Interleukin-1beta and receptor antagonist (IL-1Ra) gene polymorphisms and the prediction of the risk of end-stage renal disease

Investigating the relationship between the VNTR variant of the interleukin-1 receptor antagonist gene and coronary in-stent restenosis

OBJECTIVE

This study aimed to examine the association between the interleukin-1 receptor antagonist gene (IL-1RN) and coronary in-stent restenosis (ISR) through the analysis of the VNTR variant based on the previously reported results.

MATERIALS AND METHODS

The samples were classified into two clearly defined groups: the case group, which comprised 45 patients diagnosed with in-stent restenosis (ISR+), and the control group, which included 60 patients without ISR (ISR-). Polymerase chain reaction (PCR) was performed to examine the 86-bp VNTR variant of the IL-1RN gene.

RESULTS

In the analysis of six identified groups consisting of variant alleles of 86 base pairs of VNTR of the IL-1RN gene statistically significant difference was observed for the presence of IL1RN*2 allele between cases and controls (p = 0.04, OR; 0.045).

CONCLUSION

Individuals with allele 2 of the IL-1Ra gene may be more predisposed to ISR. This could be due to an imbalance between IL-1Ra and IL-1β which is crucial in preventing the initiation or advancement of inflammatory diseases in specific organs. The observed phenomenon can be characterized by increased production of IL-1β and potential reduction of IL-1Ra as a result of functional VNTR variation in IL-RN gene.

Clopidogrel delays and can reverse diabetic nephropathy pathogenesis in type 2 diabetic db/db mice

BACKGROUND

Diabetic nephropathy (DN) is the principal cause of end-stage renal disease. Previous studies have shown that clopidogrel can prevent the early progression of renal injury.

AIM

To elucidate whether clopidogrel is beneficial against DN by using a db/db mouse model.

METHODS

db/db mice with a higher urinary albumin/creatinine ratio (ACR) relative to age- and sex-matched wild-type control mice were randomly allocated to clopidogrel and vehicle treatment groups. Clopidogrel was administered at doses of 5, 10, and 20 mg/kg by gavage for 12 wk. Body mass, blood glucose level, and urinary creatinine and albumin concentrations in each group were measured before and after the intervention. Renal fibrosis was evaluated using periodic acid-Schiff and Masson’s trichrome staining. The renal protein expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and F4/80 was assessed using immunohistochemistry. Urinary TNF-α, monocyte chemoattractant protein-1 (MCP-1), and IL-6 levels were analyzed using enzyme-linked immunosorbent assay; TNF-α and IL-1β mRNA expression was measured using real-time quantitative polymerase chain reaction. The protein expression of fibronectin (FN) and collagen I was assessed using immunohistochemistry.

RESULTS

Clopidogrel treatment did not affect the body mass or blood glucose level of the db/db mice; however, it increased bleeding time and reduced urinary ACR in a dose-dependent manner. Immunohistochemical staining revealed an amelioration of renal fibrosis, significantly lower deposition of FN and collagen I, and significantly lower expression of the proinflammatory cytokines TNF-α and IL-1β and lower levels of urinary TNF-α and MCP-1 in the clopidogrel-treated db/db mice (P < 0.05). Furthermore, clopidogrel significantly reduced macrophage infiltration into the glomeruli of the db/db mice.

CONCLUSION

Clopidogrel significantly reduced renal collagen deposition and fibrosis and prevented renal dysfunction in db/db mice, most likely through inhibition of renal macrophage infiltration and the associated inflammation.

Genetics Insight for COVID-19 Susceptibility and Severity: A Review

Coronavirus disease (COVID-19) presents a broad spectrum of clinical manifestations ranging from an asymptomatic to a severe clinical course. The host genetic background influence on the susceptibility and outcome of multiples infectious diseases has been previously reported. Herein, we aimed to describe relevant identified genetic variants and those potentially related to the inter-individual variability of COVID-19 susceptibility and/or severity considering the physiopathological pathway of the disease The HLA-A*25:01, -B*15:27, -B*46:01, -C*01:02, and -C*07:29 alleles have been associated with COVID-19 susceptibility; while HLA-A*02:02, -B*15:03, and -C*12:03 have been identified as low-risk alleles. Variants in cytokine genes such as IL1B, IL1R1, IL1RN, IL6, IL17A, FCGR2A, and TNF could be related to disease susceptibility and cytokine storm, and/or COVID-19 complications (e.g., venous thrombosis). Several variants in ACE2 and TMPRSS2 affecting the expression of the receptors related to COVID-19 have been associated with the disease susceptibility and risk factors. Finally, two GWAS have identified the loci 3p21.31 (LZTFL1, SLC6A20, CCR9, FYCO1, CXCR6, and XCR1) and 9q34.2 (ABO) with COVID-19 severity. Heterogeneous results in the association of genetic variants with COVID-19 susceptibility and severity were observed. The mechanism of identified risk-genes and studies in different populations are still warranted.

Interleukin-1β Gene (IL1B) Polymorphism and Risk of Developing Diabetic Nephropathy

Objective: Cytokines play an important role in the pathogenesis of type 2 diabetes (T2DM) and its complications. The aim of the study was to evaluate an association of the -511 (C/T) polymorphism in the IL1B gene with diabetic nephropathy (DN). Methods: The study population included 860 patients with T2DM (506 with diabetic nephropathy and 354 without nephropathy) as well as 505 healthy individuals. Genomic DNA was genotyped for the IL1B -511 (C/T) polymorphism using PCR-RFLP technique. Results: The IL1B -511 C/T polymorphism was genotyped in 860 T2DM patients with or without DN and 505 healthy individuals. The average age of patients was 65.3 years in DN+ and 62.2 years in DN- subgroups. The genotype distribution did not differ significantly between patients and controls. Only a tendency to a slight increase of T allele frequency was observed in patient group. Genotype and allele frequencies of -511 C/T polymorphism were compared in patients with DN and those without it. The minor allele (T) and homozygote TT frequencies were significantly different between subgroups. The T allele was more frequent in DN+ patients, with odds ratio 1.45 (95% CI 1.2-1.8), p = 0.0003. The TT genotype frequency was also higher in DN+, with OR 1.76 (96% CI 1.1-2.7), p = 0.01. Conclusion: In a studied population the -511 C/T polymorphism in the IL1B gene is associated with diabetic nephropathy in dialyzed T2DM patients. Further studies are required to confirm the clinical significance of this finding.

The IL-1Ra gene variable number tandem repeat variant is associated with susceptibility to temporomandibular disorders in Turkish population

BACKGROUND

Temporomandibular joint disorders (TMD) are a group of disorders involving temporomandibular joint and related structures. Interleukine-1 receptor antagonist (IL-1Ra) is an important anti-inflammatory molecule that competes with other interleukin-1 molecules. This study was designed to investigate the possible association of the IL-1Ra VNTR variant with the risk of TMD in the Turkish population.

METHODS

Peripheral blood samples were collected from 100 patients with TMD (23 males, 77 females) and 110 healthy individuals (35 males, 75 females). Genotyping of IL-1Ra 86 bp VNTR variant was evaluated by gel electrophoresis after polymerase chain reaction (PCR).

RESULTS

Our results show that there is a statistically significant difference between TMD patients and control group with respect to IL-1Ra genotype distribution and allele frequencies. 1.2, 1.4, and 4.4 genotypes were more common in patients, while 2.2 and 3.3 genotypes were rarer (P<.000). Frequency of alleles 1 and 4 was higher in patient groups (P<.000), whereas alleles 2 and 3 had a lower frequency in patients with TMD (P<.000).

CONCLUSIONS

This is the first correlation study that evaluates the association between IL-1Ra gene VNTR variant and TMD. The VNTR variant related to IL-1Ra gene showed a strong pattern of association with TMD that may have a potential impact on disease counseling and management. Larger studies with various ethnicities are needed to establish the impact of IL-1Ra VNTR variant on risk of developing TMD.

Of Inflammasomes and Alarmins: IL-1β and IL-1α in Kidney Disease

Kidney injury implies danger signaling and a response by the immune system. The inflammasome is a central danger recognition platform that triggers local and systemic inflammation. In immune cells, inflammasome activation causes the release of mature IL-1β and of the alarmin IL-1α Dying cells release IL-1α also, independently of the inflammasome. Both IL-1α and IL-1β ligate the same IL-1 receptor (IL-1R) that is present on nearly all cells inside and outside the kidney, further amplifying cytokine and chemokine release. Thus, the inflammasome-IL-1α/IL-β-IL-1R system is a central element of kidney inflammation and the systemic consequences. Seminal discoveries of recent years have expanded this central paradigm of inflammation. This review gives an overview of arising concepts of inflammasome and IL-1α/β regulation in renal cells and in experimental kidney disease models. There is a pipeline of compounds that can interfere with the inflammasome-IL-1α/IL-β-IL-1R system, ranging from recently described small molecule inhibitors of NLRP3, a component of the inflammasome complex, to regulatory agency-approved IL-1-neutralizing biologic drugs. Based on strong theoretic and experimental rationale, the potential therapeutic benefits of using such compounds to block the inflammasome-IL-1α/IL-β-IL-1R system in kidney disease should be further explored.

Cytokine (IL-10 -1082 and -819) and chemokine receptor (CCR2 and CCR5) gene polymorphism in North Indian patients with end-stage renal disease

End-stage renal disease (ESRD) is associated with the inflammatory state characterized by infiltrating macrophages/lymphocytes, a major source of cytokines and chemokines. This study examined the role of genetic polymorphisms in cytokine, IL-10, and chemokine receptors, CCR2 and CCR5, with susceptibility to ESRD. Polymorphisms in IL-10 (-1082 G/A, PCR-RFLP; -819 C/T, ARMS-PCR), CCR2 (Val/Ile, PCR-RFLP), and CCR5Delta32 were detected in 184 ESRD patients and 180 controls. Our results demonstrated a significant difference in genotype frequencies of IL-10 -1082G/A (p<0.001), IL-10 -819C/T (p=0.007), and CCR2Val/Ile (p=0.033) between ESRD patients and controls. However, only low-producing genotype AA of IL-10 -1082G/A showed significantly threefold higher risk for all ESRD patients (odds ratio [OR]=3.164, 95%CI=1.74-5.72) as well as patients with only inflammatory causes of renal diseases (OR=2.979, 95%CI=1.61-5.52). No risk was seen in variant genotype of other genes. The genotypic frequencies of CCR5Delta32 were comparable in patients and controls (p=0.203). In haplotype analysis, A-T haplotype (low producer) of IL-10 showed 1.7-fold risk (p>0.05). No risk was seen for CCR2 and CCR5 haplotypes. The AA genotype of IL-10 -1082G/A polymorphism was associated with increased susceptibility to ESRD. This study implies the basis for defined antiinflammatory approaches to impede renal disease progression.

Effect of cytokine and pharmacogenomic genetic polymorphisms in transplantation

Consolidating the information that we have on pharmacogenetics and on cytokine genetics to produce patient-oriented individualized drug regimens is an important challenge in transplantation medicine. Using a multi-variant approach based on genetic profile and other relevant clinical factors a score system may be developed to predict the severity of rejection, infection, or other complications associated with transplantation. The ultimate goal of these studies is to improve patient outcome through individualized drug regimens.

The prevalence and incidence of end-stage renal disease in Native American adults on the Navajo reservation

Whereas members of the Navajo Nation are at high risk for diabetes mellitus, there are no recent published estimates of the burden of end-stage renal disease (ESRD), an important sequela of diabetes, on the Navajo Nation, a 16 million acre area in Arizona, New Mexico, and Utah with more than 200 000 tribal members. We used data from the US Renal Data System to estimate the prevalence and incidence of ESRD among Native American adults (>/=18 years) living on the Navajo Nation. For comparison, we estimated the prevalence and incidence of ESRD among all adults in the US, all Native American adults in the US, and Native American adults living in Arizona, New Mexico, Utah, and Colorado excluding those living on the Navajo Nation. The age-adjusted prevalence of ESRD in the Native American adults on the Navajo Nation was 0.63%, which was higher than in the US adults (0.19%, P<0.0001) and among the Native American adults in the US (0.36%, P<0.0001), but lower than among the other Native American adults in the Southwest (0.89%, P<0.0001). The age-adjusted incidence of ESRD in the Native American adults on the Navajo Nation was 0.11%, which was also higher than in the US adults (0.045%, P<0.0001) and among the Native American adults in the US (0.073%, P<0.0009), but lower than among the other Native American adults in the Southwest (0.17%, P<0.0003). The reasons behind these disparities merit further study.

Effect of MDR1 gene polymorphism on progression of end-stage renal disease

AIM

P-glycoprotein is localized at the apical brush-border membrane of the proximal renal tubule and functions as extruding toxins and xenobiotics out of cells. The difference of P-glycoproteinos function resulted from single nucleotide polymorphisms in MDR1 (multidrug resistance gene encoding for P-gp) and may be the cause of interindividual differences in susceptibility to end-stage renal disease (ESRD). The purpose of this study is to compare the genotype frequency of C3435T and G1199A polymorphisms in MDR1 between ESRD patients and healthy controls in the Chinese population to determine whether the alteration of the P-gp function is associated with ESRD.

METHODS

Two hundred and eighty-four healthy Chinese controls and 244 Chinese patients with ESRD were involved in this study. Allele specific PCR and polymerase chain reaction-restriction fragment length polymorphism assay were used to determine the genotype MDR1 G1199A and C3435T, respectively.

RESULTS

The genotype distribution of 3435CC, 3435CT, and 3435TT were 0.35, 0.50, and 0.15, respectively, in the control group and 0.38, 0.47, and 0.15 in the group with the ESRD patients. No variant allele 1199G>A was found in any of the patients. The value of serum creatinine for genotypes 3435CC, 3435CT, and 3435TT in the ESRD patients were 753.8+/-276.0 mumol/L, 849.6+/-342.2 micromol/L, and 987.0+/-512.0 micromol/L, respectively. The difference between 3435TT and 3435CC reached statistical significance (P<0.05).

CONCLUSION

The low expression of P-glycoprotein was not the etiological factor for the kidney disease, but it may contribute to the progression of ESRD and affect the severity. Chinese people do not carry the 1199G>A variant allele. More studies are needed to clarify the cause and interindividual differences in the susceptibility for the risk of ESRD.

Association study of IL10, IL1beta, and IL1RN and schizophrenia using tag SNPs from a comprehensive database: suggestive association with rs16944 at IL1beta

Genetic association studies of several candidate cytokine genes have been motivated by evidence of immune dysfunction among patients with schizophrenia. Intriguing but inconsistent associations have been reported with polymorphisms of three positional candidate genes, namely IL1beta, IL1RN, and IL10. We used comprehensive sequencing data from the Seattle SNPs database to select tag SNPs that represent all common polymorphisms in the Caucasian population at these loci. Associations with 28 tag SNPs were evaluated in 478 cases and 501 unscreened control individuals, while accounting for population sub-structure using the genomic control method. The samples were also stratified by gender, diagnostic category, and exposure to infectious agents. Significant association was not detected after correcting for multiple comparisons. However, meta-analysis of our data combined with previously published association studies of rs16944 (IL1beta -511) suggests that the C allele confers modest risk for schizophrenia among individuals reporting Caucasian ancestry, but not Asians (Caucasians, n=819 cases, 1292 controls; p=0.0013, OR=1.24, 95% CI 1.09, 1.41).