Early sign of microangiopathy in systemic sclerosis: The significance of cold stress test in dynamic laser Doppler flowmetry

A single dose of oral nattokinase accelerates skin temperature recovery after cold water immersion: A double-blind, placebo-controlled crossover study

Nattokinase (NK) intake may improve blood flow; however, its effects on skin temperature, which is predominantly controlled by skin surface blood flow, are unknown. The purpose of this study was to determine the effects of a single dose of NK on changes in skin temperature after cold water immersion. A double-blinded, placebo-controlled, crossover intervention study was performed on nine healthy men. The participants were randomised to receive either a single dose of 2,000 fibrinolytic units (FU) of NK or a placebo with subsequent crossover. Two hours after supplementation, the participants immersed both hands in a water bath maintained at 10 °C for 1 min. Skin temperature, perceived coldness, cardiac output, and sympathetic nervous activity were measured before, during, and after water immersion. Two-way analysis of variance showed a significant effect of treatment interaction on the skin temperature of the middle finger, palm, and back of the right hand (p < 0.05). These findings represented that the skin temperatures of the middle finger, palm, and back of the right hand immersed in the cold water were significantly dropped due to the cold water immersion, and then recovered more quickly by NK intake than by placebo intake. The results of the current study highlight the potential implications of NK for the prevention of excessive vasoconstriction. It may be more significant for those with cold-sensitive constitution, such as women and elderly. In contrast, the acute administration of 2,000 FU of NK did not affect changes in heart rate, cardiac output, sympathetic nervous activity compared with a placebo in healthy men.

Abnormalities in Cutaneous Microcirculation in Patients with Alzheimer's Disease, Mild Cognitive Impairment, and Chronic Insomnia Disorder

Impaired sympathetic response is frequently observed in neurodegenerative diseases, such as Alzheimer’s disease (AD). On the other hand, chronic insomnia disorder (CID) is also often accompanied by activation of sympathetic nerves. Considering that cutaneous microcirculation reflects sympathetic tone, we hypothesized that baseline cutaneous microcirculation in fingers, as detected by laser Doppler flowmetry (LDF), differs among patients with mild cognitive impairment (MCI), AD, and CID. As light therapy is one of the adjunctive treatments for AD and CID, we designed a randomized controlled cross-over trial of light therapy through eyes for 12 weeks with red light as treatment and green light as control limb, and examined if light therapy has an impact on cutaneous microcirculation. Before light therapy, patients with AD had significantly lower baseline cutaneous perfusion than those with CID in left and right first to fourth fingers. After red light therapy, however, cutaneous perfusion of fingers in CID patients significantly decreased (right fingers, before vs. after = 227.25 ± 62.00 vs. 162.00 ± 49.34, p = 0.007; left fingers, before vs. after = 228.99 ± 58.80 vs. 177.41 ± 59.41, p = 0.003) while cutaneous perfusion of fingers in CID patients did not significantly change after green light therapy. Light therapy with red light also significantly increased cutaneous finger perfusion in patients with AD (right fingers, before vs. after = 130.13 ± 49.82 vs. 172.38 ± 38.32, p = 0.043). Our results suggest that cutaneous perfusion is a useful tool to detect sympathetic dysfunction in patients with CID and AD, and that light therapy with red light is a potential therapeutic intervention to reverse impaired sympathetic function in patients with CID and patients with AD.

Abnormal nailfold videocapillaroscopic findings in heart failure patients with preserved ejection fraction

BACKGROUND

Microvascular dysfunction is one of the pathophysiological mechanisms in heart failure. Nailfold videocapillaroscopy is a noninvasive technique used to examine the microvasculature.

OBJECTIVE

In this study, we aimed to investigate the nailfold capillaroscopic abnormalities in heart failure patients with reduced and preserved ejection fraction and compare those with control group.

METHODS

Three groups of patients were recruited for the study: HFrEF group includes the patients with heart failure with reduced ejection fraction (HFrEF), HFpEF group, patients with heart failure with preserved ejection fraction (HFpEF) and control group, healthy asymptomatic individuals. Nailfold videocapillaroscopy was performed with a videodermatoscope and all nailfold images were evaluated for enlargement and hemorrhages.

RESULTS

Abnormal videocapillaroscopic findings including enlargement and/or hemorrhages were present in 7 (24%) patients in HFrEF group, 19 (66%) patients in HFpEF group and 11 (37%) in control group. The number of patients with abnormal videocapillaroscopic findings were significantly greater in HFpEF group compared to HFrEF (p < 0.05) and control groups (p < 0.05). However, no significant difference was observed in videocapillaroscopic findings between HFrEF and control groups.

CONCLUSIONS

Our study showed that microvascular abnormalities demonstrated by videodermatoscopic examination of nailfold capillaries are considerably more common in HFpEF patients compared to HFrEF and control groups.

Cutaneous microcirculation in patients with peripheral arterial occlusive disease: Comparison of capillary blood circulation in the nail fold of finger and toe

In patients with peripheral arterial occlusive disease (PAOD) a restricted circulation in cutaneous microvessels has been reported. In this study the velocity of erythrocytes (very) in finger nailfold capillaries - a vascular area without upstream macroangiopathy - and also in toe nailfold capillaries - a post-stenotic area –was investigated using capillary microscopy in apparently healthy subjects and patients with PAOD. Already in finger nailfold capillaries very of patients with PAOD under resting conditions was significantly lower than in capillaries of healthy subjects. This was also true for the circulation in toe capillaries. In addition, the erythrocyte velocities under resting conditions in the toe capillaries were significantly lower than in the finger capillaries. Similar results were found for the duration and the maximum velocity of postocclusive hyperemia. It is concluded that the resting blood flow in the skin microcirculation is impaired in PAOD patients, both under resting conditions and during postocclusive hyperemia in finger as well in toe nailfold capillaries.

Validation of a novel ultrasound Doppler monitoring device (earlybird) for detection of microvascular circulatory changes

OBJECTIVE

In this proof-of-concept study we aim to validate a novel ultrasound Doppler monitoring device for evaluating microcirculation (earlybird) against LDF and pulsed Doppler.

METHODS

In ten healthy subjects, we measured microcirculatory function at rest and during different autonomic tests (forced respiration, isometric exercise, Valsalva maneuver and cold pressor). Earlybird, LDF and pulsed Doppler were recorded simultaneously. We performed a ZNCC to determine correlation.

RESULTS

The curves for earlybird and LDF or pulsed Doppler correlates visually well. Overall median ZNCC 0.87 (interquartile range 0.77 -0.91) between the LDF and earlybird measurements, and 0.90 (0.82 - 0.95) for pulsed Doppler and earlybird. Median ZNCC for baseline and each provocation test for earlybird against LDF and pulsed Doppler were calculated; baseline: LDF 0.87 (0.73 - 0.97) pulsed Doppler 0.91 (0.81 - 0.94), forced respiration: LDF 0.87 (0.28 - 0.90) pulsed Doppler 0.90 (0.85 - 0.96), isometric exercise: LDF 0.82 (0.59 - 0.90) pulsed Doppler 0.87 (0.68 - 0.94), Valsalva maneuver: LDF 0.88 (0.82 - 0.91) pulsed Doppler 0.94 (0.92 - 0.97) and cold pressor: LDF 0.90 (0.85 - 0.95) pulsed Doppler 0.89 (0.65 - 0.94).

CONCLUSION

Earlybird records vasoconstrictions in healthy subjects as well as LDF and pulsed Doppler.