Thiamine and benfotiamine prevent apoptosis induced by high glucose-conditioned extracellular matrix in human retinal pericytes.
BACKGROUND
Early and selective loss of pericytes and thickening of the basement membrane are hallmarks of diabetic retinopathy. We reported reduced adhesion, but no changes in apoptosis, of bovine retinal pericytes cultured on extracellular matrix (ECM) produced by endothelial cells in high glucose (HG). Since human and bovine pericytes may behave differently in conditions mimicking the diabetic milieu, we verified the behaviour of human retinal pericytes cultured on HG-conditioned ECM.


METHODS
Pericytes were cultured in physiological/HG on ECM produced by human umbilical vein endothelial cells in physiological/HG, alone or in the presence of thiamine and benfotiamine. Adhesion, proliferation, apoptosis, p53 and Bcl-2/Bax ratio (mRNA levels and protein concentrations) were measured in wild-type and immortalized human pericytes.


RESULTS
Both types of pericytes adhered less to HG-conditioned ECM and plastic than to physiological glucose-conditioned ECM. DNA synthesis was impaired in pericytes cultured in HG on the three different surfaces but there were no differences in proliferation. DNA fragmentation and Bcl-2/Bax ratio were greatly enhanced by HG-conditioned ECM in pericytes kept in both physiological and HG. Addition of thiamine and benfotiamine to HG during ECM production completely prevented these damaging effects.


CONCLUSIONS
Apoptosis is strongly increased in pericytes cultured on ECM produced by endothelium in HG, probably due to impairment of the Bcl-2/Bax ratio. Thiamine and benfotiamine completely revert this effect. This behaviour is therefore completely different from that of bovine pericytes, underlining the importance of establishing species-specific cell models to study the mechanisms of diabetic retinopathy.
Beltramo
Elena
E
Laboratory of Diabetic Retinopathy, Department of Internal Medicine, University of Turin, Torino, Italy. elena.beltramo@unito.it
Nizheradze
Konstantin
K
Berrone
Elena
E
Tarallo
Sonia
S
Porta
Massimo
M
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects*; D053938:DNA Fragmentation / Q000187:drug effects; D003930:Diabetic Retinopathy / Q000503:physiopathology; D042783:Endothelial Cells / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism*; D005786:Gene Expression Regulation; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D006943:Hyperglycemia / Q000503:physiopathology; D020286:Pericytes / Q000187:drug effects / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D012171:Retinal Vessels / Q000166:cytology; D013045:Species Specificity; D013831:Thiamine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*
D051017:Apoptosis Regulatory Proteins; D012333:RNA, Messenger; D005947:Glucose; D013831:Thiamine; C013835:benphothiamine