Relation of body mass index and blood pressure to subjective and objective acral temperature

BACKGROUND: Vascular dysregulation, indicated by a positive history of cold extremities, has been postulated as a risk factor for a number of ocular diseases. In order to further characterize the phenotype of vasospastic persons, we tested the association between cold extremities, body mass index (BMI) and blood pressure (BP) in a cohort of healthy subjects. PATIENTS AND METHODS: Questionnaire data were collected from one hundred and seventeen healthy subjects. Based on the history of cold hands and feet they were divided in three groups, reporting "never", "sometimes" and "always" having cold extremities. BP was measured sphygmomanometrically and as an objective measure of finger temperature, it was recorded at the fingertips with an infrared thermometer (IRT). Two-way analysis of variance with gender as one, and group selection as the second factor was performed separately for BMI and mean BP. The correlation of finger temperature with BMI and BP was analyzed by the Pearson regression. RESULTS: Gender distribution was male/female = 41/16, 13/21 and 4/22, for the three groups, respectively, and average age 45.8 +/- 13.0 years. For BMI, factor groups was highly significant (p = 0.0012) with both genders behaving comparably (interaction p = 0.18). For BP the corresponding p values were: factor group p = 0.026, interaction p = 0.89. Correlation coefficients between IRT and BMI were 0.34 (p = 0.0002) and between IRT and BP 0.24 (p = 0.009). CONCLUSION: A statistical significant association is present in healthy subjects between body mass index and blood pressure on one, and cold extremities on the other side, defined subjectively as well as measured objectively. This relationship is gender-independent

Rigidity of retinal vessels in patients with multiple sclerosis

PURPOSE: The aim of this study was to analyze pulse wave propagation in the ocular circulation by assessing the phase delay between retinal arterioles and venules and calculating the pulse delay between the retinal and choroidal circulations in MS patients and in control subjects. SUBJECTS AND METHODS: Twenty patients with multiple sclerosis (38.3 +/- 6.2 years) and twenty healthy subjects (37.4 +/- 15.2 years) were examined with the Retinal Vessel Analyzer. In addition, an average peripapillary RNFL (retinal nerve fiber layer) thickness was measured by means of ocular coherence tomography in MS patients. The phase delay between the arteriole and venule pulsations was assessed at three sites: in the close retinal vicinity of the disc, 1 - 2 disc diameters and 3 - 4 disc diameters away from the disc. Assuming that venules are counterphased to the choroidal circulation, a choroid-to-retina pulse delay was calculated. RESULTS: The choroid-to-retina pulse delay was 0.26 +/- 0.11, 0.27 +/- 0.13 and 0.34 +/- 0.15 sec in eyes with history of optic neuritis (ON-eyes); in eyes of MS patients without such a history (non-ON eyes) the corresponding values were 0.27 +/- 0.14, 0.29 +/- 0.11 and 0.30 +/- 0.15 sec, and in control eyes 0.32 +/- 0.19, 0.38 +/- 0.16 and 0.45 +/- 0.20 sec, respectively, at three sites centrifugal from the disc. The choroid-to-retina pulse delay was significantly longer in healthy control eyes than both in ON eyes (p = 0.012) and non-ON eyes of MS patients (p = 0.004). The interocular difference of the choroid-to-retina pulse delay and OCT RNFL thickness showed a significant correlation in MS patients (Pearson r = 0.54, p = 0.015; Spearman R = 0.66, p = 0.0016). CONCLUSION: Patients with multiple sclerosis seem to demonstrate an increased rigidity of the retinal vessels. The interocular difference in retinal vessel rigidity was significantly correlated with the interocular difference in RNFL thickness in MS patients

Retinal vessels in patients with multiple sclerosis : baseline diameter and response to flicker light stimulation

BACKGROUND: Transparency of ocular media enables the precise quantitative analysis of vessels of retina, a neuronal tissue which can be affected by multiple sclerosis (MS). PATIENTS AND METHODS: Eyes with no history of optic neuritis (non-ON eyes) of 21 patients with MS were examined with Retinal Vessel Analyzer. Segments of vessels of 500 microm length were measured proximal and distal from the optic disc and compared to those of 21 age- and gender-matched controls. Baseline diameters and peak response to flicker light stimulation of retinal vessels were analyzed. RESULTS: MS eyes had thinner arterioles (p = 0.02) and thicker venules (p = 0.008) than controls: arterioles 111 +/- 14 microm (proximal), 99 +/- 11 microm (distal) in MS eyes and 121 +/- 15 and 107 +/- 9 in controls, respectively. Values for venules were 157 +/- 18 and 136 +/- 20 (MS); 147 +/- 15 and 119 +/- 20 (controls). Peak response was higher in MS eyes than in controls for arterioles (p = 0.007), but comparable for venules (p = 0.35). CONCLUSION: Narrower arterioles and wider venules might be a consequence of subclinical swelling of optic nerve axons in eyes with negative history of ON in MS patients

The primary vascular dysregulation syndrome: implications for eye diseases

Vascular dysregulation refers to the regulation of blood flow that is not adapted to the needs of the respective tissue. We distinguish primary vascular dysregulation (PVD, formerly called vasospastic syndrome) and secondary vascular dysregulation (SVD). Subjects with PVD tend to have cold extremities, low blood pressure, reduced feeling of thirst, altered drug sensitivity, increased pain sensitivity, prolonged sleep onset time, altered gene expression in the lymphocytes, signs of oxidative stress, slightly increased endothelin-1 plasma level, low body mass index and often diffuse and fluctuating visual field defects. Coldness, emotional or mechanical stress and starving can provoke symptoms. Virtually all organs, particularly the eye, can be involved. In subjects with PVD, retinal vessels are stiffer and more irregular, and both neurovascular coupling and autoregulation capacity are reduced while retinal venous pressure is often increased. Subjects with PVD have increased risk for normal-tension glaucoma, optic nerve compartment syndrome, central serous choroidopathy, Susac syndrome, retinal artery and vein occlusions and anterior ischaemic neuropathy without atherosclerosis. Further characteristics are their weaker blood-brain and blood-retinal barriers and the higher prevalence of optic disc haemorrhages and activated astrocytes. Subjects with PVD tend to suffer more often from tinnitus, muscle cramps, migraine with aura and silent myocardial ischaemic and are at greater risk for altitude sickness. While the main cause of vascular dysregulation is vascular endotheliopathy, dysfunction of the autonomic nervous system is also involved. In contrast, SVD occurs in the context of other diseases such as multiple sclerosis, retrobulbar neuritis, rheumatoid arthritis, fibromyalgia and giant cell arteritis. Taking into consideration the high prevalence of PVD in the population and potentially linked pathologies, in the current article, the authors provide recommendations on how to effectively promote the field in order to create innovative diagnostic tools to predict the pathology and develop more efficient treatment approaches tailored to the person