Co-expression of renin-angiotensin system genes in human adipose tissue.
OBJECTIVE
The renin-angiotensin system plays a central role in blood pressure regulation, both by affecting renal function and by modulating vascular tone and structure. Recent studies in rodents demonstrated the existence of several components of this system in adipose tissue. The activity of the renin-angiotensin system appears to be regulated by food intake, suggesting that it may be involved in obesity-associated hypertension. Few data are available on the presence of renin-angiotensin system components in human adipose tissue.


METHODS
In order to explore the expression of renin-angiotensin system genes in human adipose tissue and adipocytes, total RNA was isolated from whole adipose tissue (subcutaneous and omental) or cultured adipocytes (mammary) and subjected to reverse-transcriptase polymerase chain reaction with primers specific for human angiotensinogen, renin, renin-binding protein, angiotensin converting enzyme, chymase and type 1 and type 2 angiotensin receptors.


RESULTS
Angiotensinogen, angiotensin converting enzyme and type 1 angiotensin receptor genes were widely expressed, both in human adipose tissue and in cultured human adipocytes. Furthermore, we found expression of the chymase and renin-binding protein genes in these samples.


CONCLUSIONS
Our findings suggest the presence of a local renin -angiotensin system in human adipose tissue, with adipocytes being an important part of this system, and prompt speculation that this local renin-angiotensin system may be involved in obesity-related disorders, including hypertension and the metabolic syndrome.
Department of Internal Medicine, Benjamin Franklin Clinic, Free University of Berlin, Germany.
S
S
Engeli
K
K
Gorzelniak
R
R
Kreutz
N
N
Runkel
A
A
Distler
A M
AM
Sharma
D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000808:Angiotensinogen / Q000096:biosynthesis / Q000235:genetics; D002478:Cells, Cultured; D053818:Chymases; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000096:biosynthesis / Q000235:genetics; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000096:biosynthesis / Q000235:genetics; D012083:Renin / Q000096:biosynthesis / Q000235:genetics; D012084:Renin-Angiotensin System / Q000235:genetics* / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012697:Serine Endopeptidases / Q000096:biosynthesis / Q000235:genetics
D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin; D000808:Angiotensinogen; D007703:Peptidyl-Dipeptidase A; D012697:Serine Endopeptidases; D053818:Chymases; D012083:Renin