PARTIAL RESTORATION OF SCINTIGRAPHICALLY ASSESSED CARDIAC SYMPATHETICDENERVATION IN NEWLY-DIAGNOSED PATIENTS WITH INSULIN-DEPENDENT (TYPE-1) DIABETES-MELLITUS AT ONE-YEAR FOLLOW-UP

Diabetic neuropathy is thought to comprise a reversible metabolic and an irreversible structural component of neuronal abnormality. To inves tigate whether the cardiac sympathetic denervation recently described in newly diagnosed, but metabolically stabilized, diabetic patients wi thout myocardial perfusion abnormalities reflects transient or permane nt sympathetic abnormalities, 123-I-metaiodobenzylguanidine (123-I-MIB G) scintigraphy was performed in 16 patients with insulin-dependent (T ype 1) diabetes mellitus (IDDM) 1 year after initial assessment and di agnosis. All patients had been treated with an intensified insulin the rapy for 1 year. HbA(1c) had fallen from 11.5 +/- 2.0 % to 6.3 +/- 0.9 % (p < 0.001). The global myocardial 123-I-MIBG uptake (score 1-6) ha d improved in 7 patients at 1 year, remained unchanged in 7, and deter iorated in 2 patients. Regionally, the myocardial uptake score of the posterior and septal regions had improved significantly (p < 0.01, p = 0.02) with a mean uptake score in the groups of 3.8 +/- 1.1 and 3.4 /- 1.2 at diagnosis versus 2.6 +/- 0.5 and 2.5 +/- 0.9 at 1 year. Myoc ardial uptake scores of the anterior, lateral, and apical regions had also improved in 7, 6, and 9 patients, but the mean changes of these s cores did not reach significance. The study demonstrates that scintigr aphically assessed cardiac sympathetic denervation in newly diagnosed, but metabolically stabilized, IDDM patients is partially reversed wit h improved metabolic control after 1 year of intensified insulin thera py. We suggest that even in the early stage of IDDM, cardiac sympathet ic dysfunction is composed of reversible and irreversible neuronal abn ormalities.