Impaired renal clearance explains elevated troponin T fragments in hemodialysis patients

Area of Science:

• Biochemistry
• Nephrology
• Cardiology

Background:

• Patients with severe renal dysfunction often exhibit unexplained elevations in serum cardiac troponin T (cTnT).
• The underlying cause for these elevated cTnT levels in renal failure patients remains unclear.

Purpose of the Study:

• To investigate whether in vivo fragmentation of cTnT can explain the elevated serum concentrations observed in patients with severe renal dysfunction.
• To determine if kidney dysfunction leads to the accumulation of cTnT fragments.

Main Methods:

• Serum samples from 63 hemodialysis patients were analyzed for cTnT, creatine kinase isoenzyme MB, and myoglobin.
• A highly sensitive immunoprecipitation assay coupled with electrophoresis and Western blotting was employed to detect and characterize cTnT fragments.

Main Results:

• cTnT fragments, ranging from 8 to 25 kDa, were detected in the serum of all 63 dialysis patients.
• While creatine kinase isoenzyme MB levels excluded recent myocardial events in most cases (55/63), cTnT fragmentation was a universal finding.
• The detected cTnT fragments are small enough to be cleared by healthy kidneys.

Conclusions:

• Cardiac troponin T undergoes fragmentation in vivo.
• Impaired renal function leads to the accumulation of these smaller cTnT fragments.
• This accumulation of fragmented cTnT is the likely cause of unexplained elevated serum cTnT levels in patients with severe renal failure.