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Cardiac troponin I but not cardiac troponin T adheres to polysulfone dialyser membranes in an in vitro haemodialysis model: explanation for lower serum cTnI concentrations following dialysis.

Gaze DC, Collinson PO - Open Heart (2014)

Bottom Line: Serum cTnI was significantly lower (p=0.043) following a session of HD whereas cTnT concentrations were similar to those obtained before HD.The adherence of cTnI to the dialyser membrane is responsible for the observed decrease in serum cTnI following a session of dialysis.The adherence of cTnT or T-I-C complex to the dialyser membrane could not be demonstrated and supports the observation that pre-HD and post-HD serum concentrations of cTnT are similar.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Pathology , Clinical Blood Sciences, St George's Hospital & Medical School , London , UK.

ABSTRACT

Background: Elevated serum cardiac troponin T (cTnT) and I (cTnI) can occur in patients with chronic kidney disease. Differences in cTn concentrations between cTnT and cTnI have been reported but the mechanism of such discrepancy has not been investigated. This study investigates the clearance of cTn with the aid of an in vitro model of haemodialysis (HD).

Methods: Serum was obtained before and after a single session of dialysis from 53 patients receiving HD and assayed for cTnT and cTnI. An in vitro model of the dialysis process was used to investigate the mechanism of clearance of cTn during HD.

Results: Serum cTnI was significantly lower (p=0.043) following a session of HD whereas cTnT concentrations were similar to those obtained before HD. Using an in vitro model of dialysis, it was demonstrated that cTnI is not dialysed from the vascular compartment but adheres to the dialyser membrane.

Conclusions: The adherence of cTnI to the dialyser membrane is responsible for the observed decrease in serum cTnI following a session of dialysis. The adherence of cTnT or T-I-C complex to the dialyser membrane could not be demonstrated and supports the observation that pre-HD and post-HD serum concentrations of cTnT are similar.

No MeSH data available.


Related in: MedlinePlus

In vitro setup of simulated haemodialysis. (A) Blood compartment inlet; (B) blood compartment outlet; (C) dialysate outlet; (D) dialysate inlet; (E) dialysate reservoir; (F) water-driven vacuum pump; (G) efferent dialysate collection syringe.
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OPENHRT2014000108F1: In vitro setup of simulated haemodialysis. (A) Blood compartment inlet; (B) blood compartment outlet; (C) dialysate outlet; (D) dialysate inlet; (E) dialysate reservoir; (F) water-driven vacuum pump; (G) efferent dialysate collection syringe.

Mentions: In order to ascertain if cTnI crosses the dialyser membrane during the dialysis process or if it remains within the vascular compartment of the dialyser, dialysis membranes were examined after simulating the process of dialysis. Dialysate fluid and a volume of serum spiked with cTn (representing the blood compartment) were passed through the cuprophan membrane in counter-current flow, similar to that of dialysis. A water-driven vacuum pump was attached via the dialysate outlet and the tubing cannulated for effluent dialysate sample collection. The inlet was connected to a 5 L reservoir containing dialysate fluid (figure 1). Renalyte acid concentrate bicarbonate dialysate fluid (Fresenius Medical Care, Nottinghamshire, UK) was reconstituted 1 to 1.26 to 32.78 in 8.4% sodium hydrogen carbonate and reagent grade water, respectively, as per the recommended protocol of the manufacturers. The final solution had the following composition: Na+ 103 mmol/L, K+ 2 mmol/L, Ca++ 1.25 mmol/L, Mg++ 0.5 mmol/L, Cl− 108.5 mmol/L, CH3COO− 3 mmol/L and glucose 5.6 mmol/L. An aliquot of the renalyte dialysate fluid working solution was tested for possible interference in the cTnT and cTnI assays. The counter-current flow rate of dialysis fluid (Qd) was controlled at 200 mL/min. The membranes were primed with 200 mL dialysate and an effluent sample was collected for cTnT and cTnI assay testing before introduction of the blood component.


Cardiac troponin I but not cardiac troponin T adheres to polysulfone dialyser membranes in an in vitro haemodialysis model: explanation for lower serum cTnI concentrations following dialysis.

Gaze DC, Collinson PO - Open Heart (2014)

In vitro setup of simulated haemodialysis. (A) Blood compartment inlet; (B) blood compartment outlet; (C) dialysate outlet; (D) dialysate inlet; (E) dialysate reservoir; (F) water-driven vacuum pump; (G) efferent dialysate collection syringe.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4195923&req=5

OPENHRT2014000108F1: In vitro setup of simulated haemodialysis. (A) Blood compartment inlet; (B) blood compartment outlet; (C) dialysate outlet; (D) dialysate inlet; (E) dialysate reservoir; (F) water-driven vacuum pump; (G) efferent dialysate collection syringe.
Mentions: In order to ascertain if cTnI crosses the dialyser membrane during the dialysis process or if it remains within the vascular compartment of the dialyser, dialysis membranes were examined after simulating the process of dialysis. Dialysate fluid and a volume of serum spiked with cTn (representing the blood compartment) were passed through the cuprophan membrane in counter-current flow, similar to that of dialysis. A water-driven vacuum pump was attached via the dialysate outlet and the tubing cannulated for effluent dialysate sample collection. The inlet was connected to a 5 L reservoir containing dialysate fluid (figure 1). Renalyte acid concentrate bicarbonate dialysate fluid (Fresenius Medical Care, Nottinghamshire, UK) was reconstituted 1 to 1.26 to 32.78 in 8.4% sodium hydrogen carbonate and reagent grade water, respectively, as per the recommended protocol of the manufacturers. The final solution had the following composition: Na+ 103 mmol/L, K+ 2 mmol/L, Ca++ 1.25 mmol/L, Mg++ 0.5 mmol/L, Cl− 108.5 mmol/L, CH3COO− 3 mmol/L and glucose 5.6 mmol/L. An aliquot of the renalyte dialysate fluid working solution was tested for possible interference in the cTnT and cTnI assays. The counter-current flow rate of dialysis fluid (Qd) was controlled at 200 mL/min. The membranes were primed with 200 mL dialysate and an effluent sample was collected for cTnT and cTnI assay testing before introduction of the blood component.

Bottom Line: Serum cTnI was significantly lower (p=0.043) following a session of HD whereas cTnT concentrations were similar to those obtained before HD.The adherence of cTnI to the dialyser membrane is responsible for the observed decrease in serum cTnI following a session of dialysis.The adherence of cTnT or T-I-C complex to the dialyser membrane could not be demonstrated and supports the observation that pre-HD and post-HD serum concentrations of cTnT are similar.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Pathology , Clinical Blood Sciences, St George's Hospital & Medical School , London , UK.

ABSTRACT

Background: Elevated serum cardiac troponin T (cTnT) and I (cTnI) can occur in patients with chronic kidney disease. Differences in cTn concentrations between cTnT and cTnI have been reported but the mechanism of such discrepancy has not been investigated. This study investigates the clearance of cTn with the aid of an in vitro model of haemodialysis (HD).

Methods: Serum was obtained before and after a single session of dialysis from 53 patients receiving HD and assayed for cTnT and cTnI. An in vitro model of the dialysis process was used to investigate the mechanism of clearance of cTn during HD.

Results: Serum cTnI was significantly lower (p=0.043) following a session of HD whereas cTnT concentrations were similar to those obtained before HD. Using an in vitro model of dialysis, it was demonstrated that cTnI is not dialysed from the vascular compartment but adheres to the dialyser membrane.

Conclusions: The adherence of cTnI to the dialyser membrane is responsible for the observed decrease in serum cTnI following a session of dialysis. The adherence of cTnT or T-I-C complex to the dialyser membrane could not be demonstrated and supports the observation that pre-HD and post-HD serum concentrations of cTnT are similar.

No MeSH data available.


Related in: MedlinePlus