The role of IL-18 in type 1 diabetic nephropathy: The problem and future treatment

Higher Renal Net Acid Excretion, but Not Higher Phosphate Excretion, during Childhood and Adolescence Associates with the Circulating Renal Tubular Injury Marker Interleukin-18 in Adulthood

High dietary phosphorus intake (P-In) and high acid loads may adversely affect kidney function. In animal models, excessive phosphorus intake causes renal injury, which, in humans, is also inducible by chronic metabolic acidosis. We thus examined whether habitually high P-In and endogenous acid production during childhood and adolescence may be early indicators of incipient renal inflammatory processes later in adulthood. P-In and acid-base status were longitudinally and exclusively determined by biomarker-based assessment in 277 healthy children, utilizing phosphate and net acid excretion (NAE) measurements in 24 h urine samples repeatedly collected between the ages of 3 and 17 years. Standard deviation scores (by sex and age) were calculated for anthropometric data and for the urinary biomarkers available within age range 3-17 years. Multivariable linear regression was used to analyze the relations of phosphate excretion and NAE with the adulthood outcome circulating interleukin-18 (IL-18), a marker of inflammation and kidney dysfunction. After adjusting for growth- and adulthood-related covariates and pro-inflammatory biomarkers to rule out confounding by non-renal inflammatory processes, regression models revealed a significant positive relationship of long-term NAE (p = 0.01), but not of long-term phosphate excretion with adult serum IL-18. Similar significant positive regression results were obtained after replacing NAE with 24 h urinary ammonium excretion as the exposition variable. Our results suggest that even moderate elevations in renal ammonia production, as caused by habitually higher acid loading during growth, may affect the intrarenal pro-inflammatory system in the long-term, known to be boosted by acidosis-induced raised ammoniagenesis.

Causal effects of systemic inflammatory regulators on chronic kidney diseases and renal function: a bidirectional Mendelian randomization study

Background

While targeted systemic inflammatory modulators show promise in preventing chronic kidney disease (CKD) progression, the causal link between specific inflammatory factors and CKD remains uncertain.

Methods

Using a genome-wide association study of 41 serum cytokines from 8,293 Finnish individuals, we conducted a bidirectional two-sample Mendelian randomization (MR) analysis. In addition, we genetically predicted causal associations between inflammatory factors and 5 phenotypes, including CKD, estimated glomerular filtration rate (eGFR), dialysis, rapid progression of CKD, and rapid decline in eGFR. Inverse variance weighting (IVW) served as the primary MR method, while MR-Egger, weighted median, and MR-pleiotropy residual sum and outlier (MR-PRESSO) were utilized for sensitivity analysis. Cochrane's Q test for heterogeneity. Leave-one-out method ensured stability of MR results, and Bonferroni correction assessed causal relationship strength.

Results

Seventeen cytokines were associated with diverse renal outcomes. Among them, after Bonferroni correction test, higher tumor necrosis factor alpha levels were associated with a rapid decrease in eGFR (OR = 1.064, 95% CI 1.028 - 1.103, P = 0.001), higher interleukin-4 levels were associated with an increase in eGFR (β = 0.003, 95% CI 0.001 - 0.005, P = 0.002), and higher growth regulated oncogene alpha (GROα) levels were associated with an increased risk of CKD (OR=1.035, 95% CI 1.012 - 1.058, P = 0.003). In contrast, genetic susceptibility to CKD was associated with an increase in GROa, and a decrease in eGFR may lead to an increase in stem cell factor. We did not find the presence of horizontal pleiotropy during the analysis.

Conclusion

We discovered causally related inflammatory factors that contribute to the initiation and progression of CKD at the genetic prediction level.

A natural products solution to diabetic nephropathy therapy

Diabetic nephropathy is one of the most common complications in diabetes. It has been shown to be the leading cause of end-stage renal disease. However, due to their complex pathological mechanisms, effective therapeutic drugs other than angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), which have been used for 20 years, have not been developed so far. Recent studies have shown that diabetic nephropathy is characterized by multiple signalling pathways and multiple targets, including inflammation, apoptosis, pyroptosis, autophagy, oxidative stress, endoplasmic reticulum stress and their interactions. It definitely exacerbates the difficulty of therapy, but at the same time it also brings out the chance for natural products treatment. In the most recent two decades, a large number of natural products have displayed their potential in preclinical studies and a few compounds are under invetigation in clinical trials. Hence, many compounds targeting these singals have been emerged as a comprehensive blueprint for treating strategy of diabetic nephropathy. This review focuses on the cellular and molecular mechanisms of natural prouducts that alleviate this condition, including preclinical studies and clinical trials, which will provide new insights into the treatment of diabetic nephropathy and suggest novel ideas for new drug development.

The dual therapeutic effect of metformin nuclei‐based drugs modified with one of Tulbaghia violacea extract compounds

Novel Schiff base was synthesized from the condensation reaction of metformin with [4‐(Diethylamino) benzaldehyde (NBM). Different metal complexes were prepared using Pd (II), Pt (II), Cu (II), and V (IV) metal ions. All complexes showed the nonelectrolytic behavior. So, the expected molecular formulas for complexes were [Pd (NBM)Cl2], [Pt (NBM)Cl2], [Cu (NBM)2Cl2] and [VO (NBM)2]. The cytotoxicity of (NBM) Schiff base and its metal complexes on human cancer cell line, MCF‐7, was investigated. V (IV) and Cu (II) complexes showed potential blood glucose lowering effect higher than the commercial metformin drug. VO (II) complex has superior antioxidant activity more than the other synthesized compounds and the standard ascorbic acid. Molecular docking investigation proved the presence of interesting interactions between all synthesized compounds with the active site amino acids of EGFR tyrosine kinase (anticancer activity). The molecular docking of metal complexes has observed effective inhibition for the specific mTOR protein that is expected to aid the growth of the COVID‐19 virus.

Weaning Failure in Critically Ill Patients Is Related to the Persistence of Sepsis Inflammation

Introduction: Septic patients undergoing mechanical ventilation (MV) often experience difficulty in weaning. Th aim of this study was to determine whether inflammatory biomarkers of sepsis could be indicative of the failure or success of spontaneous breathing trial (SBT) in these patients. Methods: Sixty-five patients on MV (42 septic and 23 intubated for other reasons) fulfilling the criteria for SBT were included in the study. Blood samples were collected right before, at the end of (30 min) and 24 h after the SBT. Serum inflammatory mediators associated with sepsis (IL-18, IL-18BP, TNF) were determined and correlated with the outcome of SBT. Results: A successful SBT was achieved in 45 patients (69.2%). Septic patients had a higher percentage of SBT failure as compared to non-septic patients (85% vs. 15%, p = 0.026), with an odds ratio for failing 4.5 times (OR = 4.5 95%CI: 1.16–17.68, p 0.022). IL-18 levels and the relative mRNA expression in serum were significantly higher in septic as compared to non-septic patients (p < 0.05). Sepsis was independently associated with higher serum IL-18 and TNF levels in two time-point GEE models (53–723, p = 0.023 and 0.3–64, p = 0.048, respectively). IL-18BP displayed independent negative association with rapid shallow breathing index (RSBI) (95% CI: −17.6 to −4, p = 0.002). Conclusion: Sustained increased levels of IL-18 and IL-18BP, acknowledged markers of sepsis, were found to be indicative of SBT failure in patients recovering from sepsis. Our results show that, although subclinical, remaining septic inflammation that sustaines for a long time complicates the weaning procedure. Biomarkers for the estimation of the septic burden and the right time for weaning are needed.

Nucleoporin 160 (NUP160) inhibition alleviates diabetic nephropathy by activating autophagy

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease worldwide. Autophagy was reported to be related to the pathogenesis of DN. This research investigated the function of the Nucleoporin 160 (Nup160) gene in regulating autophagy in DN. A mouse model of DN was established through an intraperitoneal injection of streptozotocin (STZ). Normal rat kidney tubular epithelial cells (NRK-52E) were treated with high glucose to induce DN in vitro. Real-time quantitative polymerase chain reaction (RT-qPCR), western blot, immunofluorescence assays were conducted to measure the expression of NUP160, autophagy-associated proteins, and inflammatory cytokines in vitro and in vivo. Pathological changes of kidney and liver tissues were analyzed using hematoxylin and eosin (H&E), Masson and periodic acid-silver (PAS) staining. The body weight, blood glucose, renal and lipid profiles of DN mice were examined. In this study, DN mice showed serious pathological injury. NUP160 expression was upregulated, autophagy was inhibited, and inflammatory response was increased in DN mice. Depletion of NUP160 restored autophagy and inhibited inflammation and fibrosis in high glucose (HG)-treated NRK-52E cells and STZ-induced DN mice by downregulating the expression of p62 and Collagen IV (Col-Ⅳ), increasing the ratio of LC3II/LC3I, and inactivating nuclear factor (NF)-κB signaling. Moreover, NUP160 knockdown could ameliorate pathological damage and glucose tolerance in DN mice. Overall, this study is the first to demonstrate the key role of NUP160 silencing in promoting autophagy against diabetic injury in DN.

CCL24 Protects Renal Function by Controlling Inflammation in Podocytes

Diabetic nephropathy (DN) is one of the most lethal complications of diabetes mellitus with chronic inflammation. We have examined the role of the inflammatory chemokine CCL24 in DN. We observed that serum levels of CCL24 were significantly elevated in patients with DN. Not only that, the expression of CCL24 was significantly increased in the kidneys of DN mice. The kidney of DN mice showed increased renal fibrosis and inflammation. We characterized an in vitro podocyte cell model with high glucose. Western blot analysis showed that expression of CCL24 was significantly increased under high-glucose conditions. Stimulation with high glucose (35 mmol/L) resulted in an increase in CCL24 expression in the first 48 hours but changed little after 72 hours. Moreover, with glucose stimulation, the level of podocyte fibrosis gradually increased, the expression of the proinflammatory cytokine IL-1β was upregulated, and the expression of the glucose transporter GLUT4, involved in the insulin signal regulation pathway, also increased. It is suggested that CCL24 is involved in the pathogenesis of DN. In order to study the specific role of CCL24 in this process, we used the CRISPR-Cas9 technique to knock out CCL24 expression in podocytes. Compared with the control group, the podocyte inflammatory response induced by high glucose after CCL24 knockout was significantly increased. These results suggest that CCL24 plays a role in the development of early DN by exerting an anti-inflammatory effect, at least, in podocytes.

Elevated urinary IL-36α and IL-18 levels are associated with diabetic nephropathy in patients with type 2 diabetes mellitus

BACKGROUND

Inflammatory cytokines have been reported to be pathogenic factors for the development and progression of diabetic nephropathy (DN). Interleukin (IL)-36α is a newly discovered member of the IL-1 cytokine family that has been implicated in animal models of renal impairment. However, little is known about the role of IL-36α in DN in humans. The purpose of the present study was to assess the levels of IL-36α and IL-18 in type 2 diabetic patients (T2DM) patients with and without DN.

METHODS

Subjects were divided into 3 groups: Control (N.=20), T2DM without DN (N.=30), and T2DM with DN (N.=30). Urinary IL-36α and IL-18 levels were assessed using ELISA. Correlation analysis was performed to determine the association of the IL levels with clinical markers of T2DM and DN.

RESULTS

IL-36α and IL-18 levels were significantly elevated in T2DM patients with DN, when compared to T2DM patients without DN (P<0.0001, P=0.0025, respectively) and controls (P<0.0001, for both). IL-36α levels showed a positive correlation with urinary albumin excretion (r=0.754, P<0.0001), HbA1c (r=0.433, P=0.0168), fasting plasma glucose (r=0.433, P=0.0168) and negative correlation with glomerular filtration rate (r=-0.852 P<0.0001).

CONCLUSIONS

The results highlighted the association of IL-36α with DN. However, further extensive studies are suggested for evaluating the association.

Role of Thioredoxin-Interacting Protein in Diseases and Its Therapeutic Outlook

Thioredoxin-interacting protein (TXNIP), widely known as thioredoxin-binding protein 2 (TBP2), is a major binding mediator in the thioredoxin (TXN) antioxidant system, which involves a reduction-oxidation (redox) signaling complex and is pivotal for the pathophysiology of some diseases. TXNIP increases reactive oxygen species production and oxidative stress and thereby contributes to apoptosis. Recent studies indicate an evolving role of TXNIP in the pathogenesis of complex diseases such as metabolic disorders, neurological disorders, and inflammatory illnesses. In addition, TXNIP has gained significant attention due to its wide range of functions in energy metabolism, insulin sensitivity, improved insulin secretion, and also in the regulation of glucose and tumor suppressor activities in various cancers. This review aims to highlight the roles of TXNIP in the field of diabetology, neurodegenerative diseases, and inflammation. TXNIP is found to be a promising novel therapeutic target in the current review, not only in the aforementioned diseases but also in prolonged microvascular and macrovascular diseases. Therefore, TXNIP inhibitors hold promise for preventing the growing incidence of complications in relevant diseases.

Review on Inflammation Markers in Chronic Kidney Disease

Chronic kidney disease (CKD) is one of the major health problems of the modern age. It represents an important public health challenge with an ever-lasting rising prevalence, which reached almost 700 million by the year 2017. Therefore, it is very important to identify patients at risk for CKD development and discover risk factors that cause the progression of the disease. Several studies have tackled this conundrum in recent years, novel markers have been identified, and new insights into the pathogenesis of CKD have been gained. This review summarizes the evidence on markers of inflammation and their role in the development and progression of CKD. It will focus primarily on cytokines, chemokines, and cell adhesion molecules. Nevertheless, further large, multicenter studies are needed to establish the role of these markers and confirm possible treatment options in everyday clinical practice.

Endoplasmic reticulum stress related factor IRE1α regulates TXNIP/NLRP3-mediated pyroptosis in diabetic nephropathy

The nod-like receptor protein-3 (NLRP3)-mediated pyroptosis is involved in kidney diseases. Thioredoxin interacting protein (TXNIP) directly interacts with NLRP3. This study aimed to probe the mechanism of TXNIP and NLRP3 pathway in diabetic nephropathy (DN). Marker detection and histological staining indicated that in DN rats, the renal function was destroyed, and the TXNIP/NLRP3 axis was activated to induce inflammatory generation and pyroptosis. The protein levels of TXNIP, NLRP3 inflammatory components and endoplasmic reticulum stress (ERS)-related factors (ATF4, CHOP and IRE1α) were measured. DN rats were injected with LV-TXNIP-shRNA or IRE1α RNase specific inhibitor (STF-083010) to examine ERS- and pyroptosis-related proteins, and renal injury. Silencing TXNIP inhibited the NLRP3 axis and reduced renal damage in DN rats. ERS was activated in DN rats, and miR-200a expression was degraded by IRE1α. miR-200a bound to TXNIP. NRK-52E cells were induced by high glucose (HG) to simulate DN in vitro. The damage and pyroptosis of NRK-52E cells were analyzed. After inhibiting IRE1α, miR-200a expression increased and TXNIP expression decreased. miR-200a inhibition in HG-induced NRK-52E cells partially reversed the reduced pyroptosis by STF-083010. Overall, IRE1α upregulates miR-200a degradation in DN rats, and stimulates the TXINP/NLRP3 pathway-mediated pyroptosis and renal damage.

Targeting NLRP3 inflammasome as a promising approach for treatment of diabetic nephropathy: Preclinical evidences with therapeutic approaches

Diabetes mellitus is an increasingly prevalent disease around the globe. The epidemic of diabetes mellitus and its complications pretenses the foremost health threat globally. Diabetic nephropathy is the notable complication in diabetes, leading to end-stage renal disease (ESRD) and premature death. Abundant experimental evidence indicates that oxidative stress and inflammation are the important mediators in diabetic kidney diseases and interlinked with various signal transduction molecular mechanisms. Inflammasomes are the critical components of innate immunity and are recognized as a critical mediator of inflammation and autoimmune disorders. NOD-like receptor protein 3 (NLRP3) inflammasome is the well-characterized protein and it exhibits the sterile inflammation through the regulation of pro-inflammatory cytokines interleukin (IL)-1β and IL-18 production in tissues. In recent years, the role of NLRP3 inflammasome in the pathophysiology of diabetic kidney diseases in both clinical and experimental studies has generated great interest. In the current review, we focused on and discussed the role of NLRP3 inflammasome in diabetic nephropathy. A literature review was performed using online databases namely, PubMed, Scopus, Google Scholar and Web of science to explore the possible pharmacological interventions that blunt the NLRP3 inflammasome-caspase-1-IL-1β/IL-18 axis and shown to have a beneficial effect in diabetic kidney diseases. This review describes the inhibition of NLRP3 inflammasome activation as a promising therapeutic target for drug discovery in future.

LncRNA SNHG17 knockdown promotes Parkin-dependent mitophagy and reduces apoptosis of podocytes through Mst1

LncRNAs play important roles in the regulation of podocyte apoptosis in diabetic nephropathy (DN). However, the role of lncRNA SNHG17 in controlling mitophagy-induced apoptosis of podocytes in DN is unknown. This study aims to elucidate the underlying mechanism of lncRNA SNHG17 in the regulation of mitophagy-induced apoptosis of podocytes in DN. LncRNA SNHG17 and Mammalian Sterile 20-like kinase 1 (Mst1) expression were upregulated in glomeruli and podocytes of DM mice and high glucose-treated podocytes, whereas Parkin expression was downregulated. LncRNA SNHG17 overexpression suppressed mitophagy and induced apoptosis of podocytes while silencing lncRNA SNHG17 promoted mitophagy and reduced the apoptosis of podocytes. In addition, lncRNA SNHG17 interacted with Mst1 and regulated the degradation of Mst1. We further found lncRNA SNHG17 regulated Parkin expression through Mst1. Mechanistically, lncRNA SNHG17 regulated Parkin-dependent mitophagy and apoptosis of podocytes through regulating Mst1. Finally, silencing lncRNA SNHG17 promoted mitophagy and relieved DNin vivo. In conclusion, lncRNA SNHG17 knockdown promotes Parkin-dependent mitophagy and reduces apoptosis of podocytes through regulating the degradation of Mst1.

Comparing the renoprotective effects of the antioxidants melatonin, vitamin D and vitamin E in diabetic rats

Objectives

Diabetes mellitus is associated with oxidative stress that leads to inflammation and diabetic nephropathy. This study aimed to determine the possible renoprotective effects of the antioxidants melatonin, vitamin D and vitamin E in diabetic rats.

Methods

We divided 108 albino rats into 12 groups. G1 group was fed a normal diet and did not receive any medication. G2 to G4 consisted of non-diabetic rats that were treated as follows: G2 with melatonin; G3 with vitamin E; G4 with vitamin D. Groups G5 to G12 consisted of diabetic rats that were treated as follows: G5 received no medication; G6 treated with insulin; G7 treated with melatonin; G8 treated with melatonin and insulin; G9 treated with vitamin E; G10 treated with vitamin E and insulin; G11 treated with vitamin D and G12 treated with vitamin D and insulin. Two months after treatment commenced, histological and biochemical examinations of glucose profile, oxidative stress status, renal function, homocysteine and TNF-α were performed.

Results

Total antioxidant capacity (TAC) increased significantly in groups G2, 7, 8, 10 and 11. TNF-α significantly increased in G2, but decreased in all other groups. Creatinine increased significantly in groups G5, 6, 7, 8, 9, 11 and 12. In the kidneys of the diabetic rats, thickened capillary basement membrane, diffuse mesangial sclerosis and nodular glomerulosclerosis was observed. Rats treated with melatonin showed marked improvement in these symptoms. However, in those treated with vitamin D and E, thickened capillary basement membrane and mesangial sclerosis was still present.

Conclusions

Melatonin, administered either with or without insulin had a significant biochemical antioxidant effect and histological renoprotective effect. Conversely, vitamin D and E did not appear to have any effects on the parameters measured.

Kidney Disease in Diabetes Mellitus: Cross-Linking between Hyperglycemia, Redox Imbalance and Inflammation

Chronic hyperglycemia is the key point of macro- and microvascular complications associated with diabetes mellitus. Excess glucose is responsible for inducing redox imbalance and both systemic and intrarenal inflammation, playing a critical role in the pathogenesis of diabetic kidney disease, which is currently the leading cause of dialysis in the world. The pathogenesis of the disease is complex, multifactorial and not fully elucidated; many factors and mechanisms are involved in the development, progression and clinical outcomes of the disease. Despite the disparate mechanisms involved in renal damage related to diabetes mellitus, the metabolic mechanisms involving oxidative/inflammatory pathways are widely accepted. The is clear evidence that a chronic hyperglycemic state triggers oxidative stress and inflammation mediated by altered metabolic pathways in a self-perpetuating cycle, promoting progression of cell injury and of end-stage renal disease. The present study presents an update on metabolic pathways that involve redox imbalance and inflammation induced by chronic exposure to hyperglycemia in the pathogenesis of diabetic kidney disease.

TnI and IL-18 levels are associated with prognosis of sepsis

AIM

To evaluate the diagnostic value of interleukin-18 (IL-18) and troponin (TnI) in sepsis.

METHODS

This retrospective analysis included 117 patients with sepsis (patient group) and 92 subjects who attended regular physical examinations (control group). We compared IL-18 and TnI expressions before treatment (T1) and on day 5 (T2), day 10 (T3) and day 15 (T4) of treatment. Acute Physiology and Chronic Health Evaluation II (APACHE II) guidelines were used to analyse the correlation between IL-18, TnI and APACHE II scores.

RESULTS

At T1, T2, T3 and T4, the IL-18 and TnI levels were all higher in the patient group than in the control group (p<0.001). In the patient group, peak IL-18 and TnI levels were noted at T1, followed by T2, T3 and T4 (p<0.001). The linear correlation analysis revealed positive correlations between IL-18 and TnI levels and APACHE II score (r =0.759, 0.866, p <0.001). The 3-year survival rates of subjects with high IL-18 or TnI expression levels were all lower than of those with low expression levels (p=0.047, 0.048). In patients with sepsis, the expression of TnI and IL-18 is high and is positively correlated with APACHE II scores.

CONCLUSIONS

Monitoring TnI and IL-18 levels can effectively evaluate the severity and recovery of patients with sepsis.

The effect of A1 adenosine receptor in diabetic megalin loss with caspase-1/IL18 signaling

PURPOSE

In our previous study, exacerbation of albuminuria was observed in A1 adenosine receptor knockout (A1AR^-/-) mice with diabetic nephropathy (DN), but the mechanism was unclear. Here, we investigated the relationship of megalin loss and albuminuria, to identify the protective effect of A1AR in megalin loss associated albuminuria by inhibiting pyroptosis-related caspase-1/IL-18 signaling of DN.

METHODS

We successfully collected DN patients' samples and built diabetes mice models induced by streptozotocin. Megalin, cubilin, and A1AR expression were detected in kidney tissue samples from DN patients and mice through immunohistochemical and immunofluorescent staining. A1AR, caspase-1, interleukin-18 (IL-18) expression were analyzed using Western blotting in wild-type and A1AR ^-/- mice. Human renal proximal tubular epithelial cells (PTC) were cultured with high glucose to observe the effect of A1AR agonist and antagonist on caspase-1/IL-18 and megalin injury.

RESULTS

The loss of megalin, co-localized with A1AR at PTC, was associated with the level of albuminuria in diabetic patients and mice. The injury of megalin-cubilin was accompanied with the A1AR upregulation (1.30±0.1 vs 0.98±0.2, P=0.042), the caspase-1 (1.33±0.1 vs 1.0±0.2, P=0.036), and IL-18 (1.26±0.2 vs 0.96±0.2, P=0.026) signaling activation in mice with DN. More severe pathological injury, 24 hrs urine albumin excretion (170.8±4.1 μg/d vs 132.0±2.9 μg/d vs 17.9±2.8 μg/d, P<0.001) and megalin-cubilin loss were observed in A1AR ^-/- DN mice with more pronounced caspase-1 (1.52±0.03 vs 1.20±0.01, P=0.017) and IL-18 (1.42±0.02 vs 1.21±0.02, P=0.018) secretion. High glucose could stimulate the secretion of caspase-1 (1.72 times, P≤0.01) and IL-18 (1.64 times, P≤0.01), which was abolished by A1AR agonist and aggravated by A1AR antagonist.

CONCLUSION

A1AR played a protective role in proximal tubular megalin loss associated albuminuria by inhibiting the pyroptosis-related caspase-1/IL-18 signaling in DN.

Assessing urinary levels of IL-18, NGAL and albumin creatinine ratio in patients with diabetic nephropathy

AIMS

Diabetic nephropathy (DN) is a serious microvascular complication of a longstanding hyperglycemia. This study aims to evaluate whether urinary neutrophil gelatinase-associated lipocalin (NGAL) and urinary Interleukin-18 possess a better diagnostic value than albumin creatinine ratio in assessing the severity of nephropathy in patients with type 2 diabetes mellitus (T2DM).

MATERIAL & METHODS

Ninety participants diagnosed with T2DM were recruited and they were divided into three study groups according to their albumin/creatinine ratio (ACR): (Normoalbuminuria group, Microalbuminuria group, and Macroalbuminuria group). A matching of Ninety healthy subjects were included as controls. Blood and urine samples were collected to measure various markers of glycemic control and kidney function.

RESULTS

IL-18 levels were not changed significantly between all study groups (P > 0.05), despite a significant positive correlation between IL-18 and urinary albumin levels. NGAL levels were significantly increased in Microalbuminuria group and Macroalbuminuria group as compared to the control and Normoalbuminuria groups. NGAL was also positively correlated with urinary albumin and ACR, but negatively correlated with the age and body mass index. Receiver Operating Characteristic curves revealed that for early detection of DN, the best cutoff values to discriminate DN and diabetic without nephropathy groups were ˃ 21.4 ng/ml for NGAL (94.67 sensitivity, 26.67% specificity), ≤0.34 pg/mL for IL-18 (72% sensitivity, 53.33% specificity), and ˃29.8 mg/g for ACR (80% sensitivity, 100% specificity).

CONCLUSION

We conclude that the urinary ACR is a more accurate individual biomarker of DN when compared to both NGAL and IL-18.

Interleukin-18 and diabetic nephropathy: A review

The inflammatory response has an important role in the pathophysiology of diabetic nephropathy that is contributed to by inflammatory mediators such as interleukin-1 (IL-1), IL-6, IL-18, tumor necrosis factor-α, and macrophage chemotactic protein-1; however, the role of IL-18 seems to be more specific than other cytokines in the inflammatory process. IL-18 is expressed in renal tissue and is upregulated by several stimuli including hyperglycemia. The expression/urinary level of IL-18 is positively correlated with the progression of diabetic nephropathy and the urinary albumin excretion rate. In this review, we have focused on the molecular pathways modulating the relationship between IL-18 and diabetic nephropathy.

Spleen tyrosine kinase promotes NLR family pyrin domain containing 3 inflammasome‑mediated IL‑1β secretion via c‑Jun N‑terminal kinase activation and cell apoptosis during diabetic nephropathy

Diabetic nephropathy (DN) is a serious complication of diabetes and can cause an increased mortality risk. It was previously reported that NLR family pyrin domain containing 3 (NLRP3) inflammasome is involved in the pathogenesis of diabetes. However, the underlying mechanism is not clearly understood. In the present study, the effects of spleen tyrosine kinase (Syk) and c-Jun N-terminal kinase (JNK) on the NLRP3 inflammasome were examined in vivo and in vitro. Sprague-Dawley rats were injected intraperitoneally with streptozotocin (65 mg/kg) to induce diabetes. HK2 cells and rat glomerular mesangial cells (RGMCs) were examined to detect the expression of JNK and NLRP3 inflammasome-associated proteins following treatment with a Syk inhibitor or Syk-small interfering (si)RNA in a high glucose condition. In the present study, it was revealed that the protein and mRNA expression levels of NLRP3 inflammasome-associated molecules and the downstream mature interleukin (IL)-1β were upregulated in vivo and in vitro. The Syk inhibitor and Syk-siRNA suppressed high glucose-induced JNK activation, and subsequently downregulated the activation of the NLRP3 inflammasome and mature IL-1β in HK2 cells and RGMCs. Furthermore, high glucose-induced apoptosis of HK2 cells was reduced by the Syk inhibitor BAY61-3606. Therefore, the present results determined that high glucose-induced activation of the NLRP3 inflammasome is mediated by Syk/JNK activation, which subsequently increased the protein expression level of IL-1β and mature IL-1β. The present study identified that the Syk/JNK/NLRP3 signaling pathway may serve a vital role in the pathogenesis of DN.

Inflammatory Mechanisms as New Biomarkers and Therapeutic Targets for Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the leading cause of CKD and end-stage kidney disease (ESKD) worldwide. Approximately 30-40% of people with diabetes develop this microvascular complication, placing them at high risk of losing kidney function as well as of cardiovascular events, infections, and death. Current therapies are ineffective for arresting kidney disease progression and mitigating risks of comorbidities and death among patients with DKD. As the global count of people with diabetes will soon exceed 400 million, the need for effective and safe treatment options for complications such as DKD becomes ever more urgent. Recently, the understanding of DKD pathogenesis has evolved to recognize inflammation as a major underlying mechanism of kidney damage. In turn, inflammatory mediators have emerged as potential biomarkers and therapeutic targets for DKD. Phase 2 clinical trials testing inhibitors of monocyte-chemotactic protein-1 chemokine C-C motif-ligand 2 and the Janus kinase/signal transducer and activator of transcription pathway, in particular, have produced promising results.

Effect of Cichorium intybus L. seed extract on renal parameters in experimentally induced early and late diabetes type 2 in rats

Blood and urine biochemistry screening tests are important for initial detection of diabetes, determination of severity of its complications, and monitoring of therapy. We evaluated the effects of aqueous chicory seed extract (CSE), on renal biochemical parameters, histology, and Na+/glucose cotansporters, SGLT1 and SGLT2 expression levels using metformin, and aspirin as controls. Late stage type 2 diabetes (LT2D; FBS, >300 mg/dl) and early stage type 2 diabetes (ET2D; FBS, 140-220 mg/dl) were induced in rats by streptozotocin (STZ group) and a combination of STZ and niacinamide (NIA/STZ group), respectively. A non-diabetic group was included as control. Treatment included daily intraperitoneal injections of either CSE (125 mg/kg b.w.) or metformin (100 mg/kg b.w.) and oral aspirin (120 mg/kg b.w.) for 21 days. At the end, blood and 24 h urine samples were collected; and kidneys were saved at -80 ˚C. CSE reduced urinary α1-microgobulin excretion in ET2D (p = .043), and serum uric acid (p = .045), and glomerular diameter (p < .01) in LT2D. Metformin appeared to be more effective in LT2D with respect to serum uric acid, urea, and BUN (< .05). Both CSE and metformin improved histology. Aspirin improved several blood and urine variables, but appeared to aggravate morphological damages to the kidney tissue. The absolute values of albumin, α1-microglobulin or total protein in urine rather than their creatinine ratios seemed more useful in the detection of early kidney damage; CSE was able to repair the kidney damage and α1-microglobulin was sensitive enough to allow monitoring of the improvements caused by the treatment.

Curcumin suppresses AGEs induced apoptosis in tubular epithelial cells via protective autophagy

Renal tubular cell apoptosis and tubular dysfunction is an important process underlying diabetic nephropathy (DN). Understanding the mechanisms underlying renal tubular epithelial cell survival is important for the prevention of kidney damage associated with glucotoxicity. Curcumin has been demonstrated to possess potent anti-apoptotic properties. However, the roles of curcumin in renal epithelial cells are yet to be defined. The present study investigated advanced glycation or glycoxidation end-product (AGE)-induced toxicity in renal tubular epithelial cells via several complementary assays, including cell viability, cell apoptosis and cell autophagy in the NRK-52E rat kidney tubular epithelial cell line. The extent of apoptosis was significantly increased in the NRK-52E cells following treatment with AGEs. The results also indicated that curcumin reversed this effect by promoting autophagy through the phosphoinositide 3-kinase/AKT serine/threonine kinase signaling pathway. These conclusions suggested that curcumin exerts a renoprotective effect in the presence of AGEs, at least in part by activating autophagy in NRK-52E cells. Collectively, these findings indicate that curcumin not only exerts renoprotective effects, however may also act as a novel therapeutic strategy for the treatment of diabetic nephropathy.

Renal and Vascular Effects of Uric Acid Lowering in Normouricemic Patients With Uncomplicated Type 1 Diabetes

Higher plasma uric acid (PUA) levels are associated with lower glomerular filtration rate (GFR) and higher blood pressure (BP) in patients with type 1 diabetes (T1D). Our aim was to determine the impact of PUA lowering on renal and vascular function in patients with uncomplicated T1D. T1D patients (n = 49) were studied under euglycemic and hyperglycemic conditions at baseline and after PUA lowering with febuxostat (FBX) for 8 weeks. Healthy control subjects were studied under normoglycemic conditions (n = 24). PUA, GFR (inulin), effective renal plasma flow (para-aminohippurate), BP, and hemodynamic responses to an infusion of angiotensin II (assessment of intrarenal renin-angiotensin-aldosterone system [RAAS]) were measured before and after FBX treatment. Arterial stiffness, flow-mediated dilation (FMD), nitroglycerin-mediated dilation (GMD), urinary nitric oxide (NO), and inflammatory markers were measured before and after FBX treatment. Gomez equations were used to estimate arteriolar afferent resistance, efferent resistance (R_E), and glomerular hydrostatic pressure (P_GLO). FBX had a modest systolic BP-lowering effect in T1D patients (112 ± 10 to 109 ± 9 mmHg, P = 0.049) without impacting arterial stiffness, FMD, GMD, or NO. FBX enhanced the filtration fraction response to hyperglycemia in T1D patients through larger increases in R_E, P_GLO, and interleukin-18 but without impacting the RAAS. FBX lowered systolic BP and modulated the renal R_E responses to hyperglycemia but without impacting the RAAS or NO levels, suggesting that PUA may augment other hemodynamic or inflammatory mechanisms that control the renal response to hyperglycemia at the efferent arteriole. Ongoing outcome trials will determine cardiorenal outcomes of PUA lowering in patients with T1D.

The association between interleukin-19 concentration and diabetic nephropathy

Background

Interleukin-19 (IL-19) is a newly discovered cytokine belonging to the Interleukin-10(IL-10) family. IL-19 have indispensable functions in many inflammatory processes and also can induce the angiogenic potential of endothelial cells. The purpose of present study was to investigate the relation of serum interleukin-19 (IL-19) levels with diabetic nephropathy (DN).

Methods

Two hundred study groups of patients with type 2 diabetes mellitus (T2DM) (109 males and 91 females) were recruited, included normoalbuminuria(n = 102), microalbuminuria(n = 72) and macroalbuminuria(n = 26) . The 50 healthy blood donors were enrolled for the control group. All subjects were assessed for: IL-19, High-sensitivity C-reactive protein (Hs-CRP), Cystatin C, urinary albumin excretion rate (UAE) and glycosylated hemoglobin A1c(HbA1c).

Results

The serum IL-19 levels in DN patients were found to be significantly higher compared to controls. IL-19 levels were significantly positively correlated with Hs-CRP, Cystatin C, UAE and HbA1c(r = 0.623, 0.611,0.591 and 0.526 respectively, P < 0.01). Multivariable logistic regression analysis showed IL-19 levels (P = 0.01) were found to be independently associated with patients with DN.

Conclusions

IL-19 is significantly positive correlated with UAE and Cystatin C. IL-19 may play an important role that contributes to the progression of diabetic nephropathy.

Association Between IL-18 and Carotid Intima-Media Thickness in Patients with Type II Diabetic Nephropathy

Background

We specifically designed this study to determine the relationship between levels of IL-8 and carotid intima-media thickness (cIMT) in patients with type 2 diabetes mellitus (T2DM).

Material/Methods

A total of 149 diabetic patients at different stages of diabetic nephropathy and 72 matched controls were recruited in this study. A wide range of parameters were measured: IL-18 (by ELISA), urinary albumin excretion rates (UAER), and carotid intima-media thickness (cIMT, by pulse wave velocity [PWV]). All the diabetic patients were treated by alprostadil.

Results

ELISA indicated that the level of IL-18 in the patient group was significantly higher compared with that in the control group. The level of IL-18 apparently increased in the higher cIMT group in T2DM patients. Serum IL-18 levels were positively correlated with cIMT in patients with T2DM, the level of IL-18 was negatively correlated with cIMT, and IL-18 levels were positively correlated to age. Moreover, IMT was positively correlated with hemoglobin A1C (HbA1C) and IL-18 levels were significantly associated with cIMT (all P<0.05).

Conclusions

IL-18 levels were positively correlated with atherosclerotic burden in patients with T2DM and it may be considered as a significant therapeutic target.

An update on diabetic kidney disease, oxidative stress and antioxidant agents

Diabetes mellitus is a metabolic disease that is defined by relative or absolute deficiency of insulin secretion. Diabetic kidney disease seems to be one of the most frequent complications of diabetes mellitus. Based on evidence, increased free-radical formation and/or diminished antioxidant defenses induce oxidative stress that is implicated in the pathogenesis of diabetic kidney disease. It is evident that diabetic state induces oxidative stress through different signaling pathways as well as reactive oxygen species (ROS) formation that attributes to the activation of various downstream signaling cascade leading to structural the way to structural and functional changes in kidney.

Curcumin Ameliorates Diabetic Nephropathy by Suppressing NLRP3 Inflammasome Signaling

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease, partly because of the lack of effective treatments for DN. Curcumin has been shown to exert strong antifibrotic effects in DN, but the underlying mechanisms are not well characterized. In this study, we sought to determine the effects of curcumin on diabetic renal disease in db/db mice and characterize the underlying mechanism of action. We administered curcumin to db/db mice for 16 weeks. In comparison to mock-treated db/db mice, curcumin-treated mice showed diminished renal hypertrophy, reduced mesangial matrix expansion, and a lower level of albuminuria. Furthermore, the upregulated protein and mRNA expressions of collagen IV and fibronectin in the renal cortices of the db/db mice were inhibited by curcumin treatment. Additionally, curcumin treatment was associated with significant reductions in mature interleukin-1β, cleaved caspase-1, and NLRP3 protein levels in the renal cortices of db/db mice as well as in HK-2 cells exposed to high glucose concentration. In summary, curcumin, a potent antifibrotic agent, is a promising treatment for DN, and its renoprotective effects appear to be mediated by the inhibition of NLRP3 inflammasome activity.

Hmox1 Deficiency Sensitizes Mice to Peroxynitrite Formation and Diabetic Glomerular Microvascular Injuries

OBJECTIVE

Indirect evidence suggests a role for heme oxygenase-1 (HO-1) in limiting diabetic vasculopathy. The goal of this study was to assess the role of HO-1 in the development of microvascular lesions within glomeruli during diabetes mellitus using a mouse model with specific alteration of the Hmox1 gene.

APPROACH AND RESULTS

The effects of Hmox1 haploinsufficiency were studied as a means of assessing the intrinsic contribution of HO-1 in the development of renal microvascular lesions during diabetes. Renal function and histology were analyzed 10 weeks after diabetes induction with streptozotocin. Diabetic Hmox1^+/- mice showed higher levels of albuminuria and blood urea compared to their wild-type diabetic littermates. More severe glomerular microvascular lesions were also observed in the diabetic Hmox1^+/- mice. This was associated with a renal increase in the expression of the oxidative stress marker, nitrotyrosine.

CONCLUSIONS

Genetic Hmox1 partial deficiency is sufficient to sensitize mice to the development of diabetic glomerular microvascular lesions. HO-1 exerts antioxidant effects in the kidney during diabetes mellitus. These have protective effects on the development of glomerular endothelial injury.