An engineered gut bacterium releases GLP-1 only while sugar is high; tirzepatide starters had fewer strokes
Shanghai researchers fitted Escherichia coli Nissle 1917 to make GLP-1 when sugar rises and stop when it falls, in mice and monkeys. Tirzepatide starters had a 2.1 point lower stroke risk than other GLP-1 users.
Science··Night
The bacterium makes GLP-1 only when sugar spikes
Researchers in Shanghai reported in Nature that they fitted Escherichia coli Nissle 1917 with a glucose-sensing genetic circuit, so the bacteria make GLP-1 during a blood-sugar spike and stop once the level normalises. The switch runs on a protein called HexR: with no glucose inside the cell HexR sits on the promoter and holds the circuit off, and glucose metabolised to KDPG displaces it. The work covers diabetic mice and naturally diabetic monkeys; no human trial has been run.[1]
Mice at 30 days, monkeys at up to 3 days
In type 2 diabetic mice, 30 days of daily dosing cut fat mass, weight gain, triglycerides and total cholesterol. A single oral dose held blood sugar in naturally diabetic monkeys for up to 3 days, and dosing every 3 days for 5 weeks improved control further. Coating the bacteria with tannic acid and poloxamer 188 stretched their activity in mice from 8 to 36 hours. Mice given semaglutide lost lean muscle while the bacterial group held or slightly gained it. Because this is a genetically modified organism, clinical safety trials, stability testing and regulatory approval all remain ahead.[1]
Tirzepatide starters had a 2.1 point lower stroke risk at one year
The comparison in Nature Communications drew 14,118 matched pairs of adults with atrial fibrillation and type 2 diabetes from an international network of electronic health records. At one year the absolute difference in stroke risk was 2.1 percentage points, and the difference in death from any cause was 6.2 percentage points, with lower risks also reported for ischemic stroke and hemorrhagic stroke. The cohort came from the TriNetX Global Collaborative Network, and the work was supported by the Lo-Hsu Medical Foundation, Lotung Poh-Ai Hospital. Because treatment was not randomly assigned, the comparison cannot separate the drug from the reasons a clinician chose it and does not establish that tirzepatide accounts for the lower stroke and death rates; an alternative is those reasons, and the authors write that randomized trials are needed before treatment advice changes.[2]
