Autonomic function in type I diabetes mellitus complicated by nephropathy a cross-sectional analysis in the presymptomatic phase

Abstract

The purpose of this study was to determine the prevalence of parasympathetic and sympathetic autonomic dysfunction in long-standing type I diabetics with established nephropathy and to correlate autonomic function with cardiac risk factors. We used prospective analysis of heart rate variations to standardized testing and 24-hour blood pressure control prior to enrollment in a study utilizing various methods of intense diabetic control to prevent deterioration of kidney function. The settings were outpatient clinical research units. The patients were 42 type I diabetics with proteinuria (total urinary protein > or = 300 mg/day or urinary albumin > or = 100 mg/day) and creatinine clearance > or = 30 mL/min. Heart rate variation during respiratory cycles with change in posture from supine to upright, and during the Valsalva maneuver was recorded by a computerized method. Mean arterial blood pressure was recorded for 24 h by a computerized method. Heart rate variations in this group were abnormal during timed respiratory cycles in 26 of 40 patients (56%), during changes in posture in 15 of 40 patients (38%), and during Valsalva maneuver in 13 of 34 patients (38%) whose retinal disease permitted Valsalva testing. Blunted day/night mean arterial pressure ratios occurred in 18 of 41 (44%) patients and were more severe in men than in women (1.00 v 1.06, P < or = .05). Absence of deep tendon reflexes was associated with an increased incidence of both parasympathetic (respiratory rate variation) and sympathetic (postural rate variation) abnormalities (both P < or = .05). Loss of vibration sensation was not associated with autonomic functional abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional disorders of the sympathetic nervous system in mice lacking the α 1B subunit (Ca v 2.2) of N-type calcium channels

“…Furthermore, these mice could be useful for the study of renal or pancreatic function, because the functions of these tissues are thought to be strongly dependent on sympathetic nervous activity. Indeed, in insulin-dependent patients with type 1 diabetes mellitus, abnormal sympathetic nervous system function is associated with the progression of renal dysfunction (48). Thus, the N-type VDCC-deficient mouse is expected to be a useful system for studying autonomic failure.…”

Factors determining the 24-h blood pressure profile in normotensive patients with type 1 and type 2 diabetes

“…3,6,11 This abnormality in the absence of assessment of autonomic function was attributed to both nephropathy, through fluid retention, and presumably to AN. [3][4][5]11 Impaired nocturnal fall in BP has also been found in microalbuminuric patients although with some discrepancies and without clear identification of factors responsible. 5,[12][13][14] In our study the evaluation of AN allowed us to demonstrate a prominent relationship between day-night change in BP and AN.…”

Usefulness of ambulatory blood pressure monitoring in predicting the presence of autonomic neuropathy in type I diabetic patients

“…5 A blunted or reversed circadian pattern of BP has been increasingly described in diabetic patients and related to autonomic neuropathy 6,7 or to overt nephropathy. [8][9][10][11][12] Although some uncertainty still persists about the whole pathophysiology of the nondipping phenomenon, a series of studies have allowed to show the main pertinence of nondipping to diabetic autonomic neuropathy. [13][14][15][16][17][18] Notwithstanding, the predictive value of nondipping with regard to the presence of autonomic neuropathy has not been established.…”