1. Caffeine Treated Embryo
Caffeine Acts as Teratogen and Causes Arrhythmia in 72-hour Chicks
Manpreet (Preety) Kaur, Cheyenne Robinett
Abstract
Methods
Discussion
In humans, caffeine is known to cause erratic heartrate
In the treated embryo, the caffeine caused erratic heartrate and pauses
Representative of what could happen to human fetuses during development
The start and stop of the heartrate in the embryo could prove fatal
Erratic heart rate means potential for erratic blood flow
Could stunt growth and development of the fetus
Chick embryos showed stunted brain, heart, and limb development
Eye development was decreased
It was hypothesized that addition of caffeine will delay brain growth, limb formation, and cardiac primordium. The 48 hour caffeine treated chicks did not develop at the same rate as the control group by 72 hours and showed slowed progression. The stunted brain and limb development coupled with aortic arrhythmia reflected teratogenic effects on the 72 hour chicks.
Fertilized Chick Embryo
Windowed Embryo
Caffeine Treated Embryo
(400 micrograms per 500 microliters of Howard Ringers solution per egg)
Untreated Embryo
Caffeine traces back to plants derivatives from South America and is an integral component in beverages such as coffee and tea. Since its isolation in 1820, it has been medically used for pediatric apnea treatment by stimulation the respiratory and cardiac systems (Barone, 1984).
The 48 hour chick typically undergoes flexion that twists the embryo to reorient the head at the mesencephalon. By 72 hours, the craniocaudal body axis morphs into a chick embryo in fetal position. From 48 to 72 hours, the sections of the cranium are more distinct (showing the telencephalon, encephalon, and myelencephalon). The embryonic development of the chick closely resembles that of humans, therefore chicks serve as excellent model organisms. Caffeine addition to the 48 hour chick prevented formation of these changes which may also be the reason that pregnant mothers are cautioned to limit caffeine intake. (Wolpert., 2011).
Embryologic studies on rats indicated decreased development with caffeine introduction. Somite count was decreased, craniofacial region growth stunted, forelimb production delayed, and cardiac primordium delay (Fadel, 1992). Reduced body size was also observed in 48-hour treated chicks in 72-hours of incubation at 700 µg of caffeine concentration (Gilani, 1983). Caffeine is also an adenosine antagonist that that negatively affects the hypoxic drive necessary for respiration caused by arrhythmias and inadequate blood flow to the heart (Rivkees, 2012). In addition, heartbeat, blood pressure , and body posture are also controlled by the pons, the medulla oblongata , and cerebellum as well as the eye from the hindbrain, therefore the teratogenic activity of caffeine decreased not only brain formation but also the proper development of the heart, limb buds, and eyes (Wolpert, 2011).
Introduction
Results
Control:
Treated Embryo: A. B.
Brain
Somites
Heart
Optic Cup
Limb Buds
Brain
Heart
Somites
Optic Cup
Figure 1: Teratogenic Effect of 400 µg of Caffeine at 72 hours After Fertilization with Egg Treatment at 48 hours (A) No caffeine introduced to the chick embryo. Cardiovascular functions adequate with expected brain growth and limb development. (B) Caffeine treated embryo with retarded brain , limb, and cardiac system formation.
Graph 1: Arrhythmias Caused by Caffeine in a 72 hour Chick Embryo: The control’s heart rate was 51 steady beats per minute. The treated embryo’s heart rate was 45 erratic beats per minute. Caffeine introduction to developing embryo brain may have ceased proper heart functions leading to arrhythmia and weakened heart rate . Weakened heart rate indicates heart failure that could occur over time with caffeine in embryos.
References
Barone, J., & Roberts, H. (1984). IV Human Consumption of Caffeine. In Caffeine: Perspectives from recent research (pp ). S.l.: Springer Berlin Heidelberg.
Fadel, R., & Persaud, T. (1992). Effects of Alcohol and Caffeine on Cultured Whole Rat Embryos. Cells Tissues Organs, 144(2),
Gilani, S., Giovinazzo, J., & Persaud, T. (1983). Embryopathic effects of caffeine in the chick.Experimental Pathology, 23(2),
Rivkees, S., & Wendler, C. (2012). ATVB in Focus: The Role of Adenosine in Response to Vascular Inflammation. Arterioscler Thrombosis Vascular Biolology, 32,
Ventresca, E. (Director) (2015, March 24). Early Chick Embryogenesis. Biology 333 Developmental Biology Lab. Lecture conducted from Albright College, Reading.
Wolpert, L and Tickle, C. Principles of Development (4th edition), 2011