ALCAM a novel biomarker in patients with type 2 diabetes mellitus complicated with diabetic nephropathy.
OBJECTIVE
Activated leukocyte cell adhesion molecule (ALCAM/CD166) functions analogue to the receptor of advanced glycation end products, which has been implicated in the development of diabetic nephropathy (DN). We investigated the expression of ALCAM and its ligand S100B in patients with DN.


METHODS
A total of 34 non-diabetic patients, 29 patients with type 2 diabetes and normal albuminuria and 107 patients with type 2 diabetes complicated with DN were assessed for serum concentration of soluble ALCAM (sALCAM) by ELISA. Expression of ALCAM and S100B in kidney histology from patients with DN was determined by immunohistochemistry. Cell expression of ALCAM and S100B was analyzed through confocal immunofluorescence microscopy.


RESULTS
Serum concentration of sALCAM was increased in diabetic patients with DN compared to non-diabetic (59.85±14.99ng/ml vs. 126.88±66.45ng/ml, P<0.0001). Moreover sALCAM correlated positively with HbA1c (R=0.31, P<0.0001), as well as with the stages of chronic kidney disease and negatively correlated with eGFR (R=-0.20, P<0.05). In diabetic patients with normal albuminuria sALCAM was increased compared to patients with DN (126.88±66.45ng/ml vs. 197.50±37.17ng/ml, P<0.0001). In diabetic patients, ALCAM expression was significantly upregulated in both the glomeruli and tubules (P<0.001). ALCAM expression in the glomeruli correlated with presence of sclerosis (R=0.25, P<0.001) and localized mainly in the podocytes supporting the hypothesis that membrane bound ALCAM drives diabetic nephropathy and thus explaining sALCAM decrease in diabetic patients with DN. The expression of S100B was increased significantly in the glomeruli of diabetic patients (P<0.001), but not in the tubules. S100B was as well localized in the podocytes.


CONCLUSIONS
This study identifies for the first time ALCAM as a potential mediator in the late complications of diabetes in the kidney.
Department of Medicine I and Clinical Chemistry, University of Heidelberg, INF 410, 69120 Heidelberg, Germany. Electronic address: Sulaj.Alba@med.uni-heidelberg.de.
Alba
A
Sulaj
Department of Medicine I and Clinical Chemistry, University of Heidelberg, INF 410, 69120 Heidelberg, Germany.
Stefan
S
Kopf
Division of Cellular and Molecular Pathology, German Cancer Research Center, INF 280, 69120 Heidelberg, Germany.
Elisabeth
E
Gröne
Division of Cellular and Molecular Pathology, German Cancer Research Center, INF 280, 69120 Heidelberg, Germany.
Hermann-Josef
HJ
Gröne
Medical Research Center, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68135 Mannheim, Germany.
Sigrid
S
Hoffmann
Department of Internal Medicine, University of Tübingen, 72074 Tübingen, Germany.
Erwin
E
Schleicher
Department of Internal Medicine, University of Tübingen, 72074 Tübingen, Germany; German Center for Diabetes Research, 85764 Neuherberg, Germany.
Hans-Ulrich
HU
Häring
Department of Nephrology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany.
Vedat
V
Schwenger
Institute for Diabetes and Cancer IDC, Helmholtz Center Munich and Joint Heidelberg-IDC Translational, Diabetes Program, University of Heidelberg, INF 410, 69120 Heidelberg, Germany.
Stephan
S
Herzig
Department of Medicine I and Clinical Chemistry, University of Heidelberg, INF 410, 69120 Heidelberg, Germany; German Center for Diabetes Research, 85764 Neuherberg, Germany.
Thomas
T
Fleming
Department of Medicine I and Clinical Chemistry, University of Heidelberg, INF 410, 69120 Heidelberg, Germany; German Center for Diabetes Research, 85764 Neuherberg, Germany; Institute for Diabetes and Cancer IDC, Helmholtz Center Munich and Joint Heidelberg-IDC Translational, Diabetes Program, University of Heidelberg, INF 410, 69120 Heidelberg, Germany.
Peter P
PP
Nawroth
Department of Medicine I and Clinical Chemistry, University of Heidelberg, INF 410, 69120 Heidelberg, Germany.
Rüdiger
R
von Bauer
D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis / Q000097:blood* / Q000502:physiology; D015415:Biomarkers / Q000097:blood*; D016022:Case-Control Studies; D015816:Cell Adhesion Molecules, Neuronal / Q000032:analysis / Q000097:blood* / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications* / Q000175:diagnosis; D003928:Diabetic Nephropathies / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D018450:Disease Progression; D005260:Female; D005326:Fetal Proteins / Q000032:analysis / Q000097:blood* / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D020410:Activated-Leukocyte Cell Adhesion Molecule
D015703:Antigens, CD; D015415:Biomarkers; D015816:Cell Adhesion Molecules, Neuronal; D005326:Fetal Proteins; C105613:ALCAM protein, human; D020410:Activated-Leukocyte Cell Adhesion Molecule
ALCAM; Cell adhesion molecule; Diabetes mellitus type 2; Diabetic nephropathy; Soluble form of ALCAM