Promising use of metformin in treating neurological disorders:biomarker-guided therapies

Neurological disorders are a diverse group of conditions that affect the nervous system and include neurodegenerative diseases(Alzheimer’s disease,multiple sclerosis,Parkinson’s disease,Huntington’s disease),cerebrovascular conditions(stroke),and neurodevelopmental disorders(autism spectrum disorder).Although they affect millions of individuals around the world,only a limited number of effective treatment options are available today.Since most neurological disorders express mitochondria-related metabolic perturbations,metformin,a biguanide type II antidiabetic drug,has attracted a lot of attention to be repurposed to treat neurological disorders by correcting their perturbed energy metabolism.However,controversial research emerges regarding the beneficial/detrimental effects of metformin on these neurological disorders.Given that most neurological disorders have complex etiology in their pathophysiology and are influenced by various risk factors such as aging,lifestyle,genetics,and environment,it is important to identify perturbed molecular functions that can be targeted by metformin in these neurological disorders.These molecules can then be used as biomarkers to stratify subpopulations of patients who show distinct molecular/pathological properties and can respond to metformin treatment,ultimately developing targeted therapy.In this review,we will discuss mitochondria-related metabolic perturbations and impaired molecular pathways in these neurological disorders and how these can be used as biomarkers to guide metformin-responsive treatment for the targeted therapy to treat neurological disorders.

Coactivator-independent vitamin D receptor signaling causes severe rickets in mice,that is not prevented by a diet high in calcium,phosphate,and lactose

The vitamin D receptor(VDR)plays a critical role in the regulation of mineral and bone homeostasis.Upon binding of 1α,25-dihydroxyvitamin D_(3) to the VDR,the activation function 2(AF2)domain repositions and recruits coactivators for the assembly of the transcriptional machinery required for gene transcription.

Molecular targets in the treatment of alcoholic hepatitis

Alcohol related costs to health and society are high. One of the most serious complications of alcohol misuse to the individual is the development of alcoholic hepatitis (AH), a clinical syndrome of jaundice and progressive inflammatory liver injury in patients with a history of recent heavy alcohol use. It has a poor outcome and few existing successful therapies. The use of glucocorticoids in patients with severe AH is still controversial and there remains a group of patients with glucocorticoid-resistant disease. However, as our understanding of the pathogenesis of the condition improves there are opportunities to develop new targeted therapies with specific actions to control liver inflammation without having a detrimental effect on the immune system as a whole. In this article we review the molecular mechanisms of AH concentrating on the activation of the innate and adaptive immune response. We consider existing treatments including glucocorticoids, anti-tumor necrosis factor therapy and pentoxifylline and their limitations. Using our knowledge of the disease pathogenesis we discuss possible novel therapeutic approaches. New targets include pro-inflammatory cytokines such as interleukin (IL)-17, chemokines and their receptors (for example IL-8, CXCL9 and CXCR3) and augmentation of anti-inflam- matory molecules such as IL-10 and IL-22. And there is also future potential to consider combination therapy to selectively modulate the immune response and gain control of disease.

Biological features and biomarkers in hepatocellular carcinoma

Similar to other cancers, a multistep process of carcinogenesis is observed in hepatocellular carcinoma(HCC). Although the mechanisms underlying the development of HCC have been investigated in terms of oncology, virology, and stem cell biology, the whole picture of hepatocarcinogenesis remains to be elucidated. Recent progress in molecular biology has provided clues to the underlying cause of various diseases. In particular, sequencing technologies, such as whole genome and exome sequencing analyses, have made an impact on genomic research on a variety of cancers including HCC. Comprehensive genomic analyses have detected numerous abnormal genetic alterations, such as mutations and copy number alterations. Based on these findings, signaling pathways and cancer-related genes involved in hepatocarcinogenesis could be analyzed in detail. Simultaneously, a number of novel biomarkers, both from tissue and blood samples, have been recently reported. These biomarkers have been successfully applied to early diagnosis and prognostic prediction of patients with HCC. In this review, we focus on the recent developments in molecular cancer research on HCC and explain the biological features and novel biomarkers.

Insights of the brain damage response using antibodies identifying surface antigens on neural stem cells and neuroblasts

Similarly to other adult tissues,a hierarchical structure has been established for the brain,where the differentiated cell types（neurons,oligodendrocytes and astrocytes）are generated from primary progenitor cells,known as type B astrocytes or neural stem cells （NSC）, through one or multiple stages of amplification （transient amplifying cells） that generate precursor cells （iPC） with more restricted potential nlPCs （neural）, alPCs （astrocytes）, olPC （oligodendrocytes） （Kriegstein and Alvarez-Buvlla, 2009）.

Genomic Mosaicism of the Brain:Origin,Impact,and Utility

Genomic mosaicism describes the phenomenon where some but not all cells within a tissue harbor unique genetic mutations.Traditionally,research focused on the impact of genomic mosaicism on clinical phenotype—motivated by its involvement in cancers and overgrowth syndromes.More recently,we increasingly shifted towards the plethora of neutral mosaic variants that can act as recorders of cellular lineage and environmental exposures.Here,we summarize the current state of the field of genomic mosaicism research with a special emphasis on our current understanding of this phenomenon in brain development and homeostasis.Although the field of genomic mosaicism has a rich history,technological advances in the last decade have changed our approaches and greatly improved our knowledge.We will provide current definitions and an overview of contemporary detection approaches for genomic mosaicism.Finally,we will discuss the impact and utility of genomic mosaicism.

Acoustic radiation force imaging sonoelastography for noninvasive staging of liver fibrosis

AIM:To investigate the diagnostic accuracy of acoustic radiation force impulse (ARFI) imaging as a noninvasive method for the assessment of liver fibrosis in chronic hepatitis C (CHC) patients.METHODS:We performed a prospective blind com-parison of ARFI elastography,APRI index and FibroMax in a consecutive series of patients who underwent liver biopsy for CHC in University Hospital Bucharest. His-topathological staging of liver fibrosis according to the METAVIR scoring system served as the reference. A to-tal of 74 patients underwent ARFI elastography,APRI index,FibroMax and successful liver biopsy. RESULTS:The noninvasive tests had a good correlation with the liver biopsy results. The most powerful test in predicting fibrosis was ARFI elastography. The diagnostic accuracy of ARFI elastography,expressedas area under receiver operating characteristic curve (AUROC) had a validity of 90.2% (95% CI AUROC = 0.831-0.972,P < 0.001) for the diagnosis of significant f ibrosis (F ≥ 2). ARFI sonoelastography predicted even better F3 or F4 fibrosis (AUROC = 0.993,95% CI = 0.979-1).CONCLUSION:ARFI elastography had very good accuracy for the assessment of liver fibrosis and was superior to other noninvasive methods (APRI Index,FibroMax) for staging liver fibrosis.

miR-20b, miR-98, miR-125b-1*, and let-7e* as new potential diagnostic biomarkers in ulcerative colitis

AIM:To use microarray-based miRNA profiling of colonic mucosal biopsies from patients with ulcerative colitis (UC), Crohn's disease (CD), and controls in order to identify new potential miRNA biomarkers in inflammatory bowel disease. METHODS:Colonic mucosal pinch biopsies from the descending part were obtained endoscopically from patients with active UC or CD, quiescent UC or CD, as well as healthy controls. Total RNA was isolated and miRNA expression assessed using the miRNA microarray Geniom Biochip miRNA Homo sapiens (Febit GmbH, Heidelberg, Germany). Data analysis was carried out by principal component analysis and projection to latent structure-discriminant analysis using the SIMCA-P+12 software package (Umetrics, Umea, Sweden). The microarray data were subsequently validated by quantitative real-time polymerase chain reaction (qPCR) performed on colonic tissue samples from active UC patients (n = 20), patients with quiescent UC (n = 19), and healthy controls (n = 20). The qPCR results were analyzed with Mann-WhitneyU test.In silico prediction analysis were performed to identify potential miRNA target genes and the predicted miRNA targets were then compared with all UC associated susceptibility genes reported in the literature. RESULTS:The colonic mucosal miRNA transcriptome differs significantly between UC and controls, UC and CD, as well as between UC patients with mucosal inflammation and those without. However, no clear differences in the transcriptome of patients with CD and controls were found. The miRNAs with the strongest differential power were identified (miR-20b, miR-99a, miR-203, miR-26b, and miR-98) and found to be upregulated more than a 10-fold in active UC as compared to quiescent UC, CD, and controls. Two miRNAs, miR-125b-1* and let-7e*, were up-regulated more than 5-fold in quiescent UC compared to active UC, CD, and controls. Four of the seven miRNAs (miR-20b, miR-98, miR-125b-1*, and let-7e*) were validated by qPCR and found to be specifically upregulated in patients with UC. Usingin silico analysis we found several predicted pro-inflammatory target genes involved in various pathways, such as mitogen-activated protein kinase and cytokine signaling, which are both key signaling pathways in UC.CONCLUSION:The present study provides the first evidence that miR-20b, miR-98, miR-125b-1*, and let7e* are deregulated in patients with UC. The level of these miRNAs may serve as new potential biomarkers for this chronic disease.

MicroRNAs in inflammatory bowel disease-pathogenesis,diagnostics and therapeutics

The pathogenesis of inflammatory bowel disease (IBD) is complex and largely unknown. Until recently, research has focused on the study of protein regulators in inflammation to reveal the cellular and molecular networks in the pathogenesis of IBD. However, in the last few years, new and promising insights have been generated from studies describing an association between an altered expression of a specific class of non-coding RNAs, called microRNAs (miRs or miRNAs) and IBD. The short (approximately 22 nucleotides), endogenous, single-stranded RNAs are evolutionary conserved inanimals and plants, and regulate specific target mRNAs at the post-transcriptional level. MiRNAs are involved in several biological processes, including development, cell differentiation, proliferation and apoptosis. Furthermore, it is estimated that miRNAs may be responsible for regulating the expression of nearly one-third of the genes in the human genome. Thus, miRNA deregulation often results in an impaired cellular function, and a disturbance of downstream gene regulation and signaling cascades, suggesting their implication in disease etiology. Despite the identification of more than 1900 mature human miRNAs, very little is known about their biological functions and functional targets. Recent studies have identified dysregulated miRNAs in tissue samples of IBD patients and have demonstrated similar differences in circulating miRNAs in the serum of IBD patients. Thus, there is great promise that miRNAs will aid in the early diagnosis of IBD, and in the development of personalized therapies. Here, we provide a short review of the current state-of-the-art of miRNAs in IBD pathogenesis, diagnostics and therapeutics.

Inflammatory pathways of importance for management of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a group of chronic disorders of the gastrointestinal tract comprising Crohn&#x02019;s disease (CD) and ulcerative colitis (UC). Their etiologies are unknown, but they are characterised by an imbalanced production of pro-inflammatory mediators, e.g., tumor necrosis factor (TNF)-&#x003b1;, as well as increased recruitment of leukocytes to the site of inflammation. Advantages in understanding the role of the inflammatory pathways in IBD and an inadequate response to conventional therapy in a large portion of patients, has over the last two decades lead to new therapies which includes the TNF inhibitors (TNFi), designed to target and neutralise the effect of TNF-&#x003b1;. TNFi have shown to be efficient in treating moderate to severe CD and UC. However, convenient alternative therapeutics targeting other immune pathways are needed for patients with IBD refractory to conventional therapy including TNFi. Indeed, several therapeutics are currently under development, and have shown success in clinical trials. These include antibodies targeting and neutralising interleukin-12/23, small pharmacologic Janus kinase inhibitors designed to block intracellular signaling of several pro-inflammatory cytokines, antibodies targeting integrins, and small anti-adhesion molecules that block adhesion between leukocytes and the intestinal vascular endothelium, reducing their infiltration into the inflamed mucosa. In this review we have elucidated the major signaling pathways of clinical importance for IBD therapy and highlighted the new promising therapies available. As stated in this paper several new treatment options are under development for the treatment of CD and UC, however, no drug fits all patients. Hence, optimisations of treatment regimens are warranted for the benefit of the patients either through biomarker establishment or other rationales to maximise the effect of the broad range of mode-of-actions of the present and future drugs in IBD.

Role of PRMTs in cancer: Could minor isoforms be leaving a mark?

Protein arginine methyltransferases(PRMTs) catalyze the methylation of a variety of protein substrates, many of which have been linked to the development, progression and aggressiveness of different types of cancer. Moreover, aberrant expression of PRMTs has been observed in several cancer types. While the link between PRMTs and cancer is a relatively new area of interest, the functional implications documented thus far warrant further investigations into its therapeutic potential. However, the expression of these enzymes and the regulation of their activity in cancer are still significantly understudied. Currently there are nine main members of the PRMT family. Further, the existence of alternatively spliced isoforms for several of these family members provides an additional layer of complexity. Specifically, PRMT1, PRMT2, CARM1 and PRMT7 have been shown to have alternative isoforms and others may be currently unrealized. Our knowledge with respect to the relative expression and the specific functions of these isoforms is largely lacking and needs attention. Here we present a review of the current knowledge of theknown alternative PRMT isoforms and provide a rationale for how they may impact on cancer and represent potentially useful targets for the development of novel therapeutic strategies.

Androgens and estrogens in skeletal sexual dimorphism

Bone is an endocrine tissue expressing androgen and estrogen receptors as well as steroid metabolizing enzymes. The bioactivity of circulating sex steroids is modulated by sex hormone-binding globulin and local conversion in bone tissue, for example, from testosterone （T） to estradiol （E2） by aromatase, or to dihydrotestosterone by 5（x-reductase enzymes. Our understanding of the structural basis for gender differences in bone strength has advanced considerably over recent years due to increasing use of （high resolution） peripheral computed tomography. These microarchitectural insights form the basis to understand sex steroid influences on male peak bone mass and turnover in cortical vs trabecular bone. Recent studies using Cre/LoxP technology have further refined our mechanistic insights from global knockout mice into the direct contributions of sex steroids and their respective nuclear receptors in osteoblasts, osteoclasts, osteocytes, and other cells to male osteoporosis. At the same time, these studies have reinforced the notion that androgen and estrogen deficiency have both direct and pleiotropic effects via interaction with, for example, insulin-like growth factor 1, inflammation, oxidative stress, central nervous system control of bone metabolism, adaptation to mechanical loading, etc., This review will summarize recent advances on these issues in the field of sex steroid actions in male bone homeostasis.

Epigenetic reduction of DNA repair in progression to gastrointestinal cancer

Deficiencies in DNA repair due to inherited germ-line mutations in DNA repair genes cause increased risk of gastrointestinal(GI) cancer. In sporadic GI cancers, mutations in DNA repair genes are relatively rare. However, epigenetic alterations that reduce expression of DNA repair genes are frequent in sporadic GI cancers. These epigenetic reductions are also found in field defects that give rise to cancers. Reduced DNA repair likely allows excessive DNA damages to accumulate in somatic cells. Then either inaccurate translesion synthesis past the un-repaired DNA damages or error-prone DNA repair can cause mutations. Erroneous DNA repair can also cause epigenetic alterations(i.e., epimutations, transmitted through multiple replication cycles). Some of these mutations and epimutations may cause progression to cancer. Thus, deficient or absent DNA repair is likely an important underlying cause of cancer. Whole genome sequencing of GI cancers show that between thousands to hundreds of thousands of mutations occur in these cancers. Epimutations that reduce DNA repair gene expression and occur early in progression to GI cancers are a likely source of this high genomic instability. Cancer cells deficient in DNA repair are more vulnerable than normal cells to inactivation by DNA damaging agents. Thus, some of the most clinically effective chemotherapeutic agents in cancer treatment are DNA damaging agents, and their effectiveness often depends on deficient DNA repair in cancer cells. Recently, at least 18 DNA repair proteins, each active in one of six DNA repair pathways, were found to be subject to epigenetic reduction of expression in GI cancers. Different DNA repair pathways repair different types of DNA damage. Evaluation of which DNA repair pathway(s) are deficient in particular types of GI cancer and/or particular patients may prove useful in guiding choice of therapeutic agents in cancer therapy.

Novel diet-related mouse model of colon cancer parallels human colon cancer

AIM:To investigate the close parallels between our novel diet-related mouse model of colon cancer and human colon cancer.METHODS:Twenty-two wild-type female mice(ages 6-8 wk)were fed the standard control diet(AIN-93G)and an additional 22 female mice(ages 6-8 wk)were fed the control diet supplemented with 0.2%deoxycho-lic acid[diet+deoxycholic acid(DOC)]for 10 mo.Tu-mors occurred in the colons of mice fed diet+DOC and showed progression to colon cancer[adenocarcinoma(AC)].This progression is through the stages of tubular adenoma(TA),TA with high grade dysplasia or ad-enoma with sessile serrated morphology,intramucosal AC,AC stage T1,and AC stage T2.The mouse tumors were compared to human tumors at the same stages by histopathological analysis.Sections of the small and large intestines of mice and humans were evaluated for glandular architecture,cellular and nuclear morphology including cellular orientation,cellular and nuclear atyp-ia,pleomorphism,mitotic activity,frequency of goblet cells,crypt architecture,ulceration,penetration of crypts through the muscularis mucosa and presence of malignant crypts in the muscularis propria.In addition,preserved colonic tissues from genetically similar male mice,obtained from a prior experiment,were analyzed by immunohistochemistry.The male mice had been fed the control diet or diet+DOC.Four molecular markers were evaluated:8-OH-dG,DNA repair protein ERCC1,autophagy protein beclin-1 and the nuclear location of beta-catenin in the stem cell region of crypts.Also,male mice fed diet+DOC plus 0.007%chlorogenic acid(diet+DOC+CGA)were evaluated for ERCC1,beclin-1 and nuclear location of beta-catenin.RESULTS:Humans with high levels of diet-relatedDOC in their colons are at a substantially increased riskof developing colon cancer.The mice fed diet+DOChad levels of DOC in their colons comparable to that ofhumans on a high fat diet.The 22 mice without addedDOC in their diet had no colonic tumors while 20 ofthe 22 mice(91%)fed diet+DOC developed colonictumors.Furthermore,the tumors in 10 of these mice(45%of mice)included an adenocarcinoma.All micewere free of cancers of the small intestine.Histopatho-logically,the colonic tumor types in the mice werevirtually identical to those in humans.In humans,char-acteristic aberrant changes in molecular markers can be detected both in field defects surrounding cancers(from which cancers arise)and within cancers.In thecolonic tissues of mice fed diet+DOC similar changesin biomarkers appeared to occur.Thus,8-OH-dG wasincreased,DNA repair protein ERCC1 was decreased,autophagy protein beclin-1 was increased and,in thestem cell region at the base of crypts there was sub-stantial nuclear localization of beta-catenin as well asincreased cytoplasmic beta-catenin.However,in micefed diet+DOC+CGA(with reduced frequency ofcancer)and evaluated for ERCC1,beclin-1,and beta-catenin in the stem cell region of crypts,mouse tissueshowed amelioration of the aberrancies,suggestingthat chlorogenic acid is protective at the molecular levelagainst colon cancer.This is the first diet-related modelof colon cancer that closely parallels human progressionto colon cancer,both at the histomorphological level aswell as in its molecular profile.CONCLUSION:The diet-related mouse model of coloncancer parallels progression to colon cancer in humans,and should be uniquely useful in model studies of pre-vention and therapeutics.

Metabolomics studies identify novel diagnostic and prognostic indicators in patients with alcoholic hepatitis

AIM: To identify plasma analytes using metabolomics that correlate with the diagnosis and severity of liver disease in patients with alcoholic hepatitis(AH).METHODS: We prospectively recruited patients with cirrhosis from AH(n = 23) and those with cirrhosis with acute decompensation(AD) from etiologies other than alcohol(n = 25). We used mass spectrometry to identify 29 metabolic compounds in plasma samples from fasted subjects. A receiver operating characteristics analysis was performed to assess the utility of biomarkers in distinguishing acute AH from alcoholic cirrhosis. Logistic regression analysis was performed to build a predictive model for AH based on clinical characteristics. A survival analysis was used to construct Kaplan Meier curves evaluating transplant-free survival.RESULTS: A comparison of model for end-stage liver disease(MELD)-adjusted metabolomics levels between cirrhosis patients who had AD or AH showed that patients with AH had significantly higher levels of betaine, and lower creatinine, phenylalanine, homocitrulline, citrulline, tyrosine, octenoyl-carnitine, and symmetric dimethylarginine. When considering combined levels, betaine and citrulline were highly accurate predictors for differentiation between AH and AD(area under receiver operating characteristics curve = 0.84). The plasma levels of carnitine [0.54(0.18, 0.91); P = 0.005], homocitrulline [0.66(0.34, 0.99); P < 0.001] and pentanoyl-carnitine [0.53(0.16, 0.90); P = 0.007] correlated with MELD scores in patients diagnosed with AH. Increased levels of many biomarkers(carnitine P = 0.005, butyrobetaine P = 0.32, homocitrulline P = 0.002, leucine P = 0.027, valine P = 0.024, phenylalanine P = 0.037, tyrosine P = 0.012, acetyl-carnitine P = 0.006, propionyl-carnitine P = 0.03, butyryl-carnitine P = 0.03, trimethyl-lisine P = 0.034, pentanoyl-carnitine P = 0.03, hexanoyl-carnitine P = 0.026) were associated with increased mortality in patients with AH. CONCLUSION: Metabolomics plasma analyte levels might be used to diagnose of AH or help predict patient prognoses.

Biomarker-guided drug therapy: personalized medicine for treating Alzheimer’s disease

Alzheimer’s disease(AD)is a progressive neurodegenerative disorder associated with significant memory decline and cognitive impairment.AD is characterized by two classical neuropathological hal lmarks,namely the amyloid-beta(Aβ)plaques and neurofibril tangles.Currently,there are no disease-modifying treatments available for AD,except for a couple of the US Food and Drug Administration(FDA)-approved drugs to improve cognitive function by blocking N-methyl-D-aspartate receptors or cholinesterase activity(Panza et al.,2019).

DNA interaction networks： an information highway for regulated gene expression in the 3-dimentional space of the nucleus

In this genomic era, the research landscape has been taking a dramatic turn in discovering new biological principles that have been unapproachable from traditional studies on the basis of individual genes and this process is accelerating because of technological breakthroughs, largely fueled by the next generation sequencing. Many years of research have established a dogmatic view on transcription that gene promoters drive transcriptional initiation, which is subject to modulation by distal enhancers .

Metabolic programming determines the lineage-differentiation fate of murine bone marrow stromal progenitor cells

Enhanced bone marrow adipogenesis and impaired osteoblastogenesis have been observed in obesity,suggesting that the metabolic microenvironment regulates bone marrow adipocyte and osteoblast progenitor differentiation fate.To determine the molecular mechanisms,we studied two immortalized murine cell lines of adipocyte or osteoblast progenitors(BMSCs^adipo and BMSC^sosteo,respectively)under basal and adipogenic culture conditions.At baseline,BMSCs^adipo,and BMSCs^osteo exhibit a distinct metabolic program evidenced by the presence of specific global gene expression,cellular bioenergetics,and metabolomic signatures that are dependent on insulin signaling and glycolysis in BMSCs^osteo versus oxidative phosphorylation in BMSCs^adipo.To test the flexibility of the metabolic program,we treated BMSCsadipo with parathyroid hormone,S961(an inhibitor of insulin signaling)and oligomycin(an inhibitor of oxidative phosphorylation).The treatment induced significant changes in cellular bioenergetics that were associated with decreased adipocytic differentiation.Similarly,12 weeks of a high-fat diet in mice led to the expansion of adipocyte progenitors,enhanced adipocyte differentiation and insulin signaling in cultured BMSCs.Our data demonstrate that BMSC progenitors possess a distinct metabolic program and are poised to respond to exogenous metabolic cues that regulate their differentiation fate.

Novel Antiviral Agents Targeting HIV Entry and Transmission

Studies of the mechanism of HIV entry and transmission have identified multiple new targets for drug development. A range of inhibitors have demonstrated potent antiretroviral activity by interfering with CD4-gp120 interaction,coreceptor binding or viral-cell fusion in preclinical and clinical studies. One of these agents,fusion inhibitor enfuvirtide,is already in clinical use. Here we review the progress in the development of specific entry inhibitors as novel therapeutics. The potential of entry inhibitors as topical microbicides to block HIV transmission is also discussed.

Differential diagnosis of gallstones by using hypericin as a fluorescent optical imaging agent

AIM: To explore the feasibility of using hypericin as an optical imaging probe with affinity for cholesterol for differential fluorescent detection of human gallstones.METHODS: Cholesterol, mixed and pigment stones from cholecystectomy patients were incubated with hypericin or solvent. After 72 h, the stones were analysed for fluorescence(365 nm) and treated with 2-propanol/dimethyl sulfoxide for high performance liquid chromatography(HPLC) analysis. Rats with virtual gallbladder containing human cholesterol, mixed or pigment gallstones(VGHG) received 5 mg/kg hypericin or solvent and VGHG rats with cholesterol stones were given different hypericin doses(5-15 mg/kg). Twelve hours later, the stones were analysed at 365 nm. Biliary excretion and metabolites of hypericin were assessed in common bile duct(CBD) cannulated rats for 9 h using fluorospectrometry, HPLC and matrixassisted laser desorption/ionization-time-of-flight mass spectrometry(MALDI-TOF MS).RESULTS: Homogeneous high fluorescence was seen on cholesterol stones either pre-incubated with hypericin or extracted from VGHG rats receiving hypericin. Mixed stones showed a dotted fluorescent pattern, whereas pigment and solvent-treated ones lacked fluorescence. HPLC showed 7.68, 6.65 and 0.08 × 10^(-3) M of cholesterol in extracts from cholesterol, mixed, and pigment gallstones, respectively. Hypericin accounted for 2.0, 0.5 and 0.2 × 10-6 M in that order. On cholesterol stones from VGHG rats receiving different hypericin doses, a positive correlation was observed between dose and fluorescence. In the bile from CBD-cannulated rats, fluorescence represented 20% of the injected dose with two peaks in 9 h. HPLC analysis revealed that hypericin conjugates reached 60% of the peak area. By MALDI-TOF MS, hypericinglucuronide was detected. CONCLUSION: This study proves the potential use of hypericin for differential fluorescent detection of human gallstones regarding their chemical composition.