Day to Day Variability and Effects of Collection Conditions on Urinary Renin‐Angiotensin‐Aldosterone System Biomarkers in Vervet Monkeys ( Chlorocebus aethiops sabaeus )

Q: What is the clinical evidence from this study?

Population: Healthy adult vervet monkeys (Chlorocebus aethiops sabaeus) (n=6). Intervention: Sedated cystocentesis urine collection (intramuscular ketamine and inhaled isoflurane) vs. Non-sedated free catch (FC) urine collection. Primary outcome: Day-to-day variability (coefficient of variation, CV) and concentration differences in creatinine-normalized urinary RAAS biomarkers (ACE, ACE2, Ang-(1-7), Ang II, aldosterone, alpha-klotho) and urine creatinine (p=0.044).

Q: What does this research mean for the field?

Urinary renin-angiotensin-aldosterone system biomarkers in vervet monkeys exhibit high day-to-day within-animal variability and differ significantly between non-sedated free catch and sedated cystocentesis collection methods. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

Mary Elaine Graham; Kelli Carter; TanYa M. Gwathmey; Sarah N. Cilvik

doi:10.1111/jmp.70131

November 11, 2026Journal of Medical PrimatologyOpen Access

Day to Day Variability and Effects of Collection Conditions on Urinary Renin‐Angiotensin‐Aldosterone System Biomarkers in Vervet Monkeys ( Chlorocebus aethiops sabaeus )

View Full Paper

Ask AI

Bookmark

Share

Key result

Urinary RAAS biomarkers exhibit high daily variability and vary significantly by urine collection method.

P=0.044
n=6

Figures

Why the study?

Dysregulation of the RAAS is associated with cardiovascular and renal disease, motivating evaluation of daily variability in urinary RAAS biomarkers and differences between non-sedated free catch and sedated cystocentesis samples in vervet monkeys.

Does urine collection via sedated cystocentesis alter urinary renin-angiotensin-aldosterone system (RAAS) biomarker concentrations and day-to-day variability compared to non-sedated free catch collection in healthy adult vervet monkeys?

Key Points

To evaluate the day-to-day variability of urinary renin-angiotensin-aldosterone system (RAAS) biomarkers and assess concentration differences between non-sedated free catch and sedated cystocentesis collection conditions in vervet monkeys.
Collected repeated urine samples (six non-sedated free catch and three sedated cystocentesis) from six adult vervet monkeys (Chlorocebus aethiops sabaeus; three males, three females, mean age 7.61 ± 0.78 years).
Measured concentrations of creatinine and RAAS biomarkers—including ACE, ACE2, Ang-(1-7), Ang II, aldosterone, and alpha-klotho—via radioimmunoassays and ELISAs, normalizing RAAS analytes to creatinine.
Assessed day-to-day variability across repeated samples using coefficients of variation (CV) and evaluated sedation and collection effects using linear mixed-effects models with false discovery rate correction.
Urinary analytes demonstrated high to very high within-animal variability, with CVs ranging from 28.17% to 103.03%.
Angiotensin-converting enzyme exhibited the lowest overall variability, observed during cystocentesis sampling with a CV of 28.17% ± 18.28%.
Concentrations of creatinine, Angiotensin-(1-7), Angiotensin II, and aldosterone differed between non-sedated free catch and sedated cystocentesis samples.

Structured PICO

Does urine collection via sedated cystocentesis alter urinary renin-angiotensin-aldosterone system (RAAS) biomarker concentrations and day-to-day variability compared to non-sedated free catch collection in healthy adult vervet monkeys?

P

Population

6 healthy adult vervet monkeys (mean age 7.61 years, 50% female) undergoing repeated non-sedated free catch and sedated cystocentesis urine sampling over 11 days.

I

Intervention

Sedated cystocentesis urine collection (3 samples per monkey over 11 days) performed under ultrasound guidance within 15 minutes of starting 1%-2% inhaled isoflurane gas anesthesia following intramuscular ketamine (15 mg/kg) sedation and at least 12 hours of fasting.

C

Comparator

Non-sedated free catch (FC) urine collection aspirated from clean cage pans (6 samples per monkey over 11 days; 3 fasted and matched to cystocentesis days, 3 non-fasted).

O

Outcome

Day-to-day within-animal variability (coefficient of variation, CV) and concentration differences between collection methods for urine creatinine and creatinine-normalized urinary RAAS biomarkers (ACE, ACE2, Ang-(1-7), Ang II, aldosterone, and alpha-klotho) over an 11-day sampling schedule.surrogate

Main Result

p-value: p=0.044

Substantial day-to-day variability and significant differences between non-sedated free catch and sedated cystocentesis samples demonstrate that single-timepoint urinary RAAS measurements are insufficient in nonhuman primate models and require standardized collection protocols with repeated sampling.

Limitations

Small sample size of only six vervets limited statistical power to detect modest differences
Different number of repeated samples between collection methods (6 free catch vs. 3 cystocentesis)
Free catch variability estimates combined fasted and non-fasted conditions, and some data points were missing
Unequal sampling intervals between collections
Included only healthy adult vervets, limiting generalizability to disease models
Sedation and collection method were inseparable, making it difficult to isolate their individual effects
Imprecise timing of ketamine sedation to sample collection due to transport and protocol logistics
Different number of repeated samples between collection methods (6 FC vs. 3 cystocentesis)
FC variability estimates combined fasted and non-fasted conditions, and some data were missing or excluded
Unequal sampling intervals across the study period
Study included only healthy adult vervets, so variability patterns may differ in animals with hypertension or renal disease
Sedation and collection method were inseparable, preventing isolation of their individual effects
Imprecise timing from ketamine sedation to sample collection due to animal transport and protocol logistics

Ask about this paper

Answers are grounded in this paper and cite their sources.

Implication

High variability and collection differences caution against single urinary RAAS measurements in primate models; leaves open standardized repeated sampling for translational research.

Abstract

BACKGROUND: Dysregulation of the renin-angiotensin-aldosterone system (RAAS) is associated with cardiovascular and renal disease. Our objectives were to determine the daily variability in urinary RAAS biomarkers and differences between non-sedated free catch (FC) and sedated cystocentesis samples in vervet monkeys. METHODS: We performed repeated urine collections (six non-sedated FC, three sedated cystocentesis) from six adult vervets (Chlorocebus aethiops sabaeus). We quantified RAAS components, normalized to urine creatinine. We assessed variability using coefficients of variation (CV) and compared sedation effects using linear mixed-effects models with false discovery rate correction. RESULTS: Analytes showed high to very high variability (CV 28.17%-103.03%). Angiotensin converting enzyme demonstrated the lowest variability (cystocentesis, CV 28.17% ± 18.28%). Creatinine, Angiotensin-(1-7), Angiotensin II, and aldosterone concentrations differed between non-sedated FC and sedated cystocentesis samples. CONCLUSIONS: Substantial within-animal variability suggests that single-timepoint measurements insufficiently characterize urinary RAAS in vervets. Differences between collection conditions support standardization of collection methods and repeated sampling.

Discussion

No takes yet. Share an insight, caveat, or question.

Cite This Study

Graham et al. (2026) studied Healthy adult vervet monkeys (Chlorocebus aethiops sabaeus) (n=6). Sedated cystocentesis urine collection (intramuscular ketamine and inhaled isoflurane) vs. Non-sedated free catch (FC) urine collection was evaluated on Day-to-day variability (coefficient of variation, CV) and concentration differences in creatinine-normalized urinary RAAS biomarkers (ACE, ACE2, Ang-(1-7), Ang II, aldosterone, alpha-klotho) and urine creatinine (p=0.044). Urinary RAAS biomarkers in vervet monkeys showed high daily variability and differed between sedated cystocentesis and free catch samples.

synapsesocial.com/papers/6af5cd26a40bbe8669e89c24 https://doi.org/10.1111/jmp.70131

View Full Paper

Ask AI

Bookmark

Share

Day to Day Variability and Effects of Collection Conditions on Urinary Renin‐Angiotensin‐Aldosterone System Biomarkers in Vervet Monkeys ( Chlorocebus aethiops sabaeus )

Figures

Key Points

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Day to Day Variability and Effects of Collection Conditions on Urinary Renin‐Angiotensin‐Aldosterone System Biomarkers in Vervet Monkeys ( Chlorocebus aethiops sabaeus )

Figures

Key Points

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Keep reading

Keep reading