Relationship between birth weight and retinal microvasculature in newborn infants

Dynamic Changes in Retinal Vessel Diameters and Arteriovenous Ratio within 10 Days of Birth

PURPOSE

This study monitored the dynamic changes in retinal vascular width and the AVR in full-term neonates within 1-10 days of birth.

METHODS

It was conducted at hospitals in the Anhui province from October 2020 to March 2022. A total of 700 full-term, healthy infants were chosen randomly within 10 days of birth, and the Star Pupil Medical Cloud Data System (XBDS) was used to collect fundus images. Infants within 6 days of birth were grouped into groups one to six, while those within the 7th to 10th days were grouped into group seven. The fundus photographs were imported into Image-Pro-Plus (IPP) software. The optic disc diameter was measured. The retinal artery and vein's diameter was measured at a distance between 0.5- and 1.0-disc diameter from the optic disc's margin. The AVR was also calculated. Finally, each group's retinal vessel diameters and AVR were compared separately to show their dynamic changes.

RESULTS

There were differences in the retinal artery diameter between groups one and two, three and four, four and five, and five and six. For retinal vein diameter, there were differences between groups one and two and groups six and seven. There were also differences in the AVR between all groups. In addition, there was a significant positive correlation between the small retinal artery and vein diameters.

CONCLUSION

The retinal artery and vein diameters and AVR in neonates change dynamically during the first 10 days of life. The AVR undergoes the most dramatic change daily and is considerably smaller than the AVR in adults. Hence, this study found that the external environment undergoes significant changes following birth that affect the microcirculation. Then, the retinal central vascular system undergoes similar emergency and adaptive alterations.

Systematic review on retinal microvasculature, physical activity, sedentary behaviour and adiposity in children and adolescents

AIM

As retinal microvasculature (RMV) can be assessed non-invasively, it presents an opportunity to examine the health and disease of the human microcirculation, as RMV alterations have been recognised as one of the earliest signs of cardiovascular risk. This review summarises current literature on the associations between physical activity (PA), sedentary behaviour (SB) and/or adiposity and RMV in children and adolescents aged 0-18 years.

METHODS

Six databases were searched (MEDLINE, Scopus, Web of Science, ScienceDirect, PsycINFO and CINAHL), through to December 11, 2019. English, Portuguese, French, Spanish or Dutch were the languages searched. Meta-analyses were performed using the meta-analyst software.

RESULTS

A total of 6796 studies were screened, and 26 studies were included, representing 24 448 participants, from 12 different countries. Studies reporting results on weight status were twenty-three, PA was assessed in six studies, and SB was assessed in three studies. Four studies examined weight status and PA/SB. Meta-analysis was performed for two studies and showed that children with obesity have smaller retinal arterioles (-2.38 µm difference, 95% CI 0.62, 4.15 µm) and larger retinal venules (2.74 µm difference, 95% CI -4.78, -0.72 µm) than children without obesity.

CONCLUSION

Results showed that adiposity was associated with microvascular alterations in children and adolescents. Increased adiposity, lack of PA and high levels of SB were negatively correlated with vessel width parameters.

Tongue development in stillborns autopsied at different gestational ages

OBJECTIVES

This study aimed to analyze, through the morphometric method, the perimeter and length of the tongue, the collagen fibers, and the perimeter of blood vessels at different gestational ages and fetal weights.

MATERIAL AND METHODS

Tongues (n=55) of stillborns autopsied at 23-40 weeks of gestational age were macroscopically analyzed, and their length and perimeter were measured. Fifty-five tongue fragments were collected through a longitudinal section in the region that accompanies the median lingual sulcus and histologically processed. Slides were stained with picrosirius and immunolabeled with CD31 antibody. Quantification was performed on collagen fibers under polarized light, and on the perimeter of vessels with the CD31.

RESULTS

A positive and significant correlation of gestational age with tongue perimeter and length was found. There was a positive and significant correlation between collagen fibers and gestational age, as well as between gestational age and the perimeter of blood vessels. Between collagen fibers and fetal weight, a positive and significant increase was observed. Regarding the correlation between the perimeter of blood vessels and the fetal weight, an increase was observed.

CONCLUSION

As gestational age advances, there is an increase in tongue perimeter and length, in the percentage of collagen fibers, and in vascular perimeter, demonstrating that tongue formation is directly related to tongue growth and development.

Retinal vascular imaging in early life: insights into processes and risk of cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally. In recent years, studies have shown that the origins of CVD may be traced to vascular and metabolic processes in early life. Retinal vascular imaging is a new technology that allows detailed non-invasive in vivo assessment and monitoring of the microvasculature. In this systematic review, we described the application of retinal vascular imaging in children and adolescents, and we examined the use of retinal vascular imaging in understanding CVD risk in early life. We reviewed all publications with quantitative retinal vascular assessment in two databases: PubMed and Scopus. Early life CVD risk factors were classified into four groups: birth risk factors, environmental risk factors, systemic risk factors and conditions linked to future CVD development. Retinal vascular changes were associated with lower birth weight, shorter gestational age, low-fibre and high-sugar diet, lesser physical activity, parental hypertension history, childhood hypertension, childhood overweight/obesity, childhood depression/anxiety and childhood type 1 diabetes mellitus. In summary, there is increasing evidence supporting the view that structural changes in the retinal microvasculature are associated with CVD risk factors in early life. Thus, the retina is a useful site for pre-clinical assessment of microvascular processes that may underlie the future development of CVD in adulthood.

Skin capillary density in infants born to normotensive mothers: a comparison between singleton and twin infants

OBJECTIVE

Twin infants tend to have LBW and microvascular alterations but do not appear to have an increase in cardiovascular mortality later in life as singleton infants. We hypothesized that twin infants born to normotensive mothers would not have capillary rarefaction at birth.

METHODS

We studied 26 dizygotic twin infants and compared them with 115 consecutive singleton infants to normotensive mothers. We used orthogonal polarized spectroscopy to measure basal (i.e., functional) and maximal (i.e., structural) skin capillary density according to a well-standardized protocol.

RESULTS

Twin infants have significantly higher BCD (mean difference 4.3 capillaries/mm(2) , 95% CI: 0.4, 8.1, p = 0.03) and have marginally significantly higher MCD (mean difference 3.9 capillaries/mm(2) , 95% CI: -0.6, 8.3, p = 0.086) compared to singleton infants. Birth weight was significantly associated with BCD and MCD (p = 0.003 and 0.006).

CONCLUSIONS

Twin infants with low and NBWs tend to have higher functional and structural capillary densities compared to singleton infants. Further longitudinal studies of skin capillary density and of retinal vascular parameters commencing from birth to various stages in early childhood are essential to identify the dynamics and the exact timing, if any, of the remodeling of microcirculation in these individuals.

Can the retinal microvasculature offer clues to cardiovascular risk factors in early life?

Adulthood cardiovascular diseases (CVD) burdening in adulthood have been suggested to have possible predisposition early in life. We aimed to systematically review the literatures on retinal microvasculature among paediatric population in relation to a range of environmental and systemic changes. Papers with quantitative retinal vascular assessment and epidemiological design were reviewed.

CONCLUSION

This review supports the theory that major vascular diseases have pathological predisposition early in life by providing morphological evidence on retinal microcirculation in vivo.