Cellular ionic alterations with age: relation to hypertension and diabetes.
BACKGROUND
Cytosolic free calcium (Cai) and magnesium (Mgi) are vital to cellular homeostasis and function.


OBJECTIVE
To evaluate cellular divalent cations in normal subjects at different ages and their relationship to ion levels in essential hypertension and diabetes.


METHODS
A cross-sectional study.


METHODS
A university hospital in New York.


METHODS
A total of 103 subjects (32 older, 71.1 +/- 1.2 y/o, and 71 young/middle aged subjects, 51.1 +/- 2.3 y/o).


METHODS
Oral glucose tolerance test.


METHODS
19F and 31P NMR spectroscopy were used to measure Cai and Mgi levels in erythrocytes from normal (>65 y/o, n = 11; <65 y/o, n = 26), hypertensive (EH) (>65 y/o, n = 9; <65 y/o, n = 30), and type 2 diabetic (DM) (>65 y/o, n = 12; <65 y/o, n = 15) subjects; these levels were also compared with glucose and insulin levels before and after oral glucose loading.


RESULTS
Fasting Mgi levels were lower (207 +/- 7.8 vs 236 +/- 7.5 microM; P < .05) and Cai higher (32.2 +/- 3.0 vs 20.3 +/- 1.8 nM; P < .05) in older than in younger normal subjects. For all normal subjects, the greater the age, the higher the Cai (r = 0.622, P = .004) and the lower the Mgi (r = -0.423; P = .011). However, no significant (P = NS) differences in Mgi or Cai levels were observed between older normal and young/middle-aged subjects with EH (Mgi = 189.7 +/- 5.9 vs 182.6 +/- 9.8 microM; Cai = 33.8 +/- 4.9 vs 35.6 +/- 4.0 nM) or DM (Mgi = 182.8 +/- 10.9 vs 180.8 +/- 8.1 microM; Cai = 33.6 +/- 4.3 vs 39.7 +/- 5.9 nM). Significant relationships were also found between cellular ion content, blood pressure, and glycemic indices.


CONCLUSIONS
Aging is associated with the onset of altered Cai and Mgi levels, indistinguishable from those observed in hypertension and diabetes, independent of age. We suggest that these ionic changes may be clinically significant, underlying the predisposition of older subjects to cardiovascular and metabolic diseases.
Barbagallo
M
M
Institute of Internal Medicine and Geriatrics, University of Palermo, Italy.
Gupta
R K
RK
Dominguez
L J
LJ
Resnick
L M
LM
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D001786:Blood Glucose / Q000032:analysis; D002118:Calcium / Q000032:analysis*; D016022:Case-Control Studies; D015984:Causality; D003430:Cross-Sectional Studies; D003600:Cytosol / Q000737:chemistry*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D004912:Erythrocytes / Q000737:chemistry*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D006973:Hypertension / Q000378:metabolism*; D007328:Insulin / Q000097:blood; D008274:Magnesium / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged
D001786:Blood Glucose; D007328:Insulin; D008274:Magnesium; D002118:Calcium