Canine Cystatin C ELISA

Cystatin C is a non-glycosylated basic protein belonging to the super-family
of cysteine proteinase inhibitors. It consists of a single polypeptide chain
having 120 amino acids.
It is produced by all nucleated cells within the body and is released during
phagocytosis and inflammation. In the kidney, cystatin C is freely filtrated
through the glomerulus and reabsorbed and catabolized in the proximal
renal tubules. The rate of cystatin C synthesis is constant, independent of
age, gender and muscle mass. High concentrations can be found in serum,
seminal fluid, cerebrospinal fluid (CSF), and synovial fluid, and lower
concentrations can be found in urine.
In human medicine, cystatin C is the most important endogenous serum
marker of renal function assessment. Cystatin C evaluation is able to detect
an earlier stage of decreased glomerular filtration rate (GFR) than other
parameters (serum creatinine, creatinine clearance etc.) and it is considered
particularly useful in patients with a high risk of developing nephropathies.
Imbalance between cystatin C and cysteine proteinases is associated with
inflammation, cancer, Alzheimer’s disease, multiple sclerosis and hereditary
cystatin C amyloid angiopathy. An increased level has been found in patients
with autoimmune diseases. On the other hand, low concentration of
cystatin C presents a risk factor for secondary cardiovascular events.
In veterinary medicine, there are multiple reports of the use of cystatin C in
the evaluation of renal function indicating that cystatin C is also the most
important serum (urine) marker of renal function assessment in dogs.