Krista Fowles
Research Associate PET CenterCards
About
Research
Publications
2025
PET Imaging of Sphingosine-1-Phosphate Receptor 1 with [18F]TZ4877 in Nonhuman Primates
Gu J, Zheng M, Holden D, Fowles K, Qiu L, Felchner Z, Zhang L, Ropchan J, Gropler R, Carson R, Tu Z, Huang Y, Hillmer A. PET Imaging of Sphingosine-1-Phosphate Receptor 1 with [18F]TZ4877 in Nonhuman Primates. Molecular Imaging And Biology 2025, 27: 54-63. PMID: 39779653, DOI: 10.1007/s11307-024-01979-x.Peer-Reviewed Original ResearchConceptsSphingosine-1-phosphate receptor 1Absorbed radiation dose estimatesReceptor 1Nonhuman primatesFree fractionPlasma free fractionRadiation dose estimatesMetabolite-corrected input functionF-18 labeled radiotracersArterial blood samplesCritical organsPET/CT systemBolus injectionF-18Anesthetized nonhuman primatesDosimetry studiesHuman studiesDose estimatesVT/fPPET imaging dataS1PR1PET imagingInput functionBlood samplesPonesimod
2024
Pilot PET study of vaginally administered bioadhesive nanoparticles in cynomolgus monkeys: Kinetics and safety evaluation
Grun M, Honhar P, Wang Y, Rossano S, Khang M, Suh H, Fowles K, Kliman H, Cavaliere A, Carson R, Marquez‐Nostra B, Saltzman W. Pilot PET study of vaginally administered bioadhesive nanoparticles in cynomolgus monkeys: Kinetics and safety evaluation. Bioengineering & Translational Medicine 2024, 9: e10661. PMID: 39553429, PMCID: PMC11561825, DOI: 10.1002/btm2.10661.Peer-Reviewed Original ResearchVaginal dosage formsBioadhesive nanoparticlesCynomolgus monkeysAnalysis of inflammatory biomarkersVaginal microbicidesVaginal canalMultiple dosesInflammatory biomarkersTherapeutic efficacyVaginal fluidSystemic circulationLong-term deliveryNoninvasive imagingClinical translationDosage formsNon-human primatesDelivery vehiclesMonkeysDeliveryVaginitisUterusMicrobicidesSafety evaluationBiodistributionDose
2023
Preclinical evaluation of a brain penetrant PARP PET imaging probe in rat glioblastoma and nonhuman primates
Chen B, Ojha D, Toyonaga T, Tong J, Pracitto R, Thomas M, Liu M, Kapinos M, Zhang L, Zheng M, Holden D, Fowles K, Ropchan J, Nabulsi N, De Feyter H, Carson R, Huang Y, Cai Z. Preclinical evaluation of a brain penetrant PARP PET imaging probe in rat glioblastoma and nonhuman primates. European Journal Of Nuclear Medicine And Molecular Imaging 2023, 50: 2081-2099. PMID: 36849748, DOI: 10.1007/s00259-023-06162-y.Peer-Reviewed Original ResearchConceptsPositron emission tomographyHealthy nonhuman primatesVolume of distributionDistribution volume ratioBrain kineticsRat glioblastoma modelPreclinical evaluationBrain regionsGlioblastoma modelPET tracersNonhuman primatesTumor-bearing ratsEx vivo biodistributionPET imaging resultsActive clinical trialsTreatment of glioblastomaHigh specific uptakeDynamic PET scansNoninvasive quantificationBrain positron emission tomographyNondisplaceable volumeBrain penetrationLow nonspecific uptakePrognostic informationClinical trialsExamining mGlu5 Receptor Availability as a Predictor of Vulnerability to PTSD: An [18F]FPEB and PET Study in Male and Female Rats
Asch R, Fowles K, Pietrzak R, Taylor J, Esterlis I. Examining mGlu5 Receptor Availability as a Predictor of Vulnerability to PTSD: An [18F]FPEB and PET Study in Male and Female Rats. Chronic Stress 2023, 7: 24705470231215001. PMID: 38024327, PMCID: PMC10666551, DOI: 10.1177/24705470231215001.Peer-Reviewed Original ResearchPost-traumatic stress disorderReceptor availabilityFemale ratsPathophysiology of PTSDFootshock exposureMetabotropic glutamate receptor 5Recent preclinical findingsGlutamate receptor 5Positron emission tomographyPreclinical findingsClinical findingsFe ratsReceptor 5Lower baselineEmission tomographyGreater riskPET studiesRatsStress disorderDifferential involvementPassive copingSex differencesMalesPTSD susceptibilityBaseline
2022
Examining sex differences in responses to footshock stress and the role of the metabotropic glutamate receptor 5: an [18F]FPEB and positron emission tomography study in rats
Asch RH, Pothula S, Toyonaga T, Fowles K, Groman SM, Garcia-Milian R, DiLeone RJ, Taylor JR, Esterlis I. Examining sex differences in responses to footshock stress and the role of the metabotropic glutamate receptor 5: an [18F]FPEB and positron emission tomography study in rats. Neuropsychopharmacology 2022, 48: 489-497. PMID: 36100654, PMCID: PMC9852230, DOI: 10.1038/s41386-022-01441-y.Peer-Reviewed Original ResearchImaging the fetal nonhuman primate brain with SV2A positron emission tomography (PET)
Rossano S, Toyonaga T, Berg E, Lorence I, Fowles K, Nabulsi N, Ropchan J, Li S, Ye Y, Felchner Z, Kukis D, Huang Y, Benveniste H, Tarantal AF, Groman S, Carson RE. Imaging the fetal nonhuman primate brain with SV2A positron emission tomography (PET). European Journal Of Nuclear Medicine And Molecular Imaging 2022, 49: 3679-3691. PMID: 35633376, PMCID: PMC9826644, DOI: 10.1007/s00259-022-05825-6.Peer-Reviewed Original ResearchConceptsPositron emission tomographySynaptic densityFetal brainThird trimesterEmission tomographyBrain developmentGravid rhesus monkeysPost-mortem brain tissueEarly neonatal periodNonhuman primate brainLate gestational periodSubset of subjectsPostnatal brain developmentPost-mortem samplesGestational ageNeonatal periodPregnant monkeysSynapse numberGestational periodPrimary motorPrimate brainBrain growthSubcortical regionsBrain tissueCortical regionsImaging the effect of ketamine on synaptic density (SV2A) in the living brain
Holmes SE, Finnema SJ, Naganawa M, DellaGioia N, Holden D, Fowles K, Davis M, Ropchan J, Emory P, Ye Y, Nabulsi N, Matuskey D, Angarita GA, Pietrzak RH, Duman RS, Sanacora G, Krystal JH, Carson RE, Esterlis I. Imaging the effect of ketamine on synaptic density (SV2A) in the living brain. Molecular Psychiatry 2022, 27: 2273-2281. PMID: 35165397, PMCID: PMC9133063, DOI: 10.1038/s41380-022-01465-2.Peer-Reviewed Original ResearchConceptsKetamine's therapeutic effectsMajor depressive disorderTherapeutic effectPositron emission tomographyPosttraumatic stress disorderHealthy controlsSynaptic connectionsSynaptic vesicle protein 2APost-synaptic mechanismsEffects of ketamineDiscovery of ketamineNon-human primatesAntidepressant effectsDepressive disorderSingle administrationSynaptic densityPsychiatric disordersDepression severityKetamineEmission tomographyTerminal densityLiving brainStress disorderRobust reductionDissociative symptomsTranslational PET Imaging of Spinal Cord Injury with the Serotonin Transporter Tracer [11C]AFM
Fang H, Rossano S, Wang X, Nabulsi N, Kelley B, Fowles K, Ropchan J, Strittmatter SM, Carson RE, Huang Y. Translational PET Imaging of Spinal Cord Injury with the Serotonin Transporter Tracer [11C]AFM. Molecular Imaging And Biology 2022, 24: 560-569. PMID: 35020138, PMCID: PMC9550197, DOI: 10.1007/s11307-021-01698-7.Peer-Reviewed Original ResearchConceptsSpinal cord injurySpinal cordHealthy ratsHuman spinal cordCord injurySerotonin transporterRat modelRodent modelsPET imagingTranslational PET imagingSCI rat modelIntact spinal cordSpinal cord caudalRodent spinal cordSerotonin transporter tracerUse of PETCervical uptakeSERT changesSCI animalsSCI patientsPresynaptic serotonin transporterCord caudalAxon damageSerotonin systemSERT radioligand
2021
A metabolically stable PET tracer for imaging synaptic vesicle protein 2A: synthesis and preclinical characterization of [18F]SDM-16
Zheng C, Holden D, Zheng MQ, Pracitto R, Wilcox KC, Lindemann M, Felchner Z, Zhang L, Tong J, Fowles K, Finnema SJ, Nabulsi N, Carson RE, Huang Y, Cai Z. A metabolically stable PET tracer for imaging synaptic vesicle protein 2A: synthesis and preclinical characterization of [18F]SDM-16. European Journal Of Nuclear Medicine And Molecular Imaging 2021, 49: 1482-1496. PMID: 34761284, PMCID: PMC8940841, DOI: 10.1007/s00259-021-05597-5.Peer-Reviewed Original ResearchConceptsTest-retest variabilityVolume of distributionCentral nervous systemTime-activity curvesPET tracersCentrum semiovaleSynaptic vesicle protein 2AAbsolute test-retest variabilityWhole central nervous systemNonhuman primate brainPlasma free fractionBrain PET scansHigh specific bindingSpecific bindingNondisplaceable volumePlasma input functionNHP brainOne-tissue compartment modelArterial bloodRegional time-activity curvesPET scansNervous systemPrimate brainMonkey brainPreclinical characterizationPreclinical characterization of [18F]T-008, a novel PET imaging radioligand for cholesterol 24-hydroxylase
Koike T, Constantinescu CC, Ikeda S, Nishi T, Sunahara E, Miyamoto M, Cole P, Barret O, Alagille D, Papin C, Morley T, Fowles K, Seibyl J, Tamagnan G, Kuroita T. Preclinical characterization of [18F]T-008, a novel PET imaging radioligand for cholesterol 24-hydroxylase. European Journal Of Nuclear Medicine And Molecular Imaging 2021, 49: 1148-1156. PMID: 34651220, PMCID: PMC8921165, DOI: 10.1007/s00259-021-05565-z.Peer-Reviewed Original ResearchConceptsBrain sectionsMouse brain sectionsEnzyme occupancyBrain-specific enzymeBrain cholesterol homeostasisTreatment of seizuresWild-type miceAdult rhesus macaquesDose-dependent mannerWarrants further studyLogan graphical analysisEpileptic encephalopathySoticlestatBaseline scanAutoradiography studiesPreclinical characterizationLassen plotPreclinical validationBrain regionsCortical regionsPET studiesRhesus macaquesCholesterol homeostasisPET imagingARG study