James Hood

Sjögren's Syndrome in Scurvy

Abstract Five men were deprived of ascorbic acid until they became scorbutic. During deficiency of ascorbic acid, Sjogrens syndrome became apparent in two subjects. In these two and one other keratoconjunctivitis sicca developed. All five had one or more manifestations of the sicca syndrome, including keratoconjunctivitis sicca, enlargement of the salivary glands, xerostomia, dry skin, excessive hair loss, dental decay and recurrent breakdown of dental restorations. Sjogrens syndrome or component features of the syndrome developed when the men had obvious clinical signs of scurvy. Evidence of deficiency other than of ascorbic acid was absent. During repletion with ascorbic acid, as plasma levels of ascorbic acid rose and the size of the body pool of the vitamin increased, the signs of scurvy and of Sjogrens syndrome disappeared. An association between scurvy and Sjogrens syndrome therefore seems apparent.

Autonomic reflexes and vascular reactivity in experimental scurvy in man

Ascorbic acid is a required cofactor in the conversion of dopamine to norepinephrine in vitro, and the deficiency of this vitamin in guinea pigs is associated with degeneration of autonomic ganglion cells and with cardiac supersensitivity to norepinephrine. Because of these findings, we tested the hypothesis that ascorbic acid deficiency in man alters autonomic cardiovascular reflexes and vasomotor responses to adrenergic stimuli. We studied five normal volunteers who had been deprived of ascorbic acid for a period of 3 months; they had developed symptoms and signs of scurvy and their plasma levels of ascorbic acid averaged 0.178 +/-SE 0.07 mg/100 ml. We repeated the studies after giving the subjects vitamin C for a period of 4 months; they had become asymptomatic and their plasma ascorbic acid had increased to an average of 1.68 +/-0.151 mg/100 ml. Blood flow to the left forearm (plethysmograph), arterial and central venous pressures, and heart rate were measured before and after exposure of the lower half of the body to subatmospheric levels of pressure and before and after intravenous and intra-arterial (left brachial artery) infusions of norepinephrine and tyramine. Average values of blood flow (7.9 +/-1.4 ml/min per 100 ml), arterial pressure (91.2 +/-4.6 mm Hg), heart rate (68 +/-4.4 beats/min), central venous pressure (6.1 +/-1.1 mm Hg), and plasma catecholamines (0.68 +/-0.20 mug/liter) obtained during ascorbic acid deficiency were not altered significantly after correction of the deficiency. Vasoconstrictor responses to intra-arterial norepinephrine and tyramine were augmented after vitamin repletion. During ascorbic acid deficiency, four subjects had reduced responsiveness of resistance vessels of the forearm to lower body negative pressure as compared to the responsiveness observed after vitamin repletion. Reflex tachycardia during lower body negative pressure and reflex bradycardia during the pressor responses to intravenous tyramine and norepinephrine were similar during the two studies. The results suggest that the decreased vascular responsiveness to intra-arterial norepinephrine and tyramine and to lower body negative pressure during ascorbic acid deficiency is caused by a defect in the ability of resistance vessels to constrict in response to adrenergic stimuli. Ascorbic acid deficiency in man does not interrupt autonomic reflexes and does not appear to cause significant depletion of endogenous norepinephrine.