Abstract
Primary Sjögren’s syndrome (pSS) is an autoimmune disease affecting exocrine glands and extra-glandular organs. There are conflicting reports on the presence of autonomic dysfunction in pSS and no data are available on the functional status of sympathetic outflow to the vessels and baroreceptor [baroreflex sensitivity (BRS)] control mechanisms. We investigated the cardiac (cBRS) and sympathetic (sBRS) baroreceptor modulation in both time and frequency domains and the cardiovascular autonomic profile in pSS patients compared to healthy controls. Autonomic symptoms were quantified by the Composite Autonomic Symptom Scale (COMPASS31) three-item questionnaire. The EULAR Sjogren’s syndrome patient reported index (ESSPRI) questionnaire evaluated the magnitude of pSS clinical symptoms, i.e., fatigue, pain, and sicca symptoms. Electrocardiogram, beat-by-beat arterial pressure (AP) and respiratory activity were continuously recorded in 17 pSS patients and 16 healthy controls, while supine and during 75° head-up tilt. In seven patients and seven controls, muscle sympathetic nerve activity (MSNA) was measured. Spectrum analysis of RR variability provided markers of cardiac vagal modulation (HFRR nu) and sympatho-vagal balance [low frequency (LF)/high frequency (HF)]. The power of LF (0.1 Hz) oscillations of systolic arterial pressure (SAP) variability (LFSAP) evaluated the vasomotor response to sympathetic stimulation. Compared to controls, pSS patients scored higher in total COMPASS31 (p < 0.0001) and all ESSPRI subdomains (fatigue, p = 0.005; pain, p = 0.0057; dryness, p < 0.0001). Abnormal scialometry (<1.5 ml/15 min) and Schirmer tests (<5 mm/5 min) were found in pSS patients and salivary flow rate was negatively associated with ESSPRI dryness (p = 0.0014). While supine, pSS patients had lower SEQcBRS index of cardiac baroreceptor sensitivity, higher HFRRnu (p = 0.021), lower LF/HF (p = 0.007), and greater MSNA (p = 0.038) than controls. No differences were observed in LFSAP between groups. During orthostatic challenge, although LFSAP increased similarly in both groups, MSNA was greater in pSS patients (p = 0.003). At rest pSS patients showed lower cBR control and greater parasympathetic modulation. Furthermore, greater sympathetic nerve activity was observed in pSS patients while supine and in response to gravitational challenge. We hypothesized that such enhanced sympathetic vasoconstrictor activity might reflect an attempt to maintain blood pressure in a setting of likely reduced vascular responsiveness.
Highlights
Primary Sjogren syndrome is a chronic systemic autoimmune disease which primarily affects the exocrine glands, most commonly the salivary and lacrimal glands, leading to xerostomia and xerophthalmia (Fox, 2005)
From this final study population, because of the absence of written consent and presence of suboptimal signal/noise ratio, a muscle sympathetic nerve activity (MSNA) signal adequate for automatic analysis was obtained for seven Primary Sjogren syndrome (pSS) patients and seven controls
The results of the present study indicate that pSS patients suffer more from global symptom burden and autonomic dysfunction symptoms compared to healthy controls, in agreement with a previous study (Newton et al, 2012)
Summary
Primary Sjogren syndrome (pSS) is a chronic systemic autoimmune disease which primarily affects the exocrine glands, most commonly the salivary and lacrimal glands, leading to xerostomia and xerophthalmia (Fox, 2005). Its prevalence is estimated to be about 7 per 100,000 person-years (Qin et al, 2015). It is characterized by a high female-to-male ratio of 9:1 and the mean age of onset is around the 4th to 5th decade of life (Qin et al, 2015). At least a third of patients develop extraglandular manifestations (Vitali et al, 2002). These may involve the skin (Ramos-Casals et al, 2004), vessels (Scofield, 2011), joints (Pease et al, 1993), and muscles (Lindvall et al, 2002). Among the visceral organs affected are the lungs (Quismorio, 1996), heart (Gyongyosi et al, 1996), kidneys (Gamron et al, 2000), and the gastrointestinal tract (Ebert, 2012)
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