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1.
Hong Kong Med J ; 30(3): 218-226, 2024 Jun.
Article En | MEDLINE | ID: mdl-38835098

INTRODUCTION: The level of amniotic fluid gamma-glutamyl transferase (AFGGT) may help identify biliary atresia (BA) in cases of non-visualisation of the fetal gallbladder (NVFGB). This study aimed to validate a serum/plasma matrix-based gamma-glutamyl transferase (GGT) assay for amniotic fluid (AF) samples, establish a local gestational age-specific AFGGT reference range, and evaluate the efficacy of AFGGT for predicting fetal BA in pregnancies with NVFGB using the constructed reference range. METHODS: The analytical performance of a serum/plasma matrix-based GGT assay on AF samples was evaluated using a Cobas c502 analyser. Amniotic fluid gamma-glutamyl transferase levels in confirmed euploid singleton pregnancies (16+0 to 22+6 weeks of gestation) were determined using the same analyser to establish a local gestational age-specific reference range (the 2.5th to 97.5th percentiles). This local reference range was used to determine the positive predictive value (PPV) and negative predictive value (NPV) of AFGGT level <2.5th percentile for identifying fetal BA in euploid pregnancies with NVFGB. RESULTS: The serum/plasma matrix-based GGT assay was able to reliably and accurately determine GGT levels in AF samples. Using the constructed local gestational age-specific AFGGT reference range, the NPV and PPV of AFGGT level <2.5th percentile for predicting fetal BA in pregnancies with NVFGB were 100% and 25% (95% confidence interval=0, 53), respectively. CONCLUSION: In pregnancies with NVFGB, AFGGT level ≥2.5th percentile likely excludes fetal BA. Although AFGGT level <2.5th percentile is not diagnostic of fetal BA, fetuses with AFGGT below this level should be referred for early postnatal investigation.


Amniotic Fluid , Biliary Atresia , Gallbladder , Gestational Age , gamma-Glutamyltransferase , Humans , gamma-Glutamyltransferase/blood , Female , Pregnancy , Retrospective Studies , Reference Values , Amniotic Fluid/chemistry , Biliary Atresia/diagnosis , Biliary Atresia/blood , Predictive Value of Tests , Adult , Prenatal Diagnosis/methods
3.
Brain Behav Immun ; 118: 221-235, 2024 May.
Article En | MEDLINE | ID: mdl-38458498

The neuroinflammatory response to intracortical microelectrodes (IMEs) used with brain-machine interfacing (BMI) applications is regarded as the primary contributor to poor chronic performance. Recent developments in high-plex gene expression technologies have allowed for an evolution in the investigation of individual proteins or genes to be able to identify specific pathways of upregulated genes that may contribute to the neuroinflammatory response. Several key pathways that are upregulated following IME implantation are involved with the complement system. The complement system is part of the innate immune system involved in recognizing and eliminating pathogens - a significant contributor to the foreign body response against biomaterials. Specifically, we have identified Complement 3 (C3) as a gene of interest because it is the intersection of several key complement pathways. In this study, we investigated the role of C3 in the IME inflammatory response by comparing the neuroinflammatory gene expression at the microelectrode implant site between C3 knockout (C3-/-) and wild-type (WT) mice. We have found that, like in WT mice, implantation of intracortical microelectrodes in C3-/- mice yields a dramatic increase in the neuroinflammatory gene expression at all post-surgery time points investigated. However, compared to WT mice, C3 depletion showed reduced expression of many neuroinflammatory genes pre-surgery and 4 weeks post-surgery. Conversely, depletion of C3 increased the expression of many neuroinflammatory genes at 8 weeks and 16 weeks post-surgery, compared to WT mice. Our results suggest that C3 depletion may be a promising therapeutic target for acute, but not chronic, relief of the neuroinflammatory response to IME implantation. Additional compensatory targets may also be required for comprehensive long-term reduction of the neuroinflammatory response for improved intracortical microelectrode performance.


Complement C3 , Inflammation , Animals , Mice , Complement C3/genetics , Electrodes, Implanted , Microelectrodes
5.
Clin Oncol (R Coll Radiol) ; 36(3): 141-147, 2024 03.
Article En | MEDLINE | ID: mdl-38296662

AIMS: Most patients experience stable quality of life (QoL) after stereotactic ablative radiotherapy (SABR) treatment for oligometastases. However, a subset of patients experience clinically relevant declines in QoL on post-treatment follow-up. This study aimed to identify risk factors for QoL decline. MATERIALS AND METHODS: The SABR-5 trial was a population-based single-arm phase II study of SABR to up to five sites of oligometastases. Prospective QoL was measured using treatment site-specific tools at pre-treatment baseline and 3, 6, 9, 12, 15, 18, 21, 24, 30 and 36 months after treatment. The time to persistent QoL decline was calculated as the time from SABR to the first decline in QoL score meeting minimum clinically important difference with no improvement to baseline score on subsequent assessments. Univariable and multivariable logistic regression analyses were carried out to determine factors associated with QoL decline. RESULTS: One hundred and thirty-three patients were included with a median follow-up of 32 months (interquartile range 25-43). Thirty-five patients (26%) experienced a persistent decline in QoL. The median time until persistent QoL decline was not reached. The cumulative incidence of QoL decline at 2 and 3 years were 22% (95% confidence interval 14.0-29.6) and 40% (95% confidence interval 28.0-51.2), respectively. In multivariable analysis, disease progression (odds ratio 5.23, 95% confidence interval 1.59-17.47, P = 0.007) and adrenal metastases (odds ratio 9.70, 95% confidence interval 1.41-66.93, P = 0.021) were associated with a higher risk of QoL decline. Grade 3 or higher (odds ratio 3.88, 95% confidence interval 0.92-16.31, P = 0.064) and grade 2 or higher SABR-associated toxicity (odds ratio 2.24, 95% confidence interval 0.85-5.91, P = 0.10) were associated with an increased risk of QoL decline but did not reach statistical significance. CONCLUSIONS: Disease progression and adrenal lesion site were associated with persistent QoL decline following SABR. The development of grade 3 or higher toxicities was also associated with an increased risk, albeit not statistically significant. Further studies are needed, focusing on the QoL impact of metastasis-directed therapies.


Quality of Life , Radiosurgery , Humans , Prospective Studies , Disease Progression , Radiosurgery/adverse effects
6.
Clin Oncol (R Coll Radiol) ; 36(3): 148-156, 2024 03.
Article En | MEDLINE | ID: mdl-38087705

AIMS: To evaluate longitudinal patient-reported quality of life (QoL) in patients treated with stereotactic ablative radiotherapy (SABR) for oligometastases. MATERIALS AND METHODS: The SABR-5 trial was a population-based single-arm phase II study of SABR to up to five sites of oligometastases, conducted in six regional cancer centres in British Columbia, Canada from 2016 to 2020. Prospective QoL was measured using treatment site-specific QoL questionnaires at pre-treatment baseline and at 3, 6, 9, 12, 15, 18, 21, 24, 30 and 36 months after treatment. Patients with bone metastases were assessed with the Brief Pain Inventory (BPI). Patients with liver, adrenal and abdominopelvic lymph node metastases were assessed with the Functional Assessment of Chronic Illness Therapy-Abdominal Discomfort (FACIT-AD). Patients with lung and intrathoracic lymph node metastases were assessed with the Prospective Outcomes and Support Initiative (POSI) lung questionnaire. The two one-sided test procedure was used to assess equivalence between the worst QoL score and the baseline score of individual patients. The mean QoL at all time points was used to determine the trajectory of QoL response after SABR. The proportion of patients with 'stable', 'improved' or 'worsened' QoL was determined for all time points based on standard minimal clinically important differences (MCID; BPI worst pain = 2, BPI functional interference score [FIS] = 0.5, FACIT-AD Trial Outcome Index [TOI] = 8, POSI = 3). RESULTS: All enrolled patients with baseline QoL assessment and at least one follow-up assessment were analysed (n = 133). On equivalence testing, the patients' worst QoL scores were clinically different from baseline scores and met MCID (BPI worst pain mean difference: 1.8, 90% confidence interval 1.19 to 2.42]; BPI FIS mean difference: 1.68, 90% confidence interval 1.15 to 2.21; FACIT-AD TOI mean difference: -8.76, 90% confidence interval -11.29 to -6.24; POSI mean difference: -4.61, 90% confidence interval -6.09 to -3.14). However, the mean FIS transiently worsened at 9, 18 and 21 months but eventually returned to stable levels. The mean FACIT and POSI scores also worsened at 36 months, albeit with a limited number of responses (n = 4 and 8, respectively). Most patients reported stable QoL at all time points (range: BPI worst pain 71-82%, BPI FIS 45-78%, FACIT-AD TOI 50-100%, POSI 25-73%). Clinically significant stability, worsening and improvement were seen in 70%/13%/18% of patients at 3 months, 53%/28%/19% at 18 months and 63%/25%/13% at 36 months. CONCLUSIONS: Transient decreases in QoL that met MCID were seen between patients' worst QoL scores and baseline scores. However, most patients experienced stable QoL relative to pre-treatment levels on long-term follow-up. Further studies are needed to characterise patients at greatest risk for decreased QoL.


Quality of Life , Radiosurgery , Humans , British Columbia , Lymphatic Metastasis , Pain/etiology , Prospective Studies , Radiosurgery/adverse effects , Radiosurgery/methods
7.
QJM ; 117(2): 125-132, 2024 Feb 26.
Article En | MEDLINE | ID: mdl-37824396

BACKGROUND: It is unclear how the coronavirus disease 2019 (Covid-19) pandemic has affected multimorbidity incidence among those with one pre-existing chronic condition, as well as how vaccination could modify this association. AIM: To examine the association of Covid-19 infection with multimorbidity incidence among people with one pre-existing chronic condition, including those with prior vaccination. DESIGN: Nested case-control study. METHODS: We conducted a territory-wide nested case-control study with incidence density sampling using Hong Kong electronic health records from public healthcare facilities and mandatory Covid-19 reports. People with one listed chronic condition (based on a list of 30) who developed multimorbidity during 1 January 2020-15 November 2022 were selected as case participants and randomly matched with up to 10 people of the same age, sex and with the same first chronic condition without having developed multimorbidity at that point. Conditional logistic regression was used to estimate adjusted odds ratios (aORs) of multimorbidity. RESULTS: In total, 127 744 case participants were matched with 1 230 636 control participants. Adjusted analysis showed that there were 28%-increased odds of multimorbidity following Covid-19 [confidence interval (CI) 22% to 36%] but only 3% (non-significant) with prior full vaccination with BNT162b2 or CoronaVac (95% CI -2% to 7%). Similar associations were observed in men, women, older people aged 65 or more, and people aged 64 or younger. CONCLUSIONS: We found a significantly elevated risk of multimorbidity following a Covid-19 episode among people with one pre-existing chronic condition. Full vaccination significantly reduced this risk increase.


COVID-19 , Male , Humans , Female , Aged , COVID-19/epidemiology , COVID-19/prevention & control , Multimorbidity , Case-Control Studies , BNT162 Vaccine , Chronic Disease
9.
Adv Sci (Weinh) ; 10(35): e2302830, 2023 Dec.
Article En | MEDLINE | ID: mdl-37852942

Biological systems are composed of hierarchical structures made of a large number of proteins. These structures are highly sophisticated and challenging to replicate using artificial synthesis methods. To exploit these structures in materials science, biotemplating is used to achieve biocomposites that accurately mimic biological structures and impart functionality of inorganic materials, including electrical conductivity. However, the biological scaffolds used in previous studies are limited to stereotypical and simple morphologies with little synthetic diversity because of a lack of control over their morphologies. This study proposes that the specific protein assemblies within the cell-derived extracellular matrix (ECM), whose morphological features are widely tailorable, can be employed as versatile biotemplates. In a typical procedure, a fibrillar assembly of fibronectin-a constituent protein of the ECM-is metalized through an antibody-guided biotemplating approach. Specifically, the antibody-bearing nanogold is attached to the fibronectin through antibody-antigen interactions, and then metals are grown on the nanogold acting as a seed. The biomimetic structure can be adapted for hydrogen production and sensing after improving its electrical conductivity through thermal sintering or additional metal growth. This study demonstrates that cell-derived ECM can be an attractive option for addressing the diversity limitation of a conventional biotemplate.


Extracellular Matrix , Fibronectins , Fibronectins/metabolism , Extracellular Matrix/metabolism , Antibodies/metabolism , Biomimetics
10.
Hong Kong Med J ; 29(5): 404-411, 2023 10.
Article En | MEDLINE | ID: mdl-37822258

INTRODUCTION: During the coronavirus disease 2019 (COVID-19) pandemic, telemedicine has been regarded as a method for providing safe access to healthcare. Here, we explored the experiences of individuals using telemedicine in Hong Kong during the COVID-19 pandemic to understand their risk perceptions and preparedness measures. METHODS: We conducted a cross-sectional online survey of telemedicine users of private clinic-based COVID-19 testing services from 6 April to 11 May 2020. All users were invited to complete an anonymous online survey regarding COVID-19 risk perception and preparedness measures. The results of the survey were compared with the findings of a previous territory-wide survey. RESULTS: In total, 141 of 187 telemedicine users agreed to participate; the response rate was 75.4%. Of the participants, 95.1% (116/122) believed that telemedicine consultations were useful. Nearly half of the participants (49.0%) agreed or strongly agreed that telemedicine consultations were appropriate during the COVID-19 pandemic. Most participants believed that telemedicine consultations could perform the functions of 'health protection, promotion and disease prevention' (73.6%) and 'diagnosis' (64.0%). Concerning the choice of telemedicine provider, almost all participants (99.2%) were willing to consult medical doctors; more than half of the participants (54.1%) were willing to consult registered nurses, but only 13.1% were willing to consult non-clinical staff who had been trained to provide telemedicine services. CONCLUSION: The use of telemedicine for screening and patient education can be encouraged during the COVID-19 pandemic in Hong Kong.


COVID-19 , Telemedicine , Humans , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/prevention & control , Hong Kong/epidemiology , Pandemics/prevention & control , COVID-19 Testing , Cross-Sectional Studies , Telemedicine/methods
11.
Hong Kong Med J ; 29(6): 524-531, 2023 Dec.
Article En | MEDLINE | ID: mdl-37704569

INTRODUCTION: Because there have been changes in the management of macrosomic pregnancies and shoulder dystocia in the past decade, this study was conducted to compare the incidences of shoulder dystocia and perinatal outcomes between the periods of 2000-2009 and 2010-2019. METHODS: This retrospective study was conducted in a tertiary obstetric unit. All cases of shoulder dystocia were identified using the hospital's electronic database. The incidences, maternal and fetal characteristics, obstetric management methods, and perinatal outcomes were compared between the two study periods. RESULTS: The overall incidence of shoulder dystocia decreased from 0.23% (134/58 326) in 2000-2009 to 0.16% (108/65 683) in 2010-2019 (P=0.009), mainly because of the overall decline in the proportion of babies with macrosomia (from 3.3% to 2.3%; P<0.001). The improved success rates of the McRoberts' manoeuvre (from 31.3% to 47.2%; P=0.012) and posterior arm extraction (from 52.9% to 92.3%; P=0.042) allowed a greater proportion of affected babies to be delivered within 2 minutes (from 59.0% to 79.6%; P=0.003). These changes led to a significant reduction in the proportion of fetuses with low Apgar scores: <5 at 1 minute of life (from 13.4% to 5.6%; P=0.042) and <7 at 5 minutes of life (from 11.9% to 4.6%; P=0.045). CONCLUSION: More proactive management of macrosomic pregnancies and enhanced training in the acute management of shoulder dystocia led to significant improvements in shoulder dystocia incidence and perinatal outcomes from 2000-2009 to 2010-2019.


Dystocia , Shoulder Dystocia , Pregnancy , Female , Humans , Delivery, Obstetric , Dystocia/epidemiology , Dystocia/therapy , Dystocia/etiology , Incidence , Shoulder Dystocia/epidemiology , Shoulder Dystocia/therapy , Retrospective Studies , Hong Kong/epidemiology , Shoulder
12.
Cells ; 12(17)2023 08 24.
Article En | MEDLINE | ID: mdl-37681868

Macrophages are the principal component of the innate immune system that are found in all tissues and play an essential role in development, homeostasis, tissue repair, and immunity. Clinical and experimental studies have shown that transcriptionally dynamic pro-inflammatory macrophages are involved in the pathogenesis of diet-induced obesity and insulin resistance. However, cell-intrinsic mechanisms must exist that bridle uncontrolled pro-inflammatory macrophage activation in metabolic organs and disease pathogenesis. In this study, we show that CBP/p300-interacting transactivator with glutamic acid/aspartic acid-rich carboxyl-terminal domain 2 (CITED2) is an essential negative regulator of pro-inflammatory macrophage activation and inflammatory disease pathogenesis. Our in vivo studies show that myeloid-CITED2 deficiency significantly elevates high-fat diet (HFD)-induced expansion of adipose tissue volume, obesity, glucose intolerance, and insulin resistance. Moreover, myeloid-CITED2 deficiency also substantially augments HFD-induced adipose tissue inflammation and adverse remodeling of adipocytes. Our integrated transcriptomics and gene set enrichment analyses show that CITED2 deficiency curtails BCL6 signaling and broadly elevates BCL6-repressive gene target expression in macrophages. Using complementary gain- and loss-of-function studies, we found that CITED2 deficiency attenuates, and CITED2 overexpression elevates, inducible BCL6 expression in macrophages. At the molecular level, our analyses show that CITED2 promotes BCL6 expression by restraining STAT5 activation in macrophages. Interestingly, siRNA-mediated knockdown of STAT5 fully reversed elevated pro-inflammatory gene target expression in CITED2-deficient macrophages. Overall, our findings highlight that CITED2 restrains inflammation by promoting BCL6 expression in macrophages, and limits diet-induced obesity and insulin resistance.


Insulin Resistance , Obesity , Repressor Proteins , STAT5 Transcription Factor , Trans-Activators , Diet, High-Fat/adverse effects , Inflammation , Macrophages , Repressor Proteins/genetics , Trans-Activators/genetics , Animals
15.
Acta Biomater ; 169: 348-362, 2023 10 01.
Article En | MEDLINE | ID: mdl-37507031

Brain-Machine Interface systems (BMIs) are clinically valuable devices that can provide functional restoration for patients with spinal cord injury or improved integration for patients requiring prostheses. Intracortical microelectrodes can record neuronal action potentials at a resolution necessary for precisely controlling BMIs. However, intracortical microelectrodes have a demonstrated history of progressive decline in the recording performance with time, inhibiting their usefulness. One major contributor to decreased performance is the neuroinflammatory response to the implanted microelectrodes. The neuroinflammatory response can lead to neurodegeneration and the formation of a glial scar at the implant site. Historically, histological imaging of relatively few known cellular and protein markers has characterized the neuroinflammatory response to implanted microelectrode arrays. However, neuroinflammation requires many molecular players to coordinate the response - meaning traditional methods could result in an incomplete understanding. Taking advantage of recent advancements in tools to characterize the relative or absolute DNA/RNA expression levels, a few groups have begun to explore gene expression at the microelectrode-tissue interface. We have utilized a custom panel of ∼813 neuroinflammatory-specific genes developed with NanoString for bulk tissue analysis at the microelectrode-tissue interface. Our previous studies characterized the acute innate immune response to intracortical microelectrodes. Here we investigated the gene expression at the microelectrode-tissue interface in wild-type (WT) mice chronically implanted with nonfunctioning probes. We found 28 differentially expressed genes at chronic time points (4WK, 8WK, and 16WK), many in the complement and extracellular matrix system. Further, the expression levels were relatively stable over time. Genes identified here represent chronic molecular players at the microelectrode implant sites and potential therapeutic targets for the long-term integration of microelectrodes. STATEMENT OF SIGNIFICANCE: Intracortical microelectrodes can record neuronal action potentials at a resolution necessary for the precise control of Brain-Machine Interface systems (BMIs). However, intracortical microelectrodes have a demonstrated history of progressive declines in the recording performance with time, inhibiting their usefulness. One major contributor to the decline in these devices is the neuroinflammatory response against the implanted microelectrodes. Historically, neuroinflammation to implanted microelectrode arrays has been characterized by histological imaging of relatively few known cellular and protein markers. Few studies have begun to develop a more in-depth understanding of the molecular pathways facilitating device-mediated neuroinflammation. Here, we are among the first to identify genetic pathways that could represent targets to improve the host response to intracortical microelectrodes, and ultimately device performance.


Inflammation , Neuroinflammatory Diseases , Mice , Animals , Microelectrodes , Electrodes, Implanted , Inflammation/genetics , Inflammation/pathology , Immunity, Innate
16.
Hong Kong Med J ; 29(3): 224-232, 2023 Jun.
Article En | MEDLINE | ID: mdl-37303104

INTRODUCTION: The number of poisoning cases involving attention deficit hyperactivity disorder (ADHD) medications has reportedly risen with their increased use. However, there is limited relevant evidence from Asia. We analysed the characteristics of poisoning events involving these medications in Hong Kong. METHODS: We retrieved data regarding ADHD medication-related poisoning cases from the Hong Kong Poison Information Centre and conducted a descriptive analysis of the demographic information and poisoning information including sources of cases, exposure reason, exposure location, and outcome. The HKPIC data were linked with the Hospital Authority Clinical Data Analysis and Reporting System (CDARS) via de-identified Accident and Emergency numbers of public hospitals to investigate clinical characteristics. We also retrieved ADHD medication prescription records from the CDARS, then compared trends between poisoning cases and ADHD medication use. RESULTS: We identified 72 poisoning cases involving ADHD medications between 2009 and 2019, of which approximately 70% occurred in the affected individual's residence; most were intentional poisoning events (65.3%). No statistically significant association was observed between ADHD medication prescription trends and poisoning events involving ADHD medications. Of the 66 cases (91.7%) successfully linked to CDARS, 40 (60.6%) occurred in individuals with ADHD (median age: 14 years); 26 (39.4%) occurred in individuals who lacked ADHD (median age: 33 years) but displayed higher rates of other mental disorders including depression and anxiety. CONCLUSION: No significant correlation was evident between ADHD medication prescriptions and poisoning events involving ADHD medications. However, medication management and caregiver education must be emphasised to prevent potential poisoning events.


Attention Deficit Disorder with Hyperactivity , Central Nervous System Stimulants , Humans , Adolescent , Adult , Attention Deficit Disorder with Hyperactivity/drug therapy , Attention Deficit Disorder with Hyperactivity/epidemiology , Central Nervous System Stimulants/therapeutic use , Hong Kong/epidemiology , Anxiety Disorders/drug therapy
17.
Mol Cancer Res ; 21(9): 975-990, 2023 09 01.
Article En | MEDLINE | ID: mdl-37310811

Patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) frequently present with advanced metastatic disease and exhibit a poor response to therapy, resulting in poor outcomes. The tumor microenvironment cytokine Oncostatin-M (OSM) initiates PDAC plasticity, inducing the reprogramming to a stem-like/mesenchymal state, which enhances metastasis and therapy resistance. Using a panel of PDAC cells driven through epithelial-mesenchymal transition (EMT) by OSM or the transcription factors ZEB1 or SNAI1, we find that OSM uniquely induces tumor initiation and gemcitabine resistance independently of its ability to induce a CD44HI/mesenchymal phenotype. In contrast, while ZEB1 and SNAI1 induce a CD44HI/mesenchymal phenotype and migration comparable with OSM, they are unable to promote tumor initiation or robust gemcitabine resistance. Transcriptomic analysis identified that OSM-mediated stemness requires MAPK activation and sustained, feed-forward transcription of OSMR. MEK and ERK inhibitors prevented OSM-driven transcription of select target genes and stem-like/mesenchymal reprogramming, resulting in reduced tumor growth and resensitization to gemcitabine. We propose that the unique properties of OSMR, which hyperactivates MAPK signaling when compared with other IL6 family receptors, make it an attractive therapeutic target, and that disrupting the OSM-OSMR-MAPK feed-forward loop may be a novel way to therapeutically target the stem-like behaviors common to aggressive PDAC. IMPLICATIONS: Small-molecule MAPK inhibitors may effectively target the OSM/OSMR-axis that leads to EMT and tumor initiating properties that promote aggressive PDAC.


Carcinoma, Pancreatic Ductal , Pancreatic Neoplasms , Humans , Receptors, Oncostatin M , Signal Transduction , Oncostatin M/pharmacology , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/genetics , Epithelial-Mesenchymal Transition , Carcinoma, Pancreatic Ductal/drug therapy , Carcinoma, Pancreatic Ductal/genetics , Tumor Microenvironment
18.
Cell ; 186(13): 2839-2852.e21, 2023 06 22.
Article En | MEDLINE | ID: mdl-37352836

The gut microbiome is complex, raising questions about the role of individual strains in the community. Here, we address this question by constructing variants of a complex defined community in which we eliminate strains that occupy the bile acid 7α-dehydroxylation niche. Omitting Clostridium scindens (Cs) and Clostridium hylemonae (Ch) eliminates secondary bile acid production and reshapes the community in a highly specific manner: eight strains change in relative abundance by >100-fold. In single-strain dropout communities, Cs and Ch reach the same relative abundance and dehydroxylate bile acids to a similar extent. However, Clostridium sporogenes increases >1,000-fold in the ΔCs but not ΔCh dropout, reshaping the pool of microbiome-derived phenylalanine metabolites. Thus, strains that are functionally redundant within a niche can have widely varying impacts outside the niche, and a strain swap can ripple through the community in an unpredictable manner, resulting in a large impact on an unrelated community-level phenotype.


Gastrointestinal Microbiome , Bile Acids and Salts , Clostridiales
19.
BJA Educ ; 23(5): 182-188, 2023 May.
Article En | MEDLINE | ID: mdl-37124171
20.
Int J Tuberc Lung Dis ; 27(6): 490-491, 2023 Jun 01.
Article En | MEDLINE | ID: mdl-37231595
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