The research, led by Lingming Kong, Fengyu Shi, Hongru Kong and Haonan Xie, with Gang Chen as senior author, was carried out by teams at Wenzhou Medical University and collaborating institutions in China and the United States. The investigators focused on elderly-onset acute pancreatitis, abbreviated EOAP, and asked a deceptively simple question: does the gut microbiome of an aged organism process food differently in ways that make pancreatic injury worse? Their answer, built from mouse experiments and human clinical samples, is a carefully documented yes. The work identifies a specific microbial group, a specific metabolite and a specific cellular mechanism that together appear to convert an age-related shift in gut ecology into genuine pancreatic damage.

The starting point was a comparative analysis of metabolites. When the researchers profiled the metabolic output of the gut in aged mice and in elderly patients suffering from acute pancreatitis, two molecules stood out: phenaceturic acid, known as PAC, and phenylacetylglutamine, known as PG. Both are downstream products of phenylalanine metabolism. Phenylalanine is an essential aromatic amino acid that humans obtain from dietary protein, and gut bacteria routinely ferment it into a family of phenyl-containing compounds that are absorbed into the bloodstream and eventually excreted. In the aged animals and the elderly patients, the levels of these two phenylalanine-derived metabolites were markedly elevated compared with younger counterparts, suggesting that aging fundamentally rewires how the gut handles this amino acid.

Who was producing the extra metabolites? Metagenomic analysis of the gut communities pointed to a familiar and somewhat notorious culprit: bacteria belonging to the Escherichia-Shigella group. This cluster, which includes organisms closely related to Escherichia coli and Shigella species, was significantly more abundant in the aged mice and elderly patients. The correlation between Escherichia-Shigella expansion and elevated PAC and PG levels provided the first mechanistic thread: an age-associated bloom of particular bacteria appears to drive increased microbial processing of phenylalanine, flooding the host with metabolites that a younger gut produces in smaller quantities.

Correlation alone, however, is never enough to establish causation, and the team moved decisively to test it. Using fecal microbiota transplantation, they transferred gut communities from aged donor mice into young recipient mice. The young animals, which normally tolerate experimental pancreatic injury with a moderate inflammatory response, developed a strikingly aggravated phenotype after receiving the aged microbiota. Their pancreatitis became more severe, mirroring the pattern seen in naturally aged animals. This transfer experiment is conceptually powerful because it isolates the microbiome as a sufficient carrier of the age-related risk: the recipients’ own genomes and chronological age were unchanged, yet their disease outcome was transformed by the microbial community they received.

With the microbial contribution established, the researchers turned to the cellular level to understand how phenaceturic acid actually damages the pancreas. The pancreas’s exocrine tissue is built from acinar cells, specialized factories that produce and secrete digestive enzymes. These cells are packed with mitochondria, the organelles that generate the energy required for massive protein synthesis and export. The team found that PAC compromises mitochondrial integrity in these acinar cells. Damaged mitochondria are not merely idle; they leak reactive oxygen species, release pro-death signaling molecules and trigger quality-control responses that can themselves become destructive when overwhelmed.

One of those quality-control responses, mitophagy, sits at the center of the proposed mechanism. Mitophagy is the cellular process by which defective mitochondria are selectively engulfed and degraded, normally a protective housekeeping function that keeps the mitochondrial network healthy. The study’s findings indicate that in the context of EOAP, PAC-driven mitochondrial damage pushes mitophagy into overdrive, and rather than rescuing the cells, this excessive mitophagy coincides with enhanced cell death. The acinar cells undergo apoptosis, the programmed death pathway, at elevated rates. Widespread acinar cell death is a hallmark of severe pancreatitis because dying cells release their contents, including digestive enzymes and damage-associated molecular patterns, which amplify the inflammatory cascade and recruit further immune activation.

The chain of evidence therefore reads as follows: aging reshapes the gut microbiome, allowing Escherichia-Shigella to expand; these bacteria convert more dietary phenylalanine into phenaceturic acid and phenylacetylglutamine; elevated PAC circulates to the pancreas, where it undermines mitochondrial integrity in acinar cells; runaway mitophagy and apoptosis follow; and the resulting cell death intensifies inflammation, making the overall disease more severe. Each link in this chain was supported by the study’s combination of human sample analysis, mouse modeling, microbial transplantation and mechanistic cell biology, forming one of the more complete causal narratives in the microbiome-pancreatitis literature.

The clinical implications are considerable. Acute pancreatitis in the elderly is a growing burden as populations worldwide age, and current treatment remains largely supportive, with no approved drugs that specifically target the mechanisms of disease severity. If the findings hold up in further studies, they suggest several concrete intervention points. Microbial phenylalanine metabolism could be modulated with dietary strategies that alter protein intake or amino acid availability. The offending bacterial groups could be suppressed with targeted antimicrobials or outcompeted through microbiome-directed therapies. The metabolites themselves, PAC and PG, could serve as biomarkers, allowing clinicians to identify elderly patients at risk of severe disease before the inflammatory storm fully develops. And the downstream mitochondrial and apoptotic pathways offer pharmacological targets for drugs that stabilize mitochondrial function or restrain excessive cell death.

As with any translational study, important questions remain. The work was conducted in mouse models and human cohort samples, and the precise dose-response relationship between circulating PAC and pancreatic injury in humans will need prospective validation. It is also not yet clear whether reducing phenylalanine-derived metabolites after pancreatitis has already begun can improve outcomes, or whether the intervention window lies earlier, in maintaining a healthier microbiome throughout aging. What the study undeniably establishes is that the age-related severity of acute pancreatitis is not written solely in the pancreas or the immune system, but is partly manufactured in the gut by microbial chemistry. That reframing — treating a metabolic product of our resident bacteria as a driver of organ failure — is likely to resonate well beyond pancreatology, and it adds pancreatic disease to the expanding list of conditions, from neurodegeneration to cardiovascular disease, in which microbial metabolites of dietary amino acids are emerging as unexpected culprits.

Subject of Research: The role of gut microbiota-derived phenylalanine metabolites in exacerbating elderly-onset acute pancreatitis through mitochondrial dysfunction and cell death

Article Title: Gut microbiota-derived phenylalanine metabolites exacerbate elderly-onset acute pancreatitis by promoting mitophagy and enhancing cell death

Article References: Kong, L., Shi, F., Kong, H., Xie, H., Pan, Z., Liu, Z., Yu, D., Chen, W., Sun, H., Jin, Y., Wang, J., Ergashev, A., Li, T., Wang, Y., Zhang, J.-S., Fernandez-Zapico, M. E., Zhang, C., & Chen, G. (2026). Gut microbiota-derived phenylalanine metabolites exacerbate elderly-onset acute pancreatitis by promoting mitophagy and enhancing cell death. Microbiome. https://doi.org/10.1186/s40168-026-02518-2

Image Credits: AI Generated

DOI: 10.1186/s40168-026-02518-2

Keywords: elderly-onset acute pancreatitis, gut microbiota, phenylalanine metabolism, phenaceturic acid, phenylacetylglutamine, Escherichia-Shigella, mitophagy, apoptosis, mitochondrial dysfunction, acinar cells, fecal microbiota transplantation, Microbiome journal

The study, led by Mingqian Zhang, Ziyi Li, Lei Liu and Hai-Chen Wu of the Institute of Chemistry at the Chinese Academy of Sciences together with colleagues, reconstitutes the complete catecholamine biosynthetic pathway in a test tube using purified enzymes and their required cofactors. The researchers then coupled this miniature chemical factory to an engineered protein nanopore — a nanoscale pore embedded in a membrane through which an ionic current flows. Whenever a metabolite from the pathway interacts with the pore, it briefly perturbs that current, producing an electrical fingerprint specific to that molecule. By reading these fingerprints as they accumulate, the team could follow the transformation of each intermediate into the next, second by second.

The technical heart of the work lies in how the researchers achieved specificity. Small molecules are notoriously difficult for nanopores to distinguish because they zip through the pore too quickly and too subtly to leave clean, separable signals. The team solved this by integrating two orthogonal molecular recognition modalities within a single nanopore platform. In essence, different chemical strategies were used to make different members of the pathway register at the pore: some metabolites, such as the catecholamines themselves, generate characteristic blockade patterns as they translocate, while the amino acids phenylalanine and tyrosine were detected through a tailored probe chemistry involving a copper-coordinated molecular adaptor and a cucurbituril host that captures the amino acid and presents it to the pore as a distinct complex.

With this dual recognition scheme in place, the researchers demonstrated highly specific detection of all six key players in the pathway: phenylalanine, tyrosine, levodopa, dopamine, noradrenaline and adrenaline. Extended data traces show characteristic current blockades and dwell-time distributions for each analyte at 100 micromolar concentration, recorded in a high-salt buffer at a transmembrane potential of +100 millivolts. Gaussian fits to the blockade histograms and single-exponential fits to the dwell times confirm that each metabolite produces a statistically distinct signature, which is the prerequisite for unambiguous identification in a mixed sample.

Having validated each molecule individually, the team turned to the full cascade. They initiated the enzymatic sequence and sampled the reaction mixture every five minutes, feeding each sample to the nanopore. The resulting single-channel recordings amount to a time-lapse film of neurotransmitter synthesis: phenylalanine signals fade as tyrosine rises, tyrosine gives way to levodopa, and levodopa is converted onward to dopamine, noradrenaline and finally adrenaline. Because the readout is label-free and single-molecule, nothing was added to the reaction to make it visible, and no amplification step could distort the quantitative picture of pathway dynamics.

This time-resolved view matters because the catecholamine pathway is not a simple conveyor belt. It is a branched network whose flux is governed by enzyme kinetics, cofactor availability and regulatory feedback, and disruption at any node is implicated in conditions ranging from Parkinson’s disease and attention-deficit hyperactivity disorder to orthostatic hypotension and stress-related endocrine disorders. Conventional analytical methods — liquid chromatography, mass spectrometry, electrochemistry, ELISAs — can measure metabolite concentrations at chosen endpoints, but they are generally snapshot techniques that require aliquots, labels or lengthy separation steps, making continuous, coupled monitoring of a multi-enzyme cascade cumbersome.

The platform also opened a window on pathology. A striking application involves iodotyrosine dehalogenase 1, or DEHAL1, an enzyme best known for recycling iodide in the thyroid, where it removes iodine from iodinated tyrosine residues. Defects in the DEHAL1 gene cause hypothyroidism, and 3-iodo-L-tyrosine, the substrate of this enzyme, has long been known to inhibit tyrosine hydroxylase, the rate-limiting enzyme that converts tyrosine to levodopa. The researchers used their nanopore assay to examine what happens to the catecholamine cascade when dehalogenase activity is compromised. They found that 6-methylisothiocyanate, a compound that disrupts the dehalogenase, perturbs catecholamine biosynthesis in a way that offers a mechanistic explanation for how DEHAL1 deficiency may compromise neurotransmitter production — potentially linking an inherited thyroid disorder to impaired catecholamine output.

Figure 5 of the study, titled ‘Effect of thyroiditis-like disorders on catecholamine metabolism,’ presents this perturbation experiment, with extended recordings showing how the cascade changes when monoiodotyrosine is present. The single-molecule records reveal shifts in the relative abundance of the pathway intermediates, illustrating the value of the method: rather than inferring a block from diminished end-product levels, researchers can see exactly where flux stalls and which intermediates accumulate. That level of mechanistic detail is precisely what drug developers and enzymologists need when trying to dissect regulatory nodes in metabolic networks.

Broader implications extend well beyond catecholamines. The authors describe their integrated enzymology-and-nanopore-sensing platform as a general framework for studying complex biochemical pathways with single-molecule resolution. Because protein nanopores can be engineered with different recognition elements, the same design philosophy could in principle be applied to other branched metabolic cascades, to drug-metabolism studies, or to screening enzyme inhibitors in real time. The approach builds on two decades of stochastic sensing, in which engineered pores have been taught to identify analytes as diverse as metal ions, nucleotides, amino acids, peptides, proteins and microRNAs, and it extends that lineage from static identification to dynamic pathway monitoring.

The team has deposited its source data publicly on Zenodo, and the paper — received in December 2025, accepted in August 2026 and published on 1 September 2026 — carries no reported competing interests. What the work ultimately delivers is a new kind of laboratory instrument: a single pore through which the chemistry of a neurotransmitter can be watched being born. If the framework generalizes as its authors hope, metabolic biochemists may soon spend far less time taking snapshots of pathways and far more time watching them move.

Subject of Research: Time-resolved single-molecule monitoring of catecholamine biosynthesis from phenylalanine using an engineered nanopore sensor

Article Title: Nanopore-enabled time-resolved monitoring of catecholamine-related phenylalanine metabolism

Article References: Zhang, M., Li, Z., Hao, W., Yi, Y., Zhou, K., Liu, L., & Wu, H.-C. (2026). Nanopore-enabled time-resolved monitoring of catecholamine-related phenylalanine metabolism. Nature Nanotechnology. https://doi.org/10.1038/s41565-026-02273-3

Image Credits: AI Generated

DOI: 10.1038/s41565-026-02273-3

Keywords: nanopore sensing, catecholamines, dopamine, adrenaline, phenylalanine metabolism, single-molecule detection, neurotransmitter biosynthesis, DEHAL1, iodotyrosine dehalogenase, label-free biosensing, Nature Nanotechnology, enzymology