Elevated serum total bilirubin levels are negatively associated with major diabetic complications among Chinese senile diabetic patients

Serum total bilirubin is a risk factor of metabolic syndrome and its components in obese Egyptians

Background/Aim

The link between serum total bilirubin and metabolic syndrome and its components has been previously proposed. However, it is unknown whether total bilirubin is a risk factor of metabolic syndrome and its components in obese Egyptians. Therefore, this study was conducted to clarify the association of total bilirubin levels with metabolic syndrome and its components in obese Egyptians.

Methods

A total of 200 adults with obesity were enrolled in this study. Obese participants were evaluated for metabolic syndrome; there were 92 obese participants with metabolic syndrome and 108 obese participants without metabolic syndrome. Anthropometric measurements, fasting blood glucose (FBG), fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), HOMA-β (%), lipid profile, uric acid, alanine aminotransferase, aspartate aminotransferase, and serum total bilirubin were assessed.

Results

Total bilirubin was significantly lower in obese participants with metabolic syndrome than in those without metabolic syndrome. Compared with middle bilirubin tertile, high and low bilirubin tertiles were independently associated with metabolic syndrome. Regarding metabolic syndrome components, a significant positive association between low bilirubin tertile and hypertension was found independent of the all studied confounding factors, whereas the association of total bilirubin level with waist circumference (WC), FBG, high-density lipoprotein cholesterol, and triglycerides was dependent on body mass index (BMI), HOMA-IR, and high sensitive C-reactive protein (hs-CRP).

Conclusion

Total bilirubin is an independent risk factor of metabolic syndrome in obese Egyptians. We have found an independent association between high bilirubin level and reduced risk of metabolic syndrome, whereas low bilirubin level was associated with increased risk of metabolic syndrome. Bilirubin is also independently associated with hypertension, but its association with other components of metabolic syndrome is mainly dependent on BMI, HOMA-IR, and hs-CRP.

LncRNA HOX transcript antisense RNA mediates hyperglycemic-induced injury in the renal tubular epithelial cell via the miR-126-5pAkt axis

OBJECTIVE

To investigate the involvement of HOX transcript antisense RNA (HOTAIR) in the injury of renal tubular epithelial cells induced by high glucose. Results: In high glucose-induced HK-2 cells, the expression of HOTAIR was upregulated, resulting in suppressed cell proliferation. Meanwhile, HOTAIR upregulates the expression of pro-apoptotic proteins Bax and cleaved caspase-3, while downregulating the expression of the anti-apoptotic protein Bcl-2. Luciferase reporter assays revealed that HOTAIR could target miR-126-5p. Additionally, it was found that the PI3K/Akt signaling pathway serves as a downstream target of miR-126-5p. Knockdown of HOTAIR relieved apoptosis, whereas further inhibition of miR-126-5p led to apoptosis in HK-2 cells. Conclusions: HOTAIR plays a regulatory role in mediating high glucose-induced injuries in HK-2 cells, specifically affecting apoptosis and cell viability, via the miR-126-5p/PI3K/Akt signaling pathway.

Association between total bilirubin and gender-specific incidence of fundus arteriosclerosis in a Chinese population: a retrospective cohort study

To investigate the gender-specific relationship between total bilirubin (TBIL) and fundus arteriosclerosis in the general population, and to explore whether there is a dose-response relationship between them. In a retrospective cohort study, 27,477 participants were enrolled from 2006 to 2019. The TBIL was divided into four groups according to the quartile. The Cox proportional hazards model was used to estimate the HRs with 95% CIs of different TBIL level and fundus arteriosclerosis in men and women. The dose-response relationship between TBIL and fundus arteriosclerosis was estimated using restricted cubic splines method. In males, after adjusting for potential confounders, the Q2 to Q4 level of TBIL were significantly associated with the risk of fundus arteriosclerosis. The HRs with 95% CIs were 1.217 (1.095-1.354), 1.255 (1.128-1.396) and 1.396 (1.254-1.555), respectively. For females, TBIL level was not associated with the incidence of fundus arteriosclerosis. In addition, a linear relationship between TBIL and fundus arteriosclerosis in both genders (P < 0.0001 and P = 0.0047, respectively). In conclusion, the incidence of fundus arteriosclerosis is positively correlated with serum TBIL level in males, but not in females. In addition, there was a linear dose-response relationship between TBIL and incidence of fundus arteriosclerosis.

High-normal serum bilirubin decreased the risk of lower limb atherosclerosis in type 2 diabetes: a real-world study

BACKGROUND

Bilirubin has been found to protect against overt atherosclerotic diseases, but to date, few studies have investigated the effects of bilirubin especially within the normal range on lower limb atherosclerosis. Therefore, we aimed to assess the associations of bilirubin within normal limits including total bilirubin (TB), conjugated bilirubin (CB) and unconjugated bilirubin (UCB) with lower limb atherosclerosis in Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

7284 T2DM patients with normal levels of serum bilirubin were included in this cross-sectional, real-world study. Patients were divided into quintiles by TB levels (< 8.7, 8.7-10.19, 10.20-11.99, 12-13.99, > 13.99 µmol/L). Lower limb ultrasonography was conducted to detect lower limb plaque and stenosis. The association between serum bilirubin and lower limb atherosclerosis was explored by multiple logistic regression.

RESULTS

A remarkable decrease in the prevalence of lower limb plaque (77.5, 75.3, 70.7, 71.7 and 67.9%) and stenosis (21.1, 17.2, 13.3, 13.0 and 12.0%) was observed across the TB quintiles. Multivariable regression analysis showed that serum TB levels were negatively correlated with higher risks of lower limb plaque and stenosis, both as a continuous variable [OR (95%CI): 0.870 (0.784-0.964), p = 0.008 for plaque; and 0.835 (0.737-0.946), p = 0.005 for stenosis] and as categorized in quintiles (p = 0.015 and 0.016 for plaque and stenosis). Interestingly, serum CB levels were only negatively correlated with lower limb stenosis [OR (95%CI): 0.767 (0.685-0.858), p < 0.001], whereas serum UCB levels were only negatively associated with lower limb plaque [ OR (95%CI): 0.864 (0.784-0.952), p = 0.003] after a fully-adjusted analysis. Furthermore, serum CRP was significantly decreased across the TB quintiles and negatively associated with serum TB (r = -0.107, p < 0.001), CB (r = -0.054, p < 0.001), and UCB (r = -0.103, p < 0.001).

CONCLUSIONS

High-normal serum bilirubin levels were independently and significantly related to reduced risks of lower limb atherosclerosis in T2DM patients. Furthermore, serum bilirubin levels including TB, CB and UCB were inversely correlated with CRP. These results suggested that higher-normal serum bilirubin may exhibit an anti-inflammatory and protective effect against lower limb atherosclerotic progression in T2DM subjects.

Association between bilirubin levels and risk of stroke: a systematic review and meta-analysis

OBJECTIVE

To evaluate the association between bilirubin levels and stroke risk.

DESIGN

Systematic review and meta-analysis, reported in accordance with Meta-analysis Of Observational Studies in Epidemiology guidelines.

DATA SOURCES

The PubMed, Embase, Cochrane Central Register of Controlled Trials and China National Knowledge Infrastructure Databases were searched from inception up to 27 February 2022.

ELIGIBILITY CRITERIA

Cohort studies assessing the dose-response relationship between bilirubin levels and risk of stroke were eligible for inclusion. There were no language restrictions.

DATA EXTRACTION AND SYNTHESIS

All data from eligible studies were collected and assessed by two independent investigators. We generated pooled relative risks (RRs) with 95% CIs. We used a restricted cubic spline model for the dose-response analyses. Subsequent subgroup analyses were conducted according to stroke outcomes, follow-up duration, geographical area and size of the cohort.

RESULTS

Nine articles including results from 11 cohort studies with 7835 cases of stroke and 263 596 participants met the inclusion criteria. The summarised RR of stroke comparing the highest and lowest bilirubin level was 0.85 (95% CI 0.72 to 0.99). The dose-response analysis indicated that a 15 µmol/L increment of bilirubin level was associated with an 18% lower risk of stroke (RR=0.82, 95% CI 0.67 to 0.99). For ischaemic stroke, the RR was 0.76 (95% CI 0.58 to 0.99). Significant publication bias was not detected.

CONCLUSIONS

Elevated bilirubin levels were associated with a decreased risk of stroke among adults.

PROSPERO REGISTRATION NUMBER

CRD42017071497.

Association of Serum Bilirubin Levels with Macro- and Microvascular Complications in Chinese People with Type 2 Diabetes Mellitus: New Insight on Gender Differences

Background

Previous studies suggested protective effects of bilirubin against cardiovascular disease, with a possible gender difference. However, the relationship between serum total bilirubin (TBIL) with diabetic macro- and microvascular complications remains unknown. We aimed to examine the association of macro- and microvascular complications with serum TBIL levels.

Methods

Serum TBIL was measured in 648 patients with T2DM. Demographic and clinical data were obtained from the inpatient medical record system. Serum TBIL was measured with an automatic biochemistry analyzer according to routine protocols. Parameters of vascular complications, including ankle-brachial index, carotid intima-media thickness, estimated glomerular filtration rate and the urinary albumin to creatinine ratio, were measured and calculated. The association between TBIL and diabetic macro- and microvascular complications was analyzed.

Results

In multivariable logistic regression, after adjustment for age, sex, body mass index and diabetic duration, higher serum TBIL levels were significantly associated with decreased odds of microalbuminuria (OR = 0.31, [95% CI] 0.16-0.61, P = 0.003) and chronic kidney disease (OR = 0.19, [95% CI] 0.09-0.41, P < 0.001). These associations were only found in male but not in female patients. However, no significant relationship was found between TBIL and peripheral arterial disease or carotid hypertrophy.

Conclusion

Our findings suggest that physiological higher TBIL level might be a protective factor for diabetic microvascular complications.

Are total bilirubin and high-sensitivity C-reactive protein independently associated with Type 2 diabetes mellitus in postmenopausal women?

Background

Various studies have reported contradictory results regarding the relationship of total bilirubin and high-sensitivity C-reactive protein levels (hsCRP) with diabetes mellitus Type 2 (DM2). Therefore, we aimed to examine which one of them could be more convenient for the estimation of DM2 risk in postmenopausal women.

Materials and Methods

A total of 150 healthy postmenopausal women (mean age 57[53-60] years) and 79 postmenopausal women with DM2 (mean age 66 [61-71] years) were enrolled in cross-sectional study. Examinees were recruited consecutively in the study during their regular check-up visit in the Primary Health Care Center in Podgorica, Montenegro, in a period from October 2012 to May 2016. Anthropometric measurements, biochemical parameters, and blood pressure were obtained. Multivariable logistic regression analysis was used to find the independent predictors for DM2 development in postmenopausal women.

Results

Age, waist circumference, and total bilirubin were the independent predictors for DM2 development in postmenopausal women (odds ratio [OR] =1.224, 95% confidence interval [CI] [1.117-1.341], P < 0.001; OR = 1.137, [95% CI = 1.036-1.215], P < 0.001, and OR = 0.727, [95% CI = 0.611-0.866], P < 0.001, respectively), whereas hsCRP lost its independent predictive role (OR = 1.155, [95% CI = 0.854-1.560], P = 0.349).

Conclusion

Unlike hsCRP, total bilirubin independently correlated with DM2 in postmenopausal women.

Association of Total Bilirubin With All-Cause and Cardiovascular Mortality in the General Population

Objective: The study aims to investigate the association of total bilirubin with all-cause and cause-specific mortality in the general population.

Methods: A total of 37,234 adults from the United States National Health and Nutrition Examination Survey 1999–2014 were enrolled. Baseline levels of total bilirubin associated with risk of mortality were evaluated on a continuous scale (restricted cubic splines) and by quartile categories with Cox regression models.

Results: Higher levels of total bilirubin was positively associated with an increased risk of all-cause mortality [hazard ratio (HR) 1.59, 95% confidence interval (CI) 1.46–1.72; p < 0.001]. Compared with individuals with the lowest quartile of bilirubin, the multivariable adjusted hazard ratio for all-cause mortality was 1.25 (1.14–1.37) for individuals in the highest quartile. Restricted cubic splines indicated that the association was non-linear in cardiovascular mortality and cancer mortality while linear in all-cause mortality.

Conclusions: Total bilirubin was associated with all-cause and cause-specific mortality in the general population.

Plasma melatonin levels in patients with diabetic retinopathy secondary to type 2 diabetes

BACKGROUND

Melatonin is reported to be related to diabetes mellitus (DM) risk; however, the effect of melatonin on diabetic retinopathy (DR) risk remains unclear.

AIM

The aim of this study was to determine the effect of melatonin on DR risk.

METHODS

A hospital-based case-control study was conducted from January 2020 to June 2020. DR was assessed using the Diabetic Retinopathy preferred practice pattern (PPP)-updated 2019 criteria. The participants were divided into the DM cases without DR (NDR) group, non-proliferative DR (NPDR) group and proliferative DR (PDR) group. Plasma melatonin concentration was detected with the enzyme-linked immunosorbent assay kit. The relationship between plasma melatonin concentration and DR risk as well as severity was assessed.

RESULTS

It was found that plasma melatonin was 72.83 ± 16.25, 60.38 ± 13.43, 44.48 ± 10.30 and 44.69 ± 8.95 pg/mL in healthy controls, NDR group, NPDR and PDR group, respectively. In addition, it was found that plasma melatonin could be used as a potential diagnostic biomarker for DR (AUC = 0.893, P < 0.001). There was a significant positive relationship between total bilirubin and melatonin content (P < 0.001) based on the correlation assay. Significant associations between total bilirubin and melatonin content were also detected in the NPDR (R² = 0.360, P < 0.001) and PDR (R² = 0.183, P < 0.001) groups.

CONCLUSION

The data obtained in this study demonstrated that plasma melatonin concen-tration was decreased in DR cases and could be used as a sensitive and specific marker for the diagnosis of DR. A significant positive relationship between total bilirubin and melatonin was detected. More related studies are required to understand the role of melatonin in DR.

Bilirubin in metabolic syndrome and associated inflammatory diseases: New perspectives

Diabetes mellitus is one of the major global health issues, which is closely related to metabolic dysfunction and the chronic inflammatory diseases. Multiple studies have demonstrated that serum bilirubin is negatively correlated with metabolic syndrome and associated inflammatory diseases, including atherosclerosis, hypertension, etc. However, the roles of bilirubin in metabolic syndrome and associated inflammatory diseases still remain unclear. Here, we explain the role of bilirubin in metabolic syndrome and chronic inflammatory diseases and its therapeutic potential. Understanding the role of bilirubin activities in diabetes may serve as a therapeutic target for the treatment of chronic inflammatory diseases in diabetic patients.

Is serum total bilirubin a predictor of prognosis in arteriosclerotic cardiovascular disease? A meta-analysis

The protective role of serum total bilirubin, a widely recognized antioxidant, has been approved by numerous updating studies. However, regarding the effect of high serum total bilirubin level (STBL) in arteriosclerotic cardiovascular disease (ASCVD) are conflicting in different sources of data. We, therefore, performed this meta-analysis to evaluate the influence of STBL on risk of ASCVD.Four databases were used to identify the literature with a date of search of January, 2019. Finally, a total of 20 studies had been adopted. ASCVD was defined as acute coronary syndrome, stable angina, coronary revascularization, atherosclerotic stroke or transient ischemic attack, and peripheral arterial disease (PAD). All relevant data were collected from studies meeting the inclusion criteria.A total of 20 published studies (323,891 cases) met the inclusion criteria. The meta-analysis revealed that, in studies excluding heterogeneity, STBL was significantly positively related to in-hospital cardiovascular mortality (odds ratio [OR] 2.82, 95% confidence interval [CI] 1.83-4.36, Z = 4.69, P < .001) and major adverse cardiac events (OR 1.88, 95% CI 1.414-2.491, Z = 4.36, P < .001), also negatively associated with prognosis of acute myocardial infarction, pooled hazard ratio (HR) = 0.804 (95% CI 0.700-0.923, Z = 3.08, P = .002). The correlation similarity was also reflected in terms of patients with stroke (HR 0.78, 95% CI 0.70-0.88, Z = 4.24, P = .003). Combined analysis revealed that lower STBL was significantly associated with PAD, pooled OR = 0.91 (95% CI 0.85-0.98, Z = 2.39, P = .017). In general analysis, a conclusion can be drawn, that higher STBL was significantly negative correlated with cardiovascular disease, pooled HR = 0.83 (95% CI 0.73-0.94, Z = 3.02, P = .003).Higher STBL significantly improved the prognosis of ASCVD; furthermore, STBL was an important factor in the long-term prognosis of vascular-related disease prevention and can be used as a predictor in vascular-related disease risk prediction.

Insulin Glargine and Acarbose in the treatment of elderly patients with diabetes

Objective:

To investigate the clinical efficacy of insulin glargine combined with acarbose in the treatment of elderly patients with diabetes.

Methods:

One hundred and forty-four elderly patients with diabetes who received treatment between December 2016 and December 2017 in Binzhou People’s Hospital, China, were selected and divided into a control group and an observation group, 72 each, using random number table. The control group was treated with insulin glargine, while the observation group was treated with insulin glargine combined with acarbose. The therapeutic effect, improvement of quality of life and adverse reactions were compared between the two groups.

Results:

After treatment, fasting blood glucose (FBG), 2h postprandial blood glucose (PBG) and glycosylated hemoglobin (Hb Alc) of the two groups were lower than those before treatment, and the decrease degree of the observation group was significantly larger than that of the control group (P<0.05). The time needed for blood glucose reaching the standard level and daily insulin dosage of the observation group were significantly lower than that of the control group, and the differences were statistically significant (P<0.05). SF-36 scale score of the observation group was significantly better than the control group, and the difference was statistically significant (P<0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P>0.05).

Conclusion:

The combination of insulin Glargine and Acarbose can significantly control the blood glucose level of elderly patients with diabetes, improve the biochemical indicators, and enhance the quality of life. It is worth promotion in clinical practice.

Pharmacological actions and therapeutic potentials of bilirubin in islet transplantation for the treatment of diabetes

Islet transplantation is the experimental strategy to treat type 1 diabetes by transplanting isolated islets from a donor pancreas into the recipient. While significant progress has been made in the islet transplantation field, islet loss before and after transplantation is still the major obstacle that currently precludes its widespread application. Islet must survive from possible cellular damages during the isolation procedure, storage time, islet injection process and post-transplantation immune rejection, only then the survived islets could produce insulin, actively regulating the blood glucose level. Therefore, islet protection needs to be addressed, especially regarding oxidative stress and immune response induced islet cell damages in diabetic patients. Many clinical data have shown that mildly elevated bilirubin levels in the body negatively correlate to the occurrence of an array of diseases that are related to increased oxidative stress, especially diabetes, and its complications. Recent studies confirmed that bilirubin helps receivers to suppress immune reaction and enable prolonged tolerance to islet transplantation. In this paper, we will review the pharmacological mechanism of bilirubin to modulate oxidative cellular damage and chronic inflammatory reaction in both diabetes and islet transplantation process. Also, we will present the clinical evidence of a strong correlation in bilirubin and diabetes. More importantly, we will summarize undergoing therapeutic applications of bilirubin in islet transplantation and discuss formulation approaches designed to overcome bilirubin delivery issues for future use.

Glucuronidated bilirubin: Significantly increased in hepatic encephalopathy

Bilirubin is produced by the breakdown of hemoglobin in senescent erythrocytes by macrophages and carried by albumin from blood circulation to the liver for removal in normal physiology. Glucuronic acid modification of bilirubin by UDP-glucuronyltransferase in the liver is the key event for its subsequent elimination from human body. Conditions that accelerate the breakdown of erythrocytes may cause an elevated blood level of unconjugated bilirubin whereas the factors affect the glucuronidated bilirubin formation and subsequent elimination may cause decreased or increased blood level of glucuronidated bilirubin, the water soluble "direct bilirubin" measured by clinical blood test. Studies showed that increased total serum bilirubin has a protective effect on cardiovascular and other related diseases, but it is unknown how direct bilirubin levels were related to different diseases. By taking advantage of the data collected in the clinical laboratory of our hospital, the direct bilirubin data from 192,535 patients with 72 clinically defined diseases were compared to that of healthy controls (10,497). Based on the mean, median, and p values, we found that patients with hepatic encephalopathy had the highest serum direct bilirubin level, which resembled acute hepatic encephalopathy caused by increased serum direct bilirubin level in neonates. In contrast, patients with uremia, nephrotic syndrome, and preeclampsia had significantly lower levels of serum direct bilirubin. Taken together, our data revealed that serum direct bilirubin levels were either increased or decreased in a disease-dependent manner. The possible molecular mechanisms of increased direct bilirubin levels in patients suffering hepatic encephalopathy are discussed.

Bilirubin and Ischemic Stroke: Rendering the Current Paradigm to Better Understand the Protective Effects of Bilirubin

Novel and innovative methods are critical in fostering new treatments and improving clinical outcomes in patients who suffer from ischemic stroke. Bilirubin has long been considered metabolic waste that can be harmful to the body; however, it is now becoming recognized as one of the body's most potent antioxidant, anti-inflammatory, and neuroprotective molecules. These properties facilitate bilirubin's anti-atherogenic effects to impede and prevent the formation of thrombi in ischemic stroke. These functions allow for protection from neuronal injury during an ischemic state and suggest that elevated bilirubin levels may be linked to a lower rate of morbidity and mortality. Therefore, here we discuss the pathophysiology of stroke and the molecular properties of bilirubin to better understand their beneficial relationship. We outline clinical studies looking at the relationship between serum bilirubin levels and ischemic stroke prevalence. At this time, few studies have rigorously looked at the relationship between bilirubin and ischemic stroke, whether it is positive or negative. Thus, rigorous research is needed to provide evidence supporting the current studies, expand on these studies, and facilitate their translation to bedside therapy for patients who suffer from ischemic stroke.

Bilirubin and its changes were negatively associated with diabetic kidney disease incidence and progression: A five-year's cohort study based on 5323 Chinese male diabetic patients

AIMS

This study aimed to evaluate the association between baseline bilirubin (TBiL) and follow-up TBiL changes for diabetic kidney disease (DKD) incidence and progression based on a 5 years' cohort study.

METHODS

This cohort study was conducted in Beijing between 2009 and 2013. The subjects were consisted of 5342male diabetic patients with baseline retinopathy. Cox proportional risk model was used to calculate hazards ratio (HR).

RESULTS

The mean age of the 5342 diabetic patients was 78.68 ± 8.40 (65-102 yrs). The total five year incidence was 8.7% (95%CI: 7.9%-9.4%) for DKD and 10.5% (95%CI: 9.7%-11.3%) for eGFR decrease. The HR of baseline TBiL showed a decreasing trend for both DKD incidence and eGFR decrease. The HRs of baseline TBiL (per μmol/L increase) for DKD and eGFR decrease were 0.967(95%CI: 0.946-0.988) and 0.955(95%CI: 0.936-0.975) respectively. For follow-up TBiL changes, after adjusted for related co-variables and baseline TBiL levels (as continuous variable) in the model, the HRs (per μmol/L of follow-up TBiL changes) for DKD and eGFR decrease were 0.973(95%CI: 0.952-0.995) and 0.991(95%CI: 0.974-0.998) respectively. The results were similar when baseline TBiL and follow-up TBiL changes were used as tertiary variable.

CONCLUSION

Not only baseline TBiL, but also follow-up changes were significantly associated with DKD incidence and progression.

Effect of Repeated Freeze-Thaw on Serum Biomarkers Associated with Eye Disease

Background

Serum biomarkers are associated with eye diseases, which results in the need for cryopreservation of serum samples. However, the effect on serum biomarker levels of repeatedly freezing and thawing remains poorly understood. The aim of this study was to evaluate the effects of repeated freeze-thaw on the serum levels of the protein, complement C3c (C3c), the micromolecule, uric acid (UA), and the enzyme, angiotensin-converting enzyme (ACE).

Material/Methods

Serum samples were obtained from 50 patients who attended an ophthalmic outpatient department. Following baseline measurements, the serum samples from each subject were divided into aliquots and stored at −80°C for further analysis, following between one to six freeze-thaw cycles. The serum levels of C3c, UA, and ACE were measured immediately after the stored serum samples were thawed.

Results

The serum level of C3c was significantly changed after the first freeze-thaw cycle (p<0.05), and a significant alteration in serum ACE levels occurred after the third freeze-thaw cycle (p<0.05). The serum UA level remained unchanged after all freeze-thaw cycles. Repeated freeze-thaw cycles significantly increased the serum levels of C3c and decreased the serum levels of ACE. The serum levels of C3c, UA, and ACE, respectively were significantly correlated (p<0.001), while the correlation coefficient for C3c and UA were improved when compared with ACE.

Conclusions

Repeated freeze-thaw can have variable effects on the serum levels of biomarkers, C3c, UA and ACE, which supports the need for quality control of cryopreserved serum for biomarker evaluation.

Metabolomics-based evidence of the hypoglycemic effect of Ge-Gen-Jiao-Tai-Wan in type 2 diabetic rats via UHPLC-QTOF/MS analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Ge-Gen-Jiao-Tai-Wan (GGJTW) formula, derived from traditional Chinese herbal medicine, is composed of Pueraria montana var. lobata (Willd.) Sanjappa & Pradeep (Ge-Gen in Chinese), Coptis chinensis Franch (Huang-Lian), and Cinnamomum cassia (L.) J. Presl (Rou-Gui). GGJTW is used for treatment of diabetes in China, reflecting the potent hypoglycemic effect of its ingredients. However, little is known of the hypoglycemic effect of GGJTW and the underlying metabolic mechanism.

AIM OF THE STUDY

This study aimed to investigate the hypoglycemic effect of GGJTW in type 2 diabetic rats and the metabolic mechanism of action.

MATERIALS AND METHODS

Ultra high-performance liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry (UHPLC-QTOF/MS)-based metabolomics approach was used for monitoring hyperglycaemia induced by high-sugar high-fat fodder and streptozotocin (STZ), and the protective effect of GGJTW. Dynamic fasting blood glucose (FBG) levels, body weight, and biochemical parameters, including lipid levels, hepatic-renal function, and hepatic histopathology were used to confirm the hyperglycaemic toxicity and attenuation effects. An orthogonal partial least squared-discriminant analysis (OPLS-DA) approach highlighted significant differences in the metabolome of the healthy control, diabetic, and drug-treated rats. The metabolomics pathway analysis (MetPA) and Kyoto encyclopedia of genes and genomes (KEGG) database were used to investigate the underlying metabolic pathways.

RESULTS

Metabolic profiling revealed 37 metabolites as the most potential biomarker metabolites distinguishing GGJTW-treated rats from model rats. Most of the metabolites were primarily associated with bile acid metabolism and lipid metabolism. The most critical pathway was primary bile acid biosynthesis pathway involving the up-regulation of the levels of cholic acid (CA), chenodeoxycholic acid (CDCA), taurocholic acid (TCA), glycocholic acid (GCA), taurochenodesoxycholic acid (TCDCA), and taurine.

CONCLUSIONS

The significantly-altered metabolite levels indicated the hypoglycemic effect of GGJTW on diabetic rats and the underlying metabolic mechanism. This study will be meaningful for the clinical application of GGJTW and valuable for further exploration of the mechanism.

The Association between Serum Bilirubin Level and Electrochemical Skin Conductance in Chinese Patients with Type 2 Diabetes

Bilirubin is an antioxidant and plays a protective role against cardiovascular and microvascular disease. The aim of this study is to explore the possible protective effect of bilirubin on small nerve function. A total of 265 Chinese patients with type 2 diabetes mellitus (T2DM) were enrolled in the study. Both SUDOSCAN and other traditional diabetic neuropathy examinations including neuropathy symptom score (NSS), the neuropathy disability score (NDS) and Michigan Neuropathy Screening Instrument (MNSI) scores were performed in all patients with T2DM. Blood bilirubin levels were tested in the study. Spearman correlation analysis and multivariate regression analysis were performed to determine the relation between bilirubin level and hands and feet ESC values. Spearman correlation analysis demonstrated a correlation between total bilirubin and ESC levels including hands (r = 0.165, P < 0.05) and feet (r = 0.122, P < 0.05) as well as between UCBil and ESC levels including both hands (r = 0.172, P < 0.05) and feet (r = 0.175, P < 0.05). Multivariate regression linear analyses showed both total bilirubin and UCBil level were independently associated with hands and feet ESC levels. All these results suggested a positive association between bilirubin level and ESC level, indicating a possible protective role of bilirubin in peripheral small nerve dysfunction of type 2 diabetes mellitus.

The U-Shaped Association between Bilirubin and Diabetic Retinopathy Risk: A Five-Year Cohort Based on 5323 Male Diabetic Patients

AIMS

This study aimed at assessing the impact of baseline bilirubin (TBiL) on the incidence of diabetic retinopathy (DR) based on a five-year cohort study which consisted of 5323 Chinese male diabetic patients.

METHODS

A cohort study based on 5323 male diabetic patients was conducted in Beijing, from 2009 to 2013. Both baseline TBiL and follow-up changes were measured. Cox proportional risk model was used to calculate the hazard ratio (HR) of TBiL for DR risk.

RESULTS

During the follow-up period, there were 269 new DR cases. The incidence of five-year follow-up was 5.1% (95% CI: 4.5%~5.6%). The TBiL level of those who had diabetic retinopathy was lower than that of those without (12.51+ 1.20 mol/L and 13.11+ 1.32 μmol/L, P = 0.033). And more interestingly, along with the quintiles of baseline TBiL, there showed a U-shaped curve with DR incidence. And the RRs were 0.928 (95% CI: 0.646-1.331), 0.544 (95% CI: 0.365-0.811), 0.913 (95% CI: 0.629-1.324), and 1.035 (95% CI: 0.725-1.479) for the second, third, fourth, and fifth quintiles of baseline TBiL levels, respectively, compared with the first quintile. For follow-up TBiL changes, after being adjusted for related covariables and baseline TBiL levels (as continuous variable) in the model, the RRs for DR were 1.411 (95% CI: 1.081-1.842) for those who had decreased TBiL level and 0.858 (95% CI: 0.770-0.947) for those who had increased TBiL level during follow-up. And this association was more prominent among those with lower baseline TBiL level.

CONCLUSIONS

Serum TBiL had a U-shaped relationship with DR incidence, which was independent of control status of diabetes and other related covariates.

Inverse Relationship Between Serum Bilirubin Levels and Diabetic Foot in Chinese Patients with Type 2 Diabetes Mellitus

BACKGROUND Several studies demonstrated that bilirubin, a potent endogenous antioxidant, is a strong protective factor for many diabetic complications such as nephropathy, retinopathy, neuropathy, and vasculopathy. The purpose of this study was to assess the association between serum bilirubin levels and diabetic foot (DF) in Chinese patients with type 2 diabetes mellitus (T2DM). MATERIAL AND METHODS The present cross-sectional study of bilirubin levels in relation to DF was conducted in 1,269 T2DM patients with (n=578) and without (n=691) DF. Blood test results were obtained on hospital admission, including total bilirubin (T-BIL), direct bilirubin (D-BIL), and indirect bilirubin (I-BIL). Data on Wagner classification and amputation procedure in patients with DF were collected by reviewing electronic medical records. Univariate or multivariate analysis were performed to explore the association between bilirubin and DF. RESULTS Serum I-BIL levels were shown to play a protective role regarding the presence and severity of DF (OR=0.75, p=0.029 and OR=0.90, p=0.021, respectively). In addition, in a comparison of the lowest and highest tertiles of serum bilirubin concentration, the highest tertile of serum T-BIL (OR=0.51, p=0.011) and I-BIL (OR=0.28, p<0.001) was significantly related with a lower Wagner grade of DF. Patients with DF in the highest tertiles of T-BIL carried a significantly lower risk of amputation events than those in the lowest tertiles (OR=0.47, p=0.025). CONCLUSIONS The present study provided evidence that decreased serum bilirubin levels were independently associated with the presence and severity of DF and amputation events in patients with DF.

Effect of bilirubin concentration on the risk of diabetic complications: A meta-analysis of epidemiologic studies

Diabetes can affect many parts of the body and is associated with serious complications. Oxidative stress is a major contributor in the pathogenesis of diabetic complications and bilirubin has been shown to have antioxidant effects. The number of studies on the effect of bilirubin on the risk of diabetic complications has increased, but the results are inconsistent. Thus, we performed a meta-analysis to determine the relationship between bilirubin concentration and the risk of diabetic complications, and to investigate if there was a dose-response relationship. We carried out an extensive search in multiple databases. A fixed or random-effects model was used to calculate the pooled estimates. We conducted a dose-response meta-analysis to analyze the association between these estimates. A total of 132,240 subjects from 27 included studies were analyzed in our meta-analysis. A negative nonlinear association between bilirubin concentration and the risk of diabetic complications was identified (OR: 0.77, 95% CI: 0.73-0.81), with a nonlinear association. We also found that there was a negative association between bilirubin concentration and the risk of diabetic nephropathy, diabetic retinopathy and diabetic neuropathy. The results of our meta-analysis indicate that bilirubin may play a protective role in the occurrence of diabetic complications.

Total bilirubin level may be a biomarker of nephropathy in type 2 diabetes mellitus: A meta-analysis of observational studies based on MOOSE compliant

Recently, the number of the studies on the relationship between the total bilirubin level (TBL) and diabetic nephropathy (DN) is increasing, but their results were not consistent. Therefore, we performed a meta-analysis to analyze the relationship between TBL and the risk of DN.We searched 5 databases before October 31, 2016, and reviewed the reference list of relevant articles. The fixed or random-effects model was used to pool risk estimates. We conducted the dose-response meta-analysis to evaluate the relationship between TBL and the risk of DN.Our meta-analysis showed that TBL in the DN group was lower than that in diabetes without the kidney disease (NDN) group (standard mean difference [SMD]: -0.63, 95% CI: -0.80, -0.46). The result of each subgroup also showed that TBL in the DN group was lower than that in the NDN group. The result of meta-regression indicated that duration of diabetes mellitus might be the source of heterogeneity. Our meta-analysis also showed that there was a significant negative relationship between TBL and the risk of DN (OR: 0.86, 95%CI: 0.82, 0.90). The results of subgroup analysis were similar to those of SMD; no sources of heterogeneity were detected by meta-regression. Sensitivity analysis indicated that the results were robust. We observed a linear association between TBL and the risk of DN, and there was a negative dose-response association between TBL and the risk of DN.In conclusion, bilirubin may be used as a biomarker of DN. It helps early diagnosis and effective therapeutic strategies on DN.