**9. Biomarkers of dystal renal tubules**

of deterioration to the renal graft function is nephrotoxicity of immunosuppressive drugs (e.g. cyclosporin A) reflected by increase in activity of urinary enzymes : ALP, LDH, GGT, beta-

**Alanylaminopeptidase (AAP)** – proteolytic enzyme degrading oligopeptides. Increases in urinary concentration of hexosaminidase and AAP accompany acute renal tubular necrosis, renal graft rejection or nephrotoxic action of immunosuppresive drugs (e.g. cyclosporin A) administered to patients after kidney transplantat (Kuźniar et al., 2006; Lisowska-Myjak, 2010; Santos et al., 2010). Increases in urinary excretion of tubular enzymes testifies tubular brush border membrane damage with a loss of microvillus structure (Westhuyzen et al., 2003).

**Glutathione S-transferase (alpha-GST, pi-GST)** is a specific cytoplasmic enzyme of tubular epithelial cells consisting of two isoenzymes: α-GST with alkaline and πi-GST with acidic pH optimum. GST-α appears in epithelium of proximal tubular cells and GST-π in distal tubules (Branten et al., 2000). Determination in urine α-GST and, π-GST is applied to diagnosis acute renal graft rejection with acute tubular necrosis (Kuźniar et al., 2006; Polak, 1999). Differenti‐ ated increase in urinary GST- alpha and GST- pi excretion may point to localization of an nephron damage (Westhuyzen et al., 2003; Trof et al., 2006; Herget-Rosenthal et al., 2004;

**Fructose-1,6-bisphosphatase (FBP-1,6)** is localized mostly in contorted and to less extend in straight part of proximal renal tubules, similarly to hexosaminidase and GST, points to accurate localization of damaged nephron (Trof et al., 2006; Kotanko et al., 1986). Increase in urinary FBP-1,6 was observed in patients after kidney transplantat. Urinary FBP-1,6 excretion was significantly lower in patients with median of cold ischemia below 22 hours, than above 22 hours. Even in lack of graft dysfunction, in situation where it is a long time of cold ischemia, urinary excretion of FBP-ase correlates with a degree of damage to the renal tubules (Kotanko et al., 1997). It was reported that a panel of urinary enzymes activities: FBP-ase, glutathione Stransferase, N-acetyl-beta-D-glucosaminidase and pyruvate kinase is a good marker of the

**N-acetyl-β-D-hexosaminidase (HEX)** is one of the most frequently determined urinary markers of renal tubules damage, because its activity increased at early steps of the renal tubules damage, before occurrence of disturbances in renal excretory function. Hexosamini‐ dase localized mainly in renal proximal tubular cells, is a specific marker for proximal tubular cells because its high molecular weight (> 130 kDa) excludes its glomerular filtration. In the course of active kidney disease HEX activity is constantly increased. An increase in urinary activity HEX and its isoenzyme B indicate on damage in the renal tubular cells. Therefore urinary HEX and particularly HEX B activity may be treated as a specific marker of damage in the renal proximal tubules of the transplanted kidney (Liangos et al., 2007; Holdt−Lehmann

glucuronidase (Refaie et al., 2000; Takahashi et al., 1989; Simić-Ogrizović et al., 1994).

**7.2. Cytosolic enzymes**

Branten et al., 2000; Gautier et al., 2010).

72 Current Issues and Future Direction in Kidney Transplantation

cyclosporin A nephrotoxicity (Kotanko et al., 1986).

**7.3. Renal lysosomal enzymes**

et al., 2000;).

In the assessment of distal renal tubule dysfunction it is advised to examine urine osmo‐ larity and/or determination Tamm-Horsfall glycoprotein as well as urinary kallikrein (Bhoola et al., 1992).

**Renal kallikrein** is a serine protease which releases vasodilatatory peptides: bradykinine and calidine, from kininogen. Renal kallikrein is present in renal collecting tubules and is released to tubular fluid by terminal section of dystal segment of nephron (Manucha & Vallés, 1999; Thongboonkerd & Malasit, 2005). An increase in activity of urinary kallikrein was observed in insufficiency and loss of the renal graft function (Krimkevich, 1990).

**AnnexinA11** (**ANXA11**). Annexins are calcium-binding proteins which binds to acidic phospholipid and F-actin. Depending on calcium concentration Annexin A 11 participate in signal transduction, cell proliferation, regulation of vesicular transport and interaction with the cell membranes. Annexin occurs in high quantities in renal distal tubular cells and epithelium of renal glomeruli. Annexin physiologic role seems to be related to cell apoptosis (Rodrigues-Garcia et al., 1996). Significant correlation between urinary Annexin V and other proteins and lack of correlation with urinary urea and creatinine concentration suggests that Annexin V is not an indicator of kidney function, but rather reflects local kidney damage (Matsuda et al., 2000). Annexin A11 may act as an atypical calcium channel and useful marker of acute and chronic renal graft rejection (Srivastava et al., 2011)

**Renal papillary antigen-1 (RPA-1)** a renal papillary antigen-1, sensitive and specific antigen of renal papillary cells is a sensitive and specific urinary marker of damage renal collecting tubules (Gautier et al., 2010).

**Prominin-2 (PROM-2**) analog of **CD133 (prominin-1)** is an membrane glycoprotein (112kD) with the highest expression in epithelial cells of matured kidney. Prominin-2 is a cholesterolbinding protein associated with apical and basolateral plasmalemmal protrusions in polarized epithelial cells and released into urine (Florek et al., 2007) and a novel marker of distal tubules and collecting ducts of the human and murine kidney (Jászai et al., 2010).

**μ-glutathione-S-transferase (μ-GST)** is a conjugating glutathione with electrophilic com‐ pounds that occurs in epithelial cells of ascending part of Henle's loop (Gautier et al., 2010; Holmquist *&* Torffvit, 2008). After nephrotoxic drugs treatment (e.g. cisplatin) μ-GST quickly appear in urine. μ-GST is a more specific marker of nephrotoxicity (AUC 1.000) than α-GST (AUC 0.984) or albuminuria (AUC 0.984). μ-GST is an early biomarker for Henle's loop and distal tubules damage (Tonomura et al., 2010).

**Markers**

**Acute kidney injury (AKI); Acute graft rejection (AGR); Acute tubular necrosis (ATN)**

**Chronic allograft nephropathy (CAN/ IFTA); Delayed graft function (DGF)**

β2M,α1M + + Johnston et al., 2011; Du et al., 2011;

Netrin-1 + Ramesh et al., 2010; Urbschat et al., 2011 NGAL + Ramesh et al., 2010; Nauta et al., 2011;

IL-16,IL-2,IL-6,IL-18,TNF + + Alachkar er al., 2010; Halawa, 2011;

KIM-1 + + Nauta et al., 2011; Halawa, 2011;

NAG + Nauta et al. 2011; Câmara et al., 2009; Ting

H-FABP, L-FABP + + Nauta et al., 2011; Przybylowskiet al., 2011 Cystatin C + Przybylowski et al., 2011; Hall &Parikh, 2010 CXCL9,CXCL10 + + Ho et al., 2011; Schaub et al., 2009; Jackson

alpha-GST, pi-GST + + Câmara et al., 2009;Hall &Parikh, 2010; Ting

GzmA,GzmB (granzyme) + van Ham et al., 2010; Peng et al., 2008;

Galectin-3(Gal-3) + Dang et al., 2012 Integrin α3, integrinβ2 + + Srivastava et al., 2011 ANXA11 + + Srivastavaet al., 2011 sVCAM + Reinhold et al., 2012 MMP7, MMP-8 + Metzger et al., 2011; Ling et al., 2010 LDH, ALP, γ-GT, AAP + Refaie et al., 2000;Kuźniar et al., 2006

**References**

http://dx.doi.org/10.5772/54746

75

Utility of Urinary Biomarkers in Kidney Transplant Function Assessment

Câmara et al., 2009;Kuźniar et al., 2006

Przybyłowski et al., 2011; Halawa, 2011; Devarajan, 2011; Hall&Parikh, 2010; Du et al., 2011;Ting et al., 2012

Devarajan, 2011; Reinhold et al., 2012; Urbschat et al., 2011

Devarajan,2011; Hall &Parikh, 2010; Du et al., 2011; Ting et al., 2012; Urbschat et al., 2011

et al., 2012; Kuźniar et al., 2006; Alachkar et al., 2010

et al., 2011; Ting et al., 2012

et al., 2012; Kuźniar et al., 2006; Oberbauer , 2008

Oberbauer, 2008
