Associations Between Dietary Patterns and Skin Microcirculation in Healthy Subjects

Associations of dietary patterns with blood pressure and markers of subclinical arterial damage in adults with risk factors for CVD

OBJECTIVE

Unhealthy diet is a modifiable risk factor leading to subclinical arterial damage (SAD), high BP and CVD. It was aimed to investigate the possible associations of dietary patterns (DPs) with SAD in adults having multiple CVD risk factors.

DESIGN

Dietary intake was evaluated through two 24-h dietary recalls and principal component analysis was used to identify DPs. Oscillometry, applanation tonometry with pulse wave analysis and carotid ultrasound were used to assess peripheral and aortic BP, arterial stiffness and pressure wave reflections.

SETTING

Laiko University Hospital, Athens, Greece.

PARTICIPANTS

A total of 470 individuals (53·1 ± 14·2 years) with CVD risk factors were enrolled.

RESULTS

A pattern characterised by increased consumption of whole-grain cereals, white meat and reduced consumption of sugar was positively associated with common carotid compliance (β = 0·01, 95 % CI 0·00, 0·01), whereas a pattern high in refined cereals, red and processed meat was positively associated with brachial but not aortic systolic pressure (β = 1·76, 95 % CI 0·11, 3·42) and mean arterial pressure (MAP) (β = 1·18, 95 % CI 0·02, -2·38). Low consumption of low-fat dairy products, high consumption of full-fat cheese and butter was positively associated with MAP (β = 0·97, 95 % CI 0·01, 1·95). Increased consumption of vegetables, fruits, fresh juices, fish and seafood was inversely associated with augmentation index (AIx) (β = -1·01, 95 % CI -1·93, -0·09).

CONCLUSION

Consumption of whole grains, white meat, fruits/vegetables, fish/seafood and avoidance of sugar was associated with improved SAD. Preference in refined grains, red/processed meat, high-fat cheese/butter and low intake of low-fat dairy products were associated with BP elevation. Future studies are needed to confirm the present findings.

Microvascular Dysfunction and Hyperglycemia: A Vicious Cycle With Widespread Consequences

Microvascular and metabolic physiology are tightly linked. This Perspective reviews evidence that 1) the relationship between hyperglycemia and microvascular dysfunction (MVD) is bidirectional and constitutes a vicious cycle; 2) MVD in diabetes affects many, if not all, organs, which may play a role in diabetes-associated comorbidities such as depression and cognitive impairment; and 3) MVD precedes, and contributes to, hyperglycemia in type 2 diabetes (T2D) through impairment of insulin-mediated glucose disposal and, possibly, insulin secretion. Obesity and adverse early-life exposures are important drivers of MVD. MVD can be improved through weight loss (in obesity) and through exercise. Pharmacological interventions to improve MVD are an active area of investigation.

Assessing Microvascular Function in Humans from a Chronic Disease Perspective

Microvascular dysfunction (MVD) is considered a crucial pathway in the development and progression of cardiometabolic and renal disease and is associated with increased cardiovascular mortality. MVD often coexists with or even precedes macrovascular disease, possibly due to shared mechanisms of vascular damage, such as inflammatory processes and oxidative stress. One of the first events in MVD is endothelial dysfunction. With the use of different physiologic or pharmacologic stimuli, endothelium-dependent (micro)vascular reactivity can be studied. This reactivity depends on the balance between various mediators, including nitric oxide, endothelin, and prostanoids, among others. The measurement of microvascular (endothelial) function is important to understand the pathophysiologic mechanisms that contribute to MVD and the role of MVD in the development and progression of cardiometabolic/renal disease. Here, we review a selection of direct, noninvasive techniques for measuring human microcirculation, with a focus on methods, interpretation, and limitations from the perspective of chronic cardiometabolic and renal disease.

Compliance with dietary guidelines affects capillary recruitment in healthy middle-aged men and women

PURPOSE

Healthy microcirculation is important to maintain the health of tissues and organs, most notably the heart, kidney and retina. Single components of the diet such as salt, lipids and polyphenols may influence microcirculation, but the effects of dietary patterns that are consistent with current dietary guidelines are uncertain. It was hypothesized that compliance to UK dietary guidelines would have a favourable effect on skin capillary density/recruitment compared with a traditional British diet (control diet).

METHODS

A 12-week randomized controlled trial in men and women aged 40-70 years was used to test whether skin microcirculation, measured by skin video-capillaroscopy on the dorsum of the finger, influenced functional capillary density (number of capillaries perfused under basal conditions), structural capillary density (number of anatomical capillaries perfused during finger cuff inflation) and capillary recruitment (percentage difference between structural and functional capillary density).

RESULTS

Microvascular measures were available for 137 subjects out of the 165 participants randomized to treatment. There was evidence of compliance to the dietary intervention, and participants randomized to follow dietary guidelines showed significant falls in resting supine systolic, diastolic and mean arterial pressure of 3.5, 2.6 and 2.9 mmHg compared to the control diet. There was no evidence of differences in capillary density, but capillary recruitment was 3.5 % (95 % CI 0.2, 6.9) greater (P = 0.04) on dietary guidelines compared with control.

CONCLUSIONS

Adherence to dietary guidelines may help maintain a healthy microcirculation in middle-aged men and women. This study is registered at www.isrctn.com as ISRCTN92382106.

Retinal microcirculation in association with caffeinated and alcoholic drinks in subjects at increased cardiovascular risk

OBJECTIVES

The association of caffeinated and alcoholic drinks with microcirculation is poorly investigated. The aim of the study was to investigate the associations of daily consumption of caffeinated and alcoholic drinks with retinal vessel calibers.

METHODS

In consecutive adults at increased risk but free of CVD and diabetes mellitus, (n=181, age: 51.32±12.42 y, 51.4% women), we determined CRAE, CRVE and AVR, respectively. Daily consumption of caffeinated and alcoholic drinks was assessed through 24 h recalls.

RESULTS

After adjustment for potential confounders: (i) caffeine was positively associated with CRVE (b=0.177, P=.006 for left, b=0.208, P=.002 for right eye, respectively) (ii) decaffeinated coffee was positively associated with CRAE (b=0.141, P=.035 for left eye) and negatively associated with CRVE (b=-0.234, P<.001 for left, b=-0.189, P=.006 for right eye, respectively). Regular coffee, tea, alcohol, and any type of alcoholic drink did not associate with retinal vessel calibers.

CONCLUSIONS

Alcohol and alcoholic drinks' consumption were not associated, while decaffeinated coffee and caffeine consumption were associated in an opposing pattern with retinal vessel calibers. The reason of this controversy merits further investigation.

Association of consumption of dairy products and meat with retinal vessel calibers in subjects at increased cardiovascular risk

BACKGROUND AND AIMS

Association of dairy products and meat consumption with macrocirculation is previously described, but such association with microcirculation is poorly investigated. We aimed to test the hypothesis that the consumption of high- and low-fat dairy products as well as red, white, and processed meat is associated with retinal vessel calibers in adults at an increased risk of cardiovascular disease (CVD).

METHODS AND RESULTS

In consecutive subjects (n = 181, age: 51.3 ± 12.4 years, 51.4% women) without CVD and diabetes mellitus but with increased CVD risk, we obtained digital left and right retinal images. These images were assessed with validated software to determine central retinal arteriolar and venular equivalents and the arteriolar to venular ratio (CRAE, CRVE, and AVR, respectively). The consumption of dairy products and meat was assessed through 24-h recalls in all volunteers. After adjustment for potential confounders, the following findings were obtained: (i) low-fat milk and yogurt were positively associated with CRAE (b=0.145, p=0.031 left; b=0.141, p=0.038 right) and inversely associated with CRVE (b=-0.155, p=0.026 left; b=-0.146, p=0.041 right); (ii) low-fat cheese was positively associated with CRAE (b=0.164, p=0.011 left and b=0.155, p=0.017 right); and (iii) red meat was inversely associated with CRAE (b=-0.143, p=0.032 left; b=-0.114, p=0.050 right). High-fat milk, yogurt, and cheese or white and processed meat were not found to be associated with retinal vessel calibers.

CONCLUSIONS

High consumption of low-fat milk, yogurt, and cheese and low consumption of red meat could be beneficial for retinal microvascular health. Prospective studies are needed to verify these findings.

Association Between Arterial Stiffness and Skin Microvascular Function: The SUVIMAX2 Study and The Maastricht Study

BACKGROUND

It has been hypothesized that arterial stiffness leads to generalized microvascular dysfunction and that individuals with type 2 diabetes mellitus (T2DM) are particularly prone to the detrimental effects of arterial stiffness. However, evidence for an association between stiffness and markers of generalized microvascular dysfunction is lacking. We therefore investigated the association between arterial stiffness and skin microvascular function in individuals without and with T2DM.

METHODS

Cross-sectional data were used of The Supplementation en Vitamines et Mineraux Antioxydants 2 (SUVIMAX2) Study (n = 284/62.2 years/48.6% women/0% T2DM (by design)) and The Maastricht Study (n = 737/59.7 years/45.2% women/28.8% T2DM (by design)). Arterial stiffness was determined by carotid-femoral pulse wave velocity (cfPWV). Skin capillaroscopy was used to determine capillary density at baseline, and during reactive hyperemia and venous congestion. Laser Doppler flowmetry was used to assess acetylcholine- and local heating-induced vasoreactivity, and skin flowmotion.

RESULTS

In The SUVIMAX2 Study, cfPWV (per +1 SD) was not associated with baseline capillary density (regression coefficient: -0.48 (95% confidence interval: 2.37; 1.41)) or capillary recruitment during venous congestion (0.54% (-0.74; 1.81%)). In addition, cfPWV was not associated with acetylcholine (-0.02% (-0.14; 0.10%)) or local heating-induced vasoreactivity (0.03% (-0.07; 0.12%)). In The Maastricht Study, in individuals without T2DM, cfPWV was not associated with baseline capillary density (-1.20 (-3.17; 0.77)), and capillary recruitment during reactive hyperemia (1.22% (-0.41; 2.84%)) or venous congestion (1.50% (-0.25; 3.25%)). In addition, cfPWV was not associated with flowmotion (-0.01 (-0.07; 0.06)). Results were adjusted for age and sex. Additional adjustments for confounders did not materially change these results. Results were qualitatively similar in individuals with T2DM.

CONCLUSIONS

Arterial stiffness is not associated with skin microvascular function, irrespective of the presence of T2DM.