A Pilot Study on the Potential Pathological Link Between Oxidative Stress Markers and Renal Function in People Living with HIV

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript presents a cross-sectional pilot study examining the association between oxidative stress markers—malondialdehyde (MDA), superoxide dismutase (SOD), and total antioxidant capacity (TAC)—and renal function, assessed via cystatin C-based estimated glomerular filtration rate (eGFRcystC), in three groups: people living with HIV (PLWH) receiving antiretroviral therapy (ART), PLWH not on ART, and HIV-negative controls (PNLWH). The study was conducted within a rural South African cohort, contributing valuable insights given the high prevalence of HIV in sub-Saharan Africa. Findings indicate elevated levels of MDA among PLWH on ART and suggest a potential protective role of SOD against early renal impairment in virally suppressed individuals.

Overall, the manuscript addresses an important gap in understanding the role of oxidative stress in HIV-related comorbidities, particularly renal dysfunction. The methodology is appropriate for a pilot study, and results are clearly presented with supporting tables and figures. However, the study is limited by its pilot design, including a small sample size and cross-sectional nature. Furthermore, several aspects require refinement, as outlined below.

1. As a pilot study, the total sample size of n=151 is reasonable; however, the subgroup distribution is imbalanced (ART: n=80; no ART: n=27; HIV-negative controls: n=44). The no-ART group is notably small, increasing the risk of type II errors—for instance, the absence of significant differences in MDA or SOD levels across eGFR stages may reflect insufficient statistical power. A post-hoc power analysis should be provided for key comparisons (e.g., SOD levels in individuals with mild renal impairment) to evaluate whether the study was adequately powered to detect meaningful effects. Furthermore, the rationale for the smaller size of the no-ART group should be clarified—was this due to recruitment challenges or other factors? This limitation affects the generalizability of the findings and should be more prominently addressed in the limitations section.
2. Viral load data are missing for PLWH groups. Since the abstract claims "virally suppressed PLWH on ART," confirm this with median viral loads or suppression rates (<50 copies/mL). Without this, the "virally suppressed" claim is unsubstantiated.
3. Blood collection and storage details are provided, but assay variability (e.g., intra/inter-assay CV for MDA/SOD/TAC kits) is not reported. Include these to support data reliability.
4. TAC analyses are separated due to smaller sample sizes—explain why (e.g., sample volume limitations) and consider sensitivity analyses combining markers.
5. Spearman correlation analyses reveal weak associations (R² = 0.20–0.31), yet the interpretations are disproportionately strong (e.g., suggesting that SOD "protects" renal function). The language should be moderated to better reflect the modest effect sizes and the preliminary nature of this pilot study.
6. "PNLWH" is defined as "people not living with HIV", but the usage is inconsistent (sometimes it is "HIV-negative individuals"). Please unify it.
7. Lines 431-438: References 5 and 6 are duplicated.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors conducted a study to assess the pathological relationship between oxidative stress markers and renal function in people living with HIV.

They reported that superoxide dismutase, as a defensive antioxidant enzyme, may be a key factor contributing to kidney health in virally suppressed people living with HIV and receiving antiretroviral therapy.

I believe that the study needs to be improved with other determinations such as catalase activity, glutathione peroxidase, glutathione reductase, glutathione S-transferase, reduced glutathione concentration, in order to draw a conclusion. This study is incomplete and needs further investigation.

The title is clear, specific, and informative.

The introduction is well structured and provides information regarding the topic addressed.

Material and Method:
The details here are important for publication.
Are the number of participants and justification feasible?
What is the study period?

Results:
Not presented clearly, with simple tables.
The mean values ​​of oxidative stress biomarkers and statistical differences between groups are not found in figure 1.

The conclusions mentioned by the authors are not relevant and feasible in this study. The authors must make additional determinations to ensure that these conclusions are consistent with the objectives of the study.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have responded to the comments and the article may be published in its new form.