A Study of Creatine Metabolism in Diseases Causing Muscle Wasting *

Fitch, Coy D.; Sinton, David W.

doi:10.1172/jci104929

Cited by 79 publications

(48 citation statements)

References 14 publications

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“…Despite the strong association with protein intake, UCr remains predictive of outcomes even after adjustment for urine urea nitrogen. The nonenzymatic dehydration of creatine to creatinine appears to occur at a stable rate of roughly 1.6%-1.7% per day in healthy adults, but this rate is altered in disease states (16,42,43). We demonstrated a lower creatinine generation rate per kilogram of FFM among those with lower GFR.…”

Section: Discussionmentioning

confidence: 64%

Urinary Creatinine Excretion, Bioelectrical Impedance Analysis, and Clinical Outcomes in Patients with CKD

Wilson¹,

Xie²,

Anderson³

et al. 2014

Clinical Journal of the American Society of Nephrology

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Background and objectives Previous studies in chronic disease states have demonstrated an association between lower urinary creatinine excretion (UCr) and increased mortality, a finding presumed to reflect the effect of low muscle mass on clinical outcomes. Little is known about the relationship between UCr and other measures of body composition in terms of the ability to predict outcomes of interest.Design, setting, participants, & measurements Using data from the Chronic Renal Insufficiency Cohort (CRIC), the relationship between UCr, fat free mass (FFM) as estimated by bioelectrical impedance analysis, and (in a subpopulation) whole-body dual-energy x-ray absorptiometry assessment of appendicular lean mass were characterized. The associations of UCr and FFM with mortality and ESRD were compared using Cox proportional hazards models.Results A total of 3604 CRIC participants (91% of the full CRIC cohort) with both a baseline UCr and FFM measurement were included; of these, 232 had contemporaneous dual-energy x-ray absorptiometry measurements. Participants were recruited between July 2003 and March 2007. UCr and FFM were modestly correlated (rho=0.50; P,0.001), while FFM and appendicular lean mass were highly correlated (rho=0.91; P,0.001). Higher urinary urea nitrogen, black race, younger age, and lower serum cystatin C level were all significantly associated with higher UCr. Over a median (interquartile range) of 4.2 (3.1-5.0) years of follow-up, 336 (9.3%) participants died and 510 (14.2%) reached ESRD. Lower UCr was associated with death and ESRD even after adjustment for FFM (adjusted hazard ratio for death per 1 SD higher level of UCr, 0.63 [95% confidence interval, 0.56 to 0.72]; adjusted hazard ratio for ESRD per 1 SD higher level of UCr, 0.70 [95% confidence interval, 0.63 to 0.75]).Conclusions Among a cohort of individuals with CKD, lower UCr is associated with death and ESRD independent of FFM as assessed by bioelectrical impedance analysis.

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Section: Discussionmentioning

confidence: 64%

Urinary Creatinine Excretion, Bioelectrical Impedance Analysis, and Clinical Outcomes in Patients with CKD

Wilson¹,

Xie²,

Anderson³

et al. 2014

Clinical Journal of the American Society of Nephrology

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“…Although creatine is widely used as a dietary supplement, only few studies aimed to describe its pharmacokinetics (Fitch and Sinton 1964;Green et al 1996;Harris et al 1992;Schedel et al 1999;Vanakoski et al 1998). After ingestion of a single low dose, the time-course of plasma concentration is generally accepted to follow a one-open compartment model with first-order absorption and elimination constants (Persky et al 2003).…”

Section: Discussionmentioning

confidence: 99%

Kinetics of creatine ingested as a food ingredient

et al. 2007

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The aim of the present study was to test if the consumption of creatine incorporated in food bars modifies creatine plasma kinetics, erythrocyte retention and loss in urine and in feces when compared with its consumption in the form of an aqueous solution (AS). Seventeen healthy young men ingested 2 g creatine either in the form of AS, or incorporated in a protein (PP)-or in a beta-glucan (BG)-rich food bar. Kinetics of plasma creatine was measured for 8-h duration and urinary excretion for 24 h. Then, the subjects received the same treatment thrice a day for 1 week at the end of which creatine contents were determined in erythrocytes and in feces (n = 4 for feces). The three crossover treatments were interspaced by a 40 ± 1.2-day wash-out. Absorption of creatine was slowed down by 8-fold in the presence of BG (P \ 0.001) and by 4-fold with PP (P \ 0.001) whereas the velocity rate constant of elimination and the area under the curve were not modified. Urinary loss of creatine in the first 24 h following ingestion was 15 ± 1.9% in AS and 14 ± 2.2% in PP conditions (NS), whereas it was only 8 ± 1.2% with BG (P = 0.004). Increase in creatine concentration in erythrocyte was similar in whatever form the creatine was ingested. Creatine seems to be totally absorbed since no creatine or creatinine was detectable in feces. No side effects were reported. In conclusion, ingestion of creatine combined with BG facilitates its retention by slowing down its absorption rate and reducing its urinary excretion.

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“…In certain pediatric patient clientele, such as patients with spina bifi da (37) , neuromuscular disease, anorexia nervosa, or liver cirrhosis, serum creatinine is completely unusable because of the abnormal muscle mass in these children who are often wheelchair bound (38,39) . In addition, the production of creatinine is not constant; the rate of turnover is also variable (40) . It is also known that creatinine is also undergoing tubular secretion (41) .…”

Section: Limitations Of Serum Creatinine As Endogenous Marker Of Gfrmentioning

confidence: 99%

The usefulness of cystatin C and related formulae in pediatrics

Filler

Huang

Yasin

2012

Clinical Chemistry and Laboratory Medicine (CCLM)

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Serum creatinine does not share the properties of an ideal marker of glomerular fi ltration rate (GFR) like inulin, but continues to be the most widely used endogenous marker of GFR. In the search of a better biomarker of GFR, the small molecular weight protein cystatin C has been introduced with features more similar to that of inulin, such as constant production and no non-renal elimination. However, it has not enjoyed widespread use despite its signifi cantly improved diagnostic performance in the detection of impaired GFR and its independence of body composition. A variety of formulae based on either cystatin C or creatinine or both have been developed to estimate GFR. We summarize the currently used methods of GFR measurement, their limitations and analytical errors. The review also summarizes the history, features and the feasibility of cystatin C measurements as well as the most widely used formulae for the estimation of GFR in children. The diagnostic performance of the cystatin C derived eGFR formulae at various levels of GFR is also discussed. An eGFR formula derived from pooled studies analyzing both creatinine and cystatin C, and using a biology-based mathematical approach may be advantageous.

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A Study of Creatine Metabolism in Diseases Causing Muscle Wasting *

Cited by 79 publications

References 14 publications

Urinary Creatinine Excretion, Bioelectrical Impedance Analysis, and Clinical Outcomes in Patients with CKD

Urinary Creatinine Excretion, Bioelectrical Impedance Analysis, and Clinical Outcomes in Patients with CKD

Kinetics of creatine ingested as a food ingredient

The usefulness of cystatin C and related formulae in pediatrics

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