In insulin-dependent diabetes mellitus (IDDM) elevated exchangeable sodium (Na) levels are found even in the absence of hypertension, but it is not known whether this is associated with increased sensitivity of blood pressure to sodium level. To clarify this issue we compared 30 patients with IDDM (19 without and 11 with microalbuminuria, i.e. more than 30 mg albumin/day) and 30 control subjects matched for age, gender and body mass index. The subjects were studied on the 4th day of a low-salt diet (20 mmol/day) under in-patient conditions and were subsequently changed to the same diet with a high-salt supplement, yielding a total daily intake of 220 mmol Na/day. Circadian blood pressure, plasma renin activity (PRA), plasma atrial natriuretic factor (p-ANF), plasma cyclic guanosine 5'-phosphate (p-cGMP) and urinary albumin were measured. The proportion of salt-sensitive subjects, i.e. showing increment of mean arterial pressure > or = 3 mmHg on high-salt diet, was 43% in diabetic patients (50% of diabetic patients with and 37% without microalbuminuria) and 17% in control subjects (p < 0.05). Lying and standing PRA levels on low- or high-salt diet were significantly lower in diabetic patients than in control subjects. Salt-sensitive diabetic patients had significantly higher lying ANF on high-salt (38.7 +/- 4.2 pmol/l vs 20.1 +/- 2.3 pmol/l, p < 0.005) than on low-salt diet. The results suggest that (i) the prevalence of sodium sensitivity is high in IDDM (ii) sodium sensitivity is found even in the absence of nephropathy as indicated by albuminuria.

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Abstract. There is convincing evidence for a specific BP-independent effect of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers on albuminuria in glomerular disease. Because progression of glomerular disease is not consistently halted by these agents, there is a need to explore potential renoprotective effects of other drugs. Recent animal work documented that nonhypotensive doses of moxonidine, a sympathicoplegic agent, reduce albuminuria and development of glomerulosclerosis in a BP-independent manner. A randomized, crossover design was used to assess the human relevance of the experimental data in 15 normotensive, nonsmoking type 1 diabetic mellitus patients with good glycemic control (age, 37.3 ± 6.6 yr; 9 men/6 women; duration of diabetes, 23.6 ± 5.1 yr) with baseline urinary albumin excretion rates (AER) >20 μg/min in the run-in phase. AER was assessed in overnight timed urine collections. The patients were assigned to a 3-wk placebo and a 3-wk moxonidine (0.2 mg twice a day) period, respectively, in random order. This dose causes modest BP lowering in hypertensive individuals but does not affect BP in normotensive individuals. There was no significant effect on ambulatory BP (mean arterial pressure, 91.8 ± 7.1 mmHg in the third week of placebo and 91.1 ± 8.7 mmHg on moxonidine). There was a significant (P < 0.006) difference of the treatment effects between placebo and moxonidine, respectively, on AER; median AER at the end of the placebo period was 39.8 μg/min (range, 15.9 to 117 μg/min) versus 29.0 (range, 9.03 to 85.8 μg/min) at the end of the moxonidine period. The data document an antialbuminuric effect of nonhypotensive doses of moxonidine. Diminished sympathetic traffic to the kidney is the most plausible explanation for the finding.

In patients with diabetes mellitus, Charcot's neuroarthropathy mainly affects major weight-bearing joints, especially the foot and ankle. Remarkably, we report a case of Charcot's joint of the wrist - an unusually rare localization in type 2 diabetic patient. A review of medical literature identified only three such cases so far.

Background. Family studies point to important genetic determinants of diabetic nephropathy (DN). Blood pressure (BP) is higher in offspring of patients with type 2 diabetes and DN, but the pathomechanisms involved have not been elucidated. Methods. We examined the salt sensitivity of BP after 5 days equilibration on a low (20 mmol/day) vs high salt diet (220 mmol/day) in three matched groups of 15 subjects each: (i) control individuals; (ii) offspring of type 2 diabetic parents without DN (DNÀ); and (iii) offspring of type 2 diabetic parents with DN (DNþ). Ambulatory BP and hormones involved in sodium homeostasis [plasma renin activity (PRA), aldosterone and atrial natriuretic peptide (ANP)] as well as the tetrahydrocortisol þ 5-allotetrahydrocortisol/tetrahydrocortisone (THF þ 5aTHF)/THE) ratio in the urine as an index of 11b-hydroxysteroid dehydrogenase type 2 (11bHSD2) activity were analysed. Results. In offspring of DNþ patients on a high salt diet, systolic and diastolic BP was 137/82±10/8 mmHg vs 125/77±12/8 mmHg in offspring of DNÀ patients (P<0.01 for systolic BP). The salt-induced difference in mean BP between high and low salt diet was 5.2±3.3 mmHg in offspring of DNþ patients vs 0.7±4.7 mmHg in offspring of DNÀ patients (P<0.002). The proportion of 'salt-sensitive' individuals was 67% in offspring of DNþ patients vs 20% in offspring of DNÀ patients (P<0.05). In all groups, a high salt diet caused a comparable decrease of PRA and p-aldosterone accompanied by an increase in ANP. The urinary (THF þ 5aTHF)/THE ratio was 1.23±0.36 in salt-sensitive individuals and 0.99±0.33 (P<0.03) in salt-resistant subjects, consistent with increased activity of 11bHSD2. Conclusions. BP is more salt sensitive in offspring of type 2 diabetic patients with diabetic nephropathy. The salt sensitivity of BP may be an intermediate phenotype in individuals with a high risk of future diabetic nephropathy.