Investigation of fiber‐optic probe designs for optical spectroscopic diagnosis of epithelial pre‐cancers

Skala, Melissa C.; Palmer, Gregory M.; Zhu, Changfang; Liu, Quan; Vrotsos, Kristin M.; Marshek-Stone, Crystal L.; Gendron‐Fitzpatrick, Annette; Ramanujam, Nirmala

doi:10.1002/lsm.10239

Cited by 62 publications

(57 citation statements)

References 38 publications

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“…Time resolved fluorescence emission was collected via timecorrelated single-photon counting electronics (Becker and Hickl; SPC-730). Previous multiphoton microscopy lifetime studies (37) and our own spectroscopy results from the hamster cheek pouch (35) confirm that the main fluorophores at 800-nm (with a 490 short-pass filter) and 890-nm excitation are NADH and FAD, respectively.…”

Section: Dmba-treated Hamster Cheek Pouch Model Of Oral Cancersupporting

confidence: 73%

“…For each hamster, the right cheek pouch was either treated chronically with 0.5% DMBA in mineral oil (DMBA-treated animals) or mineral oil only (control animals) for 16 weeks. The treatment procedures were established from previous studies (19,25,35). At 16-21 weeks after the commencement of treatment, the cheek pouch of each animal was imaged by using multiphoton microscopy.…”

Section: Dmba-treated Hamster Cheek Pouch Model Of Oral Cancermentioning

confidence: 99%

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In vivo multiphoton microscopy of NADH and FAD redox states, fluorescence lifetimes, and cellular morphology in precancerous epithelia

Skala

Riching

Gendron‐Fitzpatrick

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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876

856

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Metabolic imaging of the relative amounts of reduced NADH and FAD and the microenvironment of these metabolic electron carriers can be used to noninvasively monitor changes in metabolism, which is one of the hallmarks of carcinogenesis. This study combines cellular redox ratio, NADH and FAD lifetime, and subcellular morphology imaging in three dimensions to identify intrinsic sources of metabolic and structural contrast in vivo at the earliest stages of cancer development. There was a significant (P < 0.05) increase in the nuclear to cytoplasmic ratio (NCR) with depth within the epithelium in normal tissues; however, there was no significant change in NCR with depth in precancerous tissues. The redox ratio significantly decreased in the less differentiated basal epithelial cells compared with the more mature cells in the superficial layer of the normal stratified squamous epithelium, indicating an increase in metabolic activity in cells with increased NCR. However, the redox ratio was not significantly different between the superficial and basal cells in precancerous tissues. A significant decrease was observed in the contribution and lifetime of protein-bound NADH (averaged over the entire epithelium) in both low-and high-grade epithelial precancers compared with normal epithelial tissues. In addition, a significant increase in the protein-bound FAD lifetime and a decrease in the contribution of protein-bound FAD are observed in high-grade precancers only. Increased intracellular variability in the redox ratio, NADH, and FAD fluorescence lifetimes were observed in precancerous cells compared with normal cells.T he electron transport chain is the most efficient means of energy production in cells. The electron transport chain produces energy in the form of ATP by transferring electrons to molecular oxygen. The metabolic coenzymes FAD and NADH are the primary electron acceptor and donor, respectively, in oxidative phosphorylation. Neoplastic cells have an increased metabolic demand relative to normal cells because of rapid cell division (1), and neoplastic metabolism is associated with changes in the relative concentrations of NADH and FAD (2-4). Many enzymes bind to NADH and FAD in the metabolic pathway (5), and, as favored metabolic pathways shift with cancer progression, the distribution of NADH and FAD binding sites also change (6). Thus, metabolic imaging of the relative amount of NADH and FAD, and their microenvironment (such as binding sites and/or the presence of local quenchers) can shed light on metabolic changes associated with carcinogenesis.The metabolic coenzymes NADH and FAD are autofluorescent and can be monitored nondestructively and without exogenous labels, using optical techniques. The most common optical method for metabolic imaging is the ''redox ratio,'' which is the ratio of the fluorescence intensity of FAD and NADH (7). This optical redox ratio provides relative changes in the oxidationreduction state in the cell. The redox ratio is sensitive to changes in the cellular metabolic rate and...

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Section: Dmba-treated Hamster Cheek Pouch Model Of Oral Cancersupporting

confidence: 73%

Section: Dmba-treated Hamster Cheek Pouch Model Of Oral Cancermentioning

confidence: 99%

In vivo multiphoton microscopy of NADH and FAD redox states, fluorescence lifetimes, and cellular morphology in precancerous epithelia

Skala

Riching

Gendron‐Fitzpatrick

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

876

856

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show abstract

“…Oblique-incidence illumination and/or collection geometries using angled fibers have been used to target superficial tissue regions [25][26][27]. Variations in fiber size, illumination-collection fiber separation, and probe-sample spacing have been shown to influence sensitivity to different fluorophore layers in turbid media [28].…”

Section: Introductionmentioning

confidence: 99%

Autofluorescence and diffuse reflectance spectroscopy of oral epithelial tissue using a depth-sensitive fiber-optic probe

et al. 2008

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Optical spectroscopy can provide useful diagnostic information about the morphological and biochemical changes related to the progression of precancer in epithelial tissue. As precancerous lesions develop, the optical properties of both the superficial epithelium and underlying stroma are altered; measuring spectral data as a function of depth has the potential to improve diagnostic performance. We describe a clinical spectroscopy system with a depth-sensitive, ball lens coupled fiber-optic probe for noninvasive in vivo measurement of oral autofluorescence and diffuse reflectance spectra. We report results of spectroscopic measurements from oral sites in normal volunteers and in patients with neoplastic lesions of the oral mucosa; results indicate that the addition of depth selectivity can enhance the detection of optical changes associated with precancer.

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“…This can be achieved with depth-dependent spectroscopy measurements using an angled illumination geometry, 44,45 allowing measurements of fluorescence intensity from only the surface layer. In in vivo microscopy, imaging is performed en face, which may make imaging from the surface layers more straightforward than imaging deeper layers.…”

Section: Discussionmentioning

confidence: 99%

Real‐time detection of epidermal growth factor receptor expression in fresh oral cavity biopsies using a molecular‐specific contrast agent

Hsu

Gillenwater²,

Hasan

et al. 2006

Intl Journal of Cancer

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Early diagnosis of individuals with high risk of developing head and neck squamous carcinoma should lead to decreased morbidity and increased survival. To aid in noninvasive early detection of oral neoplasia in vivo, we have developed a molecular-specific fluorescent contrast agent, consisting of a far-red fluorescent dye coupled to a monoclonal antibody targeted against the epidermal growth factor receptor. In our study, we used organ cultures of normal and neoplastic human oral tissue to evaluate the capabilities of using this contrast agent to enhance clinical diagnosis. Fresh tissue sections were prepared from 34 biopsies of clinically normal and abnormal oral mucosa from 17 consenting patients. Samples were exposed to contrast agent, rinsed and the presence of bound agent was detected using fluorescence confocal microscopy. Simple assays to assess cytotoxicity of the dye used in the agent and to determine labeling efficacy at physiologic temperatures were also performed. Results indicate that the mean fluorescence intensity (MFI) of samples with dysplasia and cancer are higher than that of the normal sample from the same patient, and that this increase in fluorescence could potentially be used in the early detection and delineation of premalignant lesions. Normal tissue could be distinguished from cancer or moderate dysplasia, using either the ratio of the MFI of abnormal to normal tissue or the MFI obtained from the epithelial surface. No detrimental effects from the dye were observed over a 4-day period. These results indicate that the use of this optical contrast agent could yield important clinical advantages for noninvasive early detection and molecular characterization of oral mucosa. ' 2006 Wiley-Liss, Inc.Key words: fluorescent contrast agent; epidermal growth factor receptor; molecular-specific contrast agentThe 5-year survival rate for oral cancer has not improved significantly in the last 3 decades, despite numerous advances in treatment modalities.

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Investigation of fiber‐optic probe designs for optical spectroscopic diagnosis of epithelial pre‐cancers

Cited by 62 publications

References 38 publications

In vivo multiphoton microscopy of NADH and FAD redox states, fluorescence lifetimes, and cellular morphology in precancerous epithelia

In vivo multiphoton microscopy of NADH and FAD redox states, fluorescence lifetimes, and cellular morphology in precancerous epithelia

Autofluorescence and diffuse reflectance spectroscopy of oral epithelial tissue using a depth-sensitive fiber-optic probe

Real‐time detection of epidermal growth factor receptor expression in fresh oral cavity biopsies using a molecular‐specific contrast agent

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