Peritoneal Protein Clearance Is a Function of Local Inflammation and Membrane Area Whereas Systemic Inflammation and Comorbidity Predict Survival of Incident Peritoneal Dialysis Patients

It is not clear whether the association of increased peritoneal protein clearance (PPCl) with worse survival on peritoneal dialysis (PD) is a consequence of either local or systemic inflammation or indicative of generalized endothelial dysfunction associated with comorbidity. To investigate this we determined the relationship of PPCl to comorbidity, membrane area (equivalent to low molecular weight peritoneal solute transport rate), local and systemic inflammation and hypoalbuminaemia, and for each of these with patient survival. 257 incident patients from three GLOBAL Fluid Study centers were included in this analysis. Clinical profiles were collected at baseline along with a peritoneal equilibration test, 24-h dialysate protein and paired plasma and dialysate cytokine measurements. Although peritoneal protein clearance was associated with increased age and severe comorbidity on univariate analysis, only dialysate IL-6, peritoneal solute transport rate, plasma albumin and cardiac comorbidities (ischaemic heart disease and left ventricular dysfunction) were independent explanatory variables on multivariate analysis. While peritoneal protein clearance and daily peritoneal protein loss were associated with survival in univariate analysis, on multivariate analysis only plasma IL-6, age, residual kidney function, comorbidity, and plasma albumin were independent predictors. Peritoneal protein clearance is primarily a function of peritoneal membrane area and local membrane inflammation. The association with comorbidity and survival is predominantly explained by its inverse relationship to hypoalbuminaemia, especially in diabetics.

Biocompatible Solutions and Long-Term Changes in Peritoneal Solute Transport

BACKGROUND AND OBJECTIVES

The inflammation-driven increase in peritoneal solute transport rate that occurs during long-term peritoneal dialysis is associated with higher mortality, hospitalization, and encapsulating peritoneal sclerosis. Because biocompatible solutions were developed to mitigate these effects, we examined the association with their use and longitudinal peritoneal solute transport rate.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We analyzed subjects from the multinational prospective Global Fluid Study with three or more peritoneal solute transport rate measurements >2 months from the start of peritoneal dialysis. Follow-up was for 7.5 years (median, 2.3 years; interquartile range, 1.8-3.6) in biocompatible solutions and 12.8 years (median, 3.2 years; interquartile range, 1.9-4.3) for standard solutions. Using a random intercept/slopes multilevel model, we examined the association of patients using biocompatible solutions and peritoneal solute transport rate over time, adjusting for center effects, dialysate dextrose concentration, baseline dialysate IL-6 concentration, icodextrin use, residual kidney function, and peritonitis.

RESULTS

Of 366 patients, the 71 receiving biocompatible solutions throughout their time on peritoneal dialysis had a mean adjusted dialysate-to-plasma creatinine ratio of 0.67 compared with 0.72 for standard solutions (P=0.02). With duration of treatment, there was a continuous increase in peritoneal solute transport rate in patients using standard solutions (range, 2 months to 4 years). In contrast, patients using biocompatible solutions had peritoneal solute transport rates that plateaued after 2 years of therapy. These changes in peritoneal solute transport rate were independent of baseline inflammation and time-varying predictors of faster peritoneal solute transport rate. In patients suffering episodes of peritonitis while using standard solutions, there was an associated increase in peritoneal solute transport rate of 0.020 (95% confidence interval, 0.01 to 0.03) per episode, whereas in patients using biocompatible solutions, there was no change in this parameter (-0.014; 95% confidence interval, -0.03 to <0.01).

CONCLUSIONS

These data suggest that a different temporal pattern in changes in peritoneal solute transport rate occurs during the course of peritoneal dialysis according to solution type and that patients using biocompatible solutions may avoid the increase in solute transport associated with peritonitis.

Bioimpedance-defined overhydration predicts survival in end stage kidney failure (ESKF): systematic review and subgroup meta-analysis

Both overhydration and comorbidity predict mortality in end-stage kidney failure (ESKF) but it is not clear whether these are independent of one another. We undertook a systematic review of studies reporting outcomes in adult dialysis patients in which comorbidity and overhydration, quantified by whole body bioimpedance (BI), were reported. PubMed, EMBASE, PsychInfo and the Cochrane trial database were searched (1990-2017). Independent reviewers appraised studies including methodological quality (assessed using QUIPS). Primary outcome was mortality, with secondary outcomes including hospitalisation and cardiovascular events. Of 4028 citations identified, 46 matched inclusion criteria (42 cohorts; 60790 patients; 8187 deaths; 95% haemodialysis/5% peritoneal dialysis). BI measures included phase angle/BI vector (41%), overhydration index (39%) and extra:intracellular water ratio (20%). 38 of 42 cohorts had multivariable survival analyses (MVSA) adjusting for age (92%), gender (66%), diabetes (63%), albumin (58%), inflammation (CRP/IL6-37%), non-BI nutritional markers (24%) and echocardiographic data (8%). BI-defined overhydration (BI-OH) independently predicted mortality in 32 observational cohorts. Meta-analysis revealed overhydration >15% (HR 2.28, 95% CI 1.56-3.34, P < 0.001) and a 1-degree decrease in phase angle (HR 1.74, 95% CI 1.37-2.21, P < 0.001) predicted mortality. BI-OH predicts mortality in dialysis patients independent of the influence of comorbidity.

Unraveling the mechanisms of progressive peritoneal membrane fibrosis

Continuous glucose exposure contributes to severe ultrafiltration failure in peritoneal dialysis. In their study, Wang et al. describe a mechanistic pathway involving direct activation by glucose of mesothelial cell protein kinase C α that, when blocked, or absent in a mouse knockout model, prevents fibrosis and the associated reduction in ultrafiltration. Interestingly, this pathway involves the 3 main mechanisms of membrane injury (inflammation, neoangiogenesis, and fibrogenesis), offering a potential target for therapeutic intervention.

A prospective, proteomics study identified potential biomarkers of encapsulating peritoneal sclerosis in peritoneal effluent

Encapsulating peritoneal sclerosis (EPS) is a potentially devastating complication of peritoneal dialysis (PD). Diagnosis is often delayed due to the lack of effective and accurate diagnostic tools. We therefore examined peritoneal effluent for potential biomarkers that could predict or confirm the diagnosis of EPS and would be valuable in stratifying at-risk patients and driving appropriate interventions. Using prospectively collected samples from the Global Fluid Study and a cohort of Greek PD patients, we utilized 2D SDSPAGE/ MS and iTRAQ to identify changes in the peritoneal effluent proteome from patients diagnosed with EPS and controls matched for treatment exposure. We employed a combinatorial peptide ligand library to compress the dynamic range of protein concentrations to aid identification of low-abundance proteins. In patients with stable membrane function, fibrinogen γ-chain and heparan sulphate proteoglycan core protein progressively increased over time on PD. In patients who developed EPS, collagen-α1(I), γ-actin and Complement factors B and I were elevated up to five years prior to diagnosis. Orosomucoid-1 and a2-HS-glycoprotein chain-B were elevated about one year before diagnosis, while apolipoprotein A-IV and α1-antitrypsin were decreased compared to controls. Dynamic range compression resulted in an increased number of proteins detected with improved resolution of protein spots, compared to the full fluid proteome. Intelectin-1, dermatopontin, gelsolin, and retinol binding protein-4 were elevated in proteome-mined samples from patients with EPS compared to patients that had just commenced peritoneal dialysis. Thus, prospective analysis of peritoneal effluent uncovered proteins indicative of inflammatory and pro-fibrotic injury worthy of further evaluation as diagnostic/prognostic markers.

Prognostic Markers of Outcome in Patients Undergoing Infra-inguinal Revascularisation: A Prospective Observational Pilot Study

OBJECTIVES

The aim was to investigate whether cardiopulmonary exercise testing (CPET) variables derived from cycle and arm ergonometry correlate, and whether CPET variables and pre-operative N-terminal pro-brain natriuretic peptide (NT-proBNP) have prognostic significance and if the combination of the two has incremental value.

METHODS

A prospective observational pilot study was conducted; 70 patients who underwent infra-inguinal bypass surgery were recruited. Pre-operatively subjects underwent CPET with both arm and leg ergonometry, to measure peak oxygen consumption, anaerobic threshold (AT), and ventilatory equivalents. In addition pre-operative serum samples of NT-proBNP were obtained. The primary endpoint was 1 year all-cause mortality; in addition, data were collected on complications, morbidity, length of stay, and major adverse cardiac events (MACE).

RESULTS

The 1 year mortality rate was 6%, the overall complications rate was 23%, and the combined incidence of MACE and 1 year mortality was 10%. Cycle ergonometry peak VO₂ 14 mL/kg/min (RR 5.5, 95% CI 1.4-22.4, p = .007) and AT < 10mL/kg/min (RR 3.0, 95% CI 1.1-7.0, p = .03) were predictors of post-operative complications. Pre-operative NT-proBNP > 320 ng/L (RR 18, 95% CI 2.5-140 p = .0003) was the sole predictor of 1 year mortality or MACE.

CONCLUSION

The measurement of pre-operative NT-proBNP in peripheral vascular disease patients undergoing infra-inguinal bypass can predict 1 year mortality and MACE. CPET variables from cycle ergonometry are predictors of post-operative complications in this patient group.

Rationale and design of BISTRO: a randomized controlled trial to determine whether bioimpedance spectroscopy-guided fluid management maintains residual kidney function in incident haemodialysis patients

Background

Preserved residual kidney function (RKF) and normal fluid status are associated with better patient outcomes in incident haemodialysis patients. The objective of this trial is to determine whether using bioimpedance technology in prescribing the optimal post-dialysis weight can reduce the rate of decline of RKF and potentially improve patient outcomes.

Methods/Design

516 pateints commencing haemodialysis, aged >18 with RKF of > 3 ml/min/1.73 m² or a urine volume >500 ml per day or per the shorter inter-dialytic period will be consented and enrolled into a pragmatic, open-label, randomized controlled trial. The intervention is incorporation of bioimpedance spectroscopy (BI) determination of normally hydrated weight to set a post-dialysis target weight that limits volume depletion, compared to current standard practice. Clinicians and participants will be blinded to BI measures in the control group and a standardized record capturing management of fluid status will be used in all participants. Primary outcome is preservation of residual kidney function assessed as time to anuria (≤100 ml/day or ≤200 ml urine volume in the short inter-dialytic period). A sample size of 516 was based upon a cumulative incidence of 30% anuria in the control group and 20% in the treatment group and 11% competing risks (death, transplantation) over 10 months, with up to 2 years follow-up.

Secondary outcomes include rate of decline in small solute clearance, significant adverse events, hospitalization, loss of vascular access, cardiovascular events and interventions, dialysis efficacy and safety, dialysis-related symptoms and quality of life. Economic evaluation will be carried out to determine the cost-effectiveness of the intervention. Analyses will be adjusted for patient characteristics and dialysis unit practice patterns relevant to fluid management.

Discussion

This trial will establish the added value of undertaking BI measures to support clinical management of fluid status and establish the relationship between fluid status and preservation of residual kidney function in incident haemodialysis patients.

Trial registration

ISCCTN Number: 11342007, completed 26/04/2016; NIHR Portfolio number: CPMS31766; Sponsor: Keele University

Longitudinal bioimpedance vector plots add little value to fluid management of peritoneal dialysis patients

Bioimpedance (BI) has the potential to enable better management of fluid balance, which can worsen over time on peritoneal dialysis (PD) due to loss of residual kidney function and progressive muscle wasting. We undertook a prospective, randomized, open-label, blinded end-point controlled trial to determine whether availability of longitudinal BI measures as vector plots helped clinicians maintain stable fluid status over 12 months in 308 peritoneal dialysis patients from the United Kingdom and Shanghai, China. Patients were recruited into 4 groups nested within a single trial design according to country and residual kidney function. Nonanuric subjects from both countries demonstrated stable fluid volumes irrespective of randomization. Hydration worsened in control anuric patients in Shanghai with increased extracellular/total body water (ECW/TBW) ratio (0.04; 95% CI: 0.01, 0.06) and reduced TBW (-1.76 L 95% CI: -2.70, -0.82), but was stable in the BI intervention group whose dialysate glucose prescription was increased. However, multilevel analysis incorporating data from both countries showed worsening ECW/TBW in active and control anuric patients. Clinicians in the United Kingdom reduced target weight in the nonanuric BI intervention group causing a reduction in TBW without beneficial effects on ECW or blood pressure. Thus, routine use of longitudinal BI vector plots to improve clinical management of fluid status is not supported.

Systematic Distortions in Vertical Placement of Features in Drawings of Faces and Houses

A crucial part of accurately drawing portraits is the correct vertical positioning of the eyes. Non-experts typically place the eyes higher on the head than they are actually located; however, the explanation for this remains unclear. In Experiment 1, participants drew faces from memory and directly copied from a photograph, to confirm whether biases in observational drawings were related to biases in memory-based drawings. In Experiment 2, participants drew a cat's face, to test explanations by Carbon and Wirth for the positional bias: the 'view-from-below, the 'head-as-box', and the 'hair-as-hat' explanations. Results indicated that none of these three explanations could fully account for the vertical positioning biases observed in drawings of the cat's face. The findings are discussed in relation to the idea that distortions of vertical alignment in drawings may be related to the position of the most salient features within a face or object.

The Current State of Peritoneal Dialysis

Technical innovations in peritoneal dialysis (PD), now used widely for the long-term treatment of ESRD, have significantly reduced therapy-related complications, allowing patients to be maintained on PD for longer periods. Indeed, the survival rate for patients treated with PD is now equivalent to that with in-center hemodialysis. In parallel, changes in public policy have spurred an unprecedented expansion in the use of PD in many parts of the world. Meanwhile, our improved understanding of the molecular mechanisms involved in solute and water transport across the peritoneum and of the pathobiology of structural and functional changes in the peritoneum with long-term PD has provided new targets for improving efficiency and for intervention. As with hemodialysis, almost half of all deaths on PD occur because of cardiovascular events, and there is great interest in identifying modality-specific factors contributing to these events. Notably, tremendous progress has been made in developing interventions that substantially reduce the risk of PD-related peritonitis. Yet the gains have been unequal among individual centers, primarily because of unequal clinical application of knowledge gained from research. The work to date has further highlighted the areas in need of innovation as we continue to strive to improve the health and outcomes of patients treated with PD.

Health-related quality of life assessment in end-stage renal failure

End-stage renal failure (ESRF) is a life-threatening condition and survival can be maintained only with renal replacement therapy. Furthermore, the complications of ESRF, its treatment and co-existing diseases have been found to have a significant impact on the physical health of patients. It is well documented that the health status of the renal patient population is worse than that of the general healthy population; for this reason the assessment of quality of life of ESRF patients has received considerable attention.

During the 1990s, the focus of health assessment moved away from the disease itself towards health status and wellbeing. The widespread use of the 36-item short-form (SF-36) questionnaire has promoted this. In ESRF studies from data using the SF-36 questionnaire it has been shown that it is the physical functional component of health that is most affected by the patient's condition, with co-morbidity having a significant impact.

There is growing consensus that health-related quality of life is more than just an assessment of health status. Rather, it is the relative importance given by the individuals themselves to the impact of the disease on their life. While this approach is emerging, some of the tools which have been developed to measure individualised quality of life require further scientific validation for use with the ESRF population.

Patient Acceptability of the Yorkshire Dialysis Decision Aid (YoDDA) Booklet: A Prospective Non-Randomized Comparison Study Across 6 Predialysis Services

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BACKGROUND

Patients are satisfied with their kidney care but want more support in making dialysis choices. Predialysis leaflets vary across services, with few being sufficient to enable patients' informed decision making. We describe the acceptability of a patient decision aid and feasibility of evaluating its effectiveness within usual predialysis practice. ♦

METHODS

Prospective non-randomized comparison design, Usual Care or Usual Care Plus Yorkshire Dialysis Decision Aid Booklet (+YoDDA), in 6 referral centers (Yorkshire-Humber, UK) for patients with sustained deterioration of kidney function. Consenting (C) patients completed questionnaires after predialysis consultation (T1), and 6 weeks later (T2). Measures assessed YoDDA's utility to support patients' decisions and integration within usual care. ♦

RESULTS

Usual Care (n = 105) and +YoDDA (n = 84) participant characteristics were similar: male (62%), white (94%), age (mean = 62.6; standard deviation [SD] 14.4), kidney disease severity (glomerular filtration rate [eGFR] mean = 14.7; SD 3.7); decisional conflict was < 25; choice-preference for home versus hospital dialysis approximately 50:50. Patients valued receiving YoDDA, reading it on their own (96%), and sharing it with family (72%). The +YoDDA participants had higher scores for understanding kidney disease, reasoning about options, feeling in control, sharing their decision with family. Study engagement varied by center (estimated range 14 - 49%; mean 45%); participants varied in completion of decision quality measures. ♦

CONCLUSIONS

Receiving YoDDA as part of predialysis education was valued and useful to patients with worsening kidney disease. Integrating YoDDA actively within predialysis programs will meet clinical guidelines and patient need to support dialysis decision making in the context of patients' lifestyle.

UK National Survey of Practice Patterns of Fluid Volume Management in Haemodialysis Patients: A Need for Evidence

BACKGROUND

Fluid management in haemodialysis (HD) affects patient experience, morbidity and mortality. Standards for best practice are lacking. A national survey of the United Kingdom was undertaken to define prevalent practice.

METHODS

An online questionnaire was distributed to all UK renal centres.

RESULTS

Forty-five of 74 centres (173 dialysis units), serving 62% (n = 14,697) of UK HD population responded. Seventy-eight per cent had no agreed policy for managing fluid balance in patients on HD; 44% did not assess fluid status routinely. Clinical assessment was the norm; 27% used bio-impedance-based device. To achieve a target-weight, 53% reduced weight as far as tolerated. Twenty-two per cent measured residual renal function (RRF). Ninety-one per cent had no policy for fluid overload. Sixty-four per cent restricted salt and water. Ninety-three per cent used diuretics in patients with RRF. Thirty-eight per cent felt management was adequate; 77% felt there was a need for better evidence. Ninety-one per cent would participate in a study addressing this.

CONCLUSION

There is an urgent need for establishing an evidence base on the optimal approaches to fluid management.

Dietary administration of a commercial mixed-species probiotic improves growth performance and modulates the intestinal immunity of tilapia, Oreochromis niloticus

The growth performance, immunological status, intestinal morphology and microbiology of tilapia, Oreochromis niloticus, were investigated after dietary administration of the commercial probiotic AquaStar(®) Growout. Tilapia (29.02 ± 0.33 g) were split into five treatments; control (CON), 1.5 g kg(-1) probiotic (PRO-1.5), 3 g kg(-1) probiotic (PRO-3), pulsed probiotic feeding (PRO-PULSE) or an initial probiotic feed followed by control feeding (PRO-INI). After six weeks of experimental feeding, fish fed PRO-3 displayed significantly higher final weight, weight gain and SGR compared to the CON or PRO-INI treatments. Supplementation of the probiotic at this dose induced an up-regulation of intestinal caspase-3, PCNA and HSP70 mRNA levels compared to the CON fed fish. Immuno-modulatory pathways were also affected; significantly higher expression of TLR2, pro-inflammatory genes TNFα and IL-1β, and anti-inflammatory genes IL-10 and TGFβ suggest that the probiotic may potentiate a higher state of mucosal tolerance and immuno-readiness. Histological appraisal revealed significantly higher numbers of intraepithelial leucocytes in the intestine of PRO-3 fed fish compared with treatments CON, PRO-PULSE and PRO-INI but not PRO-1.5. Additionally, fish receiving PRO-3 had a significantly higher abundance of goblet cells in their mid-intestine when compared with fish from all other treatments. Together, these data suggest that continuous provision of AquaStar(®) Growout at 3 g kg(-1) can improve tilapia growth and elevate the intestinal immunological status of the host.

Peritoneal inflammation precedes encapsulating peritoneal sclerosis: results from the GLOBAL Fluid Study

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is an uncommon condition, strongly associated with a long duration of peritoneal dialysis (PD), which is itself associated with increased fibrosis in the peritoneal membrane. The peritoneal membrane is inflamed during PD and inflammation is often associated with fibrosis. We hypothesized that patients who subsequently develop EPS might have a more inflamed peritoneal membrane during PD.

METHODS

We performed a nested, case-control study identifying all EPS cases in the UK arm of the GLOBAL Fluid Study and matching them by centre and duration of PD with two to three controls. Dialysate and plasma samples were taken during repeated peritoneal equilibration tests prior to cessation of PD from cases and controls. Samples were assayed by electrochemiluminescence immunoassay for interleukin-1β (IL-1β), tumour necrosis factor α (TNF-α), interferon-γ (IFN-γ) and IL-6. Results were analysed by linear mixed models adjusted for age and time on PD.

RESULTS

Eleven EPS cases were matched with 26 controls. Dialysate TNF-α {0.64 [95% confidence interval (CI) 0.23, 1.05]} and IL-6 [0.79 (95% CI 0.03, 1.56)] were significantly higher in EPS cases, while IL-1β [1.06 (95% CI -0.11, 2.23)] and IFN-γ [0.62 (95% CI -0.06, 1.29)] showed a similar trend. Only IL-6 was significantly higher in the plasma [0.42 (95% CI 0.07, 0.78)]. Solute transport was not significantly different between cases and controls but did increase in both groups with the duration of PD.

CONCLUSIONS

The peritoneal cavity has higher levels of inflammatory cytokines during PD in patients who subsequently develop EPS, but neither inflammatory cytokines nor peritoneal solute transport clearly discriminates EPS cases. Increased systemic inflammation is also evident and is probably driven by increased peritoneal inflammation.

The Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS): Unifying Efforts to Inform Practice and Improve Global Outcomes in Peritoneal Dialysis

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BACKGROUND

Extending technique survival on peritoneal dialysis (PD) remains a major challenge in optimizing outcomes for PD patients while increasing PD utilization. The primary objective of the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) is to identify modifiable practices associated with improvements in PD technique and patient survival. In collaboration with the International Society for Peritoneal Dialysis (ISPD), PDOPPS seeks to standardize PD-related data definitions and provide a forum for effective international collaborative clinical research in PD. ♦

METHODS

The PDOPPS is an international prospective cohort study in Australia, Canada, Japan, the United Kingdom (UK), and the United States (US). Each country is enrolling a random sample of incident and prevalent patients from national samples of 20 to 80 sites with at least 20 patients on PD. Enrolled patients will be followed over an initial 3-year study period. Demographic, comorbidity, and treatment-related variables, and patient-reported data, will be collected over the study course. The primary outcome will be all-cause PD technique failure or death; other outcomes will include cause-specific technique failure, hospitalizations, and patient-reported outcomes. ♦

RESULTS

A high proportion of the targeted number of study sites has been recruited to date in each country. Several ancillary studies have been funded with high momentum toward expansion to new countries and additional participation. ♦

CONCLUSION

The PDOPPS is the first large, international study to follow PD patients longitudinally to capture clinical practice. With data collected, the study will serve as an invaluable resource and research platform for the international PD community, and provide a means to understand variation in PD practices and outcomes, to identify optimal practices, and to ultimately improve outcomes for PD patients.

Assessment of oxidative damage to DNA, transcriptional expression of key genes, lipid peroxidation and histopathological changes in carp Cyprinus carpio L. following exposure to chronic hypoxic and subsequent recovery in normoxic conditions

In fish, a complex set of mechanisms deal with environmental stresses including hypoxia. In order to probe the hypothesis that hypoxia-induced stress could be manifested in varieties of pathways, a model species, mirror carp (Cyprinus carpio), were chronically exposed to hypoxic condition (dissolved oxygen level: 1.80 ± 0.6 mg/l) for 21 days and subsequently allowed to recover under normoxic condition (dissolved oxygen level: 8.2 ± 0.5 mg/l) for 7 days. At the end of these exposure periods, an integrated approach was applied to evaluate several endpoints at different levels of biological organisation. These included determination of (i) oxidative damage to DNA in erythrocytes (using modified comet assay), (ii) lipid peroxidation in liver samples by measuring the malondialdehyde production using the 2-thiobarbituric acid [i.e. thiobarbituric acid reactive substances (TBARS) assay] and (iii) histopathological changes in gills. In addition, transcriptional expression of hypoxia-inducible factor 1 α (HIF-1α) and genes involved in the repair of oxidative damage to DNA (i.e. ogg1) and base excision repair (i.e. xrcc1) using reverse transcription polymerase chain reaction in liver samples were also determined. The results suggested significantly enhanced expression of these genes in response to hypoxia compared to concurrent normoxic controls. While the expression of HIF-1α reverted to control values within 7 days exposure to normoxic condition (P < 0.05), the transcriptional expression of the two genes involved in DNA repair process remained significantly high under the recovery period, which complemented the induction of oxidative damage to DNA. Hypoxic groups showed significantly increased values for TBARS level (~2-fold) and histopathological changes in gill tissues compared to both normoxic and recovery groups. Overall, oxidative damage to DNA determined by modified comet assay reflected the observed biological responses in other tissues of the fish. Along with other parameters, this integrated experimental design further strengthens the applications of the comet assay as an important technique to assess stress-induced DNA damage in ecotoxicological studies.