1. Sublingual Microcirculation
——Characteristics and Determinants in
Chinese and Flemish Populations
Yan Li MD PhD
Shanghai Institute of Hypertension

2. Hypertension and Microcirculation
Impaired vasodilation …
Functional rarefaction
Hypertension
Structural rarefaction
Apoptosis in endothelial cells

3. Vascular Glycocalyx
Glycocalyx consists of proteoglycans and glycosaminoglycans.
This the picture of the glycocalyx under the electron microscope.
The glycocalyx forms a gel-like layer protecting the endothelial lining of the arteries.
The glycocalyx plays a role in the balance of vasoconstriction and vasodilatation, pro- and anti-coagulant activity, pro- and anti-inflammatory stimuli, and pro- and anti-oxidative factors
The glycol-calyx plays an important role in maintaining the balance between vasoconstriction and vasodilatation, pro- and anti-coagulant activity, pro- and anti- inflammatory stimuli, and pro- and anti-oxidative factors.
Most studies published to date had a small sample size or a case–control design, no previous population study focused on the sublingual microcirculation to assess capillary density and glycol-calyx width
The glycocalyx is a gel-like layer about 0.5 μm thick covering the endothelium. It serves as a physical barrier and plays an important role in vascular hemeostasis.

4. Sublingual Capillary Microscopy
and GlycoCheck
1 site=10micros, need not say first
mucosa[mju:'kəʊsə]
Handheld Video Capillary Microscope (KK Research Technology, UK) interfaced with a computer running the GlycoCheck software (GlycoCheck BV, Maastricht, The Netherlands).

5. GlycoCheck Measurement 1
― Capillary Density
Total density (RBC filling >0%)
no segments / mm2
Perfused density (RBC filling ≥50%)
Perfused-to-total density ratio
Quality control is by the software
The vertical lines are the reference lines used by the software at intervals of 10-um only choose the segment perfused by the blood flow>=50%
0.4 mm

6. GlycoCheck Measurements 2 ― Perfused Boundary Region (PBR)
RBC column width at the 3000 capillary segments 10 um apart was determined and the median and the 5th-95th percentile interval of RBC width was used for the calculation of PBR.

7. Healthy and Impaired Glycocalyx as Measured by PBR

8. Sublingual Glycocheck
Previous Studies with
Sublingual Glycocheck
The sublingual glycocalyx estimated by the PBR is decreased in patients with DM, CKD, CVD, and critically ill patients.
Limitations: case-control studies; small sample size; no population data
Glycocalyx consists of proteoglycans and glycosaminoglycans.
This the picture of the glycocalyx under the electron microscope.
The glycocalyx forms a gel-like layer protecting the endothelial lining of the arteries.
The glycocalyx plays a role in the balance of vasoconstriction and vasodilatation, pro- and anti-coagulant activity, pro- and anti-inflammatory stimuli, and pro- and anti-oxidative factors

9. Study Objective
We investigated the characteristics and associations of the sublingual capillary density and glycocalyx with common CV risk factors in general Chinese and Flemish populations.
Gu YM, et al. Hypertension. 2015;65:

10. Study Populations ― Flemish
From April 2013 to June 2014, 487 participants were invited, 320 signed informed consent(65.7%). The number of participants analyzed totaled 254.
600km far away from shanghai
Altitude: average 600m
Eksel, Belgium Coordinating Center in Leuven, Beglium

11. Study Populations ― Han and She Chinese
In May 2013, 931 Chinese were invited, 663 (71.2%) gave informed consent. The number of participants analyzed totaled 472, including 252 Han and 220 She people.
600km far away from shanghai
Altitude: average 600m
JingNing County Villages in JingNing She Minority

12. Measurements in the 3 Ethnic Groups
Sublingual GlycoCheck
Standardized questionnaires
Anthropometric measurements
Blood biochemical measurements
600km far away from shanghai
Altitude: average 600m

13. Characteristics of Participants (1)
Han (n=252)
She (n=220)
Flemish (n=254)
Age, y
51.8
51.7
49.8
BMI, kg/m2
23.2‡
23.5†
26.5
SBP/DBP, mmHg
124/78*‡
129/81
129/83
PP, mm Hg
46.8
47.6
46.5
Pulse rate, beats/min
72.1‡
73.2†
63.3
Hematocrit, %
43.3‡
42.7†
41.1
Total cholesterol, mmol/L
5.40‡
5.57†
4.82
Blood glucose, mmol/L
4.99‡
4.79†
4.57
Significance of the difference: * Han vs. She, † She vs. Flemish, ‡ Han vs. Flemish.

14. Characteristics of Participants (2)
Han (n=252)
She (n=220)
Flemish (n=254)
Women
55.6
62.7†
46.9
Smokers
21.8
17.3
14.2
Drinking alcohol
34.1‡
31.4†
76.4
HT (Anti-HT)
29 (42)
36 (48)
38 (44)
Previous CVD
3.2
1.8
5.5
Diabetes
6.4‡
0.4
Significance of the difference: * Han vs. She, † She vs. Flemish, ‡ Han vs. Flemish.

15. GlycoCheck Measurements
Han (n=252)
She (n=220)
Flemish (n=254)
PBR, nm
2019‡
2000†
1876
Total Capillary density, NO/mm2
580‡
573†
546
Perfused Capillary density, NO/mm2
342‡
334
320
Perfused-to-total density ratio
0.59
Significance of the difference : * Han vs. She, † She vs. Flemish, ‡ Han vs. Flemish.

16. PBR, Hemotocrit and Capillary Density
Han
2700
2500
2300
2100
1900
1700
1500 30 35 40 45 55 50
600
500
400
300
200
100
Perfused density (n°/mm2)
Haematocrit (%)
PBR (nm)
p<0.0001
She
Perfused density (n°/mm2)
2700
2500
2300
2100
1900
1700
1500 30 35 40 45 55 50
600
500
400
300
200
100
Haematocrit (%)
p<0.0001
Flemish
2500
2300
2100
1900
1700
1500
1200 30 35 40 45 55 50
600
500
400
300
200
100
Perfused density (n°/mm2)
Haematocrit (%)
P<0.0001
Association of the perfused boundary region with hematocrit and perfused capillary density by ethnicity. The scale of hematocrit increases from back to front, whereas the opposite is the case for perfused capillary density.

17. Distribution of Standardized PBR

18. Standardized PBR P<0.0001 Standardized PBR (nm) P<0.0001 2024
1990
1875

19. Correlates of Standardized PBR
Model 1
Model 2
Model 3
Han (vs. average)
50.4*
49.3*
53.6*
She (vs. average)
24.3
24.6
20.8
Flemish (vs. average)
–74.7*
–73.9*
–74.5*
BMI (+3.9 kg/m2)
–18.4
–17.4
–25.3*
MAP (+13.1 mmHg)
–23.3*
DBP (+11.2 mmHg)
–25.4*
The covariables considered were sex, age, BMI, smoking, cholesterol, glucose, g-GT, AH-drug, CVD, and MAP and PP in Model 1, or SBP and DBP in Model 2. or Framingham risk score in Model 3. Significance of effect size: * P≤0.05.

20. Correlates of Standardized PBR
by Ethnicities
BMI
MAP
None of the between-ethnicity comparisons reached significance.

21. Correlates of Perfused Capillary Density80
Regression line (95% CI) in individual participants
Mean (95%CI) per quintile
Perfused density (n°/mm2) 30 40 50 60 70
p=0.0024
year
375
350
325
300
Age
p=0.009 –8 –4 4 8
point 12
Framingham score
p=0.45
p=0.14 15 20 25 35
kg/m2 3 5 6 7
mmol/L
BMI
Cholesterol
Perfused capillary density was standardised for ethnicity.

22. Correlates of Capillary Density
Perfused Density
Total density
Model 1
Model 2
Han (vs. average)
10.0*
9.29*
15.2*
13.5*
She (vs. average)
1.58
1.49
6.65
6.59
Flemish (vs. average)
–11.6*
–10.8*
–21.8*
–20.1*
Age (+13.7y)
9.31† …
Framingham score (+6.53 pts)
7.93†
Correlates of the sublingual capillary density were identified by a stepwise regression procedure with P-values for covariables to enter and stay in the models set at 0.15.
Ethnicity was forced in the models and was coded using the deviation from mean coding, which expresses the ethnic differences relative to the average in the whole study population.
The covariables considered for entry in Models 1 were female sex (0, 1), age (continuous), body mass index (continuous), smoking (0, 1), total cholesterol (continuous), plasma glucose (continuous), g-glutamyltransferase (continuous), antihypertensive drug treatment (0, 1), and history of cardiovascular disease (0, 1). Mean arterial pressure and pulse pressure, or systolic and diastolic blood pressures were also offered to Model 1, but did not enter. Covariables in Model 2 were body mass index, g-glutamyltransferase, Framingham risk score, antihypertensive drug treatment, and history of cardiovascular disease.
For continuous variables, the association sizes are expressed for a 1‑SD increase.
Significance of the associations: * P≤0.05; †P≤0.01; ‡P≤0.001.
The covariables considered were sex, age, BMI, smoking, cholesterol, glucose, g-GT, AH-drug, CVD. Model1 additionally included MAP and PP, whereas Model 2 had Framingham risk score. Significance of effect size: * P≤0.05. 22

23. Correlates of Perfused-to-Total Capillary Density Ratio
Model 1
Model 2
Han (vs. average)
0.0060
0.0050
She (vs. average)
–0.0051
–0.0027
Flemish (vs. average)
–0.0009
–0.0023
Age (+14.4 y)
0.0092*
BMI (+3.90 kg/m2)
0.0085*
0.0066
Cholesterol (+1.02mm/L)
0.0102*
Smoking (0,1)
–0.0202*
Framingham risk score (+6.53pts)
0.0145†
We applied the deviation from mean coding, which expresses the ethnic differences in the ratio relative to the average in the whole study population. 23

24. Correlates of Perfused-to-Total Capillary Density Ratio by Ethnicities
Age BMI TC FRS
None of the between-ethnicity comparisons reached significance.

25. Summary
Higher age, body mass index, total cholesterol and Framingham risk score were associated with functional capillary recruitment.
In capillaries that remain perfused, glycocalyx width increased with higher BMI, MAP and DBP.
There were no ethnic differences in these associations.

26. Conclusion
A higher cardiovascular risk profile is associated with recruitment of capillaries with preserved glycocalyx that protects the endothelium.
Further research on microcirculation with the use of this novel technique is warranted.

27. Acknowledgements Leuven Shanghai Jan A. Staessen Yumei Gu Yanping Liu
Lutgarde Thijs
Tatiana Kuznetsova
Peter Verhamme
Thibault Petit
Zhengyu Zhang
Fangfei Wei
Shanghai
Jiguang Wang
Yan Li
Changsheng Sheng
Qifang Huang
Shuai Wang
Yuanyuan Kang
Feika Li
Jie Song
Yibang Cheng
Qianhui Guo

28. Thank You 谢谢