Renal Assessment for Early Detection of Renal Impairment in Systemic Sclerosis and Systemic Lupus Erythematosus Patients

Systemic sclerosis (SSc) is an autoimmune disease characterized by endothelial dysfunction, collagen deposition, and fibrosis in the skin and internal organs. Systemic lupus erythematosus (SLE) is a complex, multi-organ autoimmune disease. The presence of autoantibodies and circulating immune complexes can cause vasculitis and damage the endothelial cells, leading to multiple organ dysfunctions. Renal involvement in SSc, ranges from urinary abnormalities, reduction of glomerular filtration rate (GFR), and high resistive indices, to scleroderma renal crisis (SRC). Subclinical renal vasculopathy is characterized by progressive increase of intrarenal stiffness and reduction of parenchymal thickness due to post ischemic fibrosis secondary to the renal Raynaud phenomenon.Conversely, in SLE-related kidney manifestations, renal damage results from glomerular involve-ment secondary to immune-complex acti¬vation. Cluster of differentiation 147 (CD147) is, also named extracellular matrix metalloproteinase inducer (EMMPRIN), a transmembrane glycoprotein in the immunoglobulin superfamily that is widely expressed on the surface membrane of various cells. Higher levels of soluble CD147 were found in SSc patients compared to healthy controls and higher levels in SSc patients with scleroderma renal crisis (SRC). Suggesting that CD147 could be a useful tool for identifying SRC risk. In patients with active SLE, CD147 is overexpressed on CD3 T lymphocytes. Renal resistive index (RRI) is a useful non-invasive technique for evaluation of renal disease activity in SLE patients. It can differentiate between patients with active lupus nephritis (LN) and inactive LN. RRI was higher in SSc patients than other autoimmune diseases since subclinical renal vasculopathy is the main pathogenic mecha¬nism of all SSc renal manifestations.Multiparametric renal Magnetic Resonance Imaging (MRI) shows great promise as a non-invasive method to assess kidney structure and function without exposure to radiation or gadolinium contrast agents. In MRI microstructural changes of lupus nephritis kidney such as inflammatory cell infiltration or fibrosis could influence water molecular movement or diffusion, which indicates that diffusion-weigted imaging (DWI) may become a valuable tool in diagnosis of LN. However in systemic sclerosis there is decline of renal blood flow values that indicate microvascular pathology.