Kynurenine pathway of tryptophan metabolism in pathophysiology and therapy of major depressive disorder

Serotonin deficiency in major depressive disorder(MDD)has formed the basis of antidepressant drug development and was originally attributed to induction of the major tryptophan(Trp)-degrading enzyme,liver Trp 2,3-dioxygenase(TDO),by cortisol,leading to decreased Trp availability to the brain for serotonin synthesis.Subsequently,the serotonin deficiency was proposed to involve induction of the extrahepatic Trp-degrading enzyme indoleamine 2,3-dioxygenase(IDO)by proinflammatory cytokines,with inflammation being the underlying cause.Recent evidence,however,challenges this latter concept,as not all MDD patients are immune-activated and,when present,inflammation is mild and/or transient.A wide range of antidepressant drugs inhibit the activity of liver TDO and bind specifically to the enzyme,but not to IDO.IDO induction is not a major event in MDD,but,when it occurs,its metabolic consequences may be masked and overridden by upregulation of kynurenine monooxygenase(KMO),the gateway to production of modulators of immune and neuronal functions.KMO appears to be activated in MDD by certain proinflammatory cytokines and antidepressants with anti-inflammatory properties may block this activation.We demonstrate the ability of the antidepressant ketamine to dock(bind)to KMO.The pathophysiology of MDD may be underpinned by both the serotonin deficiency and glutamatergic activation mediated respectively by TDO induction and N-methyl-D-aspartate receptor activation.Inhibition of TDO and KMO should be the focus of MDD pharmacotherapy.

Helicobacter pylori and serum kynurenine-tryptophan ratio in patients with colorectal cancer

AIM: To evaluate how Helicobacter pylori(H. pylori) is able to evade the immune response and whether it enhances systemic immune tolerance against colorectal cancer.METHODS: This prospective randomized study involved 97 consecutive colorectal cancer patients and 108 cancer-free patients with extra-digestive diseases. Colorectal cancer and cancer-free patients were assigned into subgroups according to H. pylori Ig G seropositivity. Exposure to H. pylori was determined by Ig G seropositivity which was detected by enzyme linked immunoassay(ELISA). Serum neopterin levels were measured by ELISA. Serum tryptophan, kynurenine, and urinary biopterin concentrations were measured by high performance liquid chromatography. Serum nitrite levels were detected spectrophotometrically. Serum indoleamine 2,3-dioxygenase activity was estimated by the kynurenine to tryptophan ratio and by assessing the correlation between serum neopterin concentrations and the kynurenine to tryptophan ratio. The frequencies of increased serum kynurenine to tryptophan ratio of H. pylori seronegative and seropositive colorectal cancer subgroups were estimated by comparing them with the average kynurenine to tryptophan ratio of H. pylori seronegative tumor-free patients.RESULTS: Compared with respective controls, in both H. pylori seronegative and seropositive colorectal cancer patients, while serum tryptophan levels were decreased(controls vs patients; seronegative: 20.37 ± 0.89 μmol/L vs 15.71 ± 1.16 μmol/L, P < 0.05; seropositive: 20.71 ± 0.81 μmol/L vs 14.97 ± 0.79 μmol/L, P < 0.01) the kynurenine to tryptophan ratio was significantly increased(controls vs patients; seronegative: 52.85± 11.85 μmol/mmol vs 78.91 ± 8.68 μmol/mmol, P < 0.01, seropositive: 47.31 ± 5.93 μmol/mmol vs 109.65 ± 11.50 μmol/mmol, P < 0.01). Neopterin concentrations in cancer patients were significantly elevated compared with controls(P < 0.05). There was a significant correlation between serum neopterin levels and kynurenine/tryptophan in control and colorectal cancer patients groups(r s = 0.494, P = 0.0001 and r s= 0.293, P = 0.004, respectively). Serum nitrite levels of H. pylori seropositive cancer cases were significantly decreased compared with seropositive controls(controls vs patients; 26.04 ± 2.39 μmol/L vs 20.41 ± 1.48 μmol/L, P < 0.05) The decrease in the nitrite levels of H. pylori seropositive cancer patients may be attributed to excessive formation of peroxynitrite and other reactive nitrogen species.CONCLUSION: A significantly high kynurenine/tryptophan suggested that H. pylori may support the immune tolerance leading to cancer development, even without an apparent upper gastrointestinal tract disease.

Differences of Plasma Levels of Tryptophan, Serotonin, 5-Hydroxyindole Acetic Acid, and Kynurenine between Healthy People and Patients of Major Monopolar Depression at Various Age and Gender

Background: It is not well analyzed whether there are differences in plasma levels of tryptophan (TRP) metabolites between healthy control people (HC) and patients of major monopolar depression (MMD). Methods: Ultra high-speed liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive patients. Results: There are no significant differences between plasma levels of TRP between HC and MMD. Plasma levels of TRP of HC are higher in young men, young women, old men, and old women in this order. Serotonin (5-HT) levels are higher in MMD than HC. Plasma levels of 5-HIAA of HC are also higher than those of patients of MMD. Plasma levels of kynurenine (KYN) of healthy old men and old women are higher than those of young men and old women. Plasma levels of KYN are higher in old women and young men of MMD than those of HC. Conclusion: Plasma levels of 5-HT are higher in patients of MMD than those of HC, which may suggest that use of drugs inhibiting the 5-HT transportation may increase plasma levels of 5-HT in MMD.

Bidirectional effects of the tryptophan metabolite indole-3-acetaldehyde on colorectal cancer

BACKGROUND Colorectal cancer(CRC)has a high incidence and mortality.Recent studies have shown that indole derivatives involved in gut microbiota metabolism can impact the tumorigenesis,progression,and metastasis of CRC.AIM To investigate the effect of indole-3-acetaldehyde(IAAD)on CRC.METHODS The effect of IAAD was evaluated in a syngeneic mouse model of CRC and CRC cell lines(HCT116 and DLD-1).Cell proliferation was assessed by Ki-67 fluorescence staining and cytotoxicity tests.Cell apoptosis was analysed by flow cytometry after staining with Annexin V-fluorescein isothiocyanate and propidium iodide.Invasiveness was investigated using the transwell assay.Western blotting and real-time fluorescence quantitative polymerase chain reaction were performed to evaluate the expression of epithelial-mesenchymal transition related genes and aryl hydrocarbon receptor(AhR)downstream genes.The PharmMapper,SEA,and SWISS databases were used to screen for potential target proteins of IAAD,and the core proteins were identified through the String database.RESULTS IAAD reduced tumorigenesis in a syngeneic mouse model.In CRC cell lines HCT116 and DLD1,IAAD exhibited cytotoxicity starting at 24 h of treatment,while it reduced Ki67 expression in the nucleus.The results of flow cytometry showed that IAAD induced apoptosis in HCT116 cells but had no effect on DLD1 cells,which may be related to the activation of AhR.IAAD can also increase the invasiveness and epithelial-mesenchymal transition of HCT116 and DLD1 cells.At low concentrations(<12.5μmol/L),IAAD only exhibited cytotoxic effects without promoting cell invasion.In addition,predictions based on online databases,protein-protein interaction analysis,and molecular docking showed that IAAD can bind to matrix metalloproteinase-9(MMP9),angiotensin converting enzyme(ACE),poly(ADP-ribose)polymerase-1(PARP1),matrix metalloproteinase-2(MMP2),and myeloperoxidase(MPO).CONCLUSION Indole-3-aldehyde can induce cell apoptosis and inhibit cell proliferation to prevent the occurrence of CRC;however,at high concentrations(≥25μmol/L),it can also promote epithelial-mesenchymal transition and invasion in CRC cells.IAAD activates AhR and directly binds MMP9,ACE,PARP1,MMP2,and MPO,which partly reveals why it has a bidirectional effect.

高效液相色谱法测定孕妇血清中色氨酸及其代谢产物Kynurenine

[目的]建立一种高效液相色谱法测定孕妇血清中的色氨酸（Tyrptophan）及其代谢产物Kynurenine的方法。[方法]反相高效液相色谱法。外标法，ZORBAX Extend-C18柱，4．6mmID×250mm，流动相为甲醇：0．001mol／L磷酸二氢钾（采用PH=4）（12：88），流速1．3ml／min，检测波长245nm。[结果]色氨酸线性范围2．56～307．06μmol／L，r=0．9999；Kynurenine线性范围0．12～5．05μmol／L，r=0．9997。30例孕妇血清色氨酸为49．73±7．48μmol／L，其代谢产物KN为：0．74±0．33μmol／L。[结论]本法简便，准确，适用于临床和科研。

Kynurenine pathway metabolism and neuroinflammatory disease

Immune-mediated activation of tryptophan（TRYP） catabolism via the kynurenine pathway（KP） is a consistent finding in all inflammatory disorders.Several studies by our group and others have examined the neurotoxic potential of neuroreactive TRYP metabolites,including quinolinic acid（QUIN） in neuroinflammatory neurological disorders,including Alzheimer＇s disease（AD）,multiple sclerosis,amylotropic lateral sclerosis（ALS）,and AIDS related dementia complex（ADC）.Our current work aims to determine whether there is any benefit to the affected individuals in enhancing the catabolism of TRYP via the KP during an immune response.Under physiological conditions,QUIN is metabolized to the essential pyridine nucleotide,nicotinamide adenine dinucleotide（NAD＋）,which represents an important metabolic cofactor and electron transporter.NAD＋ also serves as a substrate for the DNA ‘nick sensor＇ and putative nuclear repair enzyme,poly（ADP-ribose） polymerase（PARP）.Free radical initiated DNA damage,PARP activation and NAD＋ depletion may contribute to brain dysfunction and cell death in neuroinflammatory disease.

Inhibiting the kynurenine pathway in spinal cord injury: multiple therapeutic potentials?

Chronic induction of the kynurenine pathway（KP） contributes to neuroinflammation by producing the excitotoxin quinolinic acid（QUIN）. This has led to significant interest in the development of inhibitors of this pathway, particularly in the context of neurodegenerative disease. However, acute spinal cord injury（SCI） also results in deleterious increases in QUIN, as secondary inflammatory processes mediated largely by infiltrating macrophages, become predominant. QUIN mediates significant neurotoxicity primarily by excitotoxic stimulation of the N-methyl-D-aspartate receptor, but other mechanisms of QUIN toxicity are known. More recent focus has assessed the contribution that neuroinflammation and modulations in the KP make in mood and psychiatric disorders with recent studies linking inflammation and modulations in the KP, to impaired cognitive performance and depressed mood in SCI patients. We hypothesize that these findings suggest that in SCI, inhibition of QUIN production and other metabolites, may have multiple therapeutic modalities and further studies investigating this are warranted. However, for central nervous system-based conditions, achieving good blood-brain-barrier permeability continues to be a limitation of current KP inhibitors.

Kynurenine plays an immunosuppressive role in 2,4,6-trinitrobenzene sulfate-induced colitis in mice

BACKGROUND Inflammatory bowel disease,such as Crohn’s disease and ulcerative colitis,is characterized by chronic intestinal inflammation leading to intestinal mucosal damage.Inflammatory bowel disease causes dysregulation of mucosal T cell responses,especially the responses of CD4+T cells.Previously,we demonstrated that indoleamine-2,3-dioxygenase plays an immunosuppressive role in 2,4,6-trinitrobenzene sulfate(TNBS)-induced colitis.Although indoleamine-2,3-dioxygenase exerts immunosuppressive effects by altering the local concentration of tryptophan(Trp)and immunomodulatory Trp metabolites,the specific changes in immune regulation during colitis caused by Trp metabolites and its related enzymes remain unclear.AIM To investigate role of kynurenine 3-monooxygenase(KMO)in TNBS-induced colitis and involvement of Trp metabolites in maintenance of intestinal homeostasis.METHODS Colitis was induced in eight-week-old male KMO+/+or KMO−/−mice of C57BL/6N background using TNBS.Three days later,the colon was used for hematoxylin-eosin staining for histological grading,immunohistochemical or immunofluorescence staining for KMO,cytokines,and immune cells.Inflammatory and anti-inflammatory cytokines were measured using quantitative RT-PCR,and kynurenine(Kyn)pathway metabolites were measured by high-performance liquid chromatography.The cell proportions of colonic lamina propria and mesenteric lymph nodes were analyzed by flow cytometry.RESULTS KMO expression levels in the colonic mononuclear phagocytes,including dendritic cells and macrophages increased upon TNBS induction.Notably,KMO deficiency reduced TNBS-induced colitis,resulting in an increased frequency of Foxp3+regulatory T cells and increased mRNA and protein levels of antiinflammatory cytokines,including transforming growth factor-βand interleukin-10.CONCLUSION Absence of KMO reduced TNBS-induced colitis via generation of Foxp3+regulatory T cells by producing Kyn.Thus,Kyn may play a therapeutic role in colon protection during colitis.

Pectin modulates intestinal immunity in a pig model via regulating the gut microbiota-derived tryptophan metabolite-AhR-IL22 pathway

Background Pectin is a heteropolysaccharide that acts as an intestinal immunomodulator,promoting intestinal development and regulating intestinal flora in the gut.However,the relevant mechanisms remain obscure.In this study,pigs were fed a corn-soybean meal-based diet supplemented with either 5%microcrystalline cellulose(MCC)or 5%pectin for 3 weeks,to investigate the metabolites and anti-inflammatory properties of the jejunum.Result The results showed that dietary pectin supplementation improved intestinal integrity(Claudin-1,Occludin)and inflammatory response[interleukin(IL)-10],and the expression of proinflammatory cytokines(IL-1β,IL-6,IL-8,TNF-α)was down-regulated in the jejunum.Moreover,pectin supplementation altered the jejunal microbiome and tryptophan-related metabolites in piglets.Pectin specifically increased the abundance of Lactococcus,Enterococcus,and the microbiota-derived metabolites(skatole(ST),3-indoleacetic acid(IAA),3-indolepropionic acid(IPA),5-hydroxyindole-3-acetic acid(HIAA),and tryptamine(Tpm)),which activated the aryl hydrocarbon receptor(AhR)pathway.AhR activation modulates IL-22 and its downstream pathways.Correlation analysis revealed the potential relationship between metabolites and intestinal morphology,intestinal gene expression,and cytokine levels.Conclusion In conclusion,these results indicated that pectin inhibits the inflammatory response by enhancing the AhR-IL22-signal transducer and activator of transcription 3 signaling pathway,which is activated through tryptophan metabolites.

T cells in pancreatic cancer stroma:Tryptophan metabolism plays an important role in immunoregulation

Several studies have shown that the immune system is highly regulated by tryptophan metabolism,which serves as an immunomodulatory factor.The indoleamine 2,3-dioxygenase 1(IDO1),as an intracellular enzyme that participates in metabolism of the essential amino acid tryptophan in the kynurenine pathway,is an independent prognostic marker for pancreatic cancer(PC).First,overexpression of IDO1 inhibits the maturation of dendritic cells and T-cell proliferation in the liver and spleen.Second,the high expression of kynurenine induces and activates the aryl hydrocarbon receptor,resulting in upregulated programmed cell death protein 1 expression.Third,the induction of IDO1 can lead to loss of the T helper 17 cell/regulatory T cell balance,mediated by the proximal tryptophan catabolite from IDO metabolism.In our study,we found that overexpression of IDO1 upregulated CD8+T cells and reduced natural killer T cells in pancreatic carcinoma in mice.Hence,it may be essential to pay more attention to tryptophan metabolism in patients,especially those who are tolerant to immunotherapy for PC.

Research progress of kynurenine pathway in Alzheimer's disease

The kynurenine pathway(KP)has been shown to be involved in the pathophysiology of dementia diseases.Among the dementia diseases,the neurodegenerative diseases Alzheimer's disease and cerebrovascular diseases are vascular.The highest incidence of dementia.KP activation results in the production of neuroactive metabolites,which may interfere with normal neuronal function,leading to the appearance of symptoms of cognitive impairment.This review investigated KP's involvement in the neurological diseases Alzheimer's disease and vascular dementia,suggesting that KP is a potential therapeutic target for both diseases.

Tryptophan Metabolism and Gut Microbiota

Background: Tryptophan metabolites such as serotonin, kynurenine, or kynurenic acids are considered to be the most important metabolites of gut microbiota. We wanted to know about changes in tryptophan metabolites in various diseases in which the etiology gut microbiota are considered to participate. Methods: Ultra-high speed liquid chromatography/mass spectroscopy (LC/MS) has been used to analyze simultaneously all the tryptophan metabolites, which we have explored for the first time in the world. Results: We analyzed plasma levels of tryptophan metabolites in patients with depression, autism, diabetes mellitus ‘DM’), and acute coronary syndrome (ACS). Of all the metabolites serotonin and kynurenine levels of these patients were higher than those of controls. Conclusion: Measurements of tryptophan metabolites in plasma of various diseases are important to know roles of gut microbiota in etiology, further therapeutic measures.

Ochratoxin A induces abnormal tryptophan metabolism in the intestine and liver to activate AMPK signaling pathway

Background Ochratoxin A(OTA)is a mycotoxin widely present in raw food and feed materials and is mainly pro-duced by Aspergillus ochraceus and Penicillium verrucosum.Our previous study showed that OTA principally induces liver inflammation by causing intestinal flora disorder,especially Bacteroides plebeius(B.plebeius)overgrowth.However,whether OTA or B.plebeius alteration leads to abnormal tryptophan-related metabolism in the intestine and liver is largely unknown.This study aimed to elucidate the metabolic changes in the intestine and liver induced by OTA and the tryptophan-related metabolic pathway in the liver.Materials and methods A total of 30 healthy 1-day-old male Cherry Valley ducks were randomly divided into 2 groups.The control group was given 0.1 mol/L NaHCO3 solution,and the OTA group was given 235μg/kg body weight OTA for 14 consecutive days.Tryptophan metabolites were determined by intestinal chyme metabolomics and liver tryptophan-targeted metabolomics.AMPK-related signaling pathway factors were analyzed by Western blot-ting and mRNA expression.Results Metabolomic analysis of the intestinal chyme showed that OTA treatment resulted in a decrease in intesti-nal nicotinuric acid levels,the downstream product of tryptophan metabolism,which were significantly negatively correlated with B.plebeius abundance.In contrast,OTA induced a significant increase in indole-3-acetamide levels,which were positively correlated with B.plebeius abundance.Simultaneously,OTA decreased the levels of ATP,NAD+and dipeptidase in the liver.Liver tryptophan metabolomics analysis showed that OTA inhibited the kynurenine metabolic pathway and reduced the levels of kynurenine,anthranilic acid and nicotinic acid.Moreover,OTA increased the phosphorylation of AMPK protein and decreased the phosphorylation of mTOR protein.Conclusion OTA decreased the level of nicotinuric acid in the intestinal tract,which was negatively correlated with B.plebeius abundance.The abnormal metabolism of tryptophan led to a deficiency of NAD+and ATP in the liver,which in turn activated the AMPK signaling pathway.Our results provide new insights into the toxic mechanism of OTA,and tryptophan metabolism might be a target for prevention and treatment.

背俞功能带推法对慢性疲劳综合征大鼠肠道菌群及色氨酸代谢的影响

目的探究背俞功能带推法改善慢性疲劳综合征(chronic fatigue syndrome,CFS)大鼠的症状,以及对其肠道菌群和色氨酸代谢的影响。方法选取SPF级SD大鼠24只,随机分为空白组8只、造模组16只,造模组制备CFS模型21 d,模型制备成功后随机分为模型组和推法组,每组8只。推法干预14 d,做旷场实验及力竭游泳实验等行为学实验后,取大鼠血清、结肠进行酶联免疫吸附法检测血清色氨酸(tryptophan,TRP)、犬尿氨酸(kynurenine,KYN)及结肠吲哚胺2,3-双加氧酶(indoleamine 2,3-dioxygenase,IDO),取肠道粪便进行16 s rRNA测序分析肠道菌群结构及多样性。结果与空白组大鼠相比,模型组大鼠总路程、跨格数、中心区时间和路程、进入中心区次数力竭游泳时间均显著减少(P<0.01);与模型组相比,推法组大鼠上述各项指标均增加(P<0.05)。在门水平,与空白组相比,模型组厚壁菌门、拟杆菌门和疣微菌门比例下降,变形菌门和酸杆菌门比例明显上升;与模型组相比,推法组厚壁菌门和酸杆菌门比例下降,而拟杆菌门和变形菌门比例升高。在属水平上,与空白组相比,模型组中罗姆布茨菌属(Romboutsia)和疣微菌科UCG-005菌属(Ruminococcaceae_UCG-005,简称UCG-005)的比例明显降低,而乳杆菌属(Lactobacillus)和双歧杆菌属(Bifidobacterium)比例明显增加;与模型组相比,推法组Lactobacillus和杜氏杆菌属(Dubosiella)比例下降,而Romboutsia和UCG-005比例上升。Alpha和Beta多样性分析,与空白组相比,模型组的菌群丰富度和多样性均降低;与模型组相比,推法组大鼠菌群丰富度和多样性有明显上升;但组间差异均无统计学意义(P>0.05)。LEfSe分析中,与空白组相比,模型组的优势物种主要聚集在目、科、属,推法组的优势物种主要聚集在科、属。与空白组大鼠相比,模型组大鼠血清TRP含量显著降低(P<0.01),血清KYN和结肠IDO含量明显升高(P<0.01);与模型组相比,推法组大鼠血清TRP含量明显升高(P<0.01),血清KYN和结肠IDO含量降低(P<0.05)。相关性分析发现,与TRP相关性较大的菌属包括Lachnospiraceae_NK4A136_group、Lactobacillus、Romboutsia等(P<0.05),与KYN相关性较大的菌属包括Bifidobacterium05、Lachnospiraceae_NK4A136_group、UCG-005(P<0.05或P<0.01),与IDO相关性较大的菌属包括Allobaculum、Lachnospiraceae_NK4A136_group、Romboutsia(P<0.05或P<0.01)。结论背俞功能带推法能明显改善CFS大鼠的疲劳以及焦虑症状,调节菌群代谢物TRP、KYN及结肠IDO含量,对肠道菌群结构及其多样性有一定的调节作用,且部分菌属与TRP、KYN、IDO具有相关性。

犬尿氨酸通路在儿童神经发育障碍性疾病中的研究进展

色氨酸在体内主要通过犬尿氨酸通路(KP)代谢为血清素、褪黑素和烟酰胺腺嘌呤二核苷酸等生物活性物质,与多种器官和细胞的生理功能密切相关。KP中重要酶活性和代谢物水平的改变通过影响受体和调节细胞信号传导的方式影响儿童脑发育。该研究主要围绕KP及其代谢产物在儿童神经发育中的作用进行综述,希望为儿童神经发育障碍性疾病的协助诊断和治疗干预提供新的切入点。

温和灸对IBS小鼠结肠Trp-kyn/5-HT代谢的调控机制研究

目的 观察温和灸干预对肠易激综合征模型小鼠结肠组织Trp-Kyn/5-HT限速酶表达及相关代谢物含量的影响,阐释艾灸治疗相关机制。方法 雄性清洁级C57BL/6J小鼠随机分为正常组、模型组、艾灸组、1-MT组、PCPA组,采用AWR评价小鼠内脏高敏感状态,采用LC-MS/MS法、免疫组织化学法及Real Time PCR法分别检测小鼠结肠组织Trp-Kyn/5-HT代谢物含量、Trp-Kyn/5-HT代谢限速酶IDO1、TPH1蛋白及m RNA表达。结果 与正常组相比,模型组小鼠30 mm Hg下AWR评分增高(P <0.05),结肠组织TPH1、IDO1蛋白及m RNA表达显著增高(P <0.05),5-HT含量及Kyn/Trp比值显著升高(P <0.05)。与模型组相比,艾灸组和1-MT组小鼠结肠组织IDO1蛋白表达明显下调(P <0.05),艾灸组和PCPA组小鼠结肠组织TPH1蛋白明显下调(P <0.05);1-MT组小鼠结肠组织IDO1 mRNA表达明显降低(P <0.05),PCPA组小鼠结肠组织TPH1 mRNA表达明显降低(P <0.05);艾灸组Kyn/Trp比值显著降低(P <0.05)。结论 温和灸可抑制IBS小鼠结肠过表达的IDO1及THP1蛋白活性,下调Kyn/Trp比值,可能是温和灸改善IBS模型小鼠内脏痛敏的机制之一。

液相色谱串联质谱法测定青少年抑郁症患者血清和尿液中色氨酸代谢物的水平

目的观察并比较液相色谱串联质谱技术检测青少年抑郁症患者血清和尿液中色氨酸-犬尿氨酸(TRP-KP)通路代谢物的浓度。方法对该通路中主要代谢物如色氨酸(TRP)、犬尿氨酸(KYN)、犬尿酸(KYNA)和3-羟基犬尿氨酸(3-HK)采用同位素标记法进行定量分析。使用岛津C18色谱柱,0.2%甲酸水溶液和乙腈进行梯度洗脱分离,7 min内采用正离子和多反应监测模式进行检测。考察线性范围、精密度等参数。用该方法检测143例青少年抑郁症患者和110例体检健康者血液和尿液样本并比较。结果以TRP为例,血清和尿液的线性范围分别为0.54~107.84μmol/L和0.74~147.06μmol/L。批内变异系数(CV)≤6.3%,批间CV≤3.22%,实验室总CV≤6.5%。抑郁组和对照组血清和尿液检测结果表明,抑郁组KYNA、KYN和TRP水平低于对照组,而3-HK水平高于对照组,差异具有统计学意义(P<0.01)。除TRP外,其他代谢物水平在尿液中显著高于血清中,差异具有统计学意义(P<0.01)。结论与血清相比,尿液中TRP-KP的代谢物即KYN、KYNA和3-HK浓度更高,由于尿液收集过程是无创的,因此检测尿液中TRP-KP代谢物具有更大的优势。

基于肠道菌群调节的膳食纤维影响抑郁的研究

由于工作和生活压力的增加,抑郁症的患病率也在逐年上升。肠道菌群作为人体的隐形器官,在人体生命健康中发挥着重要作用,近年来已成为生命科学领域的研究热点。随着对肠道菌群研究的不断深入,越来越多的证据表明:肠道菌群可以通过肠-脑轴来改善抑郁症状。膳食纤维作为一种独特的植物多糖,可有效调节肠道菌群紊乱,其在协调宿主-微生物群串扰中的关键作用已被证实。该文综述了膳食纤维对肠道菌群和抑郁症影响的证据,重点研究了膳食纤维干预肠道菌群改善抑郁症的机制,以期为抑郁症的预防及辅助治疗提供新的思路和参考。

基于代谢组学探究COPD患者KTR与CAT评分的相关性

目的基于代谢组学氨基酸代谢水平,探究慢性阻塞性肺疾病(COPD)患者血浆犬尿氨酸(Kyn)/色氨酸(Trp)的比值(KTR)与COPD评估量表(CAT)评分的相关性。方法选取2021年6月至2022年9月阜阳市人民医院收治的COPD患者85例为COPD组,另选取60例健康体检者作为对照组。根据CAT评分将COPD组分为轻度组、中度组、重度组和极重度组。比较COPD组和对照组及不同CAT评分组间血浆Trp、Kyn水平,KTR和肺功能指标[第1秒用力呼气容积(FEV_(1))、用力肺活量(FVC)、FEV_(1)/FVC比值];采用Pearson相关分析血浆Trp、Kyn、KTR水平与肺功能指标及CAT评分的相关性;比较COPD患者治疗前后CAT评分及KTR。结果COPD组FEV_(1)、FVC、Trp水平及FEV_(1)/FVC比值低于对照组,KTR高于对照组,差异均有统计学意义(P<0.05)。极重度和重度组FEV_(1)、FVC、Trp水平及FEV_(1)/FVC比值低于轻度组和中度组,差异均有统计学意义(P<0.05)。极重度组的Kyn水平和KTR高于轻度组、中度组和重度组,差异均有统计学意义(P<0.05)。FEV_(1)、FVC、FEV_(1)/FVC与Trp呈正相关,与Kyn、KTR呈负相关(P<0.05);CAT评分与Trp呈负相关,与Kyn、KTR呈正相关(P<0.05)。COPD患者出院时KTR及CAT各项评分比入院时明显下降,差异均有统计学意义(P<0.05)。结论Trp、Kyn、KTR是监测COPD患者疾病进展新的生物标志物,联合CAT评分可以更全面地反映COPD的严重程度。

色氨酸犬尿氨酸代谢、免疫细胞与炎症性肠病的研究进展

炎症性肠病(inflammatory bowel disease,IBD)是全球性疾病,现今仍无法根治,疾病负担日益加重,T细胞、DC细胞、NK细胞、巨噬细胞、ILC细胞等免疫细胞在IBD中发挥着重要作用。色氨酸犬尿氨酸代谢途径产物可通过多种方式调节免疫细胞的复制、功能、凋亡等,从而参与IBD的发生发展。该综述就关于多种免疫细胞在IBD中的作用、色氨酸犬尿氨酸途径通过调节免疫细胞参与IBD的机制进行阐述,可为生物治疗IBD以及IBD的靶向药物研究提供理论依据,为IBD患者提供更好的治疗。