From the Guidelines
Cystatin C levels are influenced by inflammatory states, including those involving interleukin levels, which can lead to elevated cystatin C production independent of kidney function. This relationship is supported by the fact that pro-inflammatory cytokines like interleukin-18 can be associated with markers of renal tubular injury and inflammation, as noted in a recent study 1. The study highlights the use of biomarkers such as cystatin C for estimating GFR and differentiating between structural and functional renal diseases, but also touches on the role of inflammatory markers like interleukin-18 in the context of renal injury.
Key points to consider include:
- Cystatin C is a more accurate estimator of GFR than serum creatinine in certain conditions, such as cirrhosis, as it is less influenced by age and diabetes 1.
- Inflammatory states can affect cystatin C levels, making it essential to consider concurrent inflammation when interpreting cystatin C as a marker of kidney function.
- The relationship between cystatin C and interleukin levels is notable in conditions with systemic inflammation, where pro-inflammatory cytokines can upregulate cystatin C gene expression.
- Clinically, this means that elevated cystatin C levels in the presence of inflammation may not solely indicate kidney impairment, but rather a combination of kidney function and the inflammatory state.
The influence of interleukin levels on cystatin C production is a critical consideration in clinical practice, as it can impact the interpretation of kidney function tests and the management of patients with inflammatory conditions. As such, it is essential to consider the potential effects of inflammation on cystatin C levels when assessing kidney function, particularly in patients with conditions characterized by systemic inflammation 1.
From the Research
Relationship Between Cystatin C and Interleukin Levels
- The relationship between cystatin C levels and interleukin (IL) levels has been investigated in several studies 2, 3, 4, 5, 6.
- A study published in 2009 found that cystatin C was not related to inflammatory markers, including IL-6, in non-diabetic patients with chronic kidney disease 2.
- However, a study published in 2011 found that IL-6 levels were associated with cystatin C levels in patients with acute heart failure, and that elevated IL-6 levels were seen in patients with high cystatin C levels 3.
- Another study published in 2007 found that cystatin C correlated with IL-6 and other inflammatory biomarkers in older adults with estimated glomerular filtration rates ≥60 ml/min/1.73 m2 4.
- A study published in 2010 found that cystatin C correlated with log natural IL-6 and log natural tumor necrosis factor-α in patients with essential hypertension 5.
- A study published in 2012 found that serum cystatin C levels were independently related to peripheral monocyte blood count, but not to other inflammatory markers such as high sensitivity C-reactive protein, haptoglobin, ferritin, and albumin 6.
Key Findings
- Cystatin C levels have been found to be associated with IL-6 levels in some studies 3, 4, 5.
- The relationship between cystatin C and IL levels may be influenced by other factors, such as renal function and cardiovascular risk factors 2, 3, 5.
- Monocytes, which play a role in chronic inflammation and atherosclerosis, have been found to be independently related to cystatin C concentrations 6.