Thousands of people in the United States are on the bricks of losing their lives, hoping that one day, their name will be taken off the waiting list, and they will receive an organ transplant. And their several family members and friends are sitting alongside feeling hopeless, helpless, and praying that their chance will come.

The harsh reality is that many on the organ transplant waiting list pass away. And this is not only in America, it's a global problem that is growing exponentially and taking a significant value. To resolve this problem, scientists and doctors have attempted to use other animal parts as replacements for human organs. For example, there have been two cases where a pig heart was transplanted into a human. These hearts are genetically modified to take on the several responsibilities of this organ. The second instance occurred this year on September 22 at the University of Maryland. After two days of the heart being placed in the military veteran, he was cracking jokes and sitting upright on the chair without any help.

Geneticists have continued to explore new ways in which they can increase the survival rate. Most notably, many are conducting experiments on growing organs and tissues specifically designed for humans inside of animals. Guangzhou Institutes of Biomedicine and Health in China spent five years in the lab deciphering ways they can best approach this potential solution. The team uses CRISPR or Cas 9 which edit two specific genes necessary for kidney development in pigs. They also tweak active genes that dampen cell death allowing enough time for the human kidney to form.

As of date, more than 1,800 embryos were transferred into the surrogate sows, or which five were harvested for study within the first 28 days. The organs in the sows contain 50% to 60% human-derived cells which is the highest percentage of human cells ever to be observed in any other animal. Today, these teams are pursuing their research even further by mapping ways in which they can create human hearts and pancreas in pigs too.