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The association between markers of inflammation and retinal microvascular parameters: A systematic review and
Mengjiao Liu1, Claire Lovern2, Kate Lycett3
1School of Public Health, Nanchang University, Jiangxi, China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Jiangxi, China; Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia.
Insights
Inflammation is linked to cardiovascular disease. This study found inflammation markers like C-reactive protein and white blood cell count are associated with retinal venular caliber, but not arteriolar caliber.
Area of Science:
- Ophthalmology
- Cardiology
- Immunology
Background:
- Microvascular changes are crucial in cardiovascular disease (CVD) pathogenesis.
- Inflammation is a primary driver of these microvascular alterations.
- Retinal microvascular parameters offer a window into systemic vascular health.
Purpose of the Study:
- To investigate the association between inflammatory markers and retinal microvascular parameters.
- To determine if inflammation impacts arteriolar versus venular caliber differently.
- To explore potential therapeutic targets for CVD by understanding microvascular inflammation.
Main Methods:
- A systematic literature search was conducted across Medline, Embase, and PubMed up to April 2021.
- Meta-analysis was performed on studies examining inflammatory markers (C-reactive protein, white blood cell count) and retinal vascular caliber.
- A narrative review encompassed all included observational studies.
Main Results:
- Meta-analysis included 12 C-reactive protein studies (22,422 participants) and 6 white blood cell count studies (15,209 participants).
- Consistent evidence showed a modest association between C-reactive protein and venular caliber (r=0.09), but not arteriolar caliber (r=0.00).
- White blood cell count showed stronger associations with venular caliber (r=0.18) than arteriolar caliber (r=0.05).
Conclusions:
- Inflammation is more strongly associated with retinal venular caliber than arteriolar caliber.
- These findings highlight a potential, overlooked therapeutic target for microvascular damage in CVD.
- Further research into inflammation's role in microvascular dysfunction is warranted for improved CVD treatment.
Background And Aims:
Adverse changes to the microcirculation play an important role in the pathogenesis of cardiovascular disease (CVD), and inflammation is a key causal mechanism. We investigated the relationship between inflammatory markers and retinal microvascular parameters.
Methods:
Studies up to April 2021 were identified in Medline, Embase and PubMed with the following terms: retinal microvascular parameters, inflammatory markers, and observational studies. Correlation coefficients of inflammatory markers and retinal vascular caliber were pooled using the random-effects model.
Results:
Of 4783 studies identified, 36 met the inclusion criteria (general population 26, patients with diseases 10). C-reactive protein (CRP) and white blood cell count (WBC) were most frequently reported. We conducted meta-analysis with 12 CRP studies (22422 participants) and six WBC studies (15209 participants), and also performed a narrative review of all studies. There was consistent evidence of a modest association between CRP and venular caliber (r = 0.09, 95%CI 0.05 to 0.12), but little evidence of an association between CRP with retinal arteriolar caliber (r = 0.00, 95%CI -0.02 to 0.02). Similarly, WBC had stronger associations with venular (r = 0.18, 95%CI 0.05 to 0.31) than arteriolar caliber (r = 0.05, 95%CI 0.01 to 0.09). Narrative review of other inflammatory markers showed consistent findings. There was little evidence of associations between inflammation markers and other microvascular parameters, fractal dimension and tortuosity.
Conclusions:
There was more evidence for an association of inflammation with retinal venular than with arterial caliber. The findings suggest a potential druggable mechanism contributing to microvascular damage that has been relatively overlooked in CVD pathogenesis and treatment.
