From Bench to Bedside, The Biomedical Techniques Tackling Global Health Threats

global health

Introduction

Medical professionals are under an increasing amount of pressure to provide early diagnoses and more efficacious treatments with fewer side effects. There is also a demand for more information about disease risk and prophylactic options.

Technology is powering developments in biomedicine, with advances in computing power and imaging techniques providing just some of the solutions to today’s biggest health issues. Effective biomedical technologies can provide new insights into the human body, provide a better understanding of disease processes, and deliver improved outcomes across the spectrum of human medical needs.

As technology advances and we begin to understand more about the human body, scientists and organizations will need to work together to deliver data-driven solutions to a global population.
Addressing Global Health Threats

The world is facing an unprecedented number of health challenges, from communicable diseases such as antimicrobial resistance, influenza, dengue fever, and HIV in the developing world; to lifestyle diseases such as cancer and environmental pollution in the western world. With so many emerging health threats, the field of biomedical sciences has never been so diverse, with research uniting us all.

This article will cover recent advances in clinical and biomedical science and the ways in which these techniques could be applied to tackle current global health threats. March 17 marks the start of Pittcon 2019, which will highlight a range of biomedical techniques that can provide improved diagnostics, better treatments and faster discovery. This includes: spectroscopy-based techniques, lab-on-a-chip, mass spectrometry (including MALDI-TOF and proteomics), and the development of ultra-small biosensors.

Biomedical Sensors

Two of the most important areas where biomedical science can be effective is non-communicable diseases and antimicrobial resistance, both of which were mentioned in the WHO’s list of global health threats for 2019. Sedentary lifestyles and environmental pollution in the Western world have increased the prevalence of non-communicable diseases such as type 2 diabetes and cancer. Diagnosing and preventing such diseases has thus never been more important.

On March 18th at Pittcon 2019, Professor Alex Lippert of Southern Methodist University will give a presentation on his work in chemiluminescent probes for deep imaging of tumor tissues in living animals. Dr Wei Gao of the California Institute of Technology will also present on his work on this date. Gao will describe the development of a fully-integrated wearable biosensor for multiplexed in situ perspiration analysis, which can be used to measure a wide spectrum of sweat analytes to aid predictive analytics and treatments.

Bacterial Resistance

Antimicrobial resistance is one of the biggest areas of concern for many global leaders. The overprescribing and misuse of antibiotics has led to the development of superbugs that are resistant to numerous antimicrobial agents, including last-resort antibiotics. The search is on for new antimicrobials and diagnostic techniques that can rapidly identify resistant organisms. At Pittcon 2019, Ester Segal will provide an overview of PRISM, a chip-based spectroscopic technique that can correctly guide a physician to the best antibiotic for an infection, reducing the misuse of these vital drugs.

Compact Instrumentation

Biomedical instruments are becoming smaller and more accessible. One of the most exciting areas for biomedical research at present is the use of NMR for the diagnosis of diabetes and metabolic syndromes. At Pittcon 2019, David Cistola of Texas Tech University Health Sciences Center in El Paso will describe a compact NMR for addressing problems in clinical medicine. He will show how NMR relaxometry measurements can be used for the early detection of metabolic syndrome.

Furthermore, the ‘Clinical Mass Spectrometry: From Bench to Bedside and Back’ symposium on Thursday 21st March will look at how mass spectrometry instrumentation with a small footprint has become integrated into the clinical environment for a range of proteomics, metabolomics in biomarker discovery. If you are interested, the timsTOF Pro™ coupled with the revolutionary PASEF™ acquisition mode from Bruker can provide additional speed, sensitivity and selectivity in proteomics (see them at Stand 2754). Thermo Fisher can also help with proteomics as they have a wide range of range of label free proteomic analytic tools for use with biological applications.

References

  • Pickersgill M, Chan S, Haddow G et al., Biomedicine, self and society: An agenda for collaboration and engagement. Wellcome Open Res 2019, 4:9
  • Ten threats to global health in 2019, https://www.who.int/emergencies/ten-threats-to-global-health-in-2019 Accessed 4th March 2019
  • Yiran Yanga and Wei Gao, Wearable and flexible electronics for continuous molecular monitoring, Chem. Soc. Rev., 2019, Advance Article. 10.1039/C7CS00730B,
  • Heidi Leonard, Raul Colodner, Sarel Halachmi, and Ester Segal, Recent Advances in the Race to Design a Rapid Diagnostic Test for Antimicrobial Resistance, ACS Sensors 2018 3 (11), 2202-2217
  • Cistola DP, Robinson MD. Compact NMR relaxometry of human blood and blood components. Trends Analyt Chem. 2016;83(A):53-64

Chapter 1 – Bringing Spectroscopy into the Clinic

Raman Scattering is a non-destructive spectroscopic method that is increasingly being used in the field of biomedical science. The main benefit of Raman is that it can be used to examine biological materials without contact and provide a qualitative measure of reflected light. Raman can be used with little or no sample preparation or staining, thus its applications in high-throughput histopathology are becoming more and more apparent. For example, diagnostic accuracy in carcinomas relies upon immunohistochemical (IHC) tissue staining, which can be a complex highly skilled process requiring precise conditions. Raman spectroscopy enables the evaluation of substances without staining or labelling and was recently evaluated in a study of stomach cell sections. In this study, Raman was able to detect high adenosine and cytosine levels indicative of adenocarcinoma in the stomach tissue.

Raman Spectroscopy

Raman spectroscopy is non-destructive and non-invasive. It is suitable to examine samples directly in vivo and clinical systems are in development to aid in therapeutic monitoring of drug dosages, identification of infectious agents, the typing of cells and detection of tumor margins. Furthermore, Raman has high chemical specificity, there is no need for labels, and it provides good spatial resolution. The method is rapid, very precise and allows ultrasensitive detection.

Despite many benefits, Raman does have some drawbacks, namely the signal to noise ratio, as there can be a much stronger fluorescence background, and there is limited penetration depth. It is for this reason that Raman-based techniques that work in conjunction with other techniques have been developed. An example of this can be provided by Ji-Xin Cheng of Boston University who will give a presentation on vibrational spectroscopy in human diagnosis on Tuesday March 19th at Pittcon 2019. By coupling photoacoustic imaging with vibrational spectroscopy, this group have developed a catheter that allows in vivo mapping of lipids inside the blood vessel wall.

There are a number of other examples of where combinatorial techniques have proved useful in biomedicine. In one example, coherent anti-Stokes Raman Scattering (CARS) imaging is used to increase imaging contrast and amplify signals but another mode called ‘cascade CARS’ provides an even better signal for improved imaging in biological tissues. A further example of a combinatorial technique that has applications in biomedicine is the use of Stimulated Raman Scattering (SRS) microscopy to image brain tissue in Alzheimer’s disease patients.
Professor Dan Fu of the University of Washington will give a presentation on Sunday March 17th at Pittcon 2019 entitled “Label-Free Chemical Imaging of Brain Structure and Function at Subcellular Resolution” where he will show that SRS can detect synaptic acetylcholine, plaque structure, and cell organization without any labelling and provide a new insight into Alzheimer’s progression.

Raman Spectroscopy is Non-Invasive

Prof. Dr. Jürgen Popp, Research Director of the Leibniz Institute of Photonic Technology (IPHT) and presenter at Pittcon 2019, said “Raman spectroscopy has already proved its effectiveness in many feasibility studies for medical diagnostics such as for cancer, cardiovascular diseases and infections. Now we have to demonstrate the transferability, so that Raman spectroscopy systems can be used in routine laboratory diagnostics or clinical in vivo diagnostics.”

Professor Popp, who received the 2016 Pittsburgh Spectroscopy Award, will give a presentation entitled “Clinical Cell and Tissue Diagnostics by Multimodal Molecular Spectroscopy”. This will highlight recent advances in utilizing spectroscopic methods, with emphasis on Raman spectroscopy and its combination with other spectroscopic or optical methodologies to characterize cells and tissue and assuage the medical needs of pathology, oncology, and infection/ sepsis. He will also demonstrate the potential of Raman spectroscopy as a point-of-care approach for a fast identification of pathogens and the determination of their antibiotic resistances and the detection and high-speed sampling of circulating cancer cells.

Transmission Raman Spectroscopy

Transmission Raman spectroscopy (TRS) is a further example of a Raman technique that is revolutionizing the field of biomedicine. Here, the sample is probed through a ≥10 mm thickness. The TRS method works by illuminating the sample on one-side and accumulating transmitted light on the other. The transmission Raman spectrum obtained provides good quality assurance over the tablet contents.

The other suggested use of TRS is as its use as a non-invasive technique for the analysis of breast calcifications detected during a mammogram. Obtaining information about surrounding breast tissue would normally require excisional biopsy, but TRS negates this. Professor Nick Stone is just one of the researchers who is using this technique in the clinic. In previous work, Stone used hydroxyapatite standards from SigmaAldrich, a Raman camera from Andor and detector from Kaiser Raman spectroscopy tools. All of these companies will be present at the Pittcon Expo.
Nick Stone is Professor of Biomedical Imaging and Biosensing at the University of Exeter. On Tuesday, March 19th, he will give a presentation entitled “Biomedical Spectroscopic Tools for Rapid Analysis of Disease Specific Changes Using Novel Raman and IR Techniques”, which will examine the increased use of Raman and IR spectroscopy for the rapid analysis of tissues in pathology and histopathology (high-speed spectral histopathology).

Over the last two decades, it has become clear that vibrational spectroscopy has both the sensitivity and specificity to provide rapid analysis of tissues and associated predication of pathology. Equipment for this technique can be provided by B&W Tek and Renishaw and experts will be at the Pittcon 2019 Expo to discuss such technology.

Lab-on-a-chip Solutions to Antibiotic Resistance

Moving away from Raman spectroscopy, PRISM (optical phase-shift reflectometric interference spectroscopic measurements), is a spectroscopy technique which is demonstrating its utility in the important area of screening for and detecting antimicrobial resistance.

Based upon microfluidic lab-on-a-chip technology, PRISM has the potential to provide benefits for several biomedical fields. The major benefit of microfluidic systems is that they are more cost effective than traditional methods, require minimal training, provide more rapid results and show better accuracy.

Dr Ester Segal of Technion in the Israel Institute of Technology, Haifa, is a principle researcher looking into microfluidic screening of antibiotic resistance and recently said “Even with advances in antibiotic therapies, bacterial infections persistently plague society and have amounted to one of the most prevalent issues in healthcare today… The past few decades have seen a promising trend in point-of-care diagnostics, with microfluidic technologies at the cornerstone of this emerging field”.

Dr Segal will describe the technology and its benefits in her presentation “On-Chip Rapid Diagnostic Susceptibility Testing of Bacteria and Fungi from Clinical Samples” at Pittcon 2019. This technique is expected to revolutionize the testing of microorganisms in antibiotic resistance testing.

PRISM uses a functionalized photonic 2D silicon microarray (solid-liquid interface) as a platform for phenotypic susceptibility testing of bacteria and fungi. This assay uses microfluidic channels interfaced with PRISM chips. The two-stage process tracks the optical responses of microorganisms to several antibiotics at different concentrations in real-time.

Minimum inhibitory concentrations can be obtained within 30-120 minutes, compared to current techniques where typical assay times are > 8 hours. For this research, Advion provided their NanoTek Microfluidic Synthesis System and IDEX Health & Science provided the microfluidic consumables and phases. Both companies will be available at the Pittcon 2019 Expo to provide advice in this area.

References

  • Santos, Inês & Barroso, Elisa & Bakker Schut, et al., (2017). Raman Spectroscopy for cancer detection and cancer surgery guidance: translation to the clinics. The Analyst. 142. 3025-3047. 10.1039/C7AN00957G.
  • Ikeda H, Ito H, Hikita M, et al. Raman spectroscopy for the diagnosis of unlabeled and unstained histopathological tissue specimens. World J Gastrointest Oncol. 2018;10(11):439-448.
  • Zachary J. Smith, Thomas R. Huser, et al., Review Article: Modern Trends in Imaging VI Raman scattering in pathology, Analytical Cellular Pathology 35 (2012) 145–163
  • Pelegati VB, Kyotoku BBC, Padilha LA, Cesar CL. Six-wave mixing coherent anti-Stokes Raman scattering microscopy. Biomed Opt Express. 2018;9(5):2407-2417. Published 2018 Apr 27
  • Ghita, A. , Matousek, P. and Stone, N. (2018), High sensitivity non‐invasive detection of calcifications deep inside biological tissue using Transmission Raman Spectroscopy. J. Biophotonics, 11: e201600260.
  • Benjamin Gardner, Nicholas Stone, and Pavel Matousek, Noninvasive Determination of Depth in Transmission Raman Spectroscopy in Turbid Media Based on Sample Differential Transmittance, Analytical Chemistry 2017 89 (18), 9730-9733
  • Leonard, Heidi & Colodner, Raul & Halachmi, Sarel & Segal, Ester. (2018). Recent Advances in the Race to Design a Rapid Diagnostic Test for Antimicrobial Resistance. ACS Sensors. 3. 10.1021/acssensors.8b00900
  • Sarah R. Delaney and Brenda B. Suh-Lailam, Microfluidics: The Future of Testing? Clinical Chemistry 64:2 (2018) 417
  • Heidi Leonard, Sarel Halachmi, Nadav Ben-Dov, Ofer Nativ, and Ester Segal, Unraveling Antimicrobial Susceptibility of Bacterial Networks on Micropillar Architectures Using Intrinsic Phase-Shift Spectroscopy, ACS Nano 2017 11 (6), 6167-6177


Chapter 2 – High-throughput Proteomics for Disease Diagnosis, Prognosis and Monitoring

Immunohistochemistry and radiolabeling have revolutionized the visualization and detection of compounds in pathological tissue samples. However, these techniques are slowly being superseded by high-throughput, high-speed MALDI (matrix assisted laser desorbed ionization) mass spectrometry imaging.
MALDI Imaging mass spectrometry (MALDI-IMS) has a broad appeal in biomedical research as it can be used to analyze complex mixtures that range from small drug molecules to the complex of peptides in a specific proteome. This method is also capable of measuring distributions of a huge number of analytes in a single analysis without harming the sample.
MALDI has been used to provide molecular fingerprints from intact cells and plot the 3D spatial distribution of the species of interest with no prior study of the tissue proteome (the technique can also be correlated with nuclear magnetic resonance images).

Other key advantages of the technique are it does not require molecule specific tags or chemical modifiers to facilitate detection, protein markers can be discovered that are only briefly expressed, and it is a label free system. Clinical applications include:

  • Distinguishing between benign and cancerous tissues in ovarian cancer
  • Producing lipid maps of neural tissues
  • Pharmacokinetic studies of drugs and metabolites
  • Determining tissue molecular signatures in personalized medicine
  • Elucidating cellular pathways using biomarker proteins
  • Identifying prognostic biomarkers to distinguish tumor grade and increase survival rates

Benefits of Mass Spectrometry Imaging

The major benefit of MALDI-IMS is that it can provide a molecular signature of tissue samples in an accurate and reproducible fashion. Professor Pierre Chaurand of the University of Montreal is a widely recognized authority in mass spectrometry imaging and will present his research during a presentation entitled “Image MS of Tissue Biopsies to Assess Diagnosis, Prognosis and Response to Therapies” at Pittcon 2019. The presentation will examine the potential of MALDI-IMS technology to establish diagnosis, prognosis and response to therapy.
Several clinical examples will be used including colorectal cancer liver metastasis and non-alcoholic fatty liver disease. Companies at Pittcon 2019 with products related to MALDI-IMS and proteomics include Shimadzu (MALDI-TOF), Horiba (Direct MS and MS/MS analysis on the SPRi micro-array biochip) and Waters corporation (MALDI SYNAPT G2-Si High Definition Mass Spectrometry). All of these companies will be showcasing their products and expertise at the Pittcon 2019 Expo.

References

  • Dale S Cornett, Michelle L Reyzer, Pierre Chaurand & Richard M Caprioli, MALDI imaging mass spectrometry: molecular snapshots of biochemical systems, Nature Methods, Vol.4 No.10, October 2007, 829
  • Michaela Aichler and Axel Walch, MALDI Imaging mass spectrometry: current frontiers and perspectives in pathology research and practice, Laboratory Investigation (2015) 95, 422–431
  • Gustafsson JO, Oehler MK, Ruszkiewicz A, McColl SR, Hoffmann P. MALDI Imaging Mass Spectrometry (MALDI-IMS)-application of spatial proteomics for ovarian cancer classification and diagnosis. Int J Mol Sci. 2011;12(1):773-94
  • Castellino, Stephen; Groseclose, M Reid; Wagner, David (November 2011). “MALDI imaging mass spectrometry: bridging biology and chemistry in drug development”. Bioanalysis. 3 (21): 2427–2441

Chapter 3 – Advancements in Biomarker Discovery Techniques

A biomarker is a quantifiable indicator of disease progression of severity. Biomarkers are naturally occurring molecules, genes or any quantifiable parameter that can indicate the physiological state of the organism and disease. Researchers are continually searching for new biomarkers for the world’s biggest health threats, including cancer, neurological diseases (e.g., Alzheimer’s) and cardiovascular diseases.

The ethos behind this is that if molecular signatures of disease can be identified at an early stage then rapid and targeted treatment can improve patient survival rates and even be and economic advantage as expensive treatments are not needed.

Unfortunately, cancer is recognized as a heterogeneous disease that may be expressed differently in different patients. In addition, different neoplastic cancers can express different biomarkers according to type and site of carcinogenesis.

If a series of biomarkers can be established, diagnosis and the development of an efficacious treatment plan becomes much easier and survival rates increase. For example, in cases of neurodegenerative diseases that are indistinguishable from clinical presentation alone, biomarkers can provide a definitive diagnosis.

Cardiovascular diseases, which are one of the main causes of death worldwide; can be identified through molecular probes, resulting in better outcomes for the patient. For example, the identification of the start of an atherosclerotic process can lead to early preventive treatment to side-step an acute myocardial infarction.

Biomarkers and Biosensors

Biomarkers are important, but biosensors are also vital to provide inexpensive sensory platforms that are capable of precise detection, even at very low concentrations, of the biomarker being measured.

A good range of biomarkers and biosensors capable of operation at low limits of detection can provide a new method of diagnosis for serious disease. One of the companies with expertise in biomarker discovery using micro-chip chromatography is PharmaFluidics. This company will be at Pittcon 2019 in Philadelphia and will be able to provide expertise and advice in the field of micro-Chip chromatography and the analytical development of biopharmaceuticals.

Exhaled Breath Condensate

A potential method for discovering new biomarkers for lung disease is the collection and analysis of exhaled breath condensate (EBC). EBC is an excellent source of biomarkers for lung disease. It is not a biomarker itself but a body fluid matrix (exhaled gas condensate) in which biomarkers may be identified. EBC is considered by many to be equivalent to blood, sweat, tears, urine and saliva.

The EBC matrix contains water droplets and a significant proportion of airway lining fluid (ALF). Thus, EBC contains potentially important inflammatory biomarkers for lung disease such as: cytokines (e.g. interleukins, tumor necrosis factor‐α, interferon‐γ), macromolecules (mucin and DNA), nitric oxide products (NOx), hydrogen peroxide (H2O2), hydrogen ions (H+), eicosanoids [e.g. 8‐isoprostane (8‐isoP), leukotrienes, prostanoids], aldehydes, peptides, adenosine and ammonia.

EBC holds many potential benefits as a source of biomarkers, as it is non-invasive, collection is rapid, and samples could be collected over a period of time to provide a better understanding of respiratory disease. EBC is also inexpensive and applicable to the measurements of biomarkers in a range of respiratory conditions. However, the methodology is not completely clear cut and care must be taken as there are no gold standards for collection and analysis. In addition, EBC can be contaminated by salivary enzymes and gastric contents, affecting the validity of results.

Professor Michael D Davis of the Children’s Hospital of Richmond, Virginia Commonwealth University (VCU) will highlight this on Tuesday March 19th at Pittcon 2019 in a presentation entitled “Human Exhaled Breath Aerosol Collection in the Clinical Setting – Techniques, Concerns, and Considerations”.

The talk will provide an overview of collection techniques for EBA that are specific to the clinical setting and also of safety and quality issues for this environment and patient population. For delegates who are interested in this area and have concerns about this technique, this presentation is a must. Professor Davis will be available to answer any questions that you may have.

Alzheimer’s Disease and Proteomics

Alzheimer’s disease is a major public health issue across the world. The condition is the 6th leading cause of death in the US with around 5.7 million American citizens living with the disease, at an estimated cost of $277 billion to the US economy.

The state of the problem is underlined by the fact that 1 in 3 senior citizens dies of Alzheimer’s or another form of dementia and a diagnosis of the condition is made every 65 seconds. The problem is becoming overwhelming and without intervention is expected to become even worse; It is thought that by 2050 more than 14 million US citizens will develop Alzheimer’s, at a cost of $1.1 trillion.

The diagnosis of Alzheimer’s, as well as methods to follow the progression of the disease, is not always easy. A traditional diagnosis is based upon taking a good patient history, blood tests, cognitive tests and neural imaging.

Due to the nature of Alzheimer’s disease, a definitive diagnosis requires the use of slides from neural material obtained post-mortem. A better method is the use of a series of biomarkers that can provide a definitive diagnosis for living patients and also help understand the mechanism and progression of the disease.

Biomarkers for Different Pathologies

There are already a range of pathologies with biomarkers used to follow the progression of Alzheimer’s disease including T-PAU, Aβ42, P-tau, neurogranin, SNAP25, YKL-40, CCL2, chitrotisidase. These markers can be followed by mass spectrometry, ELISA and other scanning methods, following the collection of blood, CSF, and a brain scan from the patient. However, the use of currently available Alzheimer’s biomarkers is limited.

Blood biomarkers, which are less invasive to collect, are further away from the brain and may therefore not yield a representative sample. CSF biomarkers come from the brain but must be obtained through a lumbar puncture; a seriously invasive procedure. Finally, brain scans provide diagnostic accuracy but require a radioactive tracer, which is expensive and invasive. It is clear that new biomarkers are needed, and significant resources are being invested into their discovery.

Disparity in Alzheimer’s Disease

Alzheimer’s disease is a complex condition that is epidemiologically challenging. There are a lot of disparities between different races and genders that are not well understood. For example, around two-thirds of US citizens with Alzheimer’s are female, senior African-Americans are around twice as likely to develop Alzheimer’s or other dementias as senior Caucasians, and Hispanics are around one and one-half times more likely to develop Alzheimer’s disease compared to senior Caucasians.

Uncovering the molecular pathways involved in Alzheimer’s disease will be vital if we are going to tackle this global health issue. One approach that is currently being used to understand these processes is sophisticated proteomics and lipidomics studies of blood and post-mortem tissues. New biomarkers that are able to describe the disease process in different genomes are crucial to increase understanding.

Genome-Wide Association Studies

Rena Robinson, who will give a presentation at Pittcon 2019 on Biomarkers and Alzheimer’s said recently; “The genomic era of biomedical research has given rise to the genome-wide association study (GWAS) approach, which attempts to discover novel genes affecting an outcome by testing a large number (i.e., hundreds of thousands to millions) of genetic variants for association.”
GWAS is an HT technique that is now proving its worth in the study of the genomics of the racial discrepancies in Alzheimer’s disease. GWAS studies conducted in Rena Robinsons research (to be presented at Pittcon 2019) has suggested a link between an abnormal lipid metabolism and the increased risk of Alzheimer’s in African Americans.

Using a combined lipidomics and proteomics approach, Rena’s team have discovered several lipid metabolism pathways that are changed in African Americans, some of which could act as biomarkers in patients of this ethnicity. Professor Robinson’s presentation at Pittcon 2019 is entitled “Comprehensive Proteomics and Lipidomics Strategies to Advance Alzheimer’s Disease Research”, and will describe a high-throughput quantitative proteomics approach to yield hundreds of proteins distinct to disease genotypes and ethnic background and also global lipidomics approaches that can produce unique lipid species across various classes.

Companies at the Pittcon Expo that have contributed to proteomics research include Thermo Fisher with their Proteome Discoverer software, which can be used to manage proteomics workflows and the Orbitrap Elite™ Hybrid Ion Trap-Orbitrap Mass Spectrometer, which is ideal for proteomics, metabolomics, lipidomics from biological samples. Waters Corporation, who provided an LC-MS proteomics discovery analysis software called Progenesis QI for the research, will also be present at the Expo. Other exhibitors include Advion and GenTech, who provide a range of mass spectrometry equipment such as the CMSL single quadrupole mass spectrometer.

References

  • de Oliveira WF, Dos Santos Silva PM, Coelho LCBB, Dos Santos Correia MT, Biomarkers, Biosensors and Biomedicine, Current Medicinal Chemistry [23 Jan 2019]
  • Walsh, Brian & Davis, Michael & Hunt, John & Kheir, John & Smallwood, Craig & H Arnold, John. (2015). The effects of lung recruitment manoeuvres on exhaled breath condensate pH. Journal of breath research. 9. 036009. 10.1088/1752-7155/9/3/036009
  • Davis MD, Montpetit A, Hunt J. Exhaled breath condensate: an overview. Immunol Allergy Clin North Am. 2012;32(3):363-75.
  • F. M. Aldakheel, P. S. Thomas, J. E. Bourke, M. C. Matheson, Relationships between adult asthma and oxidative stress markers and pH in exhaled breath condensate: a systematic review, Volume 71, Issue 6, June 2016, Pages 741-757
  • Davis MD, Montpetit A, Hunt J. Exhaled breath condensate: an overview. Immunol Allergy Clin North Am. 2012;32(3):363-75
  • Alzheimer’s disease statistics https://www.alz.org/alzheimers-dementia/facts-figures Accessed March 6th 2019
  • Kaitlyn E. Stepler, Rena A. S. Robinson, Reviews on Biomarker Studies in Psychiatric and Neurodegenerative Disorders pp 1-28, The Potential of ‘Omics to Link Lipid Metabolism and Genetic and Comorbidity Risk Factors of Alzheimer’s Disease in African Americans
  • Stepler, Kaitlyn et al., Characterizing Altered Lipid Metabolism In Health Disparities Of Alzheimer’s Disease, Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association , Volume 14 , Issue 7 , P1451
  • Shaffer JR, Feingold E, Marazita ML. Genome-wide association studies: prospects and challenges for oral health. J Dent Res. 2012;91(7):637-41
  • Khan, Mostafa J. et al. Omics Approaches To Understand Health Disparities In Alzheimer’s Disease, Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, Volume 14, Issue 7, P719
  • Stepler, Kaitlyn et al., Characterizing Altered Lipid Metabolism in Health Disparities of Alzheimer’s Disease, Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, Volume 14, Issue 7, P1451

Chapter 4 – From Biomarkers to Innovation in Metabolomics

Biomarkers are an essential tool in biomedical science. As highlighted in Chapter three, biomarkers not only provide a measurable indicator of the severity of the disease but can also provide information on its etiology and metabolism. This has led to the development of an entirely different field; metabolomics.

Metabolomics involves the study of the metabolites in an organism that are involved in a particular biological pathway. Using high-throughput techniques, a characteristic metabolic profile can be produced. If this is then combined with enzymatic assays, transcriptomics and proteomics the biomedical researcher has a powerful tool at their disposal.

Thermo Fisher, Horiba and Waters produce a range of equipment for Proteomics and Protein Mass Spectrometry that are ideal in this area of study. These companies will be available at Pittcon 2019 to provide advice and expertise.

Metabolomics is an Important Part of Medicine

Metabolites are the intermediates and products of metabolism. Every cell carries out distinct and crucial physiological processes and these are often affected by human disease. To understand this process and develop new medications, elucidating the structure and regulation of metabolic pathways is critical.

One of the areas where the interaction of metabolites is particularly complex is in the brain, central nervous system and neural pathways. Metabolomics can enhance current understanding about the complex structure of the mammalian brain and the mechanisms of neurological disorders. In the case of Alzheimer’s disease, any effective treatment will require a very deep understanding of the underlying metabolic processes.

The monitoring of brain chemistry metabolites is a very challenging area. The location of brain interstitial fluid can cause great difficulty in sampling and this is a huge challenge in bioanalytical chemistry.

Microelectrode Biosensors for Metabolomics Studies of the Brain

Understanding brain metabolism and neurochemistry is fundamental to uncovering the ways in which neuronal networks respond to both physiological and pathological stimuli. Microelectrode biosensors used in the brain are able to provide real‐time analyses with high temporal resolution and minimal damage to live tissue using oxidase enzymes for biological interaction. There are usually two types of microelectrode biosensors used: cylindrically shaped wire electrodes and microfabricated multi‐microelectrode needles. Microfabricated multi‐microelectrode needles are larger than cylindrical wire electrodes but can be used to monitor several molecule systems simultaneously using oxidase enzymes.

Biosensors have been used to provide a greater understanding of brain energy metabolism and neurotransmission, with the detection of glucose, lactate and neurotransmitters such as glutamate and acetylcholine. The sensors provide timed temporal resolution and enzymatic assaying of practically any redox or non-redox molecule. The only drawback is that despite the miniature size of the of the biosensors, implantation is often dangerous and comes with many health risks. Even with sensors as small as 50–250 µm, vascular and cellular injury, inflammation and foreign-body reactions are still common.

Monitoring the Brain Following Traumatic Brain Injury (TBI)

Traumatic brain injury is a significant cause of death and long-term disability in the world. Following a TBI, the brain can undergo several changes in gene and metabolite expression, which differ between patients. This is evident from unique metabolomic signatures that have been observed in patients following a TBI.

The heterogeneity of the disease and lack of comprehensive, characterization of multiple TBI types provides major challenges to produce effective therapeutic systems. TBI diagnosis through metabolomics might provide a better understanding of the cellular changes occurring post-TBI and potentially aid the development of therapeutics.

A recent study, which used an untargeted metabolomics approach to demonstrate altered metabolism in response to TBI, showed that gray and white matter respond very differently to TBI. A TBI classification scale was also produced based on metabolomic profile. This research showed that the pathophysiologic response to TBI is brain region dependent.

This research paved the way for more studies comparing the metabolomic response of TBI affected gray and white matter. Each of these compartments have a distinct cellular configuration and cellular structure with different response to neural injury. Furthermore, each type of brain tissue has different structural vulnerability and predisposition to excitotoxic and ischemic perturbations, and edema.

Microsensors in the Brain

The ability to monitor the neurochemical content of brain interstitial fluid is a set to be an excellent new approach to understand the way in which neurological lesions develop following brain injury. At Pittcon 2019 Dr Stéphane Marinesco of INSERM will present a talk entitled “Ultra-small Microelectrode Biosensors based on Platinized Carbon Fibers for Brain Injury Monitoring”. This presentation will describe the development of ultra-small microelectrodes which were used to produce biosensors with 15 µm external diameter. These devices were shown to be implanted in the brain with little injury to the parenchyma and blood vessels.

Compared to previous biosensors, the ultra-small biosensors showed much more accurate estimates of oxygen, glucose and lactate. These sensors can provide a real-time snap shot of how brain chemistry is altered after injury and may allow treatment to be focused and personalized.

Related products that can be found at the Pittcon Expo include the T-ReX LC-QTOF solution, the HMDB Metabolite Library 2.0 and the Metaboscape software from Bruker. These three products are ideal for untargeted metabolomics. In addition, Renishaw, who provide state-of-the-art tools to conduct brain metabolomics studies, will be present at the Expo.

References

  • Vasilopoulou Catherine G., Margarity Marigoula, Klapa Maria I., Metabolomic Analysis in Brain Research: Opportunities and Challenges, Frontiers in Physiology, vol 7, 2016, p183
  • Charles Chatard, Andrei Sabac, Laura Moreno-Velasquez, Anne Meiller, and Stephane Marinesco, Minimally Invasive Microelectrode Biosensors Based on Platinized Carbon Fibers for in Vivo Brain Monitoring, ACS Central Science 2018 4 (12), 1751-1760
  • Charles Chatard, Anne Meiller, Stéphane Marinesco, Microelectrode Biosensors for in vivo Analysis of Brain Interstitial Fluid, Electroanalysis 2018, 30, 977.
  • Baker EW, Henderson WM, Kinder HA, Hutcheson JM, Platt SR, West FD. Scaled traumatic brain injury results in unique metabolomic signatures between gray matter, white matter, and serum in a piglet model. PLoS One. 2018;13(10), Published 2018

Conclusion

How can technology best serve medicine? The answer to this is in the advances in Biomedical science that are being made to provide answers and treatment for the health issues of the modern age i.e., cancer, diabetes, cardiovascular disease, bacterial resistance, stroke and Alzheimer’s disease.

The application of spectroscopy, mass spectrometry and electrochemistry to biological systems represents one of the greatest technological advances ever seen. Companies such as Bruker, Thermo Fisher, Waters, Horiba and many others have risen to the challenge using their multi-platform expertise to develop medical imaging and analysis systems that will change the face of biomedical science. All of these companies will be at Pittcon 2019 with their experts to discuss applications and new developments.

Raman Imaging and MALDI will improve the diagnosis, prognosis and monitoring of a huge range of diseases. The incorporation of newer hyphenated and combinatorial techniques will be essential to the development of non-invasive sampling methods. Finally, high-throughput proteomic, metabolomic and other ‘omic’ methods such as GWAS will improve our understanding of biomarker discovery – which will provide the data needed to deliver the therapies and cures that are demanded.

The Pittcon 2019 symposia series will provide a range of talks featuring experts that are preeminent in their fields. Pittcon 2019 is the place to be, to examine the latest developments and expertise in biomedical science. Bring your problems and go home with solutions.