Genetic damage in patients with chronic kidney disease, peritoneal dialysis and haemodialysis: a comparative study

Baseline and oxidatively damaged DNA in end-stage renal disease patients on varied hemodialysis regimens: a comet assay assessment

Global estimates exhibit that one million people have end-stage renal disease, a disease-state characterized by irreversible loss of kidney structure and function, thus necessitating renal replacement therapy. The disease-state, oxidative stress, inflammatory responses, as well as the treatment procedure can have damaging effects on the genetic material. Therefore, the present study was carried out to investigate DNA damage (basal and oxidative) using the comet assay in peripheral blood leukocytes of patients (n = 200) with stage V Chronic Kidney Disease (on dialysis and those recommended but yet to initiate dialysis) and compare it to that in controls (n = 210). Basal DNA damage was significantly elevated (1.13x, p ≤ 0.001) in patients (46.23 ± 0.58% DNA in tail) compared to controls (40.85 ± 0.61% DNA in tail). Oxidative DNA damage was also significantly (p ≤ 0.001) higher in patients (9.18 ± 0.49 vs. 2.59 ± 0.19% tail DNA) compared to controls. Twice-a-week dialysis regimen patients had significantly elevated % tail DNA and Damage Index compared to the non-dialyzed and to the once-a-week dialysis group implying dialysis- induced mechanical stress and blood-dialyzer membrane interactions as probable contributors to elevated DNA damage. The present study with a statistically significant power implies higher disease-associated as well as maintenance therapy (hemodialysis)-induced basal and oxidatively damaged DNA, which if not repaired has the potential to initiate carcinogenesis. These findings mark the need for improvement and development of interventional therapies for delaying disease progression and associated co-morbidities so as to improve life expectancy of patients with kidney disease.

Chapter 4: CKD treatment in cancer survivors, from Clinical Practice Guidelines for the Management of Kidney Injury During Anticancer Drug Therapy 2022

Chronic kidney disease (CKD) is one of the most disabling disorders with significant comorbidity and mortality. Incidence and prevalence of CKD in cancer survivors are remarkably high in both adults and pediatric patients. The reasons for this high incidence/prevalence are multifold but kidney damage by cancer itself and cancer treatment (pharmacotherapy/surgery/radiation) are the main reasons. Since cancer survivors commonly have significant comorbidities, risk of cancer recurrence, limited physical function or life expectancy, special attentions should be paid when considering the treatment of CKD and its complications. Especially, shared decision-making should be considered when selecting the renal replacement therapies with as much information/facts/evidence as possible.

Investigation of XPD, miR-145 and miR-770 expression in patients with end-stage renal disease

BACKGROUND

The effective maintenance of genome integrity and fidelity is vital for the normal function of our tissues and organs, and the prevention of diseases. DNA repair pathways maintain genome stability, and the adequacy of genes acting in these pathways is essential for disease suppression and direct treatment responses. Chronic kidney disease is characterized by high levels of genomic damage. In this study, we examined the expression levels of the xeroderma pigmentosum group D (XPD) gene, which plays a role in the nucleotide excision repair (NER) repair mechanism, and the expression levels of miR-145 and miR-770 genes, which play a role in the regulation of the expression of the XPD gene, in hemodialysis patients with (n = 42) and without malignancy (n = 9) in pre- and post-dialysis conditions. We also evaluated these values with the clinical findings of the patients.

METHODS & RESULTS

Gene expression analysis was performed by real-time polymerase chain reaction (qRT-PCR). Compared to the individuals with normal kidney function (2.06 ± 0.32), the XPD gene expression was lower in the pre-dialysis condition both in hemodialysis patients without cancer (1.24 ± 0.18; p = 0.02) and in hemodialysis patients with cancer (0.82 ± 0.114; p = 0.001). On the other hand, we found that miR-145 and miR-770 expression levels were high in both groups. We also found that expression levels were affected by dialysis processes. A statistically significant positive correlation was found between miR-145 and mir770 expression levels in the pre-dialysis group of patients with (r=-0.988. p = 0.0001) and without (r=-0.934. p = 0.0001) malignancy.

CONCLUSIONS

Studies on DNA damage repair in the kidney will help develop strategies to protect kidney function against kidney diseases.

Evaluation of Cytogenetic Alterations in Patients of Chronic Kidney Disease

Introduction

In recent years, there has been a rise in chronic kidney disease (CKD), and it has been estimated that by 2040, CKD will be the fifth most common cause of death globally. In addition to diabetes, hypertension, obesity, hyperlipidemia, and nonalcoholic fatty liver disease commonly associated with CKD, exposure to various toxins as a result of pollution or industrial disasters is also discussed as a cause for multi-organ pathology including kidneys. Although few cytogenetic studies were undertaken to assess the genetic damage in survivors of the disaster, no studies are available on the cytogenetic damage of toxic-gas exposed population having CKD. Therefore, the present multi-group cross-sectional study was undertaken to assess the independent role of CKD as well as toxic gas exposure on cytogenetics.

Methods

The cytogenetic alterations were evaluated through chromosomal aberration analysis and micronuclei assay. The study included 608 study participants divided into four groups on the basis of history of exposure to the leaked gas and presence or absence of CKD.

Results

The results of the study showed no statistically significant difference in cytogenetic damage between gas-exposed and non-exposed patients of CKD, whereas significantly higher cytogenetic damage was observed among gas-exposed participants having CKD compared to gas-exposed participants free from CKD, suggesting that cytogenetic changes could be due to CKD itself.

Conclusions

Thus, to conclude, the cytogenetic alterations observed in the study can be partly attributed to the disease itself.

Mitochondrial ROS Triggers KIN Pathogenesis in FAN1-Deficient Kidneys

Karyomegalic interstitial nephritis (KIN) is a genetic adult-onset chronic kidney disease (CKD) characterized by genomic instability and mitotic abnormalities in the tubular epithelial cells. KIN is caused by recessive mutations in the FAN1 DNA repair enzyme. However, the endogenous source of DNA damage in FAN1/KIN kidneys has not been identified. Here we show, using FAN1-deficient human renal tubular epithelial cells (hRTECs) and FAN1-null mice as a model of KIN, that FAN1 kidney pathophysiology is triggered by hypersensitivity to endogenous reactive oxygen species (ROS), which cause chronic oxidative and double-strand DNA damage in the kidney tubular epithelial cells, accompanied by an intrinsic failure to repair DNA damage. Furthermore, persistent oxidative stress in FAN1-deficient RTECs and FAN1 kidneys caused mitochondrial deficiencies in oxidative phosphorylation and fatty acid oxidation. The administration of subclinical, low-dose cisplatin increased oxidative stress and aggravated mitochondrial dysfunction in FAN1-deficient kidneys, thereby exacerbating KIN pathophysiology. In contrast, treatment of FAN1 mice with a mitochondria-targeted ROS scavenger, JP4-039, attenuated oxidative stress and accumulation of DNA damage, mitigated tubular injury, and preserved kidney function in cisplatin-treated FAN1-null mice, demonstrating that endogenous oxygen stress is an important source of DNA damage in FAN1-deficient kidneys and a driver of KIN pathogenesis. Our findings indicate that therapeutic modulation of kidney oxidative stress may be a promising avenue to mitigate FAN1/KIN kidney pathophysiology and disease progression in patients.

Roles of DNA damage in renal tubular epithelial cells injury

The prevalence of renal diseases including acute kidney injury (AKI) and chronic kidney disease (CKD) is increasing worldwide. However, the pathogenesis of most renal diseases is still unclear and effective treatments are still lacking. DNA damage and the related DNA damage response (DDR) have been confirmed as common pathogenesis of acute kidney injury and chronic kidney disease. Reactive oxygen species (ROS) induced DNA damage is one of the most common types of DNA damage involved in the pathogenesis of acute kidney injury and chronic kidney disease. In recent years, several developments have been made in the field of DNA damage. Herein, we review the roles and developments of DNA damage and DNA damage response in renal tubular epithelial cell injury in acute kidney injury and chronic kidney disease. In this review, we conclude that focusing on DNA damage and DNA damage response may provide valuable diagnostic biomarkers and treatment strategies for renal diseases including acute kidney injury and chronic kidney disease.

Effect of oral intake of royal jelly on endothelium function in hemodialysis patients: study protocol for multicenter, double-blind, randomized control trial

Background

Hemodialysis (HD) is a common renal replacement therapy for patients with renal failure. Cardiovascular and cerebrovascular diseases are known to shorten survival periods and worsen the quality of life of HD patients. Atherosclerosis is a major cause of vascular diseases, and various factors such as abnormality of lipid metabolism and increased macrophage activity, oxidative stress, and endothelial dysfunction are associated with its pathogenesis and progression. Further, endothelial stem cells (ESCs) have been reported to play important roles in endothelial functions. Royal jelly (RJ) affects atherosclerosis- and endothelial function-related factors. The main aim of this trial is to investigate whether oral intake of RJ can maintain endothelial function in HD patients. In addition, the effects of RJ intake on atherosclerosis, ESC count, inflammation, and oxidative stress will be analyzed.

Methods

This will be a multicenter, prospective, double-blind, randomized controlled trial. We will enroll 270 participants at Nagasaki Jin Hospital, Shinzato Clinic Urakami, and Maeda Clinic, Japan. The participants will be randomized into RJ and placebo groups. The trial will be conducted according to the principles of the Declaration of Helsinki, and all participants will be required to provide written informed consent. The RJ group will be treated with 3600 mg/day of RJ for 24 months, and the placebo group will be treated with starch for 24 months. The primary endpoint will be the change in flow-mediated dilation (FMD), a parameter of endothelium function, from the time before treatment initiation to 24 months after treatment initiation. The secondary and other endpoints will be changes in FMD; ESC count; serum levels of vascular endothelial cell growth factor, macrophage colony-stimulating factor, 8-hydroxydeoxyguanosine, and malondialdehyde; the incidence of cardiovascular diseases, cerebrovascular diseases, and stenosis of blood access; and safety.

Discussion

This trial will clarify whether oral intake of RJ can maintain endothelial function and suppress the progression of atherosclerosis in HD patients. In addition, it will clarify the effects of RJ on ESCs, oxidative stress, and angiogenic activity in blood samples.

Trial registration

The Japan Registry of Clinical Trials jRCTs071200031.  Registered on 7 December 2020.

Oxidative Stress in Non-Dialysis-Dependent Chronic Kidney Disease Patients

Background: Cardiovascular complications are the leading cause of morbidity and mortality at any stage of chronic kidney disease (CKD). Moreover, the high rate of cardiovascular mortality observed in these patients is associated with an accelerated atherosclerosis process that likely starts at the early stages of CKD. Thus, traditional and non-traditional or uremic-related factors represent a link between CKD and cardiovascular risk. Among non-conventional risk factors, particular focus has been placed on anaemia, mineral and bone disorders, inflammation, malnutrition and oxidative stress and, in this regard, connections have been reported between oxidative stress and cardiovascular disease in dialysis patients. Methods: We evaluated the oxidation process in different molecular lines (proteins, lipids and genetic material) in 155 non-dialysis patients at different stages of CKD and 45 healthy controls. To assess oxidative stress status, we analyzed oxidized glutathione (GSSG), reduced glutathione (GSH) and the oxidized/reduced glutathione ratio (GSSG/GSH) and other oxidation indicators, including malondialdehyde (MDA) and 8-oxo-2’-deoxyguanosine (8-oxo-dG). Results: An active grade of oxidative stress was found from the early stages of CKD onwards, which affected all of the molecular lines studied. We observed a heightened oxidative state (indicated by a higher level of oxidized molecules together with decreased levels of antioxidant molecules) as kidney function declined. Furthermore, oxidative stress-related alterations were significantly greater in CKD patients than in the control group. Conclusions: CKD patients exhibit significantly higher oxidative stress than healthy individuals, and these alterations intensify as eGFR declines, showing significant differences between CKD stages. Thus, future research is warranted to provide clearer results in this area.

Lipid peroxidation as measured by chromatographic determination of malondialdehyde. Human plasma reference values in health and disease

Free radicals and oxidants are involved in physiological signaling pathways, although an imbalance between pro-oxidant and anti-oxidant systems in favor of the former leads to major biomolecular damage. This is the so-called oxidative stress, a complex process that affects us all and is responsible for the development of many diseases. Lipids are very sensitive to oxidant attack and to-date, malondialdehyde (MDA), 4-hydroxy-2-nonenal (4-HNE) and F2-isoprostane are the main biomarkers for lipid peroxidation assessment. They all derive from polyunsaturated fatty acids (PUFAs) either by enzyme-catalyzed reactions (physiological) or by non-enzyme reactions (pathological). The profile of PUFAs present in the tissue will determine the proportion of each biomarker. In this review we aim to discuss the proper method for MDA determination using HPLC. We also offer reference MDA values in humans in physiological and pathological conditions.

Measurement of DNA damage with the comet assay in high-prevalence diseases: current status and future directions

The comet assay is widely used in studies on genotoxicity testing, human biomonitoring and clinical studies. The simple version of the assay detects a mixture of DNA strand breaks and alkali-labile sites; these lesions are typically described as DNA strand breaks to distinguish them from oxidatively damaged DNA that are measured with the enzyme-modified comet assay. This review assesses the association between high-prevalence diseases in high-income countries and DNA damage measured with the comet assay in humans. The majority of case-control studies have assessed genotoxicity in white blood cells. Patients with coronary artery disease, diabetes, kidney disease, chronic obstructive pulmonary disease and Alzheimer's disease have on average 2-fold higher levels of DNA strand breaks compared with healthy controls. Patients with coronary artery disease, diabetes, kidney disease and chronic obstructive pulmonary disease also have 2- to 3-fold higher levels of oxidatively damaged DNA in white blood cells than controls, although there is not a clear difference in DNA damage levels between the different diseases. Case-control studies have shown elevated levels of DNA strand breaks in patients with breast cancer, whereas there are only few studies on colorectal and lung cancers. At present, it is not possible to assess if these neoplastic diseases are associated with a different level of DNA damage compared with non-neoplastic diseases.

Association between glycation biomarkers, hyperglycemia, and micronucleus frequency: A meta -analysis

Micronucleus assay has been used as a biomarker of DNA damage, chromosomal instability, cancer risk and accelerated aging. In this review, a meta-analysis was performed to assess the association between micronuclei (MNi) and diseases with increased advanced glycation end products (AGEs) and HbA1c. The review identified eight studies with 632 subjects with disease and 547 controls. The Mean Ratio (MRi) for AGE levels (MRi = 2.92, 95 %CI: 2.06-4.13, P < 0.00001) and HbA1c levels (MRi = 1.32, 95 %CI: 1.12-1.56, P = 0.001) were significantly higher in the disease group compared to healthy controls. The meta-analysis indicated that the overall estimates of MRi for MNi was 1.83 (95 %CI: 1.38-2.42, p < 0.0001) in subjects with disease compared to controls. Significant increases in MRi for MNi were also observed in the following sub-groups: subjects with disease for elevated AGEs (MRi = 1.62, 95 %CI: 1.12-2.35, P = 0.01), elevated HbA1c (MRi = 2.13, 95 %CI: 1.33-3.39, P = 0.002), lymphocytes MNi (MRi = 1.74, 95 %CI: 1.29-2.33, P = 0.0003), exfoliated buccal cells MNi (MRi = 2.86, 95 %CI: 1.19-6.87, P = 0.02), type 2 diabetes mellitus (T2DM) (MRi = 1.99, 95 %CI: 1.17-3.39, P = 0.01), chronic renal disease (MRi = 1.68, 95 %CI: 1.18-2.38, P = 0.004) and other disease groups (MRi = 2.52, 95 %CI: 1.28-4.96, P = 0.008). The results of this review suggest that MNi could be used as a biomarker of DNA damage and chromosomal instability in degenerative disease where increased AGEs and HbA1c are implicated. The lack of heterogeneity for MN frequency when considered either for all studies or subgroup strengthened the MRi of the meta-analysis. However, the lack of significant association between MRi for MNi and MRi for AGEs or HbA1c indicates that the case-control studies investigated may be confounded by other variables. Thus, larger studies with long term AGE exposure is warranted to further understand the role of MN formation in the initiation and progression of diseases caused by excessive glycation.

Micronucleus frequency in chronic kidney disease patients: A review

BACKGROUND

Chronic kidney disease (CKD) is defined as a gradual loss of renal function progressing from very mild damage, with no obvious symptoms in stage one, to complete kidney failure in stage five, which ultimately requires kidney replacement therapy by organ transplantation or dialysis. Cancer incidence and other health problems, mainly diabetes and hypertension, are elevated in CKD, ultimately leading to elevated mortality.

METHODS

A literature search on the induction of micronuclei (MN) as endpoint for genomic damage in white blood cells and buccal mucosa cells of CKD patients was conducted. Possible associations with disease stage, treatment modalities, and vitamin or antioxidant supplementations were analyzed.

RESULTS

In total, 26 studies were enclosed in the data analysis. Patient groups in the predialysis or hemodialysis state of the disease exhibit higher levels of genomic damage, measured as micronucleus frequency in peripheral blood lymphocytes and buccal mucosa cells, than healthy control groups. Genomic damage seems to increase with the disease stage during the predialysis phase. The association with dialysis regimens or with years on dialysis is less clear, but there are indications that efficient removal of uremic toxins is beneficial. Patients with CKD receive a variety of medications, some of which could modulate genomic damage levels and thus contribute to the observed heterogeneity. In addition, supplementation with vitamins or antioxidants may in some cases lower the genomic damage. Meta-Analysis confirmed the high and significant levels of genomic damage present in CKD patients compared to matched healthy controls.

CONCLUSION

Genomic damage, as measured by the MN frequency, is elevated in CKD patients. Different strategies, including supplementation with antioxidants and optimizing dialysis processes, can reduce the levels of genomic damage and the different associated pathologies. Whether MN frequency can in the future also be used to assist in certain therapeutic decisions in CKD will have to be investigated further in larger studies.

Cytotoxicity and genotoxicity assays of halobenzoquinones disinfection byproducts using different human cell lines

Recently, halobenzoquinones (HBQs) disinfection byproducts, including 2,6-dichloro-1, 4-benzoquinone (DCBQ), 2,6-dichloro-3-methyl-1, 4-benzoquinone (DCMBQ), 2,3,6-trichloro-1, 4-benzoquinone (TCBQ), and 2,6-dibromobenzoquinone (DBBQ), have been of increasing concern due to their reported ability to induce oxidative damage, and thus genotoxicity. However, data on the risk of genotoxicity due to chromosomal damage by HBQs are still scarce. Here, the cytotoxicity and genotoxicity of the four HBQs were assessed using human cell lines (bladder cancer 5637 cells, colon carcinoma Caco-2 cells, and gastric MGC-803 cells). The four HBQs exhibited significant concentration-response relationships in all the three cell lines. Cytotoxicity of DCBQ, DCMBQ, TCBQ, and DBBQ, represented by the 50% concentration of inhibition (IC₅₀ ) values, were 80.8-99.5, 41.0-57.6, 122.1-146.6, and 86.9-93.8 μM, respectively. The lowest effective concentrations for cellular micronuclei induction in the cell lines by DCBQ, DCMBQ, TCBQ, and DBBQ were 50-75, 20-41.5, 87.4-100, and 50 μM, respectively. 5637 and Caco-2 cells were more sensitive to the cytotoxic and genotoxic effects of HBQs than MGC-803 cells. These results show that HBQs can induce chromosomal damage; DCMBQ induced the highest cytotoxicity and genotoxicity in all the cell lines, and TCBQ caused the least toxicity.

Micronuclei and disease - Report of HUMN project workshop at Rennes 2019 EEMGS conference

The "Micronuclei and Disease" workshop was organized by the HUMN Project consortium and hosted by the European Environmental Mutagen and Genomics Society at their annual meeting in Rennes, France, on 23 May 2019. The program of the workshop focused on addressing the emerging evidence linking micronucleus (MN) frequency to human disease. The first objective was to review what has been published and evaluate the level and quality of evidence for the connection between MN frequency and various diseases through all life stages. The second objective was to identify the knowledge gaps and what else needs to be done to determine the clinical utility of MN assays as predictors of disease risk and of prognosis when disease is active. Speakers at the workshop discussed the association of MN frequency with inflammation, infertility, pregnancy complications, obesity, diabetes, cardiovascular disease, kidney disease, cervical and bladder cancer, oral head and neck cancer, lung cancer, accelerated ageing syndromes, neurodegenerative diseases, and a road-map on how to utilise this knowledge was proposed. The outcomes of the workshop indicated that there are significant opportunities for translating the application of MN assays into clinical practice to improve disease prevention and risk management and to inform public health policy.

New-Onset Diabetes Mellitus in Peritoneal Dialysis and Hemodialysis Patients: Frequency, Risk Factors, and Prognosis-A Review

New-onset diabetes mellitus (NODM) is observed in both hemodialysis (HD) and peritoneal dialysis (PD) patients. The prevalence of NODM in dialysis patients is slightly higher compared to subjects of the general population. Based on currently published data there is no convincing evidence that the risk of NODM is different between HD and PD patients. Data on the effect of glucose load on risk of NODM in dialysis patients remain controversial. PD modality (automated or continuous ambulatory PD) has no significant influence on NODM incidence. Chronic inflammation is associated with NODM in dialysis patients. Reported differences in NODM between PD and HD patients are possibly also influenced by differences in demographic factors between these patient groups. Mortality in NODM patients is lower than mortality in patients with preexisting DM. This may be partly explained by the younger age and lower number of comorbidities in patients with NODM.

Micronuclei and Their Association with Infertility, Pregnancy Complications, Developmental Defects, Anaemias, Inflammation, Diabetes, Chronic Kidney Disease, Obesity, Cardiovascular Disease, Neurodegenerative Diseases and Cancer

Micronuclei (MN) are a strong cytogenetic indicator of a catastrophic change in the genetic structure and stability of a cell because they originate from either chromosome breaks or whole chromosomes that have been lost from the main nucleus during cell division. The resulting genetic abnormalities can to lead to cellular malfunction, altered gene expression and impaired regenerative capacity. Furthermore, MN are increased as a consequence of genetic defects in DNA repair, deficiency in micronutrients required for DNA replication and repair and exposure to genotoxic chemicals and ultraviolet or ionising radiation. For all of these reasons, the measurement of MN has become one of the best-established methods to measure DNA damage in humans at the cytogenetic level. This chapter is a narrative review of the current evidence for the association of increased MN frequency with developmental and degenerative diseases. In addition, important knowledge gaps are identified, and recommendations for future studies required to consolidate the evidence are provided. The great majority of published studies show a significant association of increased MN in lymphocytes and/or buccal cells with infertility, pregnancy complications, developmental defects, anaemias, inflammation, diabetes, cardiovascular disease, kidney disease, neurodegenerative diseases and cancer. However, the strongest evidence is from prospective studies showing that MN frequency in lymphocytes predicts cancer risk and cardiovascular disease mortality.

Jatrophane Diterpenoids With Protective Effect on Human Lymphocytes DNA

Two sets of structurally different jatrophanes (1-11 and 13-16), jatrophane 12, and latex extract of 2 Euphorbia species (17 and 18) were tested for in vitro protective effect against chromosome aberrations in peripheral human lymphocytes using the cytokinesis-block micronucleus (CBMN) assay. Jatrophanes 1-6 in minimal doses of 1 µg/mL prominently decreased micronuclei (MN) frequency in the range 44.86% to 34.29% and manifested considerable protective effect. From the other set of jatrophanes, 13 in the same minimal dose notably decreased MN frequency by 31.05%, while extracts 17 and 18 at a concentration of 4 µg/mL remarkably decreased the frequency of MN by 37.94% and 36.12%, respectively. Jatrophanes 12, 14, and 16 showed moderate protection, while 7-11 and 15 were less active than positive control. The structure-activity relationship (SAR) studies of the tested jatrophanes (1-16) indicated the favorable position of benzoate at C-8 or C-9 (3, 4, and 13) and a preference of isobutanoyloxy group at C-3 (1-3) rather than propanoyloxy at the same position (4-6) for pronounced protective effect on human lymphocytes DNA. In a previous SAR study on 11 jatrophanes (1, 3-8, and 13-16), the same structural features in 3, 4, and 13 influenced powerful inhibition of P-gp, while growth inhibition of cancer cells was more than doubled in 1 (isobutanoyloxy group at C-3) compared to 6 (propanoyloxy at C-3).

The value of the Brazilian açai fruit as a therapeutic nutritional strategy for chronic kidney disease patients

Açai (Euterpe oleracea Mart.) fruit from the Amazon region in Brazil contains bioactive compounds such as α-tocopherol, anthocyanins (cyanidin 3-glycoside and cyanidin 3-rutinoside), and other flavonoids with antioxidant and anti-inflammatory properties. Moreover, the prebiotic activity of anthocyanins in modulating the composition of gut microbiota has emerged as an additional mechanism by which anthocyanins exert health-promoting effects. Açai consumption may be a nutritional therapeutic strategy for chronic kidney disease (CKD) patients since these patients present with oxidative stress, inflammation, and dysbiosis. However, the ability of açai to modulate these conditions has not been studied in CKD, and this review presents recent information about açai and its possible therapeutic effects in CKD.

DNA damage in kidney transplant patients. Role of organ origin

Chronic kidney disease (CKD) patients are characterized by elevated levels of genomic damage. This damage increases when kidney function decreases being maximum in hemodialysis patients. As kidney transplantation improves renal function, and it is related with better survival, the aim of our study was to evaluate potential changes in DNA damage levels after kidney transplantation, and comparing living donor recipients with cadaveric donor recipients. The alkaline comet assay was used to determine DNA breaks and oxidative damaged DNA; and the micronucleus assay was used to determine chromosomal breakage and/or aneuploidy. Fifty CKD patients were followed up after 6 and 12 months of their kidney transplantation. All patients increased their genomic damage levels after 6 and 12 months of renal transplantation, compared with those observed before transplantation, despite of the improvement of their metabolic functions. Donor advanced age correlated positively with higher DNA damage. Genomic damage was lower in living donor transplants with respect to cadaveric donor transplants. Our conclusion is that DNA damage increased in kidney transplantation patients, whereas their renal function improved. Higher levels of DNA damage were found in cadaveric donor transplants when compared to living donor transplants. Environ. Mol. Mutagen. 58:712-718, 2017. © 2017 Wiley Periodicals, Inc.

Role of cytogenetic biomarkers in management of chronic kidney disease patients: A review

Chronic kidney disease (CKD) is much more common than people recognize, and habitually goes undetected and undiagnosed until the disease is well advanced or when their kidney functions is down to 25% of normal function. Genetic and non-genetic factors contribute to cause CKD. Non-genetic factors include hypertension, High level of DNA damage due to the production of reactive oxygen species and nucleic acid oxidation has been reported in CKD patients. Main genetic factor which causes CKD is diabetic nephropathy. A three- to nine-fold greater risk of End Stage Renal Disease (ESRD) is observed in individuals with a family history of ESRD. This greater risk have led researchers to search for genes linked to diabetic and other forms of nephropathy for the management of CKD. Multicenter consortia are currently recruiting large numbers of multiplex diabetic families with index cases having nephropathy for linkage and association analyses using various cytogenetic techniques. In addition, large-scale screening studies are underway, with the goals of better defining the overall prevalence of chronic kidney disease, as well as educating the population about risk factors for nephropathy, including family history. Cytogenetic biomarkers play an imperative role for the linkage study using G banding and detection of genomic instability in CKD patients. Classical and molecular cytogenetic tools with cytogenetic biomarkers provide remarkable findings in CKD patients. The aim of the present review is to draw outline of classical and molecular cytogenetic findings in CKD patients and their possible role in management to reduce genomic instability in CKD patients.

Using the cytokinesis-block micronucleus cytome assay to evaluate chromosomal DNA damage in chronic renal patients undergoing bicarbonate haemodialysis and haemodiafiltration

INTRODUCTION

Chronic Renal Failure (CRF) patients are considered to show genomic instability and are associated with a high risk of both cardiovascular diseases and cancer. We explored DNA damage due to two dialysis treatments in 20 patients undergoing bicarbonate haemodialysis (BD), 20 undergoing haemodiafiltration (HDF) and 40 healthy subjects.

METHODS

The cytokinesis-block micronucleus (MN) assay was performed on peripheral blood lymphocytes to evaluate genetic damage.

RESULTS

A higher frequency of MN in the dialysis groups compared with controls was found. The results do not show a relationship between genetic instability and the type, frequency and duration of haemodialysis. The average BD and HDF treatment time was respectively 3.8 ± 6.3 and 3.7 ± 3.9 yrs. CAT and scintigraphy was independently correlated with high levels of MN.

CONCLUSIONS

Overall, the frequency of MN in CRF patients undergoing dialysis therapy was observed to be higher. Further studies need to be performed on a larger number of patients and for a longer period.

Levels of DNA damage in peripheral blood lymphocytes of patients undergoing standard hemodialysis vs on-line hemodiafiltration: A comet assay investigation

Chronic kidney disease (CKD) patients exhibit high levels of genetic damage. Part of this genetic damage is supposed to be caused by the hemodialysis (HD) therapy. Different and more efficient HD procedures could reduce the genetic damage and improve health status of CKD patients. In the present study, we analyzed if changing to online hemodiafiltration (OL-HDF) has a beneficial effect on the levels of genetic damage. The levels of genetic damage (DNA breaks and oxidatively damaged DNA) were analyzed in peripheral blood lymphocytes by using the comet assay. Forty-nine patients submitted to HD, 34 of them changing to OL-HDF and 15 patients continuing in low-flux HD, were included in the study. Plasma antioxidant capacity was also determined. Second sampling period was established after 6 months on the new or traditional HD protocol. A slight decrease in the levels of DNA damage was observed in patients who switched to OL-HDF (P=0.048) in relation to the reference group. This reduction is indicative that OL-HDF shows greater efficiency than low-flux HD in the reduction of basal levels of genetic damage.

DNA Damage in Chronic Kidney Disease: Evaluation of Clinical Biomarkers

Patients with chronic kidney disease (CKD) exhibit an increased cancer risk compared to a healthy control population. To be able to estimate the cancer risk of the patients and to assess the impact of interventional therapies thereon, it is of particular interest to measure the patients' burden of genomic damage. Chromosomal abnormalities, reduced DNA repair, and DNA lesions were found indeed in cells of patients with CKD. Biomarkers for DNA damage measurable in easily accessible cells like peripheral blood lymphocytes are chromosomal aberrations, structural DNA lesions, and oxidatively modified DNA bases. In this review the most common methods quantifying the three parameters mentioned above, the cytokinesis-block micronucleus assay, the comet assay, and the quantification of 8-oxo-7,8-dihydro-2′-deoxyguanosine, are evaluated concerning the feasibility of the analysis and regarding the marker's potential to predict clinical outcomes.

Genomic damage as a biomarker of chronic kidney disease status

Patients suffering from chronic kidney disease (CKD) exhibit a high incidence of cancer and cardiovascular diseases, as well as high levels of genomic damage. To confirm the association of CKD with genomic damage we have carried out the largest study to date addressing this issue, using a total of 602 subjects (187 controls, 206 pre-dialysis CKD patients and 209 CKD patients in hemodialysis). DNA oxidative damage was measured in all individuals using the comet assay. Our results indicate that CKD patients have significantly higher levels of DNA damage than controls, but no significant differences were observed between pre-hemodialysis (pre-HD) and hemodialysis (HD) patients. When oxidative damage was measured, no differences were observed between patients and controls, although HD patients showed significantly higher levels of oxidative damage than pre-HD patients. In addition, a positive relationship was demonstrated between genomic damage and all-cause mortality. Our study confirms that genomic damage can be predictive of prognosis in CKD patients, with high levels of DNA damage indicating a poor prognosis in HD patients.

Radiosensitivity in patients suffering from chronic kidney disease

PURPOSE

Patients suffering from chronic kidney disease (CKD) exhibit a high incidence of cancer, as well as high levels of genetic damage. We hypothesized that these patients show genomic instability detected as an increased chromosomal radiosensitivity in front of the genetic damage induced by ionizing radiation.

MATERIAL AND METHODS

The background levels of genetic damage and the net genetic damage after in vitro irradiation with 0.5 Gy were analyzed using the micronucleus (MN) assay in peripheral blood lymphocytes. A total number of 552 individuals (179 controls and 373 CKD patients) were included in the study.

RESULTS

The net radiation-induced genetic damage was significantly higher in CKD patients than in controls; but no differences between those patients submitted to hemodialysis and those in pre-dialytic stages were detected. A positive correlation was observed between basal and net micronucleus frequencies in CKD patients what would indicate an underlying genetic background modulating DNA damage levels.

CONCLUSIONS

Our results indicate that CKD patients present genomic instability, measured as an increased chromosomal radiosensitivity in front of ionizing radiation.