👂 Science gives ears to the deaf? (and confirmed your horse knows you're faking it)

This week in "things that sound made up but aren't," gene therapy gave deaf children the ability to hear their parents' voices for the first time, artificial saliva made from sugarcane is protecting cancer patients' teeth, and French researchers confirmed that yes, your horse absolutely knows you're terrified. Meanwhile, scientists are learning to read pain on your face while you're on the operating table, and a major roadmap just laid out how we might eventually use light to fix broken brains. Just another Tuesday in biotech land, where the future sounds increasingly like science fiction your parents wouldn't believe.

RESEARCH

Imagine being profoundly deaf your entire life because of a single broken gene, then hearing your mother's voice within weeks of a single injection. That's now reality for children treated with Regeneron's DB-OTO gene therapy (the most research published just last month!) , and it's about as close to a medical miracle as biotech gets.

The therapy targets mutations in the OTOF gene, which encodes otoferlin, a calcium sensor that triggers neurotransmitter release at the inner hair cell synapse, enabling the transmission of sound signals to the auditory nerve. Without it, kids are born into complete silence. In the pivotal CHORD trial, 11 of 12 children showed clinically meaningful hearing improvements, with three achieving normal hearing levels. Six can now hear soft speech without assistance. Three can detect whispers.

The technical challenge to tackle was elegant: the OTOF gene is too large for a single virus to carry, so researchers split it into two, packaged each half in separate AAV1 vectors, and injected both into the cochlea. A hair cell-specific promoter ensures the gene only activates where it's needed. Cellular machinery then reconstitutes the complete protein, essentially reconnecting a broken circuit. Results appeared within weeks.

Regeneron has received Orphan Drug, Rare Pediatric Disease, Fast Track, and Regenerative Medicine Advanced Therapy designations from the FDA. If approved, DB-OTO would become the first gene therapy for hearing loss in the United States. OTOF-related deafness affects only about 20 to 50 babies annually in the U.S., but researchers believe this could unlock therapies for the more than 150 other genes linked to hearing loss.

RESEARCH

Head and neck cancer patients often lose the ability to produce saliva after radiation therapy, leaving them with chronic dry mouth and teeth that essentially dissolve in place. About 80% of these patients develop xerostomia, considered the most debilitating late toxicity of head-and-neck radiotherapy. Existing artificial salivas are, frankly, terrible. But researchers at the Bauru School of Dentistry at the University of São Paulo may have found something better: fake spit made from sugarcane.

The secret ingredient is CaneCPI-5, a recombinant phytocystatin (cysteine protease inhibitor) that binds directly to tooth enamel. According to project coordinator Marília Afonso Rabelo Buzalaf, this is "the first product that uses the concept of acquired pellicle to treat xerostomia." That pellicle is a thin organic film that forms on teeth through selective adsorption of salivary proteins, glycoproteins, lipids, and other macromolecules, serving as a physical barrier against acid diffusion.

In testing on irradiated bovine enamel specimens, the complete formulation (CaneCPI-5 plus fluoride and xylitol) significantly reduced bacterial biovolume, colony counts, and mineral loss. The researchers note it performed "comparable or superior to" both commercial products and chlorhexidine, the clinical gold standard.

First author Natara Dias Gomes da Silva developed the protein during her doctoral work at FOB-USP, with Flávio Henrique-Silva at the Federal University of São Carlos handling protein engineering. The study, published in the Journal of Dentistry (DOI: 10.1016/j.jdent.2025.106176), was funded by FAPESP. No word yet on when your pharmacist might stock sugarcane-based saliva spray, but the future of oral health apparently tastes tropical.

RESEARCH

Patients under local anesthesia can struggle to communicate their pain levels. Infants can't tell you. People with dementia often can't either. So researchers at HTWK Leipzig built a contactless system that watches your face and monitors your heart to estimate how much you're suffering.

The approach, published in the IEEE Open Journal of Engineering in Medicine and Biology on November 14, 2025, combines facial expression analysis with remote photoplethysmography. That's a technique where cameras detect subtle skin color changes caused by blood volume variations during cardiac cycles (hemoglobin absorbs green light more strongly than red light). No wires, no sensors, no electrodes getting in the way of actual medical care.

Lead researcher Bianca Reichard and her team at the Laboratory for Biosignal Processing evaluated 15 heart rate variability parameters and selected the top seven most relevant to pain prediction. They trained the model on both the BioVid Heat Pain Database (87-90 subjects experiencing controlled heat pain) and real surgical footage from 29 cardiac patients undergoing catheterization procedures.

The model achieved about 45% accuracy, which sounds underwhelming until you realize previous systems were trained on pristine, short video clips where nothing ever goes wrong. Their training videos included lighting changes, obscured faces, patient movements, and all the chaos of actual operating rooms, spanning 30 minutes to 3 hours. Reichard notes that using neural networks instead of their simpler statistical model would likely improve performance further.

RESEARCH & NEWS

Optogenetics has spent two decades as neuroscience's favorite research toy, letting scientists control specific neurons with light in lab animals. A new Nature Neuroscience perspective from researchers across Switzerland, France, the U.S., and Israel now lays out a comprehensive roadmap for bringing this technology to patients.

To be clear: this is a strategic review, not a report of new clinical breakthroughs. But the 11-author paper, led by Christian Lüscher at the University of Geneva and including optogenetics pioneer Karl Deisseroth of Stanford, outlines both the obstacles and the pathways to human application. The technique works by introducing genes for light-sensitive proteins called opsins into targeted neurons via viral vectors. When illuminated, opsins function as molecular switches: channelrhodopsin responds to blue light causing excitation, while halorhodopsin enables inhibition.

The proof-of-concept for human use already exists in retinal applications. In the PIONEER trial for retinitis pigmentosa, a 58-year-old man blind for 40 years could locate and count objects after treatment combining gene therapy with light-amplifying goggles. Nine similarly treated patients have shown no safety concerns, and at least four additional trials are testing optogenetic vision restoration.

For brain applications targeting conditions like chronic pain, epilepsy, and Parkinson's disease, the technology remains in preclinical stages. Modulight Biotherapeutics, a Boston startup targeting trigeminal pain, is initiating IND-enabling studies with completion expected in 2027. Human brain trials are likely years away, but the roadmap suggests optogenetics may eventually offer something drugs can't: precision intervention at the circuit level.

RESEARCH

You've heard it your whole life: animals can smell fear. Turns out it's actually true, at least for horses, and now we have the armpit sweat samples to prove it.

Researchers from INRAE (French National Research Institute for Agriculture, Food and Environment) collected odor samples from 30 human volunteers while they watched a 20-minute excerpt from the horror film "Sinister," then again while they watched uplifting content. They selected the 14 volunteers with the strongest emotional responses and exposed 43 Welsh mares to these scents via cotton pads in specialized muzzles.

When exposed to fear-related odors, horses touched humans at 60% of the baseline rate (a 40% reduction), stared more at novel objects (rate ratio 1.32), and showed significantly heightened startle responses with elevated maximum heart rates. The study, published in PLOS One, marks the first time this interspecies chemical communication has been rigorously demonstrated in horses.

Lead author Plotine Jardat of the French Institute for Horse and Riding notes the practical implications: handlers' emotional states can directly influence horse behavior, potentially increasing accident risk in equestrian sports or therapeutic riding programs. Senior author Léa Lansade advises that riders should focus on relaxing so they "can ride calmly and without fear." Your horse already knows you're faking confidence, and now there's peer-reviewed evidence to prove it.

This week, deaf children heard their parents for the first time, fake saliva got an upgrade from sugarcane, and we confirmed that horses have been reading us all along. Meanwhile, algorithms are learning to spot our pain, and scientists are mapping out how light might eventually become medicine. The wild part is that most of this was unthinkable a decade ago.

Got thoughts on which gene therapy might be next after hearing? Curious whether your horse can smell your other emotional states? Reply and let us know. We read everything while nervously wondering what else horses know about us.

Forward this to someone who needs proof that biotech is the weirdest timeline. And if you're new here, welcome to the community of people who find all this as fascinating as we do.

Keep questioning everything (especially around horses),

Prateek & Jere

P.S. If you're a nervous equestrian, maybe try watching comedies before your next ride. Science now suggests it might actually help.