Regeneration of Hearts: Is it Possible? Fiction? Reality?

In a recent article from Science, the researchers from the University of Texas Southwestern Medical Center published their findings linking the possibility of finding a way to regenerate the hearts in humans. Their research involved the hearts of laboratory mice, which were able to grow back their hearts when a portion of the heart known as apex was removed within the first week of birth. Dr. Sadek, who was involved in this research, commented to The New York Times that the regenerative ability was lost after the 7-day period.¹

The concept of regenerative medicine is not new, but a field of growing interest. Last year, Chemical & Engineering News of American Chemical Society had an article about the current research in limb regeneration. The article provided interesting information like how an adult salamander is the only vertebrate capable of growing back a lost limb in a period of about 10 weeks.²

Two seemingly different articles - one for regeneration of heart muscles through cardiomyoctes and another for bringing back the limb with bone morphogenetic protein (BMP) - pose the important question to our body: why do we "forget" how to do something such as regeneration of old tissues and so forth, and how will we able to turn the switch from "off" to "on" if such a switch exists?

From more fundamental level, we can collect some of the answers to these questions if the animal is not human. Take a look at tadpoles, which can regenerate their limbs, and compare them to the frogs, which lack this ability. But, the process of tadpoles to frogs is a unique one, known as metamorphosis, which the species undergoes a major level of changes to become essentially a new species.

But, humans do not go through metamorphosis, so the issue becomes very complex. Still, while we certainly do not change dramatically though, there are some changes in the development that make a baby different from a fetus. In fact, when the anatomy of circulation for a fetus is compared to a baby, several major changes change the way the blood will be circulated in the baby. The anatomical differences are also reflected by the oxygen saturation curve.

So, it is evident that certain functions underlying the normal functionality of our body are based on the recognition of known factors that cause them to work the way they do. The unique difference between a fetus and a baby hints that the separate mechanisms of body are in place because of unequal living conditions between a fetus and a baby. What is unclear is, however, on whether these steps are "reversible," and allow humans to gain the control of abilities like regenerating the heart. Thus, the future research for clinical patients should concentrate on analyzing the mechanisms that surround this difference between an embryo and an adult for other mammal species (not directly humans because of ethical and practical reasons).

Works Cited

^1. Sindya N. Bhanoo, "Newborn Mice's Hearts Can Heal Themselves," The New York Times, 25 Feb. 2011

^2. Sophie L. Rovner, "Recipes For Limb Renewal," Chemical & Engineering News, 2 Aug. 2010.