Proteins of TNF-α and IL6 Pathways Are Elevated in Serum of Type-1 Diabetes Patients with Microalbuminuria

Endostatin, soluble tumour necrosis factor receptor 1 and soluble tumour necrosis factor receptor 2 cannot predict new onset of microalbuminuria in patients with type 2 diabetes

AIMS

Inflammation and angiogenesis play an important role in the development of early diabetic kidney disease. We investigated the association of soluble Tumour Necrosis Factor Receptor 1 (sTNF-R1), sTNF-R2 and endostatin with new onset microalbuminuria in normoalbuminuric patients with diabetes mellitus type 2.

METHODS

We conducted a case control study to assess serum levels of sTNF-R1, sTNF-R2 and endostatin in 169 patients with new onset microalbuminuria and in 188 matched normoalbuminuric, diabetic controls. Baseline serum samples from participants of the ROADMAP (Randomized Olmesartan and Diabetes Microalbuminuria Prevention) and observational follow-up (ROADMAP-OFU) studies were used.

RESULTS

Endostatin and sTNF-R1 but not sTNF-R2 were increased at baseline in patients with future microalbuminuria. In the multivariate analysis, each log2 increment in endostatin levels was associated with an increase of only 6% in the risk of development of microalbuminuria (adjusted HR (95% CI) 1.006 (1.001-1011). sTNF-R1 and sTNF-R2 levels were conversely associated with microalbuminuria, but the results did not reach statistical significance. The respective adjusted HRs (95% CI) were 1.305 (0.928-1.774) and 0.874 (0.711-1.074).

CONCLUSIONS

sTNF-R1 and sTNF-R2 failed to predict the occurrence of microalbuminuria in normoalbuminuric patients with type 2 diabetes. Likewise, the utility of endostatin in predicting new onset proteinuria is limited.

Multiplex analysis of inflammatory proteins associated with risk of coronary artery disease in type-1 diabetes patients

BACKGROUND

Chronic uncontrolled hyperglycemia, a precursor to chronic low-grade inflammation, is a leading cause of coronary artery disease (CAD) due to plaque buildup in type-1 diabetes (T1D) patients. We evaluated levels of 22 inflammatory markers in cross-sectional serum samples from 1222 subjects to evaluate their potential as risk factors for CAD in T1D patients.

HYPOTHESIS

Circulating levels of markers of inflammation may be the risk factors for incident CAD.

METHODS

The T1D subjects were divided into two groups: those without CAD (n = 1107) and with CAD (n = 115). Serum levels of proteins were assayed using multiplex immunoassays on a Luminex Platform. Differences between the two groups were made by univariate analysis. Multivariate logistic regression was used to ascertain the potential of proteins as risk factors for CAD. Influence of age, duration of diabetes, sex, hypertension, and dyslipidemia was determined in a stepwise manner. Serum levels of 22 proteins were combined into a composite score using Ridge regression for risk-based stratification.

RESULTS

Mean levels of CRP, IGFBP1, IGFBP2, insulin-like growth factors binding protein-6 (IGFBP6), MMP1, SAA, sTNFRI, and sTNFRII were elevated in CAD patients (n = 115) compared to T1D patients without CAD (nCAD, n = 1107). After adjusting for age, duration of diabetes, sex, hypertension, and dyslipidemia, higher levels of sTNFRI (odds ratio [OR] = 2.18, 1.1 × 10-3 ), sTNFRII (OR = 1.52, 1 × 10-2 ), and IGFBP6 (OR = 3.62, 1.8 × 10-3 ) were significantly associated with CAD. The composite score based on Ridge regression, was able to stratify CAD patients into low, medium, and high-risk groups.

CONCLUSIONS

The results show activation of the TNF pathway in CAD patients. Evaluating these markers in serum can be a potential tool for identifying high-risk T1D patients for intensive anti-inflammatory therapeutic interventions.

Albuminuria and Serum Tumor Necrosis Factor Receptor Levels in Patients with Type 2 Diabetes on SGLT2 Inhibitors: A Prospective Study

INTRODUCTION

Large-scale clinical trials of sodium-glucose cotransporter 2 inhibitors (SGLT2i) demonstrate proteinuria-reducing effects in diabetic kidney disease, even after treatment with renin-angiotensin inhibitors. The precise mechanism for this favorable effect remains unclear. This prospective open-label single-arm study investigated factors associated with a reduction in proteinuria after SGLT2i administration.

METHODS

Patients with type 2 diabetes (T2DM) who had glycated hemoglobin (HbA1c) levels ≥ 6.5% despite dietary and/or oral hypoglycemic monotherapy were recruited and administered the recommended daily dose of SGLT2i for 4 months. Dual primary outcomes were changes in the urine albumin-to-creatinine ratio (uACR) and urine liver-type fatty acid-binding protein (L-FABP)-to-creatinine ratio (uL-FABPCR) at month 4 from baseline. Changes in kidney injury, inflammation, and oxidative stress biomarkers were investigated as secondary endpoints to examine the effects of this treatment on the kidney. The correlation between renal outcomes and clinical indicators, including circulating tumor necrosis factor receptors (TNFR) 1 and 2, was evaluated using univariate and multivariate analyses.

RESULTS

Participants (n = 123) had a mean age of 64.1 years (SD 13.4), with 50.4% being male. The median BMI was 25.8 kg/m2 (interquartile range (IQR) 23.1-28.9), and the median HbA1c level was 7.3% (IQR 6.9-8.3). After SGLT2i administration, the uACR declined from 19.2 mg/gCr (IQR 7.1-48.7) to 13.3 mg/gCr (IQR 7.5-31.6), whereas the uL-FABPCR was not influenced. In univariate analysis, the change in log-transformed uACR due to SGLT2i administration showed a positive correlation with the change in serum TNFR1 level (R = 0.244, p < 0.01). Multivariate regression analysis, including confounding factors, showed that the changes in serum TNFR1 level were independently associated with the changes in the log-transformed uACR (independent t = 2.102, p < 0.05).

CONCLUSION

After the 4-month SGLT2i administration, decreased albuminuria level was associated with decreased serum TNFR level in patients with T2DM.

TRIAL REGISTRATION NUMBER

UMIN000031947.

Novel biomarkers for prognosticating diabetic kidney disease progression

The global burden of diabetic kidney disease (DKD) is escalating, and it remains as a predominant cause of the end-stage renal disease (ESRD). DKD is associated with increased cardiovascular disease and morbidity in all types of diabetes. Prediction of progression with albuminuria and eGFR is challenging in DKD, especially in non-proteinuric DKD patients. The pathogenesis of DKD is multifactorial characterized by injury to all components of the nephron, whereas albuminuria is an indicator of only glomerular injury. The limits in the diagnostic and prognostic value of urine albumin demonstrate the need for alternative and clinically significant early biomarkers, allowing more targeted and effective diabetic treatment, to reduce the burden of DKD and ESRD. Identification of biomarkers, based on multifactorial pathogenesis of DKD can be the crucial paradigm in the treatment algorithm of DKD patients. This review focuses on the potential biomarkers linked to DKD pathogenesis, particularly with the hope of broadening the diagnostic window to identify patients with different stages of DKD progression.

Anti-Inflammatory Activity of 3, 5-Diprenyl-4-hydroxyacetophenone Isolated from Ageratina pazcuarensis

Inflammation is implicated in a wide variety of physiological and pathological processes. Plants are an important source of active anti-inflammatory compounds. The compound 3, 5-diprenyl-4-hydroxyacetophenone (DHAP) was isolated from the dichloromethane extract of the aerial parts of Ageratina pazcuarensis by chromatography and identified by spectroscopic (IR, NMR) and spectrometric (GC-MS) methods. Anti-inflammatory activity was evaluated on ear edema mouse induced with 12-O-tetradecanoylphorbol 13-acetate (TPA) at 2 mg/ear. The antioxidant activity of DHAP was determined using DPPH assay. Cell viability was tested in J774A.1 macrophages, the levels of NO, TNF-α, IL-1β, IL-6, and IL-10 production in macrophages stimulated with lipopolysaccharide (LPS), and membrane lysis induced by hypotonic solution in erythrocytes were evaluated. DHAP diminished the ear edema mouse in 70.10%, and it had scavenger effect against the radical with IC₅₀ of 26.00 ± 0.37 µg/mL. Likewise, 91.78 µM of this compound inhibited the production of NO (38.96%), IL-1β (55.56%), IL-6 (51.62%), and TNF-α (59.14%) in macrophages and increased the levels of IL-10 (61.20%). Finally, 25 and 50 µg/mL DHAP provided the greatest protection against erythrocyte membrane lysis. These results demonstrate that DHAP has anti-inflammatory activity.

The association of vitamin D binding protein levels and genotypes with type 1 diabetes in the black South African population

BACKGROUND

Vitamin D deficiency and the vitamin D pathway have previously been associated with type 1 diabetes (T1D). The majority of vitamin D is transported through the blood bound to the vitamin D binding protein (VDBP). Two polymorphisms in the VDBP gene (rs4588 and rs7041) result in different VDBP variants and have been associated with T1D, however the results are not consistent. The association of VDBP levels and its polymorphisms with T1D have not been investigated in the black South African population. Therefore, this study aimed to determine whether rs4588, rs7041 or serum VDBP levels were associated with T1D in this population.

METHODS

Participants with type 1 diabetes and controls were recruited from the greater Johannesburg area, South Africa. Participants were genotyped for rs4588 and rs7041 using PCR-RFLP and serum VDBP levels were determined by ELISA.

RESULTS

There was no difference in VDBP allelic or genotypic frequencies between participants with T1D and controls (rs4588 C allele frequency 0.92 vs. 0.94; p = 0.390 and rs7041 T allele frequency 0.95 vs. 0.95; p = 0.890). In univariate analysis, the rs4588 CC genotype was associated with increased serum VDBP levels, however, this association was lost with multivariate analysis. The VDBP genotypes were not associated with any other study variables. In logistic regression analysis, higher VBDP levels were associated with T1D (OR: (95% CI): 6.58 (1.45-29.9); p = 0.015), and within a linear regression analysis, T1D disease status was found to be associated with 0.044 mg/ml higher VDBP levels (p = 0.028).

CONCLUSIONS

These data suggest that serum VDBP levels are positively associated with the presence of T1D in the African population. Whether VDBP lies in the causal pathway or its elevation is an effect of T1D is uncertain and requires further investigation.

Urinary interleukin-9 in youth with type 1 diabetes mellitus

AIMS

Interleukin-9 (IL-9) attenuates podocyte injury in experimental kidney disease, but its role in diabetic nephropathy is unknown. We sought to relate urinary IL-9 levels to the release of podocyte-derived extracellular vesicles (EVs) in youth with type 1 diabetes. We related urinary IL-9 levels to clinical variables and studied interactions between urinary IL-9, vascular endothelial growth factor (VEGF), tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) on urinary albumin/creatinine ratio (ACR) a functional measure of podocyte injury.

METHODS

We performed an analysis of urine samples and clinical data from a cohort of youth with type 1 diabetes (n = 53). Cytokines were measured using a Luminex platform (Eve Technologies), and nanoscale flow cytometry was employed to quantify urinary podocyte-derived EVs. All urinary measures were normalized to urinary creatinine.

RESULTS

Mean age was 14.7 ± 1.6 years, and the mean time from diagnosis was 6.7 ± 2.9 years. Mean HbA1c was 70.3 ± 13.9 mmol/mol, mean ACR was 1.3 ± 1.9 mg/mmol, and mean eGFR was 140.3 ± 32.6 ml/min/1.73 m². IL-9 was inversely related to podocyte EVs (r = - 0.56, p = 0.003). IL-9 was also inversely related to blood glucose, HbA1C and eGFR (r = - 0.44, p = 0.002; r = - 0.41, p = 0.003; r = - 0.49, p < 0.001, respectively) and positively correlated with systolic BP (r = 0.30, p = 0.04). There was a significant interaction between IL-9, EVs and ACR (p = 0.0143), and the relationship between IL-9 and ACR depended on VEGF (p = 0.0083), TNFα (p = 0.0231) and IL-6 levels (p = 0.0178).

CONCLUSIONS

IL-9 is associated with podocyte injury in early type 1 diabetes, and there are complex interactions between urinary IL-9, inflammatory cytokines and ACR.

Expression-based Genome-wide Association Study Links OPN and IL1-RA With Newly Diagnosed Type 1 Diabetes in Children

CONTEXT

Islet autoantibodies (IAbs) are currently the most reliable indicators of islet autoimmunity. However, IAbs do not fully meet the need for the prediction and intervention of type 1 diabetes (T1D). Serological proteins should be great sources for biomarkers.

OBJECTIVE

This work aimed to identify new proteomic biomarkers with the technology of an expression-based genome-wide association study (eGWAS) in children newly diagnosed with T1D.

METHODS

In an attempt to identify additional biomarkers, we performed an eGWAS using microarray data from 169 arrays of the pancreatic islets of T1D rodents (78 T1D cases and 91 controls). We ranked all 16 099 protein-coding genes by the likelihood of differential expression in the pancreatic islets. Our top 20 secreted proteins were screened in 170 children including 100 newly diagnosed T1D, and 50 type 2 diabetes (T2D) and 20 age-matched healthy children. With 6 proteins showing significance, we further conducted a validation study using the second independent set of 400 samples from children including 200 newly diagnosed with T1D, 100 T2D, and 100 age-matched controls.

RESULTS

We identified 2 serum proteins that were significantly changed in T1D vs both control and T2D, and 5 serum proteins were significantly changed both in T1D and T2D vs control. Serum osteopontin (OPN) levels were uniquely higher in T1D (T1D vs controls, P = 1.29E-13 ~ 9.38E-7, T1D vs T2D, P = 2.65E-8 ~ 1.58E-7) with no difference between T2D and healthy control individuals. Serum interleukin 1 receptor antagonist (IL-1RA) levels were lower in T1D compared both with T2D (P = 3.36E-9~0.0236) and healthy participants (P = 1.09E-79 ~ 2.00E-12).

CONCLUSION

Our results suggest that OPN and IL1-RA could be candidates for useful biomarkers for T1D in children.

Clinical study of autoantibodies in type 1 diabetes mellitus children with ketoacidosis or microalbuminuria

Aims

The study aimed to investigate the value of autoantibodies in predicting the risk of ketoacidosis or microalbuminuria in children with type 1 diabetes mellitus.

Methods

Clinical data and laboratory indicators of 80 patients with type 1 diabetes admitted to the Department of Endocrinology in Tianjin Children's Hospital, from June 2017 to March 2019, were retrospectively analyzed. The patients were divided into two groups: diabetes without ketoacidosis group (n = 20) and diabetes with ketoacidosis group (n = 60). The differences in general data, laboratory test indexes, and autoantibodies between the two groups were analyzed. Finally, ROC curves and multivariate logistic regression analysis were used to explore the value of autoantibodies in patients with ketoacidosis or microalbuminuria.

Results

A total of 80 children with type 1 diabetes were assessed, including 35 boys and 45 girls, ranging in age from 10 months to 15 years. The concentration of GADA, IA2A, and ZnT8A was not statistically different between the two groups, but the positive rate of ZnT8A was statistically significant (p = 0.038) and had a diagnostic value for the occurrence of ketoacidosis (p = 0.025). ZnT8A‐positive patients had a higher titer of IA2A and a more frequent prevalence of GADA and IA2A than ZnT8A‐negative patients (p < 0.01). In multivariate logistic regression analyses, the presence of positive ZnT8A was associated with a higher risk of microalbuminuria independent of age, sex, and BMI (OR = 4.184 [95% CI 1.034~16.934], p = 0.045).

Conclusions

The positive ZnT8A had diagnostic value for ketoacidosis in children with type 1 diabetes and had the highest specificity among the three kinds of autoantibodies. Moreover, ZnT8A positivity was related to a higher titer of IA2A and more frequent occurrence of multiple diabetes‐related autoantibodies. Besides, the presence of positive ZnT8A was an independent risk factor of microalbuminuria in children with type 1 diabetes. Therefore, we can infer that positive ZnT8A may be related to ketoacidosis and microalbuminuria, accelerating the progression of T1DM.

T1DMicro: A Clinical Risk Calculator for Type 1 Diabetes Related Microvascular Complications

Development of complications in type 1 diabetes patients can be reduced by modifying risk factors. We used a cross-sectional cohort of 1646 patients diagnosed with type 1 diabetes (T1D) to develop a clinical risk score for diabetic peripheral neuropathy (DPN), autonomic neuropathy (AN), retinopathy (DR), and nephropathy (DN). Of these patients, 199 (12.1%) had DPN, 63 (3.8%) had AN, 244 (14.9%) had DR, and 88 (5.4%) had DN. We selected five variables to include in each of the four microvascular complications risk models: age, age of T1D diagnosis, duration of T1D, and average systolic blood pressure and HbA1C over the last three clinic visits. These variables were selected for their strong evidence of association with diabetic complications in the literature and because they are modifiable risk factors. We found the optimism-corrected R2 and Harrell’s C statistic were 0.39 and 0.87 for DPN, 0.24 and 0.86 for AN, 0.49 and 0.91 for DR, and 0.22 and 0.83 for DN, respectively. This tool was built to help inform patients of their current risk of microvascular complications and to motivate patients to control their HbA1c and systolic blood pressure in order to reduce their risk of these complications.

Intestinal Region-Specific and Layer-Dependent Induction of TNFα in Rats with Streptozotocin-Induced Diabetes and after Insulin Replacement

Tumour necrosis factor alpha (TNFα) is essential in neuroinflammatory modulation. Therefore, the goal of this study is to reveal the effects of chronic hyperglycaemia and insulin treatment on TNFα expression in different gut segments and intestinal wall layers. TNFα expression was mapped by fluorescent immunohistochemistry and quantitative immunogold electron microscopy in myenteric ganglia of duodenum, ileum and colon. Tissue TNFα levels were measured by enzyme-linked immunosorbent assays in muscle/myenteric plexus-containing (MUSCLE-MP) and mucosa/submucosa/submucous plexus-containing (MUC-SUBMUC-SP) homogenates. Increasing density of TNFα-labelling gold particles is observed in myenteric ganglia from proximal to distal segments and TNFα tissue levels are much more elevated in MUSCLE-MP homogenates than in MUC-SUBMUC-SP samples in healthy controls. In the diabetics, the number of TNFα gold labels is significantly increased in the duodenum, decreased in the colon and remained unchanged in the ileal ganglia, while insulin does not prevent these diabetes-related TNFα changes. TNFα tissue concentration is also increased in MUSCLE-MP homogenates of diabetic duodenum, while decreased in MUC-SUBMUC-SP samples of diabetic ileum and colon. These findings support that type 1 diabetes has region-specific and intestinal layer-dependent effects on TNFα expression, contributing to the regional damage of myenteric neurons and their intestinal milieu.

Dietary Regulation of Oxidative Stress in Chronic Metabolic Diseases

Oxidative stress is a status of imbalance between oxidants and antioxidants, resulting in molecular damage and interruption of redox signaling in an organism. Indeed, oxidative stress has been associated with many metabolic disorders due to unhealthy dietary patterns and may be alleviated by properly increasing the intake of antioxidants. Thus, it is quite important to adopt a healthy dietary mode to regulate oxidative stress and maintain cell and tissue homeostasis, preventing inflammation and chronic metabolic diseases. This review focuses on the links between dietary nutrients and health, summarizing the role of oxidative stress in ‘unhealthy’ metabolic pathway activities in individuals and how oxidative stress is further regulated by balanced diets.

Serum Levels of Inflammatory Proteins Are Associated With Peripheral Neuropathy in a Cross-Sectional Type-1 Diabetes Cohort

Chronic low-grade inflammation is involved in the pathogenesis of type-1 diabetes (T1D) and its complications. In this cross-section study design, we investigated association between serum levels of soluble cytokine receptors with presence of peripheral neuropathy in 694 type-1 diabetes patients. Sex, age, blood pressure, smoking, alcohol intake, HbA1c and lipid profile, presence of DPN (peripheral and autonomic), retinopathy and nephropathy was obtained from patient’s chart. Measurement of soluble cytokine receptors, markers of systemic and vascular inflammation was done using multiplex immunoassays. Serum levels were elevated in in DPN patients, independent of gender, age and duration of diabetes. Crude odds ratios were significantly associated with presence of DPN for 15/22 proteins. The Odds ratio (OR) remained unchanged for sTNFRI (1.72, p=0.00001), sTNFRII (1.45, p=0.0027), sIL2Rα (1.40, p=0.0023), IGFBP6 (1.51, p=0.0032) and CRP (1.47, p=0.0046) after adjusting for confounding variables, HbA1C, hypertension and dyslipidemia. Further we showed risk of DPN is associated with increase in serum levels of sTNFRI (OR=11.2, p<10), sIL2Rα (8.69, p<10^-15), sNTFRII (4.8, p<10^-8) and MMP2 (4.5, p<10^-5). We combined the serum concentration using ridge regression, into a composite score, which can stratify the DPN patients into low, medium and high-risk groups. Our results here show activation of inflammatory pathway in DPN patients, and could be a potential clinical tool to identify T1D patients for therapeutic intervention of anti-inflammatory therapies.

Plants as Sources of Anti-Inflammatory Agents

Plants represent the main source of molecules for the development of new drugs, which intensifies the interest of transnational industries in searching for substances obtained from plant sources, especially since the vast majority of species have not yet been studied chemically or biologically, particularly concerning anti-inflammatory action. Anti-inflammatory drugs can interfere in the pathophysiological process of inflammation, to minimize tissue damage and provide greater comfort to the patient. Therefore, it is important to note that due to the existence of a large number of species available for research, the successful development of new naturally occurring anti-inflammatory drugs depends mainly on a multidisciplinary effort to find new molecules. Although many review articles have been published in this regard, the majority presented the subject from a limited regional perspective. Thus, the current article presents highlights from the published literature on plants as sources of anti-inflammatory agents.

A cytokine super cyclone in COVID-19 patients with risk factors: the therapeutic potential of BCG immunization

The seventh human coronavirus SARS-CoV2 belongs to the cluster of extremely pathogenic coronaviruses including SARS-CoV and MERS-CoV, which can cause fatal lower respiratory tract infection. Likewise, SARS-CoV2 infection can be fatal as the disease advances to pneumonia, followed by acute respiratory distress syndrome (ARDS). The development of lethal clinical symptons is associated with an exaggerated production of inflammatory cytokines, referred to as the cytokine storm, is a consequence of a hyperactivated immune response aginst the infection. In this article, we discuss the pathogenic consequences of the cytokine storm and its relationship with COVID-19 associated risk factors. The increased pro-inflammatory immune status in patients with risk factors (diabetes, hypertension, cardiovascular disease, COPD) exacerbates the Cytokine-storm of COVID-19 into a 'Cytokine Super Cyclone'. We also evaluate the antiviral immune responses provided by BCG vaccination and the potential role of 'trained immunity' in early protection against SARS-CoV2.

Rupatadine, a dual antagonist of histamine and platelet-activating factor (PAF), attenuates experimentally induced diabetic nephropathy in rats

The role of histamine and platelet activating factor (PAF) as involved mediators in the pathophysiology of diabetic complications, in particular diabetic nephropathy (DN), has become a new focus of concern. Accordingly, the present study designed to explore the effect of rupatadine (RUP), a dual antagonist of histamine (H1) and PAF, on the progression of experimentally induced DN in rats. Rats were divided into five groups: control, RUP alone, streptozotocin (STZ)-diabetic model, STZ/RUP (3 mg/kg/day), and STZ/RUP (6 mg/kg/day). Treatment has continued for 4 weeks after diabetes confirmation. At the end of the study, serum was collected for measurement of glucose, insulin, urea, creatinine, histamine, and PAF. Renal tissue homogenates were prepared for measuring oxidative stress indices, tumor necrosis factor (TNF-α), cystatin C, and p21. Moreover, immunohistochemical expression of transforming growth factor-β1 (TGF-β1) and p53 along with histological pictures was also conducted. Antagonizing H1 and PAF receptors by RUP ameliorated the experimentally induced DN as evident by decreasing all serum parameters augmented by STZ together with improvement of the histopathological picture. RUP administration also improved oxidative-antioxidative agents with reduction in the anti-inflammatory marker, TNF-α. Additionally, the immunohistochemical expression of the fibrosis marker; TGF-β1, was also decreased. STZ-induced DN showed a p21/p53-dependent induction of premature senescence and RUP administration decreased the expression of p21 and p53 levels in injured renal tissue. RUP represents a novel promising drug to prevent DN complicated diabetes probably via its inhibitory effect on H1 and PAF receptors. The renal protection was also related to the anti-inflammatory and antioxidant roles and PAF-facilitated senescence effect via p21/p53 signaling.

Liraglutide treatment reduced interleukin-6 in adults with type 1 diabetes but did not improve established autonomic or polyneuropathy

AIMS

Type 1 diabetes can be complicated with neuropathy that involves immune-mediated and inflammatory pathways. Glucagon-like peptide-1 receptor agonists such as liraglutide, have shown anti-inflammatory properties, and thus we hypothesized that long-term treatment with liraglutide induced diminished inflammation and thus improved neuronal function.

METHODS

The study was a randomized, double-blinded, placebo-controlled trial of adults with type 1 diabetes and confirmed symmetrical polyneuropathy. They were randomly assigned (1:1) to receive either liraglutide or placebo. Titration was 6 weeks to 1.2-1.8 mg/d, continuing for 26 weeks. The primary endpoint was change in latency of early brain evoked potentials. Secondary endpoints were changes in proinflammatory cytokines, cortical evoked potential, autonomic function and peripheral neurophysiological testing.

RESULTS

Thirty-nine patients completed the study, of whom 19 received liraglutide. In comparison to placebo, liraglutide reduced interleukin-6 (-22.6%; 95% confidence interval [CI]: -38.1, -3.2; P = .025) with concomitant numerical reductions in other proinflammatory cytokines. However neuronal function was unaltered at the central, autonomic or peripheral level. Treatment was associated with -3.38 kg (95% CI: -5.29, -1.48; P < .001] weight loss and a decrease in urine albumin/creatinine ratio (-40.2%; 95% CI: -60.6, -9.5; P = .02).

CONCLUSION

Hitherto, diabetic neuropathy has no cure. Speculations can be raised whether mechanism targeted treatment, e.g. lowering the systemic level of proinflammatory cytokines may lead to prevention or treatment of the neuroinflammatory component in early stages of diabetic neuropathy. If ever successful, this would serve as an example of how fundamental mechanistic principles are translated into clinical practice similar to those applied in the cardiovascular and nephrological clinic.