“As the number one cause of common colds and a major cause of breathing problems in people with asthma and other chronic lung conditions, rhinoviruses are very important in human health,” says senior author Ellen Foxman of Yale School of Medicine. “This research allowed us to peer into the human nasal lining and see what is happening during rhinovirus infections at both the cellular and molecular levels.”

Creating Lab Grown Human Nasal Tissue

To closely observe how nasal cells respond to infection, the research team built a lab grown model of human nasal tissue. They grew nasal stem cells for four weeks while exposing the upper surface of the tissue to air. This setup encouraged the cells to mature into a structure that closely resembles the lining of the nasal passages and lung airways.

The resulting tissue contained multiple cell types found in the human airway, including mucus producing cells and cells with cilia. Cilia are tiny hair like structures that help move mucus and trapped particles out of the lungs.

“This model reflects the responses of the human body much more accurately than the conventional cell lines used for virology research,” Foxman says. “Since rhinovirus causes illness in humans but not other animals, organotypic models of human tissues are particularly valuable for studying this virus.”

Interferons and Early Antiviral Protection

Using this model, the researchers were able to monitor how thousands of individual cells respond together during infection. They also examined what happened when the cellular sensors responsible for detecting rhinovirus were blocked. These experiments revealed a powerful defense system coordinated by interferons, which are proteins that interfere with viral entry and replication.

When nasal cells detect rhinovirus, they release interferons that activate antiviral defenses not only in infected cells but also in nearby healthy cells. This coordinated response makes it difficult for the virus to reproduce and spread. If interferon activity begins quickly, the infection can be contained early. When the researchers blocked this response, the virus spread rapidly, infecting many more cells and causing significant damage. In some cases, the infected organoids did not survive.

“Our experiments show how critical and effective a rapid interferon response is in controlling rhinovirus infection, even without any cells of the immune system present,” says first author Bao Wang of Yale School of Medicine.

When Viral Growth Triggers Harmful Responses

The study also uncovered additional responses that occur when viral replication increases. Under these conditions, rhinovirus can activate a separate sensing system that leads both infected and uninfected cells to produce large amounts of mucus and inflammatory signals. This reaction can contribute to airway inflammation and breathing difficulties in the lungs.

According to the researchers, these pathways may offer useful targets for treatments aimed at reducing harmful symptoms while supporting effective antiviral defenses.

Limits of the Model and Future Research

The team notes that their organoid model includes fewer cell types than are present in the human body. During real infections, additional cells, including immune cells, are drawn to the site to help fight the virus. The researchers say that understanding how these additional cell types and environmental factors in the nasal passages and airways influence the body’s response to rhinovirus will be an important focus of future work.

“Our study advances the paradigm that the body’s responses to a virus, rather than the properties inherent to the virus itself, are hugely important in determining whether or not a virus will cause illness and how severe the illness will be,” Foxman says. “Targeting defense mechanisms is an exciting avenue for novel therapeutics.”

The study was carried out by an international research team led by Mauro D’Amato, Professor of Medical Genetics at LUM University and Ikerbasque Research Professor at CIC bioGUNE, member of BRTA. The researchers used a large-scale genetic strategy to look for common DNA differences linked to how often people have bowel movements, referred to in the study as stool frequency. To do this, they analyzed genetic data and health questionnaires from 268,606 individuals of European and East Asian ancestry. Advanced computational methods helped identify which genes and biological processes were most strongly connected to gut movement.

Known Gut Pathways Confirm the Findings

The analysis uncovered 21 regions of the human genome that influence bowel movement frequency, including 10 regions that had not been identified before. Many of the genetic signals pointed to biological systems already known to regulate gut motion, offering reassurance that the results fit with established biology. These included bile-acid regulation (bile acids help digest fats and also act as signaling molecules in the gut) and nerve signaling involved in intestinal muscle contractions (including acetylcholine-related signaling, which helps nerves communicate with muscle). Together, these findings reinforce existing knowledge about how the gut functions.

Vitamin B1 Stands Out as a Surprise Signal

The most notable discovery emerged when researchers focused on two high-priority genes connected to vitamin B1 biology. These genes, SLC35F3 and XPR1, play a role in how thiamine is transported and activated in the body. To see whether this genetic signal was reflected in everyday life, the team analyzed dietary data from the UK Biobank. Among 98,449 participants, higher intake of dietary thiamine was linked to more frequent bowel movements.

This relationship was not uniform across all individuals. The effect of thiamine intake on bowel movement frequency depended on genetic variation in the SLC35F3 and XPR1 genes (analysed together as a combined genetic score). These results suggest that inherited differences in how the body handles thiamine may shape how vitamin B1 intake influences bowel habits in the general population.

Links to IBS and Future Research

Dr. Cristian Diaz-Muñoz, the study’s first author, said “We used genetics to build a roadmap of biological pathways that set the gut’s pace. What stood out was how strongly the data pointed to vitamin B1 metabolism, alongside established mechanisms like bile acids and nerve signaling.”

The findings also suggest a meaningful biological connection between bowel movement frequency and IBS, a condition that affects millions of people worldwide. “Gut motility problems sit at the heart of IBS, constipation and other common gut-motility disorders” says Prof Mauro D’Amato, “but the underlying biology is very hard to pin down. These genetic results highlight specific pathways, especially vitamin B1, as testable leads for the next stage of research, including lab experiments and carefully designed clinical studies.”

The study was led by Mauro D’Amato’s Gastrointestinal Genetics Research Group and involved investigators from CIC bioGUNE in Spain, LUM University, Institute for Genetics and Biomedical Research – CNR, CEINGE and University of Naples Federico II in Italy, University of Groningen in The Netherlands, University of Oxford in UK, Concordia University and Ontario Institute for Cancer Research in Canada, and Monash University in Australia. The research was supported by grants from MCIU/AEI/10.13039/501100011033 and ERDF/EU (PID2023-148957OB-I00); PRIN2022/NextGenerationEU (2022PMZKEC; CUP E53D23004910008 and CUP B53D23008300006); ERC Starting Grant (101075624); PNRR/NextGenerationEU (PE00000015/Age-it); NWO-VICI (VI.C.232.074); NWO Gravitation ExposomeNL (024.004.017); EU Horizon DarkMatter program (101136582).

For many years, doctors have relied on a blood marker called creatinine to estimate how well the kidneys filter waste produced by muscle activity. More recent medical guidelines also recommend measuring cystatin C, a small protein produced by all cells in the body, as another way to assess kidney function. Because these two markers are affected by different biological processes, using both together can offer a clearer picture of kidney health and future risk than either test alone.

Two Tests, One Concerning Gap

Researchers from NYU Langone Health found that large differences between creatinine and cystatin C results are common, particularly among people who are already ill. In a large international analysis, more than one third of hospitalized patients had cystatin C results that suggested kidney function was at least 30% worse than what their creatinine levels indicated. This gap, the researchers say, may point to underlying disease that would otherwise go unnoticed.

“Our findings highlight the importance of measuring both creatinine and cystatin C to gain a true understanding of how well the kidneys are working, particularly among older and sicker adults,” said study co-corresponding author Morgan Grams, MD, PhD. “Evaluating both biomarkers may identify far more people with poor kidney function, and earlier in the disease process, by covering the blind spots that go with either test.”

The study was published in the Journal of the American Medical Association and was presented at the American Society of Nephrology’s annual Kidney Week conference.

Why Kidney Testing Matters Beyond Diagnosis

Accurate kidney function measurements are critical not only for detecting disease, but also for determining safe medication doses. Kidney performance helps guide dosing for cancer treatments, antibiotics, and many commonly prescribed drugs, according to Grams, who is the Susan and Morris Mark Professor of Medicine at the NYU Grossman School of Medicine.

In a separate study released the same day, the same research group reported that chronic kidney disease now affects more people worldwide than ever before and has become the ninth leading cause of death globally. Grams notes that better tools for early detection could allow patients to begin treatment sooner and reduce the need for extreme measures such as dialysis or organ transplantation. She is also a professor in the Department of Population Health at NYU Grossman School of Medicine.

A Massive Global Analysis

For the current study, investigators reviewed medical records, blood test results, and demographic information from 860,966 adults representing six different nationalities. All participants had both creatinine and cystatin C measured on the same day and were followed for an average of 11 years. The analysis accounted for factors that can influence these markers but are not directly related to kidney function, including smoking, obesity, and a history of cancer.

Conducted through the international Chronic Kidney Disease Prognosis Consortium, the research is the largest investigation so far to examine how differences between these two tests relate to long-term health outcomes. The consortium was created to improve understanding of chronic kidney disease and to support consistent global definitions of the condition and its risks.

Higher Risks Linked to Larger Differences

The study found that people whose cystatin C results showed kidney filtration at least 30% lower than their creatinine results faced significantly higher risks of death, heart disease, and heart failure. They were also more likely to develop severe chronic kidney disease that required dialysis or an organ transplant. Similar patterns were observed in 11% of outpatients and individuals who appeared healthy at the time of testing.

Grams pointed out that cystatin C testing was first recommended in 2012 by the international organization Kidney Disease — Improving Global Outcomes. Despite that guidance, a 2019 survey showed that fewer than 10% of clinical laboratories in the United States performed the test in-house. Since then, the two largest laboratory companies, Quest Diagnostics and Labcorp, have begun offering it.

“These results underscore the need for physicians to take advantage of the fact that more hospitals and health care providers are starting to offer cystatin C testing,” said study co-corresponding author Josef Coresh, MD, PhD, director of NYU Langone’s Optimal Aging Institute. “Physicians might otherwise miss out on valuable information about their patients’ well-being and future medical concerns.”

Coresh, who is also the Terry and Mel Karmazin Professor of Population Health at NYU Grossman School of Medicine, noted that among hospitalized Americans included in the study, fewer than 1% had been tested for cystatin C.

Study Support and Contributors

The research was funded by National Institutes of Health grant R01DK100446 and by the National Kidney Foundation.

Michelle Estrella, MD, MHS, of the University of California, San Francisco, served as the study’s first author, while Kai-Uwe Eckardt, MD, of Charite-Universitatsmedizin Berlin in Germany, was the senior author. Along with Grams and Coresh, co-leaders of the Chronic Kidney Disease Prognosis Consortium, NYU Langone contributors included Shoshana Ballew, PhD; Yingying Sang, MS; and Aditya Surapaneni, PhD. Additional investigators came from institutions across the United States, Europe, Asia, and Australia, reflecting the global scope of the research effort.

In a recent study published in Microbiology Spectrum, Heil and researchers at North Carolina State University in Raleigh set out to explore how flour choice affects the microbes living in sourdough starters. Their analysis showed that yeasts from the genus Kazachstania were consistently the most common across all starters. In contrast, the bacterial communities varied depending on the type of flour used.

What This Means for Bakers and Flavor

The findings suggest that changing flour types could influence the microbial makeup of a starter. “And because the microbial composition affects different traits, by altering the flour you could potentially alter how your bread tastes,” said Heil, the study’s senior author. More broadly, she explained that the results show just how responsive the sourdough microbiome is to environmental conditions.

Earlier research has shown that sourdough microbes are shaped by multiple influences, including the flour itself, the surrounding air and surfaces, and even the hands of the baker. Starters can be made with wheat, rye, barley, teff, millet, or other grains, each supplying a distinct set of nutrients that microbes depend on to grow.

A Classroom Experiment Sparks the Study

The research began with an educational project led by Enrique Schwarzkopf, Ph.D., a postdoctoral researcher in Heil’s lab and an avid sourdough baker. He created a program at a local middle school to teach students about fermentation and evolution. Schwarzkopf, who maintains a sourdough starter named Seth, encouraged students to test different flour combinations and feeding schedules to see which starter would grow the fastest.

To analyze the starters, the researchers used metabarcoding, a genetic method that quickly identifies which microbes are present in a sample. Each starter began with one of three substrates: all-purpose flour, bread flour or whole wheat flour. At the start of the experiment, the flours showed similar bacterial profiles and contained a variety of yeasts.

Unexpected Yeast Dominance

After several weeks of repeated feeding, the microbial communities shifted. The starters all ended up dominated by the same yeast, while bacteria showed greater diversity. Heil said she originally expected to find Saccharomyces cerevisiae, also known as brewer’s yeast, which is commonly used in baking and is central to much of her lab’s research.

Instead, Kazachstania emerged as the leading yeast in every starter, regardless of flour type or feeding schedule. Genetic analysis also revealed differences among bacteria. Starters made with whole wheat flour contained higher levels of Companilactobacillus, while those made with bread flour had more Levilactobacillus.

Flour as an Ecological Driver

Heil, whose work focuses on how organisms adapt to new environments and compete at the genetic level, explained that each flour type offers unique nutritional conditions. Linking those differences to the environments microbes experience, she said, can help scientists better understand how diverse microbial communities form, compete, and persist.