Table 1.

Data to be extracted from included studies, stratified by study characteristics and outcome measures

Study characteristics
Category	Description
Study ID	Authors Year Journal Language
Study design	Experimental groups, including type of control group(s) Number of animals per group Duration of follow-up Number of experiments and replications
Animal model	Species Strain Age Gender Weight Comorbidities: Obesity—yes/no Diabetes—yes/no (if yes, type 1 or type 2 diabetes mellitus model) Dyslipidaemia—yes/no Hypertension—yes/no Kidney disease characteristics: AKI model vs CKD model vs acute-on-chronic renal injury model vs renal transplant model Kidney disease manifests as part of natural history or induced Modality of kidney disease induction
Intervention	PPAR isotypes pharmacologically targeted: PPARα PPARβ/δ PPARγ Two PPAR isotypes Three PPAR isotypes Route of administration: Oral Intravenous Subcutaneous Intraperitoneal Dose of PPAR-targeting pharmacological agent Timing of intervention Preventative if given before or during kidney disease induction Rescue if given after kidney disease induction Frequency of intervention (n times per day, once daily, once every n number of days, once weekly) Duration of intervention (in days/weeks/months)
Other	Study quality indicators (adapted from CAMARADES study quality checklist)68 69: Publication in a peer-reviewed journal—yes/no Species/strain of animals reported in title or abstract and in full-text—yes/no Provision of author conflict of interest statements—yes/no Statement of compliance with animal welfare regulations—yes/no Basic animal and housing characteristics reported—yes/no Sample size calculation reported—yes/no Randomisation of treatment allocation reported—yes/no Concealment of treatment allocation reported—yes/no Statement on blinded outcome assessment provided—yes/no Criteria for inclusion and/or exclusion of data provided—yes/no Risk of bias assessment using the SYRCLE risk of bias tool 10 items will be recorded as ‘yes’, ‘no’ or ‘unclear’
Outcome measures
Category	Description (data type; unit)
Primary	Renal injury and function indices: Plasma/serum creatinine (continuous; mg/dL or μmol/L) Plasma/serum urea or blood urea nitrogen (continuous; mg/dL or μmol/L) Creatinine clearance (continuous; mL/min) Glomerular filtration rate (continuous; mL/min) Urinary albumin/protein excretion (continuous; μg/hour (excretion rate) or μg/mg (normalised to urinary creatinine)) Histological parameters of renal injury (continuous; arbitrary units) Kidney size parameters (continuous; grams (kidney weight) or percentage (kidney weight/body weight ratio)) Kidney cyst size parameters (continuous; mL (kidney cyst volume) or percentage (kidney cystic index)
Secondary	Mechanistic mediators explored (all categorical; yes/no) Renal fibrosis Renal inflammation Renal oxidative stress Renal apoptosis Renal epithelial-to-mesenchymal transition Renal lipotoxicity Renal glucotoxicity Renal nicotinamide adenine dinucleotide metabolism Urinary biochemical evidence of renal injury (biomarkers) Neutrophil gelatinase-associated lipocalin (continuous; μg/hour (excretion rate) or μg/mg (normalised to urinary creatinine)) Kidney injury molecule-1 (continuous; μg/hour (excretion rate) or μg/mg (normalised to urinary creatinine)) Metabolic parameters Body weight (continuous; g) Glycaemia Circulating glucose (continuous; mg/dL or mmol/L) HbA1c (continuous; % or mmol/mol) Fructosamine (continuous; mg/dL or mmol/L) Dyslipidaemia (all continuous; mg/dL or mmol/L) Circulating total cholesterol LDL-cholesterol HDL-cholesterol Triglycerides Blood pressure (all continuous; mm Hg) Systolic blood pressure Diastolic blood pressure Mean arterial blood pressure Safety outcomes Hepatotoxicity Liver enzyme elevation (continuous; mg/dL or mmol/L) Histological evidence of liver injury (categorical; yes/no) Cardiotoxicity Ejection fraction (continuous; %) Heart failure (categorical; yes/no) Histological evidence of cardiac injury (categorical; yes/no) Carcinogenicity Tumour development (categorical; yes/no) Tumour site (categorical; organ) Mortality Mortality (categorical; yes/no) Number who died (continuous; n) Timing of death from start of intervention (continuous; days/weeks/months)

AKI, acute kidney injury; CAMARADES, Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies; CKD, chronic kidney disease; HbA_1c, glycated haemoglobin; HDL, high-density lipoprotein; LDL, low-density lipoprotein; PPAR, peroxisome proliferator-activated receptor; SYRCLE, Systematic Review Centre for Laboratory Animal Experimentation.