{
  "abstract": "IntroductionLens stiffening contributes to impaired accommodation and age-related optical dysfunction, but whether metabolic syndrome (MetS) accelerates this biomechanical change in association with microbiota-linked metabolic disturbances remains unclear. This study evaluated whether nicotinamide mononucleotide (NMN) reduces lens stiffening in mice with diet-induced metabolic syndrome and whether changes in gut microbial metabolites, systemic inflammatory markers, and ocular biochemical injury accompany this response.MethodsMale and female C57BL/6J mice were fed a high-fat/high-sucrose regimen and assigned to vehicle, NMN dose, antibiotic-depletion, NMN plus antibiotic-depletion, and fecal microbiota transfer arms. A total of 96 mice were randomized, and 94 mice contributed valid week-16 lens stiffness measurements. The primary endpoint was lens apparent Young’s modulus. Secondary endpoints included Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), serum triglyceride, fecal microbiota diversity, fecal short-chain fatty acids, serum lipopolysaccharide (LPS) and trimethylamine N-oxide (TMAO), lens nicotinamide adenine dinucleotide (NAD+), oxidative and glycation-related injury, and molecular fibrosis-associated lens markers.ResultsCompared with controls, metabolic-syndrome mice showed higher HOMA-IR, serum triglyceride, serum LPS, serum TMAO, lens malondialdehyde (MDA), lens advanced glycation end-products (AGEs), and lens apparent Young’s modulus, with lower fecal butyrate and lens NAD+. Lens apparent Young’s modulus increased from 7.4 ± 1.3 kPa in controls to 17.9 ± 2.1 kPa in metabolic-syndrome mice. NMN reduced lens stiffness to 14.8 ± 2.0 kPa at 150 mg/kg/day and 11.9 ± 2.4 kPa at 300 mg/kg/day. Fecal butyrate increased from 8.1 ± 1.9 μmol/g in metabolic-syndrome mice to 12.0 ± 2.4 μmol/g and 13.7 ± 2.8 μmol/g in the two NMN groups, while lens NAD+ increased from 1.50 ± 0.28 to 1.96 ± 0.31 pmol/mg and 2.34 ± 0.35 pmol/mg, respectively. Antibiotic depletion weakened but did not abolish the high-dose NMN ocular response, and fecal transfer from NMN-treated donors partially shifted microbial metabolite and lens stiffness endpoints toward the direct NMN-treatment profile.DiscussionThese findings support an NMN-associated reduction in metabolic-syndrome-related lens stiffening accompanied by coordinated systemic metabolic, microbial-metabolite, and ocular biochemical changes; the microbiota-related component appeared contributory rather than sufficient to explain the ocular response.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Original Research",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "name": "Qiting Feng"
    },
    {
      "name": "Wanying Song"
    },
    {
      "name": "Lai Wei"
    },
    {
      "name": "Quan Liu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8v1bfs40j87jj.bib",
  "cited_by": 0,
  "doi": "10.3389/fmicb.2026.1939489",
  "fulltext_url": null,
  "id": "8v1bfs40j87jj",
  "issns": [
    "1664-302X"
  ],
  "landing_url": "https://www.frontiersin.org/articles/10.3389/fmicb.2026.1939489",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "feed-journal",
      "biology/microbiology"
    ]
  ],
  "openalex": null,
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-02",
  "publisher": "Frontiers Media SA",
  "ris": "https://research.draconitic.com/paper/8v1bfs40j87jj.ris",
  "sources": [
    {
      "first_seen": "2026-11-02T12:20:43Z",
      "native_id": "10.3389/fmicb.2026.1939489",
      "source": "feed-frontiers",
      "url": "https://www.frontiersin.org/articles/10.3389/fmicb.2026.1939489"
    },
    {
      "first_seen": "2026-11-02T12:23:22Z",
      "native_id": "10.3389/fmicb.2026.1939489",
      "source": "crossref",
      "url": "https://www.frontiersin.org/articles/10.3389/fmicb.2026.1939489/full"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "feed-journal:biology/microbiology",
      "subfield": "microbiology"
    }
  ],
  "title": "Nicotinamide mononucleotide reduces metabolic-syndrome-associated lens stiffening and gut microbiota–metabolic–ocular changes in mice",
  "title_text": "Nicotinamide mononucleotide reduces metabolic-syndrome-associated lens stiffening and gut microbiota–metabolic–ocular changes in mice",
  "type": "peer-reviewed",
  "updated_at": "2026-11-04T00:25:26Z",
  "url": "https://research.draconitic.com/paper/8v1bfs40j87jj",
  "venue": "Frontiers in Microbiology",
  "versions": []
}