Lachnospira

Classification and Ecology#

Lachnospira belongs to the Lachnospiraceae family (Clostridium cluster XIVa), one of the largest and most functionally diverse bacterial families in the human colon.

Unlike many Lachnospiraceae that broadly degrade diverse fibers, L. pectinoschiza is a pectin specialist, reflecting an ecological niche defined by plant cell wall pectin—a polysaccharide abundant in fruits, vegetables, and legumes. This dietary substrate specificity makes Lachnospira abundance a sensitive readout of plant-rich dietary intake.

Metal Dependencies#

Iron dependency is documented for fermentation enzymes across the Lachnospiraceae family. Iron-sulfur cluster enzymes are required for the anaerobic ferredoxin-dependent electron transport that drives SCFA production.

Iron depletion or heavy metal displacement of iron (Fe) cofactors (by cadmium, lead) would impair Lachnospira fermentation capacity—consistent with the depletion observed in conditions with metal dyshomeostasis.

Protective Associations in Cardiovascular and Thyroid Disease#

Cardiovascular Disease#

Depleted in acute coronary syndrome (ACS) patients post-STEMI compared to healthy controls, while pathobionts like Escherichia-Shigella and Acinetobacter are enriched.^{[2]Gut microbial taxa as potential predictive biomarkers for acute coronary syndrome and post-STEMI cardiovascular eventsJing Gao, Kun-Tao Yan, Ji-Xiang Wang et al. · 2020Open reference 2 ↓} The loss of Lachnospira alongside other SCFA producers likely contributes to reduced colonocyte barrier integrity and increased endotoxemia in ACS.

Thyroid Disease—Graves' and Plummer#

MR evidence identifies Lachnospira as protective against Graves' disease and Plummer disease (toxic nodular goiter), likely through SCFA-mediated immune regulation and propionate/acetate effects on thyroid-immune axis modulation.^{[3]Uncovering a Causal Connection between Gut Microbiota and Six Thyroid Diseases: A Two-Sample Mendelian Randomization StudyChen J, Wang Y, Yao H et al. · 2024Open reference 3 ↓}

In Hashimoto's thyroiditis patients, Lachnospira and Eubacterium_ventriosum_group and Dorea are enriched at the genus level relative to Graves' patients^{[4]Alterations and Mechanism of Gut Microbiota in Graves' Disease and Hashimoto's ThyroiditisZhao H, Yuan L, Zhu D et al. · 2022Open reference 4 ↓}—this enrichment in HT vs. GD suggests that the direction of thyroid immune dysregulation (autoantibody type) differentially modulates Lachnospira abundance.

Endometriosis#

Significantly decreased (p=0.00008) in women with Endometriosis compared to healthy controls, consistent with the broader loss of SCFA-producing commensals in inflammatory gynecological conditions.^{[5]Gut microbiota imbalance and its correlations with hormone and inflammatory factors in patients with stage 3/4 endometriosisShan J, Ni Z, Cheng W et al. · 2021Open reference 5 ↓}

The loss of acetate production may contribute to reduced epithelial barrier protection and altered estrogen metabolism in the endometriosis gut environment.

Menstrual Disorders#

Lachnospira shows signals in MR analysis of gut microbiota and menstrual disorders, alongside Anaerotruncus and Haemophilus, implicating SCFA depletion in menstrual cycle disruption.^{[6]Yao 2024 — Gut Microbiota and Menstrual Disorders: Two-Sample MR StudyYufan Yao, Haoran Hu, Longhao Chen et al. · 2024Open reference 6 ↓}

Risk Associations—The Paradox#

Paradoxically, Lachnospira shows risk associations in several conditions:

Hidradenitis Suppurativa—Causal Risk#

Causal risk factor (OR = 2.45) via MR analysis for Hidradenitis Suppurativa, a chronic inflammatory skin disease characterized by recurrent abscesses.^{[8]Causal Relationship Between Gut Microbiota and Hidradenitis Suppurativa: A Two-Sample Mendelian Randomization StudyLiu C, Liu X, Li X · 2024Open reference 8 ↓} The skin-gut axis mechanism may involve SCFA-mediated alteration of cutaneous immune responses or microbiome-driven systemic inflammatory priming.

Autism Spectrum Disorder—Enriched in Some Cohorts#

Significantly more abundant in ASD children in Chinese cohorts^{[9]Niu 2019 — Intestinal Microbiota and Probiotics Treatment in Chinese ASD ChildrenManman Niu, Qinrui Li, Jishui Zhang et al. · 2019Open reference 9 ↓} and identified as part of the robust ASD microbiome signature in machine-learning analysis.^{[10]Peralta-Marzal 2024 — A Robust Microbiome Signature for Autism Spectrum Disorder Across Different Studies Using Machine LearningLucia N. Peralta-Marzal, David Rojas-Velazquez, Douwe Rigters et al. · 2024Open reference 10 ↓}

This enrichment in ASD contrasts with its depletion in cardiovascular and renal disease, suggesting context-dependent immune effects.

Schizophrenia—Causally Elevated by SCZ#

In reverse MR analysis, schizophrenia causally increases Lachnospira (OR=1.05), establishing that SCZ as a disease state alters the Gut Microbiome to enrich this genus.^{[11]Zhou 2024 — Gut Microbiome and Schizophrenia: Insights from Two-Sample Mendelian RandomizationKeer Zhou, Ancha Baranova, Hongbao Cao et al. · 2024Open reference 11 ↓}

This is bidirectional: SCZ enriches Lachnospira as a disease consequence, separate from whatever causal effects Lachnospira may have on SCZ risk.

Context-Dependent Effects—Interpretive Framework#

The dual nature of Lachnospira—depleted in cardiovascular, renal, and endocrine conditions but enriched or risk-associated in CRC, ASD, and inflammatory skin disease—reflects several overlapping factors:

1. Species heterogeneity: The genus contains multiple species with distinct metabolite profiles; genus-level analysis may obscure species-specific protective vs. risk associations.
2. Metabolic environment: In cardiovascular/renal disease, Lachnospira depletion is a direct consequence of SCFA niche disruption. In CRC, certain Lachnospira species may thrive in the altered metabolic environment of the tumor-adjacent colon without causing cancer.
3. Immune context dependence: Acetate and formate have bidirectional immune effects depending on host Th cell balance—in immunosuppressive disease states, the same SCFA production may accelerate pathology.

What Wikipedia Doesn't Cover#

Wikipedia lacks a Lachnospira species entry.

This page provides: the pectin-degradation specialization linked to plant-rich diet; CKD early biomarker status as the earliest-declining Lachnospiraceae genus detectable at stage 3a; the bidirectional thyroid disease associations (protective in GD, enriched in HT); the causal CRC risk despite SCFA production (OR=4.43); and the schizophrenia reverse-MR evidence establishing SCZ as a cause of Lachnospira enrichment.

Cross-References#

• Short-Chain Fatty Acids (SCFAs)—pectin fermentation to acetate, formate, and ethanol
• Chronic Kidney Disease—earliest-depleted Lachnospiraceae genus; CKD stage 3a biomarker
• Cardiovascular Disease—depleted in ACS; protective metabolic role
• Endometriosis—significantly depleted in endometriosis patients
• Colorectal Cancer—paradoxical MR risk association despite SCFA production
• Autism Spectrum Disorder—enriched in ASD; part of robust ASD microbiome signature
• Graves' Disease—protective via MR; depleted in GD
• Schizophrenia—SCZ causally increases Lachnospira abundance (reverse MR)
• Faecalibacterium prausnitzii—co-member of the SCFA-producing commensal consortium
• Lachnospiraceae—family-level context; shares depletion-in-disease pattern with related genera
• Iron—iron (Fe)-S cluster dependency for anaerobic fermentation enzymes