Pigs could end the transplant waiting list
Why Read This
What Makes This Article Worth Your Time
Summary
What This Article Is About
Transplant surgeon Joshua D. Mezrich opens with a vivid 2 a.m. phone call — the brutal reality of evaluating a compromised donor kidney for a patient who will otherwise remain on dialysis indefinitely. He contextualizes the crisis: over 100,000 Americans wait for organ transplants, while hundreds of thousands more with end-stage disease are never even placed on the list. Transplantation itself only became viable in the mid-1980s with the drug cyclosporine, and the waiting list has since exploded as older, sicker patients qualify.
Mezrich then makes the case for xenotransplantation — transplanting genetically modified pig organs into humans. Pigs are ideal donors due to their size, litter frequency, and ethical acceptability. Two breakthroughs drove progress: the cloning of Dolly the sheep in 1996 enabled early “knockout pigs,” and CRISPR-Cas9 gene editing since made multi-gene modification routine. Clinical trials using pig kidneys and livers are already underway. Mezrich envisions a near future of personalized, bespoke pig organs cloned to match individual recipients — eventually requiring minimal immunosuppression and lasting a lifetime.
Key Points
Main Takeaways
The Organ Crisis Is Catastrophic
Over 100,000 Americans await organs, while hundreds of thousands more with end-stage disease are never referred or listed — a silent, systemic tragedy.
Pigs Are the Ideal Donor Species
Pigs offer the right organ size, fast reproduction, low housing costs, and fewer ethical obstacles than primates — making them the universal donor species of choice.
CRISPR Changed Everything
The advent of CRISPR-Cas9 gene editing made it possible to modify dozens of pig genes in months, transforming xenotransplantation from theory into active clinical trials.
Pig Kidneys Already Function in Humans
Two clinical trials using genetically modified pig kidneys are currently ongoing; pig liver and heart transplant trials are also imminent, making xeno a present-day medical reality.
Personalized Organs Are the Next Frontier
Mezrich envisions bespoke pig organs cloned to match each patient’s genetics, requiring minimal immunosuppression and available within months of a diagnosis.
The Future Is Faster Than We Think
Mezrich reminds readers that human-to-human transplantation seemed like science fiction in the 1950s — a caution against dismissing xenotransplantation’s radical potential today.
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Article Analysis
Breaking Down the Elements
Main Idea
Genetically Engineered Pig Organs Can Solve the Organ Shortage
Mezrich argues that xenotransplantation — especially using CRISPR-modified pig organs — is the only realistic path to ending the chronic, deadly shortage of human donor organs. The technology has already moved from theory to clinical trial, and with ongoing advances in gene editing, personalized pig organs could soon replace the waiting list entirely.
Purpose
To Inform and Inspire Optimism About Xenotransplantation
Writing as both a practicing surgeon and a researcher, Mezrich aims to make a complex scientific development accessible and emotionally compelling to a general audience. He uses personal narrative, historical perspective, and a three-stage predictive roadmap to shift readers from skepticism to cautious optimism about the medical revolution already underway.
Structure
Narrative → Crisis → Historical → Scientific → Predictive
The article opens with a personal anecdote to humanize the organ shortage, scales up to statistical crisis, traces transplantation history from the 1950s through cyclosporine, explains the science of pig organ rejection and gene editing, and closes with a three-generation forecast. This layered structure takes the reader from bedside emotion to frontier science seamlessly.
Tone
Authoritative, Empathetic & Visionary
Mezrich writes with the authority of a 30-year surgical career, the warmth of a clinician who genuinely cares about his patients, and the forward-looking excitement of a researcher at the edge of a revolution. He is honest about current limitations — the need for intense immunosuppression, organs that last under a year — while remaining genuinely and credibly optimistic about what lies ahead.
Key Terms
Vocabulary from the Article
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Tough Words
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A powerful immunosuppressive drug derived from a fungus, whose introduction in the mid-1980s transformed organ transplantation from an experimental procedure into a reliable, life-saving discipline.
“Transplantation finally emerged as the modern life-saving discipline that it is now in the mid-’80s, with the advent of the immunosuppressive drug cyclosporine.”
A revolutionary gene-editing system borrowed from bacterial immune defenses, enabling precise, rapid modification of multiple genes in living organisms — reducing what once took years to a matter of months.
“All of this changed in the last decade with the advent of CRISPR-Cas9, a gene-editing system borrowed from microbes that enables the generation of genetically manipulated transgenic animals in a matter of months rather than years.”
An early, painstaking gene-editing technique that uses DNA sequence similarity to swap or knock out specific genes; far slower and less precise than modern CRISPR methods.
“Even with the relatively primitive and painstaking gene editing techniques available (homologous recombination) in the ’90s, it would be possible to knock out the gene for this sugar in pig cells…”
To reduce the force, effect, or strength of something; in a medical context, to weaken an immune response so that it is less severe or destructive.
“In the ’80s and ’90s, efforts were made to attenuate the immune response to these sugars, with limited success.”
Prevented from making progress; obstructed or thwarted by circumstances or obstacles that make it impossible to move forward with a plan or goal.
“However, labs were stymied by animal protests and the discovery of a virus that resides in the cells of virtually all pigs…”
A haunting or threatening prospect; a looming possibility of something dangerous or frightening that casts a shadow over a situation or plan.
“…raising the specter of a xeno-fueled pandemic.”
Reading Comprehension
Test Your Understanding
5 questions covering different RC question types
1According to Mezrich, chimpanzees and other primates remained the preferred animal organ donors for humans well into the 2000s because of their greater genetic compatibility.
2What was the fundamental biological reason pig organs were rapidly rejected when first transplanted into primates?
3Which sentence best explains why CRISPR-Cas9 was such a turning point for xenotransplantation research?
4Evaluate these statements about the organ transplant crisis as described in the article.
Transplant programs in the U.S. must maintain at least a 90 percent chance of one-year survival to avoid being placed on probation.
The transplant waiting list has shrunk in recent years because modern medicine has reduced the number of patients with organ failure.
The waiting list has grown partly because older and sicker patients with chronic conditions like diabetes and high blood pressure now qualify for transplants.
Select True or False for all three statements, then click “Check Answers”
5Mezrich ends the article by saying “Medical revolutions have a way of arriving much faster than skeptics expect.” What is the most reasonable inference about why he includes this closing statement?
FAQ
Frequently Asked Questions
Despite being more genetically compatible, primates were abandoned as donors by the late 1980s due to four problems: slow reproduction making gene editing and scaling difficult; ethical and emotional objections (intensified by the 1984 Baby Fae case); body size too small for human organ needs; and serious infection risk, as HIV originated in chimpanzees. Pigs solve all four issues — right size, fast breeding, low ethical resistance, and manageable infection risk.
The first was the cloning of Dolly the sheep in 1996, which proved that gene editing in animal cells could produce cloned “knockout” animals — enabling the first pig without the rejection-triggering sugar molecule by 2002. The second was CRISPR-Cas9, which from the 2010s onward allowed dozens of gene edits in months rather than years, making it practical to engineer pig organs that closely resemble human tissue and suppress immune responses.
Mezrich outlines three generations of progress. First, current pig organs sustain life for six months to a year but require intense immunosuppression. Second, more advanced transgenic pigs will make standard immunosuppression sufficient, allowing pig organs to rival human ones — clearing the waiting list, though with ongoing side effects. Third, fully personalized organs cloned to each patient’s genetics will require minimal immunosuppression and could eventually be designed for longevity, disease resistance, and even extreme environments.
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This article is rated Advanced. While Mezrich writes accessibly for a general audience, the piece requires readers to follow complex medical and genetic concepts — including immunosuppression mechanisms, gene-editing techniques like CRISPR-Cas9 and homologous recombination, and a multi-stage predictive scientific roadmap. Readers must also synthesize the personal narrative, historical context, and technical argument into a coherent understanding of the article’s central thesis.
Joshua D. Mezrich is a transplant surgeon with 30 years of experience who has witnessed the field evolve from its early failures to its modern successes. This article is adapted from his book “Every Living Creature,” published by MIT Press. His dual perspective — as a practicing clinician who takes 2 a.m. calls about imperfect donor organs, and as a researcher tracking the frontier of xenotransplantation — gives him unusual authority to write about both the human cost of the organ shortage and the scientific promise of its solution.
The Ultimate Reading Course covers 9 RC question types: Multiple Choice, True/False, Multi-Statement T/F, Text Highlight, Fill in the Blanks, Matching, Sequencing, Error Spotting, and Short Answer. This comprehensive coverage prepares you for any reading comprehension format you might encounter.
