Validation of biomarkers as early predictors of disease

Biomarkers of genotoxic damage in pulmonary alveolar macrophages: a review

DNA damage is one of the primary mechanisms underlying cancer and other chronic degenerative diseases. Early evaluation of this damage in the affected cells and tissues is crucial for understanding pathogenesis and implementing effective prevention strategies. However, isolating target cells from affected organs, such as the lungs, can be challenging. Therefore, an alternative approach is to evaluate genotoxic damage in surrogate cells. Pulmonary alveolar macrophages are ideally suited for this purpose because they are in close contact with the target cells of the bronchial and alveolar epithelium, share the exact mechanisms and levels of exposure, and are easily recoverable in large numbers. This review comprehensively lists all studies using alveolar macrophages as surrogate cells to show genotoxic lung damage in humans or laboratory animals. These investigations provide fundamental information on the mechanisms of DNA damage in the lung and allow for better assessment and management of risk following exposure to inhalable genotoxic agents. Furthermore, they may be a valuable tool in cancer chemoprevention, helping the right choice of agents for clinical trials.

The Impact of Genetic Polymorphisms for Detecting Genotoxicity in Workers Occupationally Exposed to Metals: A Systematic Review

The present study aims to provide a systematic review of studies on the essential and nonessential metal exposure at occupational level, genotoxicity, and polymorphisms and to answer the following questions: Are genetic polymorphisms involved in metal-induced genotoxicity? In this study, 14 publications were carefully analyzed in this setting. Our results pointed out an association between polymorphism and genotoxicity in individuals exposed to metals, because 13 studies (out of 14) revealed positive relations between genotoxicity and polymorphisms in xenobiotics metabolizing and DNA repair genes. Regarding the quality of these findings, they can be considered reliable, as the vast majority of the studies (12 out of 14) were categorized as strong or moderate in the quality assessment. Taken as a whole, occupational exposure to metals (essentials or not) induces genotoxicity in peripheral blood or oral mucosa cells. Additionally, professional individuals with certain genotypes may present higher or lower DNA damage as well as DNA repair potential, which will certainly impact the level of DNA damage in the occupational environment.

Does waterpipe smoke induce genotoxicity (DNA damage) in mammalian cells in vivo? A systematic review

The waterpipe works by placing tobacco in a bowl with holes at the bottom, which is connected to a tube leading to a water-filled container. Upon heating the tobacco product with hot charcoal placed atop it, the emanating smoke is inhaled by the user via a hose linked to the water receptacle. The aim of this literature review is to evaluate whether the use of waterpipes can indeed induce genotoxicity in mammalian cells in vivo. Additionally, the study aims to assess the quality of the included research articles on this topic to ensure the reliability of the findings. We performed comprehensive searches in PubMed, SCOPUS, and Web of Science to identify relevant articles published until July 2024. The findings confirmed that waterpipe smoke induces genetic damage. This assertion is supported by the fact that 11 studies (out of 15) received a Strong or Moderate assessment categorization, suggesting that the majority of studies adhered to most technical standards, thereby enhancing the reliability of the research findings. Regarding the types of DNA damage reported, DNA strand breaks, chromosome damage and oxidative DNA damage were found in this review. Taken together, this study holds significant importance in assessing the efficacy of genotoxicity assays in detecting DNA damage due to waterpipe smoke and the comet and micronucleus assays are suitable biomarkers for biomonitoring people who use waterpipe.

Soluble CD40 Ligand as a Promising Biomarker in Cancer Diagnosis

Cancer remains a significant challenge in medicine due to its complexity and heterogeneity. Biomarkers have emerged as vital tools for cancer research and clinical practice, facilitating early detection, prognosis assessment, and treatment monitoring. Among these, CD40 ligand (CD40L) has gained attention for its role in immune response modulation. Soluble CD40 ligand (sCD40L) has shown promise as a potential biomarker in cancer diagnosis and progression, reflecting interactions between immune cells and the tumor microenvironment. This review explores the intricate relationship between sCD40L and cancer, highlighting its diagnostic and prognostic potential. It discusses biomarker discovery, emphasizing the need for reliable markers in oncology, and elucidates the roles of CD40L in inflammatory responses and interactions with tumor cells. Additionally, it examines sCD40L as a biomarker, detailing its significance across various cancer types and clinical applications. Moreover, the review focuses on therapeutic interventions targeting CD40L in malignancies, providing insights into cellular and gene therapy approaches and recombinant protein-based strategies. The clinical effectiveness of CD40L-targeted therapy is evaluated, underscoring the need for further research to unlock the full potential of this signaling pathway in cancer management.

The role of genetic polymorphisms for inducing genotoxicity in workers occupationally exposed to benzene: a systematic review

Benzene is used worldwide as a major raw material in a number of industrial processes and also a potent airborne pollutant emitted from traffic exhaust fume. The present systematic review aimed to identify potential associations between genetic polymorphisms and occupational benzene-induced genotoxicity. For this purpose, a total of 22 selected studies were carefully analysed. Our results revealed a positive relation between gene polymorphism and genotoxicity in individuals exposed to benzene, since 17 studies (out of 22) observed positive relations between genotoxicity and polymorphisms in xenobiotics metabolizing genes influencing, therefore, individuals' susceptibility to genomic damage induced by benzene. In other words, individuals with some genotypes may show increase or decrease DNA damage and/or higher or lower DNA-repair potential. As for the quality assessment, 17 studies (out of 22) were categorized as Strong or Moderate and, therefore, we consider our findings to be trustworthy. Taken together, such findings are consistent with the notion that benzene induces genotoxicity in mammalian cells being strongly dependent on the genetic polymorphism. Certainly, such findings are important for clarifying the role of biomarkers related to genotoxicity in human biomonitoring studies.

Evaluation of novel biomarkers for early pregnancy outcome prediction†

OBJECTIVE

To assess performance and discriminatory capacity of commercially available enzyme-linked immunosorbent assays of biomarkers for predicting first trimester pregnancy outcome in a multi-center cohort.

DESIGN

In a case-control study at three academic centers of women with pain and bleeding in early pregnancy, enzyme-linked immunosorbent assays of biomarkers were screened for assay performance. Performance was assessed via functional sensitivity, assay reportable range, recovery/linearity, and intra-assay precision (%Coefficient of Variation). Top candidates were analyzed for discriminatory capacity for viability and location among 210 women with tubal ectopic pregnancy, viable intrauterine pregnancy, or miscarriage. Assay discrimination was assessed by visual plots, area under the curve with 95% confidence intervals, and measures of central tendency with two-sample t-tests.

RESULTS

Of 25 biomarkers evaluated, 22 demonstrated good or acceptable assay performance. Transgelin-2, oviductal glycoprotein, and integrin-linked kinase were rejected due to poor performance. The best biomarkers for discrimination of pregnancy location were pregnancy-specific beta-1-glycoprotein 9, pregnancy-specific beta-1-glycoprotein 1, insulin-like growth factor binding protein 1, kisspeptin (KISS1), pregnancy-specific beta-1-glycoprotein 3, and beta parvin (PARVB). The best biomarkers for discrimination of pregnancy viability were pregnancy-specific beta-1-glycoprotein 9, pregnancy-specific beta-1-glycoprotein 3, EH domain-containing protein 3, KISS1, WAP four-disulfide core domain protein 2 (HE4), quiescin sulfhydryl oxidase 2, and pregnancy-specific beta-1-glycoprotein 1.

CONCLUSION

Performance of commercially available enzyme-linked immunosorbent assays was acceptable for a panel of novel biomarkers to predict early pregnancy outcome. Of these, six and seven candidates demonstrated good discriminatory capacity of pregnancy location and viability, respectively, when validated in a distinct external population. Four markers demonstrated good discrimination for both location and viability.

Improper Proteostasis: Can It Serve as Biomarkers for Neurodegenerative Diseases?

Cells synthesize new proteins after multiple molecular decisions. Damage of existing proteins, accumulation of abnormal proteins, and basic requirement of new proteins trigger protein quality control (PQC)-based alternative strategies to cope against proteostasis imbalance. Accumulation of misfolded proteins is linked with various neurodegenerative disorders. However, how deregulated components of this quality control system and their lack of general mechanism-based long-term changes can serve as biomarkers for neurodegeneration remains largely unexplored. Here, our article summarizes the chief findings, which may facilitate the search of novel and relevant proteostasis mechanism-based biomarkers associated with neuronal disorders. Understanding the abnormalities of PQC coupled molecules as possible biomarkers can help to determine neuronal fate and their contribution to the aetiology of several nervous system disorders.

Human disease biomarker panels through systems biology

As more uses for biomarkers are sought after for an increasing number of disease targets, single-target biomarkers are slowly giving way for biomarker panels. These panels incorporate various sources of biomolecular and clinical data to guarantee a higher robustness and power of separation for a clinical test. Multifactorial diseases such as psychiatric disorders show great potential for clinical use, assisting medical professionals during the analysis of risk and predisposition, disease diagnosis and prognosis, and treatment applicability and efficacy. More specific tests are also being developed to assist in ruling out, distinguishing between, and confirming suspicions of multifactorial diseases, as well as to predict which therapy option may be the best option for a given patient's biochemical profile. As more complex datasets are entering the field, involving multi-omic approaches, systems biology has stepped in to facilitate the discovery and validation steps during biomarker panel generation. Filtering biomolecules and clinical data, pre-validating and cross-validating potential biomarkers, generating final biomarker panels, and testing the robustness and applicability of those panels are all beginning to rely on machine learning and systems biology and research in this area will only benefit from advances in these approaches.

IL-8 as a Potential Therapeutic Target for Periodontitis and Its Inhibition by Caffeic Acid Phenethyl Ester In Vitro

Salivary levels of interleukin-8 (IL-8) are elevated in patients with periodontitis. Caffeic acid phenethyl ester (CAPE) improves the periodontal status in subjects. However, whether CAPE can reduce IL-8 expression is unclear. We collected saliva to determine proinflammatory cytokine levels and used subgingival calculus and surrounding tissues from patients with periodontitis for oral microbiota analysis via 16s ribosomal RNA gene sequencing. THP-1 cells were stimulated with sterile-filtered saliva from patients, and target gene/protein expression was assessed. IL-8 mRNA expression was analyzed in saliva-stimulated THP-1 cells treated with CAPE and the heme oxygenase-1 (HO-1) inhibitor tin-protoporphyrin (SnPP). In 72 symptomatic individuals, IL-8 was correlated with periodontal inflammation (bleeding on probing, r = 0.45; p < 0.001) and disease severity (bleeding on probing, r = 0.45; p < 0.001) but not with the four oral microbiota species tested. Reduced salivary IL-8 secretion was correlated with effective periodontitis treatment (r = 0.37, p = 0.0013). In THP-1 cells, saliva treatment induced high IL-8 expression and IKK2 and nuclear factor-κB (NF-κB) phosphorylation. However, the IKK inhibitor BMS-345541, NF-κB inhibitor BAY 11-7082, and CAPE attenuated saliva-induced IL-8 expression. CAPE induced HO-1 expression and inhibited IKK2, IκBα, and NF-κB phosphorylation. Blocking HO-1 decreased the anti-inflammatory activity of CAPE. The targeted suppression of IL-8 production using CAPE reduces inflammation and periodontitis.

Biomarkers of metabolic disorders and neurobehavioral diseases in a PCB- exposed population: What we learned and the implications for future research

Polychlorinated biphenyls (PCBs) are one of the original twelve classes of toxic chemicals covered by the Stockholm Convention on Persistent Organic Pollutants (POP), an international environmental treaty signed in 2001. PCBs are present in the environment as mixtures of multiple isomers at different degree of chlorination. These compounds are manmade and possess useful industrial properties including extreme longevity under harsh conditions, heat absorbance, and the ability to form an oily liquid at room temperature that is useful for electrical utilities and in other industrial applications. They have been widely used for a wide range of industrial purposes over the decades. Despite a ban in production in 1979 in the US and many other countries, they remain persistent and ubiquitous in environment as contaminants due to their improper disposal. Humans, independent of where they live, are therefore exposed to PCBs, which are routinely found in random surveys of human and animal tissues. The prolonged exposures to PCBs have been associated with the development of different diseases and disorders, and they are classified as endocrine disruptors. Due to its ability to interact with thyroid hormone, metabolism and function, they are thought to be implicated in the global rise of obesity diabetes, and their potential toxicity for neurodevelopment and disorders, an example of gene by environmental interaction (GxE). The current review is primarily intended to summarize the evidence for the association of PCB exposures with increased risks for metabolic dysfunctions and neurobehavioral disorders. In particular, we present evidence of gene expression alterations in PCB-exposed populations to construct the underlying pathways that may lead to those diseases and disorders in course of life. We conclude the review with future perspectives on biomarker-based research to identify susceptible individuals and populations.

The Association Between Some Macro and Trace Elements in Saliva and Periodontal Status

Changes in the macro and trace element composition of saliva might be indicative for pathological changes in periodontal tissues. However, there is a lack of evidence in the literature showing associations between mineral elements and periodontal status. The aim of this study was to determine whether such associations occur. Totally, 190 systemically healthy non-smoker participants (mean age 32.2 ± 6.02; 50 periodontally healthy, 50 gingivitis, 50 chronic periodontitis, and 40 aggressive periodontitis individuals) were included in this cross-sectional study. Salivary levels of some macro and trace elements were measured by using inductively coupled plasma mass spectrometry (ICP-MS). Kruskal-Wallis's test was used for statistical analysis. Statistically significant differences were found in sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), vanadium (V), chromium Cr), manganese (Mn), iron (Fe), rubidium (Rb), strontium (Sr), and selenium (Se) concentrations among the groups. Significant increases in the essential minerals Na, Mg, K, Ca, Fe, and Se occurred in both periodontitis groups when compared to the gingivitis and periodontally healthy groups. Lower Se, Sr, Fe, Mn, and V concentrations were found in the aggressive periodontitis group than in the chronic periodontitis group. The results of this study demonstrated that assessment of mineral element concentrations in saliva might be useful in assessing periodontal health and disease. However, further studies are required to determine whether the change in a specific mineral element is the result of periodontal disease or is involved in its pathogenesis.

Biomarkers of susceptibility and effect in car painters exposed to organic solvents

Introduction

Car painters are routinely exposed to organic solvents classified as carcinogenic and mutagenic substances.

Objective

To characterize the population susceptibility and evaluate the genotoxic effects of exposure to organic solvents.

Methods

A cross-sectional study comparing a group of car painters exposed to organic solvents with a non-exposed group. CYP2E1 polymorphisms and the presence of micronuclei in lymphocytes were determined.

Results

One hundred twenty-two workers participated in the study: 62 who worked in car paint shops and were exposed to solvents, and 60 who were not exposed. There were statistically significant differences between the two groups regarding micronucleated cells and nucleoplasmic bridges frequencies (p= 0.042 and p= 0.046, respectively; exact likelihood ratio). Significant differences were found at the interaction between the CYP2E1 genotype c1c1 and occupational exposure to solvents, with higher frequencies of micronuclei (p= 0.013) and micronucleated cells (p= 0.015). However, when the frequencies of micronuclei, micronucleated cells and nucleoplasmic bridges in the exposure group were compared between the c1c1 and c2c2/c1c2 allele groups of the CYP2E1 polymorphism, statistically significant differences were found.

Conclusions

This study confirms that when workers with CYP2E1 polymorphisms, specifically the c1c1 genotype, are exposed to organic solvents, they are more likely to have somatic cell mutations, a condition associated with increased susceptibility to diseases such as cancer.

Biomarkers of health and welfare: A One Health perspective from the laboratory side

A biomarker is any measurement reflecting an interaction between a biological system and a potential hazard, which may be chemical, physical, or biological. The One World, One Health concept established that human and animal health and the environmental state are highly interconnected, sharing common aspects that can be applied globally in these three components. In this paper, we review how the concept of One Health can be applied to biomarkers of health and welfare, with a special focus on five points that can be applied to any biomarker when it is expected to be used to evaluate the human, animal or environmental health. Three of these points are: (1) the different biomarkers that can be used, (2) the different sample types where the biomarkers can be analysed, and (3) the main methods that can be used for their measurement. In addition, we will evaluate two key points needed for adequate use of a biomarker in any situation: (4) a proper analytical validation in the sample that it is going to be used, and (5) a correct selection of the biomarker. It is expected that this knowledge will help to have a broader idea about the use of biomarkers of health and welfare and also will contribute to a better and more accurate use of these biomarkers having in mind their One Health perspective.

Vagal Tone as a Putative Mechanism for Pragmatic Competence: An Investigation of Carriers of the FMR1 Premutation

Pragmatic language skills exist across a continuum in typical and clinical populations, and are impaired in many neurodevelopmental disorders, most notably autism. The mechanisms underlying pragmatic impairment are poorly understood, although theory suggests dampened vagal tone plays a role. This study investigated the FMR1 premutation as a genetic model that may lend insight into the relationship between vagal function and pragmatic ability. Participants included 38 women with the FMR1 premutation and 23 controls. Vagal tone accounted for significant variance in pragmatics across both groups and statistically mediated the effect of FMR1 premutation status on pragmatic ability. Results support vagal tone as a biophysiological correlate of pragmatic ability, which informs potential mechanistic underpinnings and could have implications for targeted treatment.

Kisspeptin as a new serum biomarker to discriminate miscarriage from viable intrauterine pregnancy

OBJECTIVE

To validate the ability of serum kisspeptin-54 to discriminate between first-trimester viable pregnancies and miscarriages.

DESIGN

Case-control study.

SETTING

Academic medical centers.

PATIENT(S)

Women with confirmed viable intrauterine pregnancy (IUP) at estimated gestational age 6-10 weeks (n = 20), women with confirmed miscarriage (spontaneous abortion [SAB]) at estimated gestational age 6-10 weeks (n = 20), and nonpregnant women (n = 19).

INTERVENTION(S)

Collection of serum samples from women with confirmed IUP, SAB, and nonpregnant women for the measurement of serum kisspeptin and serum hCG levels.

MAIN OUTCOME MEASURE(S)

Serum kisspeptin and hCG.

RESULT(S)

The limit of detection was 0.024 ng/mL; intra- and interassay coefficients of variation were 5.1% and 8.6%, respectively. Kisspeptin levels differed between the pregnant and nonpregnant state and by viability. Kisspeptin levels were positively associated with gestational age. There was also a significant positive association with hCG in SAB, but not in IUP.

CONCLUSION(S)

Plasma levels of kisspeptin have been suggested as a biomarker for miscarriage. This study demonstrates kisspeptin assay stability in serum and its potential clinical utility as a biomarker for early pregnancy viability.

Evaluation, validation and refinement of noninvasive diagnostic biomarkers for endometriosis (ENDOmarker): A protocol to phenotype bio-specimens for discovery and validation

OBJECTIVE

Endometriosis is a chronic, estrogen dependent condition that affects 5-10% of reproductive aged women and is associated with pelvic pain and infertility. As the approach to therapy shifts from surgical ablation to pharmacological control, a non-surgical mode of diagnosis would be desirable. The ENDOmarker study was designed by the NICHD Reproductive Medicine Network (RMN) to obtain well characterized and phenotyped bio specimens in a standardized fashion from women with and without endometriosis.

DESIGN

Development of a diagnostic test.

SETTING

Academic medical centers.

PATIENTS

This study will enroll up to 500 participants, and follow them for up to 5 months. Included subjects are aged 18-44, scheduled to undergo gynecologic surgery (laparoscopy/laparotomy) for clinical reasons.

INTERVENTIONS

Presence and stage of endometriosis (or its absence) is characterized by visual examination at the time of surgery. Subjects will undergo extensive clinical evaluation pre-operatively and at visits one and four months postoperatively. Endometrial biopsy, blood, urine and disease specific questionnaires will be collected at each visit.

MAIN OUTCOME

Samples will be placed in a bio-repository to be used to validate and optimize the clinical use of genomic classifiers of the endometrium alone or in combination with serum cytokines as a non-surgical composite marker of endometriosis.

CONCLUSION

This protocol can serve as a reference for objective collection of high quality bio specimens for discovery or validation of potential nonsurgical diagnosis of presence or severity of disease.

RNA Profiling of Cell-free Saliva Using Microarray Technology

Saliva, like other bodily fluids, has been used to monitor human health and disease. This study tests the hypothesis that informative human mRNA exists in cell-free saliva. If present, salivary mRNA may provide potential biomarkers to identify populations and patients at high risk for oral and systemic diseases. Unstimulated saliva was collected from ten normal subjects. RNA was isolated from the cell-free saliva supernatant and linearly amplified. High-density oligonucleotide microarrays were used to profile salivary mRNA. The results demonstrated that there are thousands of human mRNAs in cell-free saliva. Quantitative PCR (Q-PCR) analysis confirmed the present of mRNA identified by our microarray study. A reference database was generated based on the mRNA profiles in normal saliva. Our finding proposes a novel clinical approach to salivary diagnostics, Salivary Transcriptome Diagnostics (STD), for potential applications in disease diagnostics as well as normal health surveillance.

MicroRNAs as biomarkers for dental diseases

MicroRNAs (miRNAs) are short, noncoding RNAs that act as key regulators of diverse biological processes by mediating translational repression or mRNA degradation of target genes. Recent studies discovered miRNAs in saliva, and these miRNAs are promising candidates for use as biomarkers of dental diseases. In this review, the results of miRNA studies in the dental field are presented, and a brief overview of the current progress, limitations, and perspectives regarding miRNA biomarkers for dental diseases is given.

DNA damage in non-communicable diseases: A clinical and epidemiological perspective

Non-communicable diseases (NCDs) are a leading cause of death and disability, representing 63% of the total death number worldwide. A characteristic phenotype of these diseases is the accelerated aging, which is the result of phenomena such as accumulated DNA damage, telomere capping loss and subcellular irreversible/nonrepaired oxidative damage. DNA damage, mostly oxidative, plays a key role in the development of most common NCDs. The present review will gather some of the most relevant knowledge concerning the presence of DNA damage in NCDs focusing on cardiovascular diseases, diabetes, chronic obstructive pulmonary disease, and neurodegenerative disorders, and discussing a selection of papers from the most informative literature. The challenge of comorbidity and the potential offered by new systems approaches for introducing these biomarkers into the clinical decision process will be discussed. Systems Medicine platforms represent the most suitable approach to personalized medicine, enabling to identify new patterns in the pathogenesis, diagnosis and prognosis of chronic diseases.

Salivary biomarkers: toward future clinical and diagnostic utilities

The pursuit of timely, cost-effective, accurate, and noninvasive diagnostic methodologies is an endeavor of urgency among clinicians and scientists alike. Detecting pathologies at their earliest stages can significantly affect patient discomfort, prognosis, therapeutic intervention, survival rates, and recurrence. Diagnosis and monitoring often require painful invasive procedures such as biopsies and repeated blood draws, adding undue stress to an already unpleasant experience. The discovery of saliva-based microbial, immunologic, and molecular biomarkers offers unique opportunities to bypass these measures by utilizing oral fluids to evaluate the condition of both healthy and diseased individuals. Here we discuss saliva and its significance as a source of indicators for local, systemic, and infectious disorders. We highlight contemporary innovations and explore recent discoveries that deem saliva a mediator of the body's physiological condition. Additionally, we examine the current state of salivary diagnostics and its associated technologies, future aspirations, and potential as the preferred route of disease detection, monitoring, and prognosis.

Ochratoxin A: developmental and reproductive toxicity-an overview

Ochratoxin A (OTA) is nephrotoxic, hepatotoxic, reprotoxic, embryotoxic, teratogenic, neurotoxic, immunotoxic, and carcinogenic for laboratory and farm animals. Male and female reproductive health has deteriorated in many countries during the last few decades. A number of toxins in environment are suspected to affect reproductive system in male and female. OTA is one of them. OTA has been found to be teratogenic in several animal models including rat, mouse, hamster, quail, and chick, with reduced birth weight and craniofacial abnormalities being the most common signs. The presence of OTA also results in congenital defects in the fetus. Neither the potential of OTA to cause malformations in human nor its teratogenic mode of action is known. Exposure to OTA leads to increased embryo lethality manifested as resorptions or dead fetuses. The mechanism of OTA transfer across human placenta (e.g., which transporters are involved in the transfer mechanism) is not fully understood. Some of the toxic effects of OTA are potentiated by other mycotoxins or other contaminants. Therefore, OTA exposure of pregnant women should be minimized. OTA has been shown to be an endocrine disruptor and a reproductive toxicant, with abilities of altering sperm quality. Other studies have shown that OTA is a testicular toxin in animals. Thus, OTA is a biologically plausible cause of testicular cancer in man.

Evaluation of salivary biomarker profiles following non-surgical management of chronic periodontitis

OBJECTIVES

Soluble toll-like receptor-2 (sTLR-2) and cytokines in saliva were assessed as clinical markers for chronic periodontitis in a longitudinal study.

MATERIALS AND METHODS

Unstimulated whole saliva was collected from 20 periodontally healthy individuals and 20 patients with chronic periodontitis at diagnosis and at 1 and 6 weeks following scaling and root planing (SRP). Biomarkers including the cytokines (IL-4, IL-6, IL-10, and IL-17), sTLR-2, and sCD14 in saliva were measured by enzyme-linked immunosorbent assay. Mann-Whitney U-test and Student's t-test were used to determine the significance between healthy and chronic periodontitis groups and that between pre- and post-SRP samples, respectively.

RESULTS

Salivary sTLR-2, IL-17, and IL-10 levels were significantly lower and those of sCD14, IL-6, and IL-4 were significantly higher in patients with chronic periodontitis as compared with healthy controls. Furthermore, sTLR-2 and IL-4 in saliva reached levels comparable to those of healthy individuals at 6-week re-evaluation visit, implicating a correlation of the two markers with the disease process.

CONCLUSIONS

Our data suggest that salivary sTLR-2 is a potential prognostic or maintenance marker for chronic periodontitis. The observed variability of salivary cytokines is consistent with the role of these cytokines in the progression of chronic periodontitis.

Biomarkers in reproductive medicine: the promise, and can it be fulfilled?

A biomarker can be used for early diagnosis of a disease, identification of individuals for disease prevention, as a potential drug target, or as a potential marker for a drug response. A biomarker may also limit the use of drug (and therefore costs) to the population of patients for which the drug will be safe and efficacious. A biomarker in reproduction could be used to improve assessment of exposure, identify subgroups susceptible to treatment, predict outcome, and/or differentiate subgroups with potentially different etiologies of disease. Despite many potential uses there is low participation in reproductive biology to develop molecular biomarkers, which may be directly related to the low number of new molecular entities entering clinical trials. As the number of candidate markers in reproductive medicine is increasing, it is important to understand the pathway of development from discovery to clinical utility and recognize that the vast majority of potential markers will not be clinically useful, owing to a variety of pitfalls. Extensive testing, validation, and modification needs to be performed before a biomarker is demonstrated to have clinical utility. New opportunities and partnerships exist and should hasten the development of biomarkers in reproduction. As more biomarkers are moved into practice, a better-educated biomarker consumer will enhance the possibility that biomarker(s) will realize their great potential.

Evaluation of insulin-like growth factor acid-labile subunit as a potential biomarker of effect for deoxynivalenol-induced proinflammatory cytokine expression

Consumption of the trichothecene deoxynivalenol (DON) suppresses growth in experimental animals - an adverse effect that was used to establish the tolerable daily intake for this toxin. DON ingestion has been recently found to suppress plasma insulin-like growth factor acid-labile subunit (IGFALS), a protein essential for growth. Studies were conducted to explore the feasibility of using plasma IGFALS as a biomarker of effect for DON. In the first study, weanling mice were fed 0, 1, 2.5, 5 and 10 ppm DON and weight and plasma IGFALS determined at intervals over 9 wk. Reduced body weight gains were detectable beginning at wk 5 in the 10 ppm dose and wk 7 at the 5 ppm dose. Plasma IGFALS was significantly depressed at wk 5 in the 5 and 10 ppm groups at wk 9 in the 10 ppm group. Depressed IGFALS significantly correlated with reduced body weight at wk 5 and 9. Benchmark dose modeling revealed the BMDL and BMD for plasma IGFALS reduction were 1.1 and 3.0 ppm DON and for weight reduction were 2.1 and 4.5 ppm DON. In the second study, it was demonstrated that mice fed 15 ppm DON diet had significantly less plasma IGFALS than mice fed identical amounts of control diet. Thus DON's influence on IGFALS likely reflects the combined effects of reduced food intake as well as its physiological action involving suppressors of cytokine signaling. Taken together, these findings suggest that plasma IGFALS might be a useful biomarker for DON's adverse effects on growth.

Biomarkers for ectopic pregnancy and pregnancy of unknown location

Early pregnancy failure is the most common complication of pregnancy, and 1% to 2% of all pregnancies will be ectopic. As one of the leading causes of maternal morbidity and mortality, diagnosing ectopic pregnancy and determining the fate of a pregnancy of unknown location are of great clinical concern. Several serum and plasma biomarkers for ectopic pregnancy have been investigated independently and in combination. The following is a review of the state of biomarker discovery and development for ectopic pregnancy and pregnancy of unknown location.

Serum biomarkers for detecting ectopic pregnancy

Unless an ectopic pregnancy is visible by ultrasound, diagnosis can be a challenge. Differentiating ectopic pregnancies from intrauterine pregnancies can be impossible without intervention or follow-up. This poses a clinical dilemma to the practitioner given the inherent danger to the mother of tubal rupture of an ectopic pregnancy versus the fear of intervening in the case of a desired pregnancy without certainty of diagnosis. Early diagnostic modalities are clearly lacking, and serum biomarkers are currently being investigated as a solution to need for a rapid and accurate test for ectopic pregnancy.

The application of statistical methods using VOCs to identify patients with lung cancer

In this work, an attempt was made to determine a group of lung cancer biomarkers. For this study, breath samples collected from 137 patients with confirmed lung cancer were analyzed by the SPME-GC/MS method. As a reference group, exhaled air from 143 healthy volunteers with different smoking habits (active smokers, passive smokers and nonsmokers) was applied. Statistical methods such as discriminant analysis (DA) and the CHAID model tree were used for data processing and evaluation. In the breath of patients with lung cancer, increased concentration of ethanol, acetone, butane, dimethyl sulfide, isoprene, propanal, 1-propanol, 2-pentanone, furan, o-xylene and ethylbenzene was observed in comparison to healthy nonsmokers. Furthermore, pentanal, hexanal and nonane were identified only in the breath of people who suffered from cancer. DA confirmed the importance of these compounds and allowed us to identify patients with lung cancer from healthy volunteers. In the exhaled air of healthy smokers (passive and active), a higher concentration of acetonitrile, benzene and furan derivatives was observed than in nonsmokers. DA revealed that in order to recognize healthy volunteers with different smoking habits by breath analysis, butyrolactone, carbon disulfide and dimethyl sulfide have to be considered.

Cytogenetic biomonitoring on a group of petroleum refinery workers

Workers employed in petroleum refineries are exposed to a wide range of toxic compounds (benzene, polycyclic aromatic hydrocarbons, heavy metals, etc.) with known mutagenic and carcinogenic potential. In this study, we investigated by using the cytokinesis block micronucleus (CBMN) assay on human peripheral blood lymphocytes (PBL) whether general occupational exposure in petroleum refineries resulted in early biological effects, which would be indicative of adverse health effects in the long term. In this study, out of more 500 workers enrolled in the study, 79 male subjects (46 nonsmokers and 33 smokers), employed in two different Italian petroleum refineries, and a total of 50 male control subjects (34 nonsmokers and 16 smokers) were selected by using very strict selection criteria. The comparison of chromosome damage in PBL between exposed and control populations pointed out a significant increase of micronuclei in the exposed group, correlated with the length of employment. Results confirm that smoking is the principal confounding factor for the responses. In conclusion, our results are indicative of a potential genotoxic risk related to the complex occupational exposure in petroleum refineries, despite the measures adopted in the plants, and corroborate the need to increase safety measures to avoid exposure to chemical agents.

Advances in proteomic techniques for biomarker discovery in COPD

Chronic obstructive pulmonary disease (COPD) is a disorder characterized by chronic inflammation of the lung with airflow obstruction and progressive deterioration of pulmonary function. The need to discover and validate biomarkers as prognostic tools of development and progression of the disease has received further support with the advent of proteomic techniques. Liquid chromatography-mass spectrometry (LC/MS) and gel electrophoresis-mass spectrometry (2-DE/MS) have been applied to investigate the proteome of a number of lung-origin samples, including sputum, bronchoalveolar lavage fluid, exhaled-breath condensate, cells and biopsies from COPD patients. In particular, 2-DE and MS are the main proteomic approaches with 2-DE presenting the major approach for quantitative proteomics. The molecules identified as potential biomarkers of COPD may represent a preliminary step for better comprehension of the mechanisms involved in the onset/progression of the disease.

A disintegrin and metalloprotease protein-12 as a novel marker for the diagnosis of ectopic pregnancy

OBJECTIVE

To evaluate the performance of a novel biomarker, a disintegrin and metalloprotease-12 (ADAM-12), to differentiate an ectopic pregnancy (EP) from normal intrauterine pregnancies (IUPs).

DESIGN

Case-control study.

SETTING

Three urban academic centers.

PATIENT(S)

Women who were seen in the emergency department with pain or bleeding in the first trimester of pregnancy.

INTERVENTION(S)

Sera from women with diagnosed EP or IUP were evaluated via proteomics and an ADAM-12 dissociation-enhanced lanthanide fluoroimmunoassay.

MAIN OUTCOME MEASURE(S)

Differences between groups, area under the receiver operating curve, sensitivity, and specificity.

RESULT(S)

Via a proteomics evaluation, we found a statistically significant decrease in ADAM-12 in the sera of patients with EP, which we confirmed in a larger group of 199 patients (median IUP 18.6 ng/mL versus median EP 2.5 ng/mL with good discrimination between the groups as assessed by receiver operating characteristics [area under the curve = 0.82]). At a low cut-point, the sensitivity was 70% and specificity 84%, but, at a higher cut-point optimizing sensitivity, the ADAM-12 test demonstrated a sensitivity of 97%.

CONCLUSION(S)

ADAM-12 is a promising marker for the diagnosis of EP in women with symptoms in the first trimester, validating the proteomics findings. Further studies in additional patient populations and in combination with other biomarkers are needed.

Smoking affects diagnostic salivary periodontal disease biomarker levels in adolescents

BACKGROUND

The effects of smoking on periodontal biomarkers in adolescents are unknown. This study investigates matrix metalloproteinase (MMP)-8 and polymorphonuclear leukocyte elastase levels in saliva together with periodontal health indices accounting for body mass index and smoking in a birth cohort from Finland.

METHODS

The oral health of boys (n = 258) and girls (n = 243) aged 15 to 16 years was examined clinically. Health habits were assessed by questionnaire. Saliva samples were collected and analyzed by immunofluorometric and peptide assays for MMP-8 levels and polymorphonuclear leukocyte elastase activities, and investigated statistically with the background factors.

RESULTS

Median MMP-8 values of male smokers were 112.03 microg/l compared to 176.89 microg/l of non-smokers (P = 0.05). For female smokers corresponding values were 170.88 microg/l versus 177.92 microg/l in non-smokers (not statistically significant). Elastase values in male smokers were 5.88 x 10(-3) Delta OD(405)/h versus 11.0 x 10(-3) Delta OD(405)/h in non-smokers (P = 0.02), and in female smokers 9.16 x 10(-3) Delta OD(405)/h versus 10.88 x 10(-3) Delta OD(405)/h in non-smokers (P = 0.72). The effect was strengthened by high pack-years of smoking (MMP-8, P = 0.04; elastase, P = 0.01). Both biomarkers increased with gingival bleeding. However, statistically significant associations were observed with bleeding on probing and MMP-8 (P = 0.04); MMP-8 was suggestively associated with probing depth (P = 0.09) in non-smoking boys. In smokers with calculus, MMP-8 increased after adjusting with body mass index (P = 0.03). No corresponding differences were seen in girls.

CONCLUSIONS

Smoking significantly decreased both biomarkers studied. Compared to girls, boys seem to have enhanced susceptibility for periodontitis as reflected in salivary MMP-8 values.

Response to Comments of Peter G. Mantle

The apparently high yield of testis tumors (25%) in rats exposed long-term to Ochratoxin A (OTA) is uninterpretable without data on tumor yield in unexposed rats. Conversely, our demonstration that prenatal exposure to OTA induces DNA adducts in the testes of newborn mice and the absence of these adducts in the testes of mice not exposed prenatally to OTA, is evidence for the presumptive carcinogenicity of OTA in the testis. Together with recent data showing that prenatal exposure to OTA depresses expression of DMRT1, a tumor suppressor gene in the testis, our findings suggest that OTA may be a cause of testicular cancer.

Whole blood genomic biomarkers of acute cardiac allograft rejection

BACKGROUND

Significant progress has been made in cardiac transplantation over the past 30 years; however, the means for detection of acute cardiac allograft rejection remains in need of improvement. At present, the endomyocardial biopsy, an invasive and inconvenient procedure for patients, is required for the surveillance and diagnosis of acute cardiac allograft rejection. In the Biomarkers in Transplantation initiative, we investigated gene expression profiles in peripheral blood of cardiac transplant subjects as potential biomarkers for diagnosis of allograft rejection.

METHODS

Whole blood samples were obtained from 28 cardiac transplant subjects who consented to the study. Serial samples were collected from pre-transplant through 3 years post-transplant according to the standard protocol. Temporally correspondent biopsies were also collected, reviewed in a blinded manner, and graded according to current ISHLT guidelines. Blood samples were analyzed using Affymetrix microarrays. Genomic profiles were compared in subjects with acute rejection (AR; ISHLT Grade > or =2R) and no rejection (NR; Grade 0R). Biomarker panel genes were identified using linear discriminant analysis.

RESULTS

We found 1,295 differentially expressed probe-sets between AR and NR samples and developed a 12-gene biomarker panel that classifies our internal validation samples with 83% sensitivity and 100% specificity.

CONCLUSIONS

Based on our current results, we believe whole blood genomic biomarkers hold great potential in the diagnosis of acute cardiac allograft rejection. A prospective, Canada-wide trial will be conducted shortly to further evaluate the classifier panel in diverse patients and a range of clinical programs.

Searching for 'omic' biomarkers

Cardiovascular diseases impose enormous social and economic burdens on both individual citizens and on society as a whole. Clinical indicators such as high blood pressure, blood cholesterol and obesity have had some utility in identifying those who are at increased risk of cardiovascular events. However, there remains an urgent need for sensitive and specific indicators, preferably acquired through minimally invasive means, to help stratify patients for more personalized health care. As such, there has been a steadily growing interest in searching for 'omic' biomarkers of cardiovascular diseases. Historically, the transition of cardiac biomarker discovery to implementation has been a lengthy and somewhat unregulated process. Recent technological advancements, as well as concurrent efforts by regulatory agencies such as the Food and Drug Administration (United States) and Health Canada to establish policies and guidelines in the 'omic' arena, have helped propel the discovery and validation of biomarkers forward. The present paper provides perspective on current strategies in the biomarker development pathway, as well as the potential limitations associated with each step from discovery to clinical uptake. Canadian biomarker studies now underway illustrate the possibilities for assessment of risk, diagnosis, prognosis and response to therapy, and for the drug discovery process.

PAH biomarkers for human health risk assessment: a review of the state-of-the-art

Polycyclic aromatic hydrocarbons (PAH) are widely distributed in the environment, and some are carcinogenic to human beings. The study of biomarkers has helped clarify the nature and magnitude of the human health risks posed by such substances. This article provides a review of the state-of-the-art on PAH biomarkers for human health risk assessment and also discusses their applicability within the context of environmental management in Brazil. The article discusses the methodologies for determination of some biomarkers such as 1-hydroxypyrene and PAH-DNA adducts. Cytogenetic markers, frequency of chromosomal aberrations, and micronucleus induction were considered for the evaluation of cancer risk. The current stage of studies on validation of such biomarkers was also approached.

Metabolic profiling of the response to an oral glucose tolerance test detects subtle metabolic changes

Background

The prevalence of overweight is increasing globally and has become a serious health problem. Low-grade chronic inflammation in overweight subjects is thought to play an important role in disease development. Novel tools to understand these processes are needed. Metabolic profiling is one such tool that can provide novel insights into the impact of treatments on metabolism.

Methodology

To study the metabolic changes induced by a mild anti-inflammatory drug intervention, plasma metabolic profiling was applied in overweight human volunteers with elevated levels of the inflammatory plasma marker C-reactive protein. Liquid and gas chromatography mass spectrometric methods were used to detect high and low abundant plasma metabolites both in fasted conditions and during an oral glucose tolerance test. This is based on the concept that the resilience of the system can be assessed after perturbing a homeostatic situation.

Conclusions

Metabolic changes were subtle and were only detected using metabolic profiling in combination with an oral glucose tolerance test. The repeated measurements during the oral glucose tolerance test increased statistical power, but the metabolic perturbation also revealed metabolites that respond differentially to the oral glucose tolerance test. Specifically, multiple metabolic intermediates of the glutathione synthesis pathway showed time-dependent suppression in response to the glucose challenge test. The fact that this is an insulin sensitive pathway suggests that inflammatory modulation may alter insulin signaling in overweight men.

Fluoride concentration in dentin of exfoliated primary teeth as a biomarker for cumulative fluoride exposure

A biomarker for lifetime fluoride exposure would facilitate population-based research and policy making but currently does not exist. This study examined the suitability of primary tooth dentin as a biomarker by comparing dentin fluoride concentration and fluoride exposures. Ninety-nine children's exfoliated primary teeth were collected from 2 fluoridated and 2 fluoride-deficient communities in North Carolina. Coronal dentin was isolated by microdissection and fluoride concentration assayed using the microdiffusion, ion-specific electrode technique. Information on children's fluoride exposures since birth from drinking water, toothpaste, supplements, rinses, food and beverages was collected by a self-reported questionnaire administered to caregivers. Only a small portion of the variance (10%) in incisor dentin fluoride (mean 792, SD 402 mg/kg) was accounted for by the best linear regression model as evaluated by the adjusted R(2). A moderate portion of the variance (60%) of molar dentin fluoride (mean 768, SD 489 mg/kg) was predicted by dietary fluoride supplement exposures, community of residence, and frequent tea consumption. Results for molars suggest that primary tooth dentin concentration may prove to be a satisfactory biomarker for fluoride exposure.

Metabolic profiling of an Echinostoma caproni infection in the mouse for biomarker discovery

BACKGROUND

Metabolic profiling holds promise with regard to deepening our understanding of infection biology and disease states. The objectives of our study were to assess the global metabolic responses to an Echinostoma caproni infection in the mouse, and to compare the biomarkers extracted from different biofluids (plasma, stool, and urine) in terms of characterizing acute and chronic stages of this intestinal fluke infection.

METHODOLOGY/PRINCIPAL FINDINGS

Twelve female NMRI mice were infected with 30 E. caproni metacercariae each. Plasma, stool, and urine samples were collected at 7 time points up to day 33 post-infection. Samples were also obtained from non-infected control mice at the same time points and measured using (1)H nuclear magnetic resonance (NMR) spectroscopy. Spectral data were subjected to multivariate statistical analyses. In plasma and urine, an altered metabolic profile was already evident 1 day post-infection, characterized by reduced levels of plasma choline, acetate, formate, and lactate, coupled with increased levels of plasma glucose, and relatively lower concentrations of urinary creatine. The main changes in the urine metabolic profile started at day 8 post-infection, characterized by increased relative concentrations of trimethylamine and phenylacetylglycine and lower levels of 2-ketoisocaproate and showed differentiation over the course of the infection.

CONCLUSION/SIGNIFICANCE

The current investigation is part of a broader NMR-based metabonomics profiling strategy and confirms the utility of this approach for biomarker discovery. In the case of E. caproni, a diagnosis based on all three biofluids would deliver the most comprehensive fingerprint of an infection. For practical purposes, however, future diagnosis might aim at a single biofluid, in which case urine would be chosen for further investigation, based on quantity of biomarkers, ease of sampling, and the degree of differentiation from the non-infected control group.

Fifty years of cytogenetics: a parallel view of the evolution of cytogenetics and genotoxicology

A parallelism exists between human cytogenetics and cytogenetic toxicology. The breakthroughs, mostly coming from and used in clinical genetics, are widely used in genetic toxicology. The birth of human cytogenetics occurred in 1956 when it was published that the diploid number of chromosomes in humans is 46. The first stage in chromosome-induced mutagenesis began in 1938 when Sax published the effects of X-rays on the chromosomes of Drosophila. In 1959, the cytogenetic anomalies for Down, Klinefelter, and Turner syndromes were described, and parallelly in 1960, the first publication on chromosomal aberrations in man caused by ionizing radiation appeared. The cytogenetic analysis of chromosomal aberrations in cell cultures is considered one of the primary methods to evaluate induced mutagenesis. At the end of the 1960s, banding techniques allowed chromosomes to be individually identified, in parallel, the sister chromatid exchange analysis technology was described. Another milestone in the history of induced mutagenesis was the discovery that mutagenic agents were able to alter chromosomal division and segregation in gonads inducing meiotic nondisjunction. Here we review new approaches and applications such as biological dosimetry, translocation scoring using FISH, and micronucleus test. Chromosomal aberrations and micronucleus test are now effective cytogenetic biomarkers of early effect used as cancer predictors. Human cytogenetics has proven to be effective over its 50-year lifespan and, although each new technique that has appeared seemed to announce its end, the fact is that the current state of cytogenetics is in reality a collection of techniques that, while common, are cheap, fast, and wide-ranging. Therefore, in genotoxicology, they continue to be useful to identify mutagenic agents as well as to evaluate and analyze exposed populations.

Biomarkers and environmental risk assessment: guiding principles from the human health field

Although the potential use of biomarkers within environmental risk assessment (ERA) has long been recognised their routine use is less advanced compared with clinical human health risk assessment, where a number of familiar biomarkers (such as blood pressure and serum cholesterol) are in common usage. We have examined how biomarkers are incorporated into human health risk assessment and have identified several 'required elements'. These include identification of the (clinical) assessment endpoint at the outset, rational selection of the biomarker(s) (the measurement endpoint), biomarker 'validation' (e.g. QA/QC) and biomarker 'qualification' (evidence linking the measurement and assessment endpoints). We discuss these elements in detail and propose that their adoption will facilitate the routine use of biomarkers in environmental risk assessment. Furthermore, our analysis highlights the need for cooperation between those working with biomarkers within human and environmental risk assessment to exchange best practice between common disciplines for mutual advantage.

Basal level micronucleus frequency in stimulated lymphocytes of untreated patients with leukemia

Structural chromosomal aberrations have been described in various types of human leukemia. The micronucleus technique provides a measure of both chromosome breakage and chromosome loss. The present study investigated micronucleus (MN) frequency in mitogen-stimulated peripheral blood lymphocytes from 20 newly diagnosed and untreated leukemia patients: 4 with acute lymphoblastic leukemia (ALL), 10 with acute myeloid leukemia (AML), and 6 with chronic lymphocytic leukemia (CLL). The mean MN frequency for untreated patients was 3.65 +/- 1.47 in ALL, 3.55 +/- 1.24 in AML, 3.03 +/- 1.05 in CLL. No differences in MN frequency were seen between leukemia types ALL, AML, and CLL (P = 0.503). The mean basal MN frequency for all patients, regardless of leukemia type, was 3.41 +/- 1.19, which was significantly higher (P = 0.001) than that of 20 age-matched control subjects, 1.87 +/- 0.75. Although no significant relationship was found between age and MN frequency in patients with leukemia (r = 0.050; P = 0.835), the MN frequency in the lymphocytes of healthy control increased regularly and significantly with age (r = 0.531; P = 0.016). These data indicate that the increased baseline MN frequency in lymphocytes of untreated patients with leukemia may reflect genomic instability or deficiency of DNA repair capacity. MN enhancement in this disease may thus be a consequence of the disease process.