Increased urine IgM excretion predicts cardiovascular events in patients with type 1 diabetes nephropathy

Patterns of urinary albumin and IgM associate with markers of vascular ageing in young to middle-aged individuals in the Malmö offspring study

BACKGROUND

Increased urinary excretion of IgM and low-grade albuminuria are associated with increased risk of cardiovascular morbidity and mortality. The objective of this study was to investigate the association between urinary IgM, albuminuria, and vascular parameters reflecting arterial structure and function.

METHODS

Subjects of the present study were from the Malmö Offspring study (MOS) cohort, and included 1531 offspring (children and grand-children) to first-generation subjects that participated in the Malmö Diet Cancer-Cardiovascular Arm study cohort. At baseline, technical measurements of arterial stiffness (carotid-femoral pulse wave velocity; c-f PWV), carotid arterial morphology, 24-h ambulatory blood pressure recordings, ankle-brachial-index (ABI), and evaluation of endothelial function (reactive hyperemia index, RHI) were performed. Urinary (U) IgM, U-albumin, and U-creatinine were measured. Multivariate adjusted logistic regression was used to test whether U-IgM excretion and increasing urinary albumin excretion were related to vascular parameters.

RESULTS

Detectable U-IgM was independently associated with higher systolic blood pressure, odds ratio (OR) 1.021, 95% confidence interval (CI, 1.003-1.039), p = 0.025 and lower ABI; ABI dx: OR 0.026, 95% CI (0.002-0.381), p = 0.008, ABI sin: OR 0.040, 95% CI (0.003-0.496), p = 0.012. Low-grade albuminuria was independently associated with systolic and diastolic blood pressure, aortic blood pressure, the c-f PWV and the number of carotid intima plaques (p < 0.05).

CONCLUSIONS

In young to middle-aged, mostly healthy individuals, increased U-IgM excretion and low-grade albuminuria are associated with adverse vascular parameters. Increased U-IgM excretion may reflect subclinical peripheral atherosclerosis, whereas increased U-albumin excretion is associated with a wide range of cardiovascular abnormalities. This may reflect different pathophysiological mechanisms.

The detection of anti-dengue virus IgM in urine in participants enrolled in an acute febrile illness study in Puerto Rico

BACKGROUND

Dengue is an important arboviral disease with about 100 million dengue cases per year, of which, ~5% result in severe disease. Clinical differentiation of dengue from other acute febrile illnesses (AFI) is difficult, and diagnostic blood tests are costly. We evaluated the utility of anti-DENV IgM in urine to identify dengue cases among AFI patients enrolled in a clinical study.

METHODS

Between May 2012-March 2013, 1538 study participants with fever for ≤7 days were enrolled, a medical history was obtained, and serum and urine specimens were collected. Serum was tested for DENV RNA and anti-DENV IgM. Urine was tested for anti-DENV IgM, and its sensitivity and specificity to detect sera laboratory-positive dengue cases were calculated. We evaluated if urine anti-DENV IgM positivity early (≤5 days post-illness onset [DPO]) and late (6-14 DPO) in the clinical course was associated with dengue severity.

RESULTS

Urine anti-DENV IgM sensitivity and specificity were 47.4% and 98.5%, respectively, when compared with serum anti-DENV IgM ELISA results, and 29.7% and 91.1% when compared with serum rRT-PCR results. There was no correlation between urine anti-DENV IgM positivity and patient sex or pre-existing chronic disease. Early in the clinical course, a significantly higher proportion of those who developed dengue with warning signs had anti-DENV IgM in their urine when compared to those without warning signs (20.4% vs. 4.3%). There was no difference in the proportion with urine anti-DENV IgM positivity between severity groups late in the clinical course.

CONCLUSION

While detection of urine anti-DENV IgM lacked adequate diagnostic sensitivity, it is a highly specific marker for laboratory-positive dengue, and its presence early in the clinical course may distinguish those with more severe disease. Further assessment of urine anti-DENV IgM by DPO is warranted to determine its utility as an early diagnostic (and possibly prognostic) marker for dengue.

Effect of diabetes mellitus on the recovery of changes in renal functions and glomerular permeability following reversible 24-hour unilateral ureteral obstruction

BACKGROUND

Following reversal of short periods of ureteral obstruction (UO), glomerular and tubular renal dysfunction recovers with time. Diabetes mellitus (DM) affects glomerular function; thus, the ability of diabetic kidneys to recover from UO may be impaired. This study investigated the effects of long-term DM on the recovery of glomerular and tubular function, as well as permeability of the glomerular filtration barrier (GFB), after unilateral UO (UUO) reversal.

METHODS

Diabetes mellitus was induced in Wistar rats by intraperitoneal streptozotocin. All diabetic and age-matched control rats underwent reversible 24-hour left UUO. The renal function of both kidneys was measured using clearance techniques 3 hours and 7 and 30 days after UUO reversal. Glomerular permeability was assessed by measuring the glomerular sieving coefficients for fluorescein isothiocyanate-conjugated Ficoll (molecular radius: 20-90 Å).

RESULTS

Unilateral UO induced transient changes in the size selectivity of GFB small pores. However, the size selectivity function of large pores had not returned to baseline even 30 days after UUO reversal. Diabetes mellitus caused exaggerated early alterations in glomerular hemodynamic and tubular function, as well as size selectivity dysfunction of both small and large pores. At 30 days after UUO reversal, despite glomerular hemodynamic and tubular function and the size selectivity of small pores returning to normal in both diabetic and non-diabetic rats, the residual size selectivity dysfunction of large pores was more severe in diabetic rats.

CONCLUSION

Unilateral UO caused long-term dysfunction in the size selectivity of large pores of the GFB. In addition, DM significantly exaggerated this dysfunction, indicating a more ominous outcome in diabetic kidneys following UUO.

Urinary IgM excretion: a reliable marker for adverse pregnancy outcomes in women with chronic kidney disease

Objective

Chronic kidney disease (CKD) pregnancies are at high risk of developing adverse outcomes. In non-pregnant subjects with CKD, higher urinary IgM levels are associated with poor renal survival and higher rates of cardiovascular deaths. In this study, we assessed whether urinary IgM levels are associated with an increased risk of adverse pregnancy outcomes (APO) in CKD pregnancies.

Methods

We performed a nested case–control study within a cohort of CKD patients with singleton pregnancies attended at a tertiary care hospital. The study included 90 CKD patients who eventually developed one or more APO and 77 CKD patients who did not. Urinary IgM excretion was determined from the 24-h urine samples at enrollment by an ultrasensitive enzyme immunoassay.

Results

The risk for combined APO and for preeclampsia (PE) was higher among women with urinary IgM and proteinuria levels values in the highest quartile or with CKD stages 4–5 (odds ratios, OR ≥ 2.9), compared with the lowest quartile or with CKD stage 1. Urinary IgM levels were more closely associated with the risk of either combined or specific APO (PE, preterm birth, and for having a small-for-gestational-age infant; OR ≥ 5.9) than either the degree of total proteinuria or CKD stages. Among patients with CKD stage 1, the risk of combined APO, PE, and preterm birth was higher in women with urinary IgM levels values in the highest quartile (OR ≥ 4.8), compared with the three lower quartiles, independently of proteinuria.

Conclusion

In CKD pregnancies, at the time of initial evaluation, proteinuria and CKD stage are associated with increased risk of combined APO. However, urinary IgM concentrations appear to be better predictors of an adverse outcome and may be useful for risk stratification in CKD pregnancies.

Detection of inflammatory biomarkers in saliva and urine: Potential in diagnosis, prevention, and treatment for chronic diseases

Inflammation is a part of the complex biological response of inflammatory cells to harmful stimuli, such as pathogens, irritants, or damaged cells. This inflammation has been linked to several chronic diseases including cancer, atherosclerosis, rheumatoid arthritis, and multiple sclerosis. Major biomarkers of inflammation include tumor necrosis factor, interleukins (IL)-1, IL-6, IL-8, chemokines, cyclooxygenase, 5-lipooxygenase, and C-reactive protein, all of which are regulated by the transcription factor nuclear factor-kappaB. Although examining inflammatory biomarkers in blood is a standard practice, its identification in saliva and/or urine is more convenient and non-invasive. In this review, we aim to (1) discuss the detection of these inflammatory biomarkers in urine and saliva; (2) advantages of using salivary and urinary inflammatory biomarkers over blood, while also weighing on the challenges and/or limitations of their use; (3) examine their role(s) in connection with diagnosis, prevention, treatment, and drug development for several chronic diseases with inflammatory consequences, including cancer; and (4) explore the use of innovative salivary and urine based biosensor strategies that may permit the testing of biomarkers quickly, reliably, and cost-effectively, in a decentralized setting.

Correlation of Urine and Serum Biomarkers with Renal Damage and Survival in Dogs with Naturally Occurring Proteinuric Chronic Kidney Disease

Background

Urine protein loss is common in dogs with chronic kidney disease (CKD).

Hypothesis/Objectives

To evaluate new biomarkers of glomerular and tubulointerstitial (TI) damage compared with histology and as survival indicators in dogs with naturally occurring, proteinuric CKD.

Animals

One hunderd and eighty dogs with naturally occurring kidney disease.

Methods

Retrospective study using urine, serum, and renal biopsies from dogs with kidney disease, 91% of which had proteinuric CKD. Biomarkers were evaluated and correlated with pathologic renal damage, and significant associations, sensitivities, and specificities of biomarkers for renal disease type were determined.

Results

Fractional excretions of immunogloblin M (IgM_FE) and immunoglobulin G (IgG_FE) correlated most strongly with glomerular damage based on light microscopy (r = 0.58 and 0.56, respectively; P < .01). Serum creatinine (SCr) correlated most strongly with TI damage (r = 0.70, P < .01). Urine IgM/creatinine and urine NAG/creatinine had the highest sensitivity (75%) and specificity (78%) for detection of immune complex‐mediated glomerulonephritis. Although individually most biomarkers were significantly associated with decreased survival time (P < .05), in a multivariate analysis, SCr, IgM_FE, and glomerular damage based on transmission electron microscopy (TEM) were the only biomarkers significantly associated with survival time (SCr: P = .001; IgM_FE: P = .008; TEM: P = .017).

Conclusions and Clinical Importance

Novel urine biomarkers and FEs are useful for detection of glomerular and TI damage in dogs with proteinuric CKD and might predict specific disease types and survival.

Plasma pro-inflammatory cytokines, IgM-uria and cardiovascular events in patients with chest pain: A comparative study

BACKGROUND

Risk stratification of patients presenting with acute chest pain is crucial for immediate and long-term management. Traditional predictors are suboptimal; therefore inflammatory biomarkers are studied for clinical assessment of patients at risk. Recently, we reported the association of IgM-uria with worse cardiovascular outcome in patients with acute chest pain. In this study, in the same cohort of patients with chest pain, we compared the value of IgM-uria to pro-inflammatory cytokines in predicting the occurrence of subsequent cardiovascular events.

METHODS

A total of 178 consecutive patients presenting with acute chest pain to the emergency department at the University Hospital of Lund, were recruited. Twenty-seven of 57 patients with acute coronary syndrome (ACS), and 18 of 118 patients with non-specific chest pain at baseline developed a subsequent major cardiovascular event during the 18 months follow-up. Urinary proteins (IgM-uria and Microalbuminuria) and plasma inflammatory markers (IL-6, Il-8, IL-10, IFN-γ and TNF-α) were measured at time of admission.

RESULTS

Using the receiver operating characteristic curves, the area under the curve for predicting cardiovascular events was 0.71 (95%CI 0.61-0.81) for IgM-uria, 0.61 (95%CI 0.51-0.71) for IL-6, 0.63 (95%CI 0.53-0.72) for IL-8, 0.65 (95%CI 0.56-0.74) for IL-10, and 0.64 (95% CI 0.54-0.74) for TNF-α. In multivariate Cox-regression analysis adjusted for age, microalbuminuria, IgM-uria, IL-10, TNF-α, troponin T, hsCRP and ACS at baseline; IgM-uria was the only biomarker that remained an independent predictor of outcome (HR = 4.2, 95%CI 2.2-7.8, p < 0.001).

CONCLUSION

In patients with chest pain with or without acute coronary syndrome, IgM-uria could better predict the occurrence of cardiovascular events than plasma pro-inflammatory cytokines.

The association between urinary lgM excretion and diabetic retinopathy in diabetic patients

Background

Diabetic Retinopathy is one of the most common causes of blindness among adults. Microvascular complications may have common origins. The objective of the present study is to analyze the correlation between urinary IgM excretion and diabetic retinopathy based on the type of diabetes.

Methods

The present study is cross-sectional analytic and was carried out on 140 type2 diabetic patients (of which 70 patients diagnosed with retinopathy) and 76 type1 diabetic patients (of which 37 patients diagnosed with retinopathy). For every patient in each of the test groups, fasting plasma glucose, triglyceride, cholesterol, creatinin and HbA1c tests were done. The value of IgM, the albumin- to- creatinine ratio and the urine analysis test were also used to rule out the significant proteinuria of the patients. Then, IgM Index was measured using the following equation: Igm Index = Urine IgM/Urine Cr.

Results

The level of IgM index in the diabetic patients (type1 and type2) had no significant correlation with retinopathy. Cut point = 1.49, sensitivity = 0.703 and specificity = 0.308 in type1 diabetes were used for screen retinopathy. In type1 diabetic patients, the duration of diabetes had a significant correlation with urinary protein while in type 2 diabetic patients, the diabetes duration and HbA1c were significantly correlated with retinopathy.

Conclusion

The results of this study demonstrate that the level of urinary IgM in diabetic patients has no difference in those who have or lack retinopathy, but the urinary IgM level of more than 1.49 mg/dl can be considered as a cut point in type1 diabetic patients to screen retinopathy.

Tubular reabsorption of high, middle and low molecular weight proteins according to the tubulo-interstitial damage marker N-acetyl-β-D-glucosaminidase in glomerulonephritis

BACKGROUND

Proteinuria, the hallmark of glomerular diseases, is an independent predictor of end-stage renal disease (ESRD) progression. Proteinuria is a mixture of proteins of different molecular weight (MW) dependent on alterations of glomerular filtration barrier (GFB) and reabsorption impairment by proximal tubular epithelial cells (PTECs). We aimed to evaluate the excretion of different-MW proteins according to the tubulo-interstitial damage marker N-acetyl-β-D-glucosaminidase (NAG) in glomerulonephritides (GNs).

METHODS

In 189 patients [idiopathic membranous nephropathy (IMN) n = 84, primary focal segmental glomerulosclerosis (FSGS) n = 48, crescentic IgA nephropathy (CIgAN) n = 37, minimal change disease (MCD) n = 20] several urinary proteins were measured at biopsy: α2-macroglobulin/creatinine ratio; fractional excretion of IgG, transferrin, albumin and α1-microglobulin, and the NAG/creatinine ratio divided by estimated glomerular filtration rate (eGFR) (NAG/C/eGFR), as NAG excretion is dependent on functioning nephron mass. Protein excretion was compared between 4th vs. 1st quartile of NAG/C/eGFR.

RESULTS

In IMN, FSGS and CIgAN high-MW proteins excretion (α2-macroglobulin, IgG) was greater than that of middle- (transferrin, albumin) and low-MW proteins (α1-microglobulin) in 4th vs. 1st quartile of NAG/C/eGFR; the mean fold excretion increase of high-MW proteins in 3 GNs was 74.9, higher than that of middle- (34.8) and low-MW proteins (12.0). Higher excretion of high-MW proteins may be dependent on lower reabsorption by PTECs. By contrast, in MCD the difference in excretion of different-MW proteins is probably due to high GFB selectivity.

CONCLUSION

High-MW protein excretion is dependent on GFB alteration and reduced reabsorption; its prognostic significance is ominous because in several glomerular diseases progression is associated with high-MW protein excretion.

Urinary Smad1 is a new biomarker for diagnosis and evaluating the severity of diabetic nephropathy

The aim of this study was to analyze urinary Smad1 level in patients with type 2 diabetes, explore the possibility of Smad1 being a biomarker for early diagnosis and evaluation of severity of diabetic nephropathy, and explore the impact factors affecting urinary Smad1 concentration. In this study, 132 subjects with type 2 diabetes and 50 healthy volunteers were enrolled. Subjects were grouped according to urine albumin to creatinine ratio (ACR) into: normal albumin in urine (NAU), low albumin in urine (LAU), high albumin in urine (HAU), and very high albumin in urine (VHAU). Among those, LAU, HAU, and VHAU were regarded as the diabetic nephropathy group (DN group), NAU was regarded as nondiabetic nephropathy (non-DN group), and the healthy volunteers were the controls. Enzyme-linked immunosorbent assay was used to detect the urinary Smad1 concentration, urinary Smad1 to creatinine ratio (SCR) was used as the standard reference. Compared with non-DN group, SCR of DN group was higher (P < 0.05), while there was no difference between the non-DN group and controls (P > 0.05). There was no significant difference for SCR between LAU and NAU groups (P > 0.05). The SCR was higher in VHAU group than those in HAU and LAU groups, and higher in HAU than that in LAU group (P < 0.05). Pearson correlation analysis showed that SCR measures were positively correlated to ACR, duration and diabetic retinopathy of the disease (r = 0.285, 0.230, 0.202; P = 0.001, 0.008, 0.019, respectively). Multiple linear regression analysis showed that ACR and duration were independent impact factors for SCR (P < 0.05). This is the first known study examining the correlation of Smad1 and DN in clinical practice. It suggested that the urinary Smad1 may be a potential diagnostic parameter for DN and may be used to evaluate the severity of DN. However, it cannot predict those in patients with the earliest DN and low urine albumin concentration. Furthermore, ACR and duration may be independent impact factors for urinary Smad1.

Increased urinary IgM excretion in patients with chest pain due to coronary artery disease

BACKGROUND

Micro-albuminuria is a recognized predictor of cardiovascular morbidity and mortality in patients with coronary artery disease. We have previously reported, in diabetic and non-diabetic patients, that an increased urinary excretion of IgM is associated with higher cardiovascular mortality. The purpose of this study was to investigate the pattern of urinary IgM excretion in patients with acute coronary syndrome (ACS) and its correlation to cardiovascular outcome.

METHODS

Urine albumin, and IgM to creatinine concentration ratios were determined in 178 consecutive patients presenting with chest pain to the Department of Emergency Medicine (ED) at the University Hospital of Lund. Fifty eight (23 female) patients had ACS, 55 (19 female) patients had stable angina (SA), and 65 (35 female) patients were diagnosed as non-specific chest pain (NS).

RESULTS

Urine albumin and IgM excretions were significantly higher in patients with ACS (p = 0.001, and p = 0.029, respectively) compared to patients with NS-chest pain. During the 2 years follow-up time, 40 (19 female) patients suffered a new major cardiovascular event (ACS, acute heart failure, stroke) and 5 (4 male/1 female) patients died of cardiovascular cause. A high degree of albuminuria and IgM-uria significantly predicted cardiovascular mortality and morbidity (HR = 2.89, 95% CI: 1.48 - 5.66, p = 0.002). Microalbuminuric patients (≥3 mg/mmol) with high IgM-uria (≥0.005 mg/mmol) had a 3-fold higher risk for cardiovascular new events compared to patients with low IgM-uria (RR = 3.3, 95% CI: 1.1 - 9.9, p = 0.001).

CONCLUSION

In patients with chest pain, an increased urine IgM excretion, is associated with coronary artery disease and long-term cardiovascular complications. Measuring urine IgM concentration could have a clinical value in risk stratification of patients with ACS.

New urinary biomarkers for diabetic kidney disease

Diabetic kidney disease is the leading cause of end-stage renal disease in developed and developing countries. Microalbuminuria is the gold standard for detection and prediction of diabetic kidney disease and cardiovascular risk disease in clinical practice. However, microalbuminuria has several limitations, such as lower sensitive, larger variability. It is urgent to explore higher sensitivity and specificity for earlier detection of diabetic kidney disease and more accurate prediction of the progression to end stage renal disease. We reviewed some new and important urinary biomarkers, such as: transferrin, immunoglobulin G, immunoglobulin M, Cystanic C, podocytes, type IV collagen, 8-oxo-7, 8-dihydro-2'-deoxyguanosine, ceruloplasmin, monocyte chemoattractant protein-1 and so on. We need good quality, long-term, large longitudinal trials to validate published biomarkers and find new biomarkers, considering biomarkers reviewed here are from small cross-sectional studies.

Urinary markers of glomerular injury in diabetic nephropathy

Diabetic nephropathy, the leading cause of renal failure worldwide, affects approximately one-third of all people with diabetes. Microalbuminuria is considered the first sign and the best predictor of progression to renal failure and cardiovascular events. However, albuminuria has several limitations. Therefore, earlier, more sensitive and specific biomarkers with greater predictability are needed. The aim of this paper is to discuss the current literature on biomarkers of glomerular injury that have been implicated in diabetic kidney disease.

Urine IgM-excretion as a prognostic marker for progression of type 2 diabetic nephropathy

Although the clinical manifestations of type 2 diabetic nephropathy and decline in kidney function are similar to those in type 1, the clinical course and the renal structural changes are more heterogeneous in type 2 diabetic patients. Previous studies have shown that an increased urine IgM excretion in patients with type 1 diabetic nephropathy was associated with poor outcome. In the present follow-up study we examine the prognostic value of baseline urine IgM excretion in patients with type 2 diabetes mellitus.

METHODS

A cohort of 106 (74 male and 32 female) patients with type 2 diabetes regularly attending our diabetes out-patient clinic at Skane University Hospital in Lund. They were recruited prospectively under the period between 1992 and 2004. Patients were followed-up until January 2009. The end point was cardiovascular (CV) death or end-stage renal disease (ESRD). The median follow-up time was 5 years (0.5-13 years). Participants were divided according to degree of albuminuria and IgM-uria.

RESULTS

During follow-up time, 28 (19 male and 9 female) patients died of CV events and 41 (26 male and 15 female) developed ESRD. The risk of CV mortality was 2.4 fold, and the risk of renal failure 4.9 fold higher in patients with increased urine IgM excretion compared to patients with low urine IgM excretion. Stratified analysis showed that an increased urine IgM excretion was an independent predictor of renal and cardiovascular death irrespective of the degree of albuminuria (HR=3.6, 95% CI: 2.1-6.0, P<0.001). In conclusion, type 2 diabetic nephropathy patients with high urine IgM excretion rates carry an increased risk of renal and cardiovascular death.