Butyrate enhances the intestinal barrier by facilitating tight junction assembly via activation of AMP-activated protein kinase in Caco-2 cell monolayers

Butyrate, one of the SCFA, promotes the development of the intestinal barrier. However, the molecular mechanisms underlying the butyrate regulation of the intestinal barrier are unknown. To test the hypothesis that the effect of butyrate on the intestinal barrier is mediated by the regulation of the assembly of tight junctions involving the activation of the AMP-activated protein kinase (AMPK), we determined the effect of butyrate on the intestinal barrier by measuring the transepithelial electrical resistance (TER) and inulin permeability in a Caco-2 cell monolayer model. We further used a calcium switch assay to study the assembly of epithelial tight junctions and determined the effect of butyrate on the assembly of epithelial tight junctions and AMPK activity. We demonstrated that the butyrate treatment increased AMPK activity and accelerated the assembly of tight junctions as shown by the reorganization of tight junction proteins, as well as the development of TER. AMPK activity was also upregulated by butyrate during calcium switch-induced tight junction assembly. Compound C, a specific AMPK inhibitor, inhibited the butyrate-induced activation of AMPK. The facilitating effect of butyrate on the increases in TER in standard culture media, as well as after calcium switch, was abolished by compound C. We conclude that butyrate enhances the intestinal barrier by regulating the assembly of tight junctions. This dynamic process is mediated by the activation of AMPK. These results suggest an intriguing link between SCFA and the intracellular energy sensor for the development of the intestinal barrier.

Clearance of Alzheimer's amyloid-ss(1-40) peptide from brain by LDL receptor-related protein-1 at the blood-brain barrier

Elimination of amyloid-ss peptide (Ass) from the brain is poorly understood. After intracerebral microinjections in young mice, (125)I-Ass(1-40) was rapidly removed from the brain (t(1/2) Collapse

Key Words Collapse

MESH Headings

• Aging/physiology
• Alzheimer Disease/metabolism
• Amino Acid Sequence
• Amyloid beta-Peptides/metabolism
• Amyloid beta-Peptides/pharmacokinetics
• Animals
• Apolipoproteins E/genetics
• Apolipoproteins E/metabolism
• Biological Transport
• Blood-Brain Barrier
• Brain/metabolism
• Brain/pathology
• Catheterization
• Genotype
• Half-Life
• Humans
• Immunohistochemistry
• Inulin/metabolism
• Iodine Radioisotopes
• Kinetics
• Low Density Lipoprotein Receptor-Related Protein-1
• Male
• Mice
• Mice, Inbred C57BL
• Mice, Knockout
• Molecular Sequence Data
• Peptide Fragments/metabolism
• Peptide Fragments/pharmacokinetics
• Receptors, Immunologic/metabolism
• alpha-Macroglobulins/metabolism

Collapse

Grants

• R01 HL050784 NHLBI NIH HHS
• P50 AG005142 NIA NIH HHS
• NS33466 NINDS NIH HHS
• R01 AG013956 NIA NIH HHS
• R37 AG013956 NIA NIH HHS
• AG05891 NIA NIH HHS
• R01 NS038777 NINDS NIH HHS
• AG16223 NIA NIH HHS
• R37 AG005891 NIA NIH HHS

Collapse

Collaborators Collapse

Specificity of polysaccharide use in intestinal bacteroides species determines diet-induced microbiota alterations

The intestinal microbiota impacts many facets of human health and is associated with human diseases. Diet impacts microbiota composition, yet mechanisms that link dietary changes to microbiota alterations remain ill-defined. Here we elucidate the basis of Bacteroides proliferation in response to fructans, a class of fructose-based dietary polysaccharides. Structural and genetic analysis disclosed a fructose-binding, hybrid two-component signaling sensor that controls the fructan utilization locus in Bacteroides thetaiotaomicron. Gene content of this locus differs among Bacteroides species and dictates the specificity and breadth of utilizable fructans. BT1760, an extracellular beta2-6 endo-fructanase, distinguishes B. thetaiotaomicron genetically and functionally, and enables the use of the beta2-6-linked fructan levan. The genetic and functional differences between Bacteroides species are predictive of in vivo competitiveness in the presence of dietary fructans. Gene sequences that distinguish species' metabolic capacity serve as potential biomarkers in microbiomic datasets to enable rational manipulation of the microbiota via diet.

The bifidogenic nature of chicory inulin and its hydrolysis products

Research data on the bifidogenic effect of beta(2-1)fructans, which at present are commercialized in the U.S., Japan and Europe as food ingredients, are presented. These food ingredients originate from two different sources. Short-chain fructo-oligosaccharides are synthesized from sucrose and are composed of GFn [n beta(2-1) linked fructose moieties bound to a glucose molecule; 2 10 are fermented on average half as quickly as molecules with a DP < 10. All beta(2-1)fructans are bifidogenic and classified as biobiotics.

Effects of the in vitro fermentation of oligofructose and inulin by bacteria growing in the human large intestine

The in vitro fermentability of oligofructose and inulin was compared with a range of reference carbohydrates by measuring bacterial end-product formation in batch culture. Short chain fatty acid and gas formation indicated that these substrates, which occur naturally in the diet and reach the colon in a largely intact form, were utilized by mixed populations of gut bacteria. Bacterial growth data showed that oligofructose and inulin exerted a preferential stimulatory effect on numbers of the health-promoting genus Bifidobacterium, whilst maintaining populations of potential pathogens (Escherichia coli, Clostridium) at relatively low levels. Pure culture studies confirmed the enhanced ability of bifidobacteria to utilize these substrates in comparison with glucose. Batch culture experiments demonstrated that the growth of Bifidobacterium infantis had an inhibitory effect towards E. coli and Clostridium perfringens. Potentially, an increase in the concentration of these substrates in the diet may therefore improve the composition of the large intestinal microflora and have positive effects on the quality of the Western diet.

Prebiotic digestion and fermentation

Prebiotics, as currently conceived of, are all carbohydrates of relatively short chain length. To be effective they must reach the cecum. Present evidence concerning the 2 most studied prebiotics, fructooligosaccharides and inulin, is consistent with their resisting digestion by gastric acid and pancreatic enzymes in vivo. However, the wide variety of new candidate prebiotics becoming available for human use requires that a manageable set of in vitro tests be agreed on so that their nondigestibility and fermentability can be established without recourse to human studies in every case. In the large intestine, prebiotics, in addition to their selective effects on bifidobacteria and lactobacilli, influence many aspects of bowel function through fermentation. Short-chain fatty acids are a major product of prebiotic breakdown, but as yet, no characteristic pattern of fermentation acids has been identified. Through stimulation of bacterial growth and fermentation, prebiotics affect bowel habit and are mildly laxative. Perhaps more importantly, some are a potent source of hydrogen in the gut. Mild flatulence is frequently observed by subjects being fed prebiotics; in a significant number of subjects it is severe enough to be unacceptable and to discourage consumption. Prebiotics are like other carbohydrates that reach the cecum, such as nonstarch polysaccharides, sugar alcohols, and resistant starch, in being substrates for fermentation. They are, however, distinctive in their selective effect on the microflora and their propensity to produce flatulence.

Effects of butyrate on intestinal barrier function in a Caco-2 cell monolayer model of intestinal barrier

Production of short-chain fatty acids (SCFA) in the intestinal lumen may play an important role in the maintenance of the intestinal barrier. However, overproduction/accumulation of SCFA in the bowel may be toxic to the intestinal mucosa and has been hypothesized to play a role in the pathogenesis of neonatal necrotizing enterocolitis (NEC). By using a Caco-2 cell monolayer model of intestinal barrier, we report here that the effect of butyrate on the intestinal barrier is paradoxical. Butyrate at a low concentration (2 mM) promotes intestinal barrier function as measured by a significant increase in transepithelial electrical resistance (TER) and a significant decrease in inulin permeability. Butyrate at a high concentration (8 mM) reduces TER and increases inulin permeability significantly. Butyrate induces apoptosis and reduces the number of viable Caco-2 cells in a dose-dependent manner. Intestinal barrier function impairment induced by high concentrations of butyrate is most likely related to butyrate-induced cytotoxicity due to apoptosis. We conclude that the effect of butyrate on the intestinal barrier is paradoxical; i.e. whereas low concentrations of butyrate may be beneficial in promoting intestinal barrier function, excessive butyrate may induce severe intestinal epithelial cell apoptosis and disrupt intestinal barrier.

Fermentation of fructooligosaccharides and inulin by bifidobacteria: a comparative study of pure and fecal cultures

The utilization of fructooligosaccharides (FOS) and inulin by 55 Bifidobacterium strains was investigated. Whereas FOS were fermented by most strains, only eight grew when inulin was used as the carbon source. Residual carbohydrates were analyzed by high-performance anion-exchange chromatography with pulsed amperometric detection after batch fermentation. A strain-dependent capability to degrade fructans of different lengths was observed. During batch fermentation on inulin, the short fructans disappeared first, and then the longer ones were gradually consumed. However, growth occurred through a single uninterrupted exponential phase without exhibiting polyauxic behavior in relation to the chain length. Cellular beta-fructofuranosidases were found in all of the 21 Bifidobacterium strains tested. Four strains were tested for extracellular hydrolytic activity against fructans, and only the two strains which ferment inulin showed this activity. Batch cultures inoculated with human fecal slurries confirmed the bifidogenic effect of both FOS and inulin and indicated that other intestinal microbial groups also grow on these carbon sources. We observed that bifidobacteria grew by cross-feeding on mono- and oligosaccharides produced by primary inulin intestinal degraders, as evidenced by the high hydrolytic activity of fecal supernatants. FOS and inulin greatly affected the production of short-chain fatty acids in fecal cultures; butyrate was the major fermentation product on inulin, whereas mostly acetate and lactate were produced on FOS.

Prebiotic inulin-type fructans induce specific changes in the human gut microbiota

OBJECTIVE

Contrary to the long-standing prerequisite of inducing selective (ie, bifidogenic) effects, recent findings suggest that prebiotic interventions lead to ecosystem-wide microbiota shifts. Yet, a comprehensive characterisation of this process is still lacking. Here, we apply 16S rDNA microbiota profiling and matching (gas chromatography mass spectrometry) metabolomics to assess the consequences of inulin fermentation both on the composition of the colon bacterial ecosystem and faecal metabolites profiles.

DESIGN

Faecal samples collected during a double-blind, randomised, cross-over intervention study set up to assess the effect of inulin consumption on stool frequency in healthy adults with mild constipation were analysed. Faecal microbiota composition and metabolite profiles were linked to the study's clinical outcome as well as to quality-of-life measurements recorded.

RESULTS

While faecal metabolite profiles were not significantly altered by inulin consumption, our analyses did detect a modest effect on global microbiota composition and specific inulin-induced changes in relative abundances of Anaerostipes, Bilophila and Bifidobacterium were identified. The observed decrease in Bilophila abundances following inulin consumption was associated with both softer stools and a favourable change in constipation-specific quality-of-life measures.

CONCLUSIONS

Ecosystem-wide analysis of the effect of a dietary intervention with prebiotic inulin-type fructans on the colon microbiota revealed that this effect is specifically associated with three genera, one of which (Bilophila) representing a promising novel target for mechanistic research.

TRIAL REGISTRATION NUMBER

NCT02548247.

Occluding junction structure-function relationships in a cultured epithelial monolayer

Electrical circuit analysis was used to study the structural development of occluding junctions (OJs) in cultured monolayers composed to T84 cells. The magnitude of the increments in transepithelial resistance predicted by such analysis was compared with the magnitude of the measured increments in resistance. Confluent sheets of epithelial cells were formed after cells were plated at high density on collagen-coated filters. Using Claude's OJ strand count-resistance hypothesis (1978, J. Membr. Biol. 39:219-232), electrical circuit analysis of histograms describing OJ strand count distribution at different time points after plating predicted that junctional resistance should rise in a proportion of 1:21:50 from 18 h to 2 d to 5 d. This reasonably paralleled the degree of rise in transepithelial resistance over this period, which was 1:29:59. The ability to predict the observed resistance rise was eliminated if only mean strand counts were analyzed or if electrical circuit analysis of OJ strand counts were performed using an OJ strand count-resistance relationship substantially different from that proposed by Claude. Measurements of unidirectional fluxes of inulin, mannitol, and sodium indicated that restriction of transjunctional permeability accounted for the observed resistance rise, and that T84 junctional strands have finite permeability to molecules with radii less than or equal to 3.6 A but are essentially impermeable to molecules with radii greater than or equal to 15 A. The results suggest that general correlates between OJ structure and OJ ability to resist passive ion flow do exist in T84 monolayers. The study also suggests that such correlates can be obtained only if OJ structural data are analyzed as an electrical circuit composed of parallel resistors.

Renal functional reserve in humans. Effect of protein intake on glomerular filtration rate

This study was designed to investigate the effect of protein intake on glomerular filtration rate, and to demonstrate and evaluate the functional reserve of the kidney. Normal subjects ingesting a protein diet had a significantly higher creatinine clearance than a comparable group of normal subjects ingesting a vegetarian diet. A progressive increment in protein intake in normal volunteers resulted in a significant increase in creatinine clearance. Diurnal variations in creatinine clearance were found. These daily variations correlated well with the periods of food intake. The capacity of the kidney to increase its level of function with protein intake suggests a renal function reserve. In short-term studies, the effect of a protein load on glomerular filtration rate was evaluated. Normal subjects showed an increase in glomerular filtration rate two and a half hours after protein load to a maximal glomerular filtration rate of 171.0 +/- 7.7 ml per minute. In patients with a reduced number of nephrons, renal functional reserve may be diminished or absent.

Contribution of acetate to butyrate formation by human faecal bacteria

Acetate is normally regarded as an endproduct of anaerobic fermentation, but butyrate-producing bacteria found in the human colon can be net utilisers of acetate. The butyrate formed provides a fuel for epithelial cells of the large intestine and influences colonic health. [1-(13)C]Acetate was used to investigate the contribution of exogenous acetate to butyrate formation. Faecalibacterium prausnitzii and Roseburia spp. grown in the presence of 60 mm-acetate and 10 mm-glucose derived 85-90 % butyrate-C from external acetate. This was due to rapid interchange between extracellular acetate and intracellular acetyl-CoA, plus net acetate uptake. In contrast, a Coprococcus-related strain that is a net acetate producer derived only 28 % butyrate-C from external acetate. Different carbohydrate-derived energy sources affected butyrate formation by mixed human faecal bacteria growing in continuous or batch cultures. The ranking order of butyrate production rates was amylopectin > oat xylan > shredded wheat > inulin > pectin (continuous cultures), and inulin > amylopectin > oat xylan > shredded wheat > pectin (batch cultures). The contribution of external acetate to butyrate formation in these experiments ranged from 56 (pectin) to 90 % (xylan) in continuous cultures, and from 72 to 91 % in the batch cultures. This is consistent with a major role for bacteria related to F. prausnitzii and Roseburia spp. in butyrate formation from a range of substrates that are fermented in the large intestine. Variations in the dominant metabolic type of butyrate producer between individuals or with variations in diet are not ruled out, however, and could influence butyrate supply in the large intestine.

Dietary synbiotics reduce cancer risk factors in polypectomized and colon cancer patients

BACKGROUND

Animal studies suggest that prebiotics and probiotics exert protective effects against tumor development in the colon, but human data supporting this suggestion are weak.

OBJECTIVE

The objective was to verify whether the prebiotic concept (selective interaction with colonic flora of nondigested carbohydrates) as induced by a synbiotic preparation-oligofructose-enriched inulin (SYN1) + Lactobacillus rhamnosus GG (LGG) and Bifidobacterium lactis Bb12 (BB12)-is able to reduce the risk of colon cancer in humans.

DESIGN

The 12-wk randomized, double-blind, placebo-controlled trial of a synbiotic food composed of the prebiotic SYN1 and probiotics LGG and BB12 was conducted in 37 colon cancer patients and 43 polypectomized patients. Fecal and blood samples were obtained before, during, and after the intervention, and colorectal biopsy samples were obtained before and after the intervention. The effect of synbiotic consumption on a battery of intermediate bio-markers for colon cancer was examined.

RESULTS

Synbiotic intervention resulted in significant changes in fecal flora: Bifidobacterium and Lactobacillus increased and Clostridium perfringens decreased. The intervention significantly reduced colorectal proliferation and the capacity of fecal water to induce necrosis in colonic cells and improve epithelial barrier function in polypectomized patients. Genotoxicity assays of colonic biopsy samples indicated a decreased exposure to genotoxins in polypectomized patients at the end of the intervention period. Synbiotic consumption prevented an increased secretion of interleukin 2 by peripheral blood mononuclear cells in the polypectomized patients and increased the production of interferon gamma in the cancer patients.

CONCLUSIONS

Several colorectal cancer biomarkers can be altered favorably by synbiotic intervention.

Inulin-type fructans modulate gastrointestinal peptides involved in appetite regulation (glucagon-like peptide-1 and ghrelin) in rats

The hypothesis tested in the present study is that dietary fructans are able to modulate gastrointestinal peptides involved in the control of food intake, namely glucagon-like peptide (GLP)-1 (7-36) amide and ghrelin. After 3 weeks of treatment with a standard diet (control) or the same diet enriched with 100 g fructans varying in their degrees of polymerization (oligofructose (OFS), Synergy 1 (Syn) or long chain inulin)/kg, male Wistar rats were deprived of food for 8 h before sample collection. Dietary energy intake throughout the experiment was significantly lower (P<0.05) in fructans-fed rats than in control rats, leading to a significant decrease (P<0.01) in epidydimal fat mass at the end of the treatment in OFS- and Syn-treated rats. GLP-1 (7-36) amide concentration in portal vein serum was higher in OFS- and Syn-fed than in control rats. Both GLP-1 (7-36) amide concentration and proglucagon mRNA concentrations were significantly greater (P<0.05) in the proximal colonic mucosa of fructans-fed rats v. controls. Normally active ghrelin concentration in plasma increases during food deprivation and rapidly falls during a meal. In the present study, after 8 h of food deprivation, active ghrelin in the plasma remained significantly lower (P<0.05) in OFS and Syn-fed than in control rats. These results are in accordance with the modifications of dietary intake and fat-mass development in short-chain fructans-treated rats and demonstrate the potential modulation of GLP-1 (7-36) amide and ghrelin by fermentable fibres such as fructans, which are rapidly and extensively fermented in the proximal part of the colon.

Potential role of MCP-1 in endothelial cell tight junction 'opening': signaling via Rho and Rho kinase

The expression of the monocyte chemoattractant protein-1 (MCP-1) receptor CCR2 by brain endothelial cells suggests that MCP-1 may have other functions than purely driving leukocyte migration into brain parenchyma during inflammation. This study examines one of these potential novel roles of MCP-1 regulation of endothelial permeability using primary cultures of mouse brain endothelial cells. MCP-1 induces reorganization of actin cytoskeleton (stress fiber formation) and redistribution of tight junction proteins, ZO-1, ZO-2 occludin and claudin-5, from the Triton X-100-soluble to the Triton X-100-insoluble fractions. These morphological changes are associated with a decrease in transendothelial electrical membrane resistance and an increase in [14C]inulin permeability. MCP-1 did not induce these events in brain endothelial cells prepared from mice genotype CCR2-/-. The Rho kinase inhibitor Y27632 and inhibition of Rho (C3 exoenzyme, and dominant negative mutant of Rho, RhoT19N) prevented MCP-1-induced stress fiber assembly, reorganization of tight junction proteins and alterations in endothelial permeability. In all, this suggests that a small GTPase Rho and Rho kinase have a pivotal role in MCP-1-induced junction disarrangement. These data are the first to strongly suggest that MCP-1, via CCR2 present on brain endothelial cells, contributes to increased brain endothelial permeability.

Probiotics ameliorate the hydrogen peroxide-induced epithelial barrier disruption by a PKC- and MAP kinase-dependent mechanism

Probiotics promote intestinal epithelial integrity and reduce infection and diarrhea. We evaluated the effect of Lactobacillus rhamnosus GG-produced soluble proteins (p40 and p75) on the hydrogen peroxide-induced disruption of tight junctions and barrier function in Caco-2 cell monolayers. Pretreatment of cell monolayers with p40 or p75 attenuated the hydrogen peroxide-induced decrease in transepithelial resistance and increase in inulin permeability in a time- and dose-dependent manner. p40 and p75 also prevented hydrogen peroxide-induced redistribution of occludin, ZO-1, E-cadherin, and beta-catenin from the intercellular junctions and their dissociation from the detergent-insoluble fractions. Both p40 and p75 induced a rapid increase in the membrane translocation of PKCbetaI and PKCepsilon. The attenuation of hydrogen peroxide-induced inulin permeability and redistribution of tight junction proteins by p40 and p75 was abrogated by Ro-32-0432, a PKC inhibitor. p40 and p75 also rapidly increased the levels of phospho-ERK1/2 in the detergent-insoluble fractions. U0126 (a MAP kinase inhibitor) attenuated the p40- and p75-mediated reduction of hydrogen peroxide-induced tight junction disruption and inulin permeability. These studies demonstrate that probiotic-secretory proteins protect the intestinal epithelial tight junctions and the barrier function from hydrogen peroxide-induced insult by a PKC- and MAP kinase-dependent mechanism.

Symmetric dimethylarginine (SDMA) as endogenous marker of renal function--a meta-analysis

BACKGROUND

Dosing of most drugs must be adapted in renal insufficiency, making accurate assessment of renal function essential in clinical medicine. Furthermore, even modest impairment of renal function has been recognized as a cardiovascular risk factor. The purpose of this analysis was to identify the role of symmetric dimethylarginine (SDMA), the structural isomer of the cardiovascular risk marker asymmetric dimethylarginine, as an endogenous marker of renal function.

METHODS

Comprehensive searches of Medline and the Cochrane Library from 1970 to February 2006 were performed to identify studies that evaluated the correlation between SDMA and renal function. The search was augmented by scanning references of identified articles and reviews. The correlation coefficients (R) were recorded from each study for the values of 1/SDMA and clearance estimates and for SDMA and creatinine levels. The summary correlation coefficients with 95% confidence intervals (CIs) were pooled using the random-effects method.

RESULTS

In 18 studies involving 2136 patients systemic SDMA concentrations correlated highly with inulin clearance [R = 0.85 (CI 0.76-0.91, P < 0.0001)], as well as with various clearance estimates combined [R = 0.77 (CI 0.65-0.85, P < 0.0001)] and serum creatinine [R = 0.75 (CI 0.46-089, P < 0.0001)].

CONCLUSIONS

SDMA exhibits some properties of a reliable marker of renal function. Future studies have to clarify whether SDMA is indeed suited to improve diagnosis and eventually optimize care of patients.

Probiotics: determinants of survival and growth in the gut

Bifidobacteria and lactobacilli are purportedly beneficial to human health and are called probiotics. Their survival during passage through the human gut, when administered in fermented milk products, has been investigated intensely in recent years. Well-controlled, small-scale studies on diarrhea in both adults and infants have shown that probiotics are beneficial and that they survive in sufficient numbers to affect gut microbial metabolism. Survival rates have been estimated at 20-40% for selected strains, the main obstacles to survival being gastric acidity and the action of bile salts. Although it is believed that the maximum probiotic effect can be achieved if the organisms adhere to intestinal mucosal cells, there is no evidence that exogenously administered probiotics do adhere to the mucosal cells. Instead, they seem to pass into the feces without having adhered or multiplied. Thus, to obtain a continuous exogenous probiotic effect, the probiotic culture must be ingested continually. Certain exogenously administered substances enhance the action of both exogenous and endogenous probiotics. Human milk contains many substances that stimulate the growth of bifidobacteria in vitro and also in the small intestine of infants; however, it is unlikely that they function in the colon. However, lactulose and certain fructose-containing compounds, called prebiotics, are not digested in the small intestine but pass into the cecum unchanged, where they are selectively utilized by probiotics. Beneficial effects may thus accrue from exogenously administered probiotics, often administered with prebiotics, or by endogenous bifidobacteria and lactobacilli, whose metabolic activity and growth may also be enhanced by the administration of prebiotics.

Cystatin C--a new marker of glomerular filtration rate in children independent of age and height

OBJECTIVES

Serum creatinine is the most common endogenous marker of renal function. The proportionality between creatinine production and muscle mass requires adjustment for height and body composition. The low molecular weight protein cystatin C is produced by all nucleated cells and eliminated by glomerular filtration. Therefore, cystatin C was studied as an alternative marker of glomerular filtration rate (GFR) in children.

METHODS

Cystatin C and creatinine were measured in sera from inulin clearance (CIn) examinations performed in 184 children aged 0.24 to 17.96 years. CIn ranged from 7 to 209 mL/min/1.73 m (median, 77).

RESULTS

The reciprocal of cystatin C correlated better with CIn (r = 0.88) than the reciprocal of creatinine (r = 0.72). Stepwise regression analysis identified no covariates for the correlation between cystatin C and CIn, whereas height was a covariate for creatinine. Using an estimate of GFR from serum creatinine and height, correlation with CIn was similar to cystatin C, but female gender and dystrophy were associated with an overestimation of GFR. Diagnostic accuracy in the identification of reduced GFR measured as area under the receiver-operating characteristic plot was 0.970 +/- 0.135 (mean +/- SE) for cystatin C and 0.894 +/- 0.131 for creatinine (NS). A cutoff cystatin C concentration of 1.39 mg/L had 90% sensitivity and 86% specificity for detecting abnormal GFR.

CONCLUSION

Unlike creatinine, serum cystatin C reflects renal function in children independent of age, gender, height, and body composition.