknown.

Methods

Clinical participants from phlegm-dampness constitution with the prediabetic state (T), phlegm-dampness constitution with marginally elevated blood lipids (Z), and phlegm-dampness constitution before sickness (W) were included in this study, who orally took HTQSR for 12 weeks and, respectively, marked AT, AZ, and AW. Data-independent acquisition (DIA) and parallel reaction monitoring (PRM) were performed to identify the differential proteins; then, Venn analysis was used to investigate coexpressed and coregulated proteins. In addition, ingenuity pathway analysis (IPA) software was utilized to explore the related pathways and diseases and biofunctions.

Results

LXR/RXR activation, acute phase response signaling, and production of nitric oxide and reactive oxygen species in macrophages were obviously activated between the T and AT groups, as well as the Z and AZ groups. In contrast, these three pathways were inhibited between the W and AW groups. Importantly, one coexpressed and coregulated differential protein, B2MG, was validated by PRM among all groups.

Conclusions

This work firstly reported the underlying proteomic mechanisms of GLMD with the treatment of HTQSR targeting on phlegm-dampness constitution, indicating that intervention of phlegm-dampness constitution might be a novel strategy for the preventive treatment of GLMD.

Circulating β2 and α1 microglobulins predict progression of nephropathy in diabetic patients: a meta-analysis of prospective cohort studies

AIMS

To study the association of circulating β2 (B2M) and α1 microglobulins (A1M) with diabetic nephropathy (DN) progression, a meta-analysis was performed on the prospective cohort studies.

METHODS

Up to October 2021, a comprehensive search of the PubMed, EMBASE, Scopus, Web of Science, and Cochrane Library databases was performed. The primary outcome (progression of DN) was defined as a decrease in eGFR or the occurrence of end stage renal disease or DN-related mortality. Eligible studies were included in a pooled analysis that used either fixed-effect or random-effect models to compensate for variation in measurement standards between studies. The funnel plot and Egger's test were used to assess publication bias.

RESULTS

The meta-analysis included 4398 people from 9 prospective trials (8 cohorts) for B2M and 3110 people from 4 prospective trials (3 cohorts) for A1M. Diabetic individuals with higher B2M levels had an increased risk for DN (relative risk [RR]: 1.81, 95% confidence interval [CI]: 1.56-2.09). Likewise, higher A1M was associated with augmented probability of DN (RR: 1.96, 95% CI: 1.46-2.62). The funnel plot and Egger's tests indicated no publication bias for A1M. Additionally, to compensate for putative publication bias for B2M, using trim and fill analysis, four studies were filled for this marker and the results remained significant (RR: 1.62, 95% CI: 1.37-1.92).

CONCLUSIONS

The elevated serum levels of B2M and A1M could be considered as potential predictors of DN progression in diabetic patients.

PROTOCOL REGISTRATION

PROSPERO CRD42021278300.

Associations of exposure to melamine, cyanuric acid, phthalates with markers of early kidney impairment, and their interactions in US adults: analyses of NHANES 2003-2004 data

Melamine (MEL), cyanuric acid (CYA), and phthalates have kidney toxicity, respectively. Still, no study has explored whether there is an interaction of co-exposure to MEL, CYA, and phthalates on early kidney impairment, including cystatin C (CYST), beta 2-microglobulin (β2-MG), albumin creatinine ratio (ACR), and estimated glomerular filtration rate (eGFR). Urine samples were collected from 333 adults in the National Health and Nutrition Examination Survey (NHANES) 2003-2004, and urinary MEL, CYA, and ten metabolites of phthalates were quantified. The multiple markers of early kidney impairment were also measured, including serum CYST, β2-MG, urinary ACR, and eGFR. Their associations were explored by multiple linear and multivariate logistic regression models. Meanwhile, the interactions of co-exposure to MEL, CYA, and phthalates on early kidney impairment were analyzed by Wilcoxon rank-sum test combined with the LSD test. In the multiple linear regression model, urinary concentrations of monobenzyl phthalate (MBzP), mono(3-carboxypropyl) phthalate (MCPP), mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), and mono(2-ethylhexyl) phthalate (MEHP) were positively associated with urinary ACR, serum β2-MG, and CYST, respectively. Urinary concentrations of MBzP and MCPP were negatively associated with eGFR. In the multivariate logistic regression model, increased urinary CYA concentration was the risk factor of CYST abnormality with an odds ratio (OR) (95% confidence interval, 95% CI) of 2.38 (1.01, 5.60) (P = 0.047) and increased urinary MBzP concentration was the risk factor of ACR abnormality with an OR of 2.59 (1.41, 4.75) (P = 0.002). The co-exposure to MEL, CYA, and four phthalate metabolites (MEHP, MBzP, MCPP, and MECPP) presented significantly interactive effects on the markers of early kidney impairment, respectively. There were the independent and interactive effects of exposure to MEL, CYA, and specific phthalate metabolites on early kidney impairment. Due to co-exposure to multiple environmental chemicals in our daily life, more attention should be paid to the health damage raised by the synergistic effects of environmental chemicals.

The independent and interactive effects of phthalates exposure and hypertension on the indicators of early renal injury in US adults: Evidence from NHANES 2001-2004

The association between phthalates and early renal injury is largely unknown in adults. We aim to explore the associations of phthalates and hypertension with early renal injury, and the interactive effects of phthalate and hypertension on the early renal injury. This study enrolled 3283 U.S. adults from NHANES 2001-2004. We detected nine phthalate metabolites in spot urine. We also measured the multiple indicators of early renal injury, including albumin-to-creatinine (Cr) ratio (ACR), β2-microglobulin (B2M), cystatin C (CYST), and calculated the estimated glomerular filtration rate (eGFR), including Cr-based eGFR, CYST-based eGFR, and Cr-CYST-based eGFR. Multiple linear regression and multivariable logistic regression were used to explore the associations among urinary phthalate metabolites, hypertension, and the indicators of early renal injury. The results showed that monobenzyl phthalate (MBzP), mono (3-carboxypropyl) phthalate (MCPP), and mono (2-ethylhexyl) phthalate (MEHP) were positively associated with ACR, B2M, CYST and negatively associated with three eGFR. Mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) was positively associated with ACR, with a β value of 0.099 (95% CI: 0.046, 0.152). Meanwhile, MEHP was associated with a higher risk of ACR abnormality, with an OR value of 1.258 (95% CI: 1.067, 1.482). MBzP, MCPP, and MEOHP increased the risks of ACR, B2M, CYST, and eGFR abnormality. Hypertension was positively associated with ACR, with a β value of 0.460 (95% CI: 0.360, 0.561). We also found interactive effects of monoethyl phthalate (MEP), MCPP, MBzP, monobutyl phthalate (MnBP), and hypertension on B2M, CYST, and three kinds of eGFR. Our results indicated that certain phthalate metabolites might contribute to increased risks of early renal injury. The hypertension population may be more sensitive to the early renal injury caused by phthalates exposure than the non-hypertension population.

Analysis of circRNA-mRNA expression profiles and functional enrichment in diabetes mellitus based on high throughput sequencing

To study the pathogenesis of diabetes mellitus (DM) and identify new biomarkers, high‐throughput RNA sequencing provides a technical means to explore the regulatory network of MD gene expression. To better elucidate the genetic basis of DM, we analysed the circRNA and mRNA expression profiles in serum samples from diabetic patients. The circRNAs and mRNAs with abnormal expression in the DM group and non‐diabetic group (NDM) were classified by RNA sequencing and differential expression analysis. The circRNA‐miRNA‐mRNA regulatory network reveals the mechanism by which competitive endogenous RNAs (ceRNAs) regulate gene expression. The biological functions and interactions of circRNA and mRNA were analysed by gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Differential expression analysis showed that 441 circRNAs (366 up‐regulated, 75 down‐regulated) and 683 mRNAs (354 up‐regulated, 329 down‐regulated) were significantly differentially expressed in the DM group compared with the NDM group. Screening of the differential genes at the nodes of the interaction network showed that a single circRNA could interact with multiple miRNAs and then jointly regulate more mRNAs. In addition, the expressions of circRNA CNOT6 and AXIN1 as well as mRNA STAT3, MYD88, and B2M were associated with the progression of diabetes. Enrichment pathway analysis indicated that differentially expressed circRNA and mRNA may participate in Nod‐like receptor signalling pathway, insulin signalling pathway, sphinolipid metabolism pathway, and ribosome pathway, and play a role in the pathogenesis of diabetes. This study provides a theoretical basis for elucidating the molecular mechanism of DM occurrence and development at circRNA and mRNA levels.

The usefulness of serum beta-2 microglobulin as a biomarker for evaluating renal function decline in type II diabetes mellitus

Background and objective: Serum beta-2 microglobulin (β2M) has been used as a useful clinical marker of chronic kidney dysfunction. The current study aims to evaluate the diagnostic accuracy of β2M for the early detection of diabetic nephropathy among Iraqi patients with type II diabetes mellitus. Methods: The study included 84 participants divided into four groups, three of them were type II diabetics and the fourth is the healthy individuals’ (control) group. The diabetic’ subgroups were named according to the Micral test as: normoalbuminuria (21 patients), microalbuminuria (21 patients), and macroalbuminuria group (21 patients). The control group included 21, age- and sex-matched, healthy participants. Biochemical markers for diabetes mellitus as well as β2M were determined for each participant and then were analyzed statistically. Results: The serum β2M of normoalbuminuria group was (2.86±0.95 µg/mL), microalbuminuria group was (5.06±1.97 µg/mL) and macroalbuminuria group (3.6±1.59 µg/mL). The results showed significant increase (p˂0.05) in the β2M level of microalbuminuria group when compared with that of normoalbuminuria and macroalbuminuria groups. In addition, a highly significant increase (p˂0.01) in β2M concentration was observed in microalbuminuria group when compared with that of the control group. Conclusions: β2M can be used as a useful biomarker for the early detection of nephropathy.

Prognostic value of beta-2 microglobulin on mortality in chronic kidney disease patients: A systematic review and meta-analysis

The aim of this study was to delve into whether beta-2 microglobulin could assess all-cause mortality in patients with chronic kidney disease. PubMed and Embase were systematically searched. Hazard risk and 95% CI were pooled using random-effect models. A total of eight studies were involved according to the inclusion and exclusion criterions. By meta-analysis, each 1 mg/L increase in beta-2 microglobulin displayed positive relationships to the risk of all-cause mortality (hazard risk 1.03, 95% CI = 1.02-1.03) and cardiovascular events (hazard risk 1.04, 95% CI = 1.00-1.08) in patients with dialysis. However, the relationship between elevated level of serum beta-2 microglobulin as a categorical variable and mortality was not significant. The prognostic value of elevated beta-2 microglobulin might be significant in ESRD patients with dialysis and a proper cutoff value to predict mortality should be determined in the future.

Beta 2 microglobulin correlates with oxidative stress in elderly

Beta 2 microglobulin (Β2M) is expressed in all nucleated cells, it interplays with mediators to regulate and modulate cellular functions. Its role in aging associated disorders has been documented recently. Oxidative stress has been known to play a direct implication on these disorders. Therefore, there is a rationality to explore the function of Β2M in oxidative stress in elderly people. The aim of the study was to assess the Β2M levels in different group of age, and to study the correlation between Β2M and oxidative stress. Actually, the serum levels of Β2M increased significantly in old people comparing to youngers. In addition, there was a positive correlation between Β2M levels and the age of participants (p < 0.001). In addition, there was a positive correlation between Β2M levels and Malondialdehyde (MDA) (p < 0.001), which underscored the possible role of Β2M in oxidative stress. To confirm the previous result, the correlation between total antioxidant capacity (TAC) and Β2M was assessed. There was a negative correlation between them (p < 0.001). These results suggested a possible role of Β2M in oxidative stress status in elderly people; in addition, it suggested the ability of using Β2M as a novel biomarker for oxidative stress. However, further work should be conducted to explore the exact role of Β2M in oxidative stress, and to include large sample size to confirm the results before translating the findings to clinic.

Circulating plasma factors involved in rejuvenation

Aging is defined as a time-dependent functional decline that occurs in many physiological systems. This decline is the primary risk factor for prominent human pathologies such as cancer, metabolic disorders, cardiovascular disorders, and neurodegenerative diseases. Aging and age-related diseases have multiple causes. Parabiosis experiments, in which the circulatory systems of young and old mice were surgically joined, revealed that young plasma counteracts aging and rejuvenates organs in old mice, suggesting the existence of rejuvenating factors that become less abundant with aging. Diverse approaches have identified a large number of plasma proteins whose levels differ significantly between young and old mice, as well as numerous rejuvenating factors that reverse aged-related impairments in multiple tissues. These observations suggest that increasing the levels of key rejuvenating factors could promote restorative biological processes or inhibit pathological degeneration. Inspired by such findings, several companies have begun selling “young blood transfusions,” and others have tested young plasma as a treatment for Alzheimer’s disease. Here, we summarize the current findings regarding rejuvenating factors.

The prognostic values of beta-2 microglobulin for risks of cardiovascular events and mortality in the elderly patients with isolated systolic hypertension

Background:

The present study aimed to investigate the effects of serum beta-2 microglobulin (B2M) on the risks of major cardiovascular events (MACEs) and all-cause death in Chinese elderly isolated systolic hypertension (ISH) patients without severe renal insufficiency (estimated glomerular filtration rate [eGFR] <30 ml/min/1.73 m²).

Materials and Methods:

Serum B2M concentration, creatinine-eGFR, and blood pressure variability were evaluated in 460 elderly patients (mean age, 82.6 years; 28 women) with ISH in this observational study. The Cox proportional hazard model was adopted to calculate adjusted hazard ratios (HRs) of risk factors for cardiovascular events and all-cause deaths.

Results:

During a median follow-up period of 37.6 months, 63 patients (13.7%) died, and 65 patients (14.1%) had MACEs. Multivariable analysis showed that the higher serum B2M concentration (B2M ≥0.28 mg/dl) was an independent predictor of increased risk of MACEs (nonfatal acute myocardial infarction, acute heart failure, ischemic stroke, and cardiovascular deaths) and all-cause death (HR: 2.62, 95% confidence interval [CI]: 1.46–4.69, P = 0.001 and HR: 3.40, 95% CI: 1.78–6.48, P < 0.001, respectively) adjusting for other multiple confounders including creatinine-eGFR and cystatin C. In addition, blood pressure variability derived from ambulatory blood pressure measurement was not associated with incidence of MACEs and all-cause mortality (P > 0.05).

Conclusion:

Our data suggest that serum B2M concentration may be individually associated with MACEs and all-cause death in elderly ISH patients without severe renal insufficiency even after adjusted for creatinine-eGFR and cystatin C.

Biochemical and Clinical Impact of Organic Uremic Retention Solutes: A Comprehensive Update

In this narrative review, the biological/biochemical impact (toxicity) of a large array of known individual uremic retention solutes and groups of solutes is summarized. We classified these compounds along their physico-chemical characteristics as small water-soluble compounds or groups, protein bound compounds and middle molecules. All but one solute (glomerulopressin) affected at least one mechanism with the potential to contribute to the uremic syndrome. In general, several mechanisms were influenced for each individual solute or group of solutes, with some impacting up to 7 different biological systems of the 11 considered. The inflammatory, cardio-vascular and fibrogenic systems were those most frequently affected and they are one by one major actors in the high morbidity and mortality of CKD but also the mechanisms that have most frequently been studied. A scoring system was built with the intention to classify the reviewed compounds according to the experimental evidence of their toxicity (number of systems affected) and overall experimental and clinical evidence. Among the highest globally scoring solutes were 3 small water-soluble compounds [asymmetric dimethylarginine (ADMA); trimethylamine-N-oxide (TMAO); uric acid], 6 protein bound compounds or groups of protein bound compounds [advanced glycation end products (AGEs); p-cresyl sulfate; indoxyl sulfate; indole acetic acid; the kynurenines; phenyl acetic acid;] and 3 middle molecules [β₂-microglobulin; ghrelin; parathyroid hormone). In general, more experimental data were provided for the protein bound molecules but for almost half of them clinical evidence was missing in spite of robust experimental data. The picture emanating is one of a complex disorder, where multiple factors contribute to a multisystem complication profile, so that it seems of not much use to pursue a decrease of concentration of a single compound.

Associations among Serum Beta 2 Microglobulin, Malnutrition, Inflammation, and Advanced Cardiovascular Event in Patients with Chronic Kidney Disease

OBJECTIVES

This study examines the associations among serum β2 microglobulin (B2M), malnutrition, inflammation, and atherosclerosis (MIA) in those with chronic kidney disease (CKD).

METHODS

CKD patients who were followed in Taoyuan General Hospital from 2009 to 2015 were enrolled. Demographic and biochemical data, including B2M and C-reactive protein (CRP) were reviewed. The participants were stratified according to B2M tertiles. Adjusted hazard ratios (AHRs) and cumulative survival curves for death and MIA syndrome were evaluated by Cox hazard model and Kaplan-Meier method. We also calculated the area under the curve for the receiver operating characteristic curve (AUROC).

RESULTS

From a total of 312 CKD patients, mean follow-up time was 39.7 months. Compared to those with lowest tertile of B2M, the highest tertile group had lower serum albumin, hemoglobin, and estimated glomerular filtration rate. After multivariate adjustment, the associations among tertiles of B2M, death or dialysis, cardiovascular events (CVEs), and MIA syndrome remained significant. The AHRs for the highest tertile group in death or dialysis, CVEs, and MIA syndrome were 25.91 and 65.84 and 152.50(all Ps <0.05).The AUROC for B2M in death or dialysis, CVEs, and MIA syndrome were greater than that for creatinine. The best cut-off value of B2M for predicting death or dialysis, CVEs, and MIA syndrome were 5.39 mg/dL(sensitivity: 67.1%, specificity 62.5%), 4.21 mg/dL(sensitivity: 85.1%, specificity 52.1%), and 5.40 mg/dL(sensitivity: 79.7%, specificity 64.1%).

CONCLUSIONS

In those with CKD, serum B2M was more sensitive than creatinine in predicting CVEs and MIA syndrome.

Beta-2-microglobulin (B2M) expression in the urinary sediment correlates with clinical markers of kidney disease in patients with type 1 diabetes

PURPOSE

After observing variation in the expression of the housekeeping gene B2M in cells of the urinary sediment during a study of candidate genes potentially involved in diabetic kidney disease (DKD), we hypothesized that B2M mRNA expression in the urinary sediment could reflect the presence of DKD.

METHODS

qPCR was used to quantify B2M mRNA expression in cells of the urinary sediment of 51 type 1 diabetes (T1D) patients (61% women, 33.5 [27.0-39.7] years old, with diabetes duration of 21.0 [15.0-28.0] years and HbA1c of 8.2% [7.3-8.9]; median [interquartile interval]) sorted according to the diabetic nephropathy (DN) stages; 8 focal segmental glomerulosclerosis (FSGS) patients and 10 healthy controls. B2M mRNA expression was also evaluated in human embryonic kidney epithelium-like (HEK-293) cells exposed to 25mM glucose and to albumin in order to mimic, respectively, a diabetic and a proteinuric milieu.

RESULTS

No differences were found in B2M mRNA expression among healthy controls, FSGS and T1D patients. Nonetheless B2M mRNA expression was higher in the group composed by T1D patients with incipient or overt DN combined with FSGS patients versus T1D patients without DN combined with healthy controls (P=0.0007). B2M mRNA expression was higher in T1D patients with incipient or overt DN versus without DN (P=0.03). B2M mRNA expression positively correlated with albuminuria in the overall T1D population (r=0.43; P=0.01) and negatively correlated with estimated glomerular filtration rate in male T1D patients (r=- 0.57; P=0.01). Increased B2M expression was observed in HEK-293 cells exposed to 25mM glucose and to albumin.

CONCLUSIONS

Β2M mRNA expression in cells of the urinary sediment is higher in T1D patients with DKD and in patients with FSGS in comparison to healthy subjects, maybe reflecting a tubulointerstitial injury promoted by albumin. Given the proinflammatory nature of B2M, we suggest that this protein contributes to diabetic (and possibly, to non-diabetic) tubulopathy.

Determinants of mortality in patients with type 2 diabetes: a review

We aimed to review and summarize the evidence from accomplished trials analyzing factors influencing mortality in patients with T2DM and to provide some recommendations for targets and treatment in the European region. The following databases were searched for relevant trials: PubMed and the Cochrane Library. Of 3.806 citations, 134 trials met our inclusion criteria.

RESULTS

The reduction in lifetime for 65 + -years-old patients having less than 10 years T2DM amounts to 1.8 years. Having T2DM for more than 10 years lifetime will be reduced by 2.7 years. However, the lifetime shortening factor of T2DM will even be stronger for 40 + -years-old patients at onset. Males will lose 11.6 years of life and 18.6 QUALYs. T2DM among females will reduce life by 14 QUALYs by 22 years. From a statistical point of view, the highest mortality rate will occur in an over 55-years-old European smoking and non-compliant diabetic woman with alcohol abuse living in a rural area with a low level of education and a low socio-economic status. Furthermore, other co-morbidities such as cardiovascular diseases, gout, and depression affect mortality. Additionally, mortality will increase with a BMI over 35 and also with a BMI under 20-25. This refers to the obesity paradox indicating a higher mortality rate among normal weight patients with T2DM compared to overweight patients with T2DM. HbA1c-levels between 6.5 % and 7 % are associated with the lowest impact on mortality.

Circulating Beta-2 Microglobulin and Risk of Cancer: The Atherosclerosis Risk in Communities Study (ARIC)

BACKGROUND

Serum β-2 microglobulin (B2M), a major histocompatibility complex class I molecule that is a biomarker of kidney filtration and increased cell turnover, is elevated at the time of diagnosis in hematological and some solid cancers. However, serum B2M was not examined prospectively as a marker for cancer risk. We hypothesized that in a population without a prior cancer diagnosis, serum B2M is associated with risk of cancer (n = 2,436), including colorectal (n = 255), lung (n = 298), breast (n = 424), and prostate (n = 524) cancers, and hematological (n = 176) malignancies.

METHODS

The analytical cohort (n = 12,300) was followed for incident cancers from 1990 through 2006. B2M (range, 0.9-57.8 mg/L) was measured in stored serum collected in 1990-1992. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals for cancer incidence and mortality in relation to quartiles of B2M.

RESULTS

Adjusting for age, sex, race, center, education, body mass index, smoking, aspirin, and hormone therapy (in women) and comparing highest to lowest B2M quartiles, HRs were 1.25 (1.06-1.47; Ptrend = 0.002) for total cancer risk and 2.21 (1.32-3.70; Ptrend=0.001) for colorectal cancer risk, with similar HRs for colon and rectal cancers. These associations remained after adjustment for an inflammatory biomarker, C-reactive protein, and after excluding the first three years of follow-up. Significant associations were also observed for mortality from total, lung, and hematological cancers.

CONCLUSIONS

These findings provide the first evidence that higher serum B2M is associated with increased colorectal cancer risk.

IMPACT

This study supports B2M as a potential biomarker for colorectal cancer risk. Cancer Epidemiol Biomarkers Prev; 25(4); 657-64. ©2016 AACR.

Effects of GH replacement therapy on thyroid volume and nodule development in GH deficient adults: a retrospective cohort study

OBJECTIVE

Despite the well-known effects of GH/IGF1 signaling on the thyroid, few data are available on the risk of developing nodular goiter in hypopituitary subjects during GH replacement therapy (GHRT). We aimed to define the effects of GH therapy on thyroid volume (TV) and nodular growth.

DESIGN

The records of 96 subjects (47 males and 49 females, median age 48 years) with GH deficit (GHD) were investigated. Seventy also had central hypothyroidism (CH). At the time of our retrospective evaluation, median treatment duration was 5 years.

RESULTS

Pre-treatment TV was smaller in GHD patients than in healthy subjects (P=0.030). During GH treatment, TV significantly increased (P=0.016 for the entire group and P=0.014 in euthyroid GHD patients). Before starting GH therapy, 17 patients harbored thyroid nodules. During GH therapy, nodule size increased slightly in seven patients, and new thyroid nodules occurred in nine patients. Among the 79 patients without pre-existing thyroid nodules, 17 developed one or more nodules. There was no difference in the prevalence of CH in GHD patients with or without thyroid nodules (P=0.915; P=0.841, when patients with pre-therapy nodular goiter were excluded), the main predictor for nodule development being serum IGF1 (P=0.038).

CONCLUSIONS

GHRT is associated with TV's increase in GHD patients. Thyroid nodules developed in 27% of patients, mainly in relation to pre-therapy IGF1 levels, independently of normal or impaired TSH stimulation.

Association between plasma Beta-2 microglobulin level and cardiac performance in patients with chronic kidney disease

Background:

Beta-2 microglobulin (B2M) is considered as a surrogate marker for middle molecule uremic toxins and a key component in dialysis-related amyloidosis. However, few studies have evaluated role of B2M in patients with chronic kidney disease (CKD).

Objectives:

The purpose of this study was to evaluate the association of plasma B2M level with some metabolic and cardiac performance factors in patients with CKD.

Patients and Methods:

In this case-control study, we measured plasma B2M level in 86 patients with different stages of CKD and 78 age- and sex-matched individuals, as healthy control group. Then we investigated the association between plasma B2M level and left ventricular hypertrophy, ejection fraction (EF), and left ventricular end-diastolic diameter (LVEDD) in echocardiography and some inflammatory and metabolic factors in patients with CKD.

Results:

Mean plasma B2M level was significantly higher in patients with CKD than in control group (P < 0.001). It was directly correlated with serum C-reactive protein (r = 0.167, P < 0.001), phosphate (r = 0.112, P < 0.001) levels, and left ventricular mass index (r = 0.438, P < 0.001) and LVEDD (r = 0.275, P < 0.001) in echocardiography. It was also inversely correlated with glomerular filtration rate (r = -0.033, P < 0.001), albumin (r = -0.521, P < 0.001), hemoglobin (r = -0.748, P < 0.001), and EF (r = -0.625, P < 0.001).

Conclusions:

Our findings suggested that plasma B2M level is inversely associated with GFR and EF and directly correlated with some metabolic and cardiac performance factors.

Non-invasive score identifies ultrasonography-diagnosed non-alcoholic fatty liver disease and predicts mortality in the USA

BACKGROUND

Several non-invasive prediction scores for non-alcoholic fatty liver disease (NAFLD) have been developed, but their performance has not been compared and validated in the same population, and whether these prediction scores can predict clinical outcomes remains unknown. In this study, we aimed to validate and compare the performance of four NAFLD prediction scores: fatty liver index, hepatic steatosis index, lipid accumulation product, and NAFLD liver fat score (LFS), and to evaluate the ability of the best NAFLD prediction score to predict mortality.

METHODS

We analyzed data from the National Health and Nutrition Examination Survey conducted in 1988 to 1994, and subsequent follow-up data for mortality up to December 31, 2006. NAFLD was defined by ultrasonographic detection of hepatic steatosis in the absence of other known liver diseases.

RESULTS

In a group of 5,184 participants, LFS consistently showed the highest area under the curve for predicting the presence of NAFLD. During a median follow-up of 14.7 years (range 0.1 to 18.2 years) and 83,830.5 person-years, participants in the high LFS group (LFS ≥1.257) had a higher cardiovascular and liver-related mortality than participants in the low (LFS ≤ -1.413; cardiovascular hazard ratio (HR) = 2.24, 95% CI 1.03 to 4.88; liver HR = 31.25, 95% CI 3.13 to 333.33) or intermediate (-1.413 < LFS < 1.257; cardiovascular HR = 2.3, 95% CI 1.19 to 4.48; liver HR = 30.3, 95% CI 4 to 250) LFS groups in the fully adjusted model. Similar results were obtained when LFS was treated as a continuous variable.

CONCLUSIONS

LFS is the best non-invasive prediction score for NAFLD, and people with a high LFS score have an increased risk for cardiovascular and liver-related mortality.

The peptidic middle molecules: is molecular weight doing the trick?

Chronic kidney disease (CKD) is characterized by a gradual endogenous intoxication caused by the progressive accumulation of bioactive compounds that in normal conditions would be excreted and/or metabolized by the kidney. Uremic toxicity now is understood as one of the potential causes for the excess of cardiovascular disease and mortality observed in CKD. An important family of uremic toxins is that of the peptidic middle molecules, with a molecular weight ranging between 500 and 60,000 Da, which makes them, as a consequence, difficult to remove in the process of dialysis unless the dialyzer pore size is large enough. This review provides an overview of the main and best-characterized peptidic middle molecules and their role as potential culprits of the cardiometabolic complications inherent to CKD patients.