Kidney Function and the Transplant Shortage, Genetically Modified Pig Kidneys as Bridge Transplants, Full-Body MRI False Positive Risks, and Probiotics Facts vs. Marketing

Broadcast from KSQD, Santa Cruz on 9-17-2026:

Dr. Dawn opens with a primer on kidney function: their embryonic origin adjacent to the gonads, their central role in blood pressure regulation (retaining fluid in hemorrhage but paradoxically worsening heart failure), erythropoietin production (both an athletic doping agent and a mechanism by which severe sleep apnea can cause stroke-risk polycythemia), acid-base balance via bicarbonate, and nitrogen waste removal including uric acid.

The U.S. waiting list holds 95,492 people needing kidney transplants—88% of all organ waitlist patients—against only 27,500 annual donations, with 12-13 people dying daily on the list. Dr. Dawn walks through a Wired magazine analysis of paid donation, noting Iran is the only country with a legal regulated kidney market (Iranian citizens only, with a waiting list of donors and compensation around two months of median income). She frames the ethical debate: current U.S. altruistic donation implicitly rewards those with money and social networks who can afford time off, while poorer populations bear disproportionate end-stage renal disease burden. Proposed compensation alternatives include lifetime congressional-quality health insurance, student loan forgiveness, six-month waiting periods for informed consent, and 20-year payout structures. Donation mortality risk is comparable to childbirth—several-fold lower than logging.

Tim Andrews became the first patient to receive a genetically modified pig kidney as a bridge to human transplant, sustaining him 271 days until a human kidney became available (the pig kidney ultimately lost to pyelonephritis, not rejection). eGenesis used CRISPR to delete three highly antigenic pig genes—GGTA1 (which produces alpha-gal, the tick-transmitted meat allergy trigger), CMAH, and one other—along with porcine endogenous retroviruses, and added seven human genes for coagulation compatibility and anti-inflammation. Dr. Dawn notes the animal welfare implications of farming 50,000 modified pigs annually and unknown long-term graft survival.

An emailer asks about direct-to-consumer full-body MRI screening. Dr. Dawn explains MRI's advantages (no ionizing radiation, no kidney-toxic contrast) but emphasizes false positive harms: indeterminate findings that require invasive follow-up biopsies for lesions unlikely to be lethal, and the psychological burden of "ghost" diagnoses. Whole-body MRI also poorly evaluates lungs, intestines, and breasts (different sc