Mathew L. Thakur
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Previous Organizations / Institutes
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Research Interests
Mathew L. Thakur has a total of 497 co-authors. Here are the top co-authors by number of shared publications:
Eric Wickstrom
Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
18 shared publications- Eric Wickstrom
Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
13 shared publications Kaijun Zhang
Department of Radiology, Thomas Jefferson University, Philadelphia PA 19107
13 shared publicationsMohan R. Aruva
Laboratory of Nucleic Acids Chemistry, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia, and Departments of Biochemistry & Molecular Biology and Radiology, and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
8 shared publicationsA Gottschalk
7 shared publicationsChang-Po Chen
School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, China
7 shared publications
Latest Publications
- Open Access
- 3 March 2025
- Published by MDPI AG in Diagnostics
- Vol. 15 (5) , 607
Non-DRE Voided Urine Test to Diagnose Prostate Cancer: Updated Results
Background: The standard diagnostic approach for prostate cancer (PCa) diagnosis consists of serum prostate-specific antigen (PSA) testing, digital rectal examination (DRE) and image-guided targeted biopsies. Given the invasive nature, potential adverse events and costs associated with these techniques, alternative approaches have been investigated, specifically with serum and urine assays. The work presented here is intended to further validate a novel noninvasive optical technique for PCa detection, targeting the VPAC genomic receptors that are overexpressed on prostate cancer’s malignant cells (MC), in non-DRE voided urine. Methods: Patients (N = 62) who had image-guided biopsy and histologically confirmed localized PCa, and who were scheduled for radical prostatectomy, provided a non-DRE voided urine sample prior to surgery. Urine was cytocentrifuged and cells fixed on a glass slide, incubated with 0.5 μg TP4303 (a receptor-specific fluorophore developed in our laboratory with high affinity for VPAC), excess washed and treated with 4,6-diamidodino-2-phenylindole (DAPI) for nuclear staining. The field of cells on each slide was analyzed using a Zeiss AX10 Observer microscope (20×). The total number of cells and MC were then counted, and the florescent intensity around each MC was measured using Zeiss software. Additionally, non-DRE voided urine samples collected from clinically determined BPH patients (N = 97), were also analyzed similarly. Results: Urine samples from 62 patients were processed and analyzed. Mean PSA levels by Gleason grade (GG) group were 6.5 ± 4.1 ng/mL for GG1 (N = 10), 7.2 ± 3.8 for GG2 (N = 31), 13.2 ± 14.6 for GG3 (N = 13), 6.2 ± 2.2 for GG4 (N = 2) and 50.2 ± 104.9 for GG5 (N = 6). Like the PSA, % MC shed (66.7 ± 27.7) in voided urine and the fluorescent intensity (35.8 ± 5.7) were highest in patients with GG5 prostate cancer. All PCa patients in GG1 to GG5 shed MC in voided urine with increasing % of MC and increasing fluorescence intensity which correlated with the increasing GG for PCa. For BPH, the specificity for the assay was 89.6% (95% CI:81.9–94.9%), PPV was 0.0% and NPV was 100% (95.9% CI, 95.9–100%). Conclusions: These data indicate the following: (i) PCa MC shed in non-DRE voided urine can be detected by targeting VPAC receptors, (ii) MC are shed in non-DRE voided urine with increasing quantity, corresponding to the severity of the disease, and (iii) this non-DRE voided urine optical assay provides a simple, noninvasive, and reliable method for the preliminary detection of PCa with potentially a lower cost than the currently available pre-biopsy detection technologies.
- 3 March 2025
- Published by MDPI AG in Diagnostics
- Vol. 15 (5) , 607
Open AccessNon-DRE Voided Urine Test to Diagnose Prostate Cancer: Updated Results
Background: The standard diagnostic approach for prostate cancer (PCa) diagnosis consists of serum prostate-specific antigen (PSA) testing, digital rectal examination (DRE) and image-guided targeted biopsies. Given the invasive nature, potential adverse events and costs associated with these techniques, alternative approaches have been investigated, specifically with serum and urine assays. The work presented here is intended to further validate a novel noninvasive optical technique for PCa detection, targeting the VPAC genomic receptors that are overexpressed on prostate cancer’s malignant cells (MC), in non-DRE voided urine. Methods: Patients (N = 62) who had image-guided biopsy and histologically confirmed localized PCa, and who were scheduled for radical prostatectomy, provided a non-DRE voided urine sample prior to surgery. Urine was cytocentrifuged and cells fixed on a glass slide, incubated with 0.5 μg TP4303 (a receptor-specific fluorophore developed in our laboratory with high affinity for VPAC), excess washed and treated with 4,6-diamidodino-2-phenylindole (DAPI) for nuclear staining. The field of cells on each slide was analyzed using a Zeiss AX10 Observer microscope (20×). The total number of cells and MC were then counted, and the florescent intensity around each MC was measured using Zeiss software. Additionally, non-DRE voided urine samples collected from clinically determined BPH patients (N = 97), were also analyzed similarly. Results: Urine samples from 62 patients were processed and analyzed. Mean PSA levels by Gleason grade (GG) group were 6.5 ± 4.1 ng/mL for GG1 (N = 10), 7.2 ± 3.8 for GG2 (N = 31), 13.2 ± 14.6 for GG3 (N = 13), 6.2 ± 2.2 for GG4 (N = 2) and 50.2 ± 104.9 for GG5 (N = 6). Like the PSA, % MC shed (66.7 ± 27.7) in voided urine and the fluorescent intensity (35.8 ± 5.7) were highest in patients with GG5 prostate cancer. All PCa patients in GG1 to GG5 shed MC in voided urine with increasing % of MC and increasing fluorescence intensity which correlated with the increasing GG for PCa. For BPH, the specificity for the assay was 89.6% (95% CI:81.9–94.9%), PPV was 0.0% and NPV was 100% (95.9% CI, 95.9–100%). Conclusions: These data indicate the following: (i) PCa MC shed in non-DRE voided urine can be detected by targeting VPAC receptors, (ii) MC are shed in non-DRE voided urine with increasing quantity, corresponding to the severity of the disease, and (iii) this non-DRE voided urine optical assay provides a simple, noninvasive, and reliable method for the preliminary detection of PCa with potentially a lower cost than the currently available pre-biopsy detection technologies.
- Open Access
- 22 April 2024
- Published by Wiley in BJUI Compass
- Vol. 5 (7) , 789-794
Targeting genomic receptors in voided urine for confirmation of benign prostatic hyperplasia
Objectives: The objective of this study is to validate a hypothesis that a non‐invasive optical imaging assay targeting genomic VPAC receptors on malignant cells shed in voided urine will represent either benign prostatic hyperplasia (BPH) or prostatic cancer (PCa). Risk for BPH in men 50–70 years old is 50–70% and PCa is 17%. BPH and PCa can coexist in 20% of men with BPH. Most commonly practiced methods to diagnose BPH do not distinguish BPH from PCa.Patients (or Materials) and Methods: Males with BPH (N = 97, 60.8 ± 6.3 years, prostate‐specific antigen 0.7 ± 0.4 ng/mL) and without oncologic disease (N = 35, 63.4 ± 5.8 years, prostate‐specific antigen < 1.5 ng/mL) signed informed consent form and provided voided urine. Urine was cytocentrifuged, cells collected on glass slide, fixed, treated with VPAC specific fluorophore TP4303 (Kd 3.1 × 10−8M), washed, incubated with DAPI and observed using a fluorescence microscope. Cells with no VPAC did not fluoresce (BPH) and those with VPAC had red‐orange fluorescence (PCa). Real‐time polymerase chain reaction analyses for VPAC and NKX3.1 assay for cell origin were performed.Results: Eighty‐seven subjects were negative for VPAC expression. Positive VPAC expression was noted in 10 subjects. Patient chart review for clinical data on these 10 VPAC positive subjects showed five had nephrolithiasis, three had renal cysts, one had prostatitis and one was being treated with finasteride. Real‐time polymerase chain reaction analysis‐VPAC expressions for 7 normal and 12 BPH subjects were 1.31 ± 1.26 and 0.94 ± 0.89, respectively (P = 0.46). NKX3.1 showed cells of prostate origin for finasteride‐treated patient. Specificity for VPAC urine assay for excluding prostate cancer in this BPH cohort was 88.5%, positive predictive value 0.00% and negative predictive value 100%.Conclusion: VPAC assay may contribute extensively for BPH diagnosis and warrant continued investigation.
- 22 April 2024
- Published by Wiley in BJUI Compass
- Vol. 5 (7) , 789-794
Open AccessTargeting genomic receptors in voided urine for confirmation of benign prostatic hyperplasia
Objectives: The objective of this study is to validate a hypothesis that a non‐invasive optical imaging assay targeting genomic VPAC receptors on malignant cells shed in voided urine will represent either benign prostatic hyperplasia (BPH) or prostatic cancer (PCa). Risk for BPH in men 50–70 years old is 50–70% and PCa is 17%. BPH and PCa can coexist in 20% of men with BPH. Most commonly practiced methods to diagnose BPH do not distinguish BPH from PCa.Patients (or Materials) and Methods: Males with BPH (N = 97, 60.8 ± 6.3 years, prostate‐specific antigen 0.7 ± 0.4 ng/mL) and without oncologic disease (N = 35, 63.4 ± 5.8 years, prostate‐specific antigen < 1.5 ng/mL) signed informed consent form and provided voided urine. Urine was cytocentrifuged, cells collected on glass slide, fixed, treated with VPAC specific fluorophore TP4303 (Kd 3.1 × 10−8M), washed, incubated with DAPI and observed using a fluorescence microscope. Cells with no VPAC did not fluoresce (BPH) and those with VPAC had red‐orange fluorescence (PCa). Real‐time polymerase chain reaction analyses for VPAC and NKX3.1 assay for cell origin were performed.Results: Eighty‐seven subjects were negative for VPAC expression. Positive VPAC expression was noted in 10 subjects. Patient chart review for clinical data on these 10 VPAC positive subjects showed five had nephrolithiasis, three had renal cysts, one had prostatitis and one was being treated with finasteride. Real‐time polymerase chain reaction analysis‐VPAC expressions for 7 normal and 12 BPH subjects were 1.31 ± 1.26 and 0.94 ± 0.89, respectively (P = 0.46). NKX3.1 showed cells of prostate origin for finasteride‐treated patient. Specificity for VPAC urine assay for excluding prostate cancer in this BPH cohort was 88.5%, positive predictive value 0.00% and negative predictive value 100%.Conclusion: VPAC assay may contribute extensively for BPH diagnosis and warrant continued investigation.
- Open Access
- 6 January 2024
- Published by Springer Nature
- p. 321-330
Can VPAC-Targeted Cu-67-TP3805 Play a Theranostic Role for Prostate Cancer?: A Quest
Early and accurate detection of prostate cancer (PCa) together with effective treatment can save lives. Despite the recent advances in its treatment, the mortality trends due to PCa, in the USA, continue to be alarming with annual increase of 3%. In this brief communication, we propose a novel approach to treat PCa, its metastasis and recurrence. This is guided by a large quantity of preliminary data driven by targeting an endogenous genetic product, VPAC, expressed in high density on the cell surface at the onset of genetic mutation that ignites the cancerous transformation.A large body of preclinical and clinical data generated in our laboratory used a positron-emitting radionuclide Copper-64 (Cu-64), conjugated to a small biomolecule, TP 3805 that has a high in vivo stability and high affinity (Kd 3.1 × 10−9 M) for VPAC. The data depict high uptake of Cu-64-TP3805 in primary and metastatic lesions and malignant lymph nodes with minimal uptake in normal tissues except the liver, prompted by the hepatobiliary excretion.Reflecting on the present and planning for the future, our quest is to systematically investigate the use of the beta-emitting sister radionuclide Cu-67 to target VPAC receptors for theranostic applications of primary and metastatic PCa.
- 6 January 2024
- Published by Springer Nature
- p. 321-330
Open AccessCan VPAC-Targeted Cu-67-TP3805 Play a Theranostic Role for Prostate Cancer?: A Quest
Early and accurate detection of prostate cancer (PCa) together with effective treatment can save lives. Despite the recent advances in its treatment, the mortality trends due to PCa, in the USA, continue to be alarming with annual increase of 3%. In this brief communication, we propose a novel approach to treat PCa, its metastasis and recurrence. This is guided by a large quantity of preliminary data driven by targeting an endogenous genetic product, VPAC, expressed in high density on the cell surface at the onset of genetic mutation that ignites the cancerous transformation.A large body of preclinical and clinical data generated in our laboratory used a positron-emitting radionuclide Copper-64 (Cu-64), conjugated to a small biomolecule, TP 3805 that has a high in vivo stability and high affinity (Kd 3.1 × 10−9 M) for VPAC. The data depict high uptake of Cu-64-TP3805 in primary and metastatic lesions and malignant lymph nodes with minimal uptake in normal tissues except the liver, prompted by the hepatobiliary excretion.Reflecting on the present and planning for the future, our quest is to systematically investigate the use of the beta-emitting sister radionuclide Cu-67 to target VPAC receptors for theranostic applications of primary and metastatic PCa.
- Open Access
- 2 November 2022
- Published by MDPI AG in Biomedicines
- Vol. 10 (11) , 2787
Theragnostic Radionuclide Pairs for Prostate Cancer Management: 64Cu/67Cu, Can Be a Budding Hot Duo
Prostate cancer (PCa) is one of the preeminent causes of mortality in men worldwide. Theragnostic, a combination of therapy and diagnostic, using radionuclide pairs to diagnose and treat disease, has been shown to be a promising approach for combating PCa. In PCa patients, bone is one of the most common sites of metastases, and about 90% of patients develop bone metastases. This review focuses on (i) clinically translated theragnostic radionuclide pairs for the management of PCa, (ii) radionuclide therapy of bone metastases in PCa, and (iii) a special emphasis on emerging theragnostic radionuclide pair, Copper-64/Copper-67 (64Cu/67Cu) for managing the disease.
- 2 November 2022
- Published by MDPI AG in Biomedicines
- Vol. 10 (11) , 2787
Open AccessTheragnostic Radionuclide Pairs for Prostate Cancer Management: 64Cu/67Cu, Can Be a Budding Hot Duo
Prostate cancer (PCa) is one of the preeminent causes of mortality in men worldwide. Theragnostic, a combination of therapy and diagnostic, using radionuclide pairs to diagnose and treat disease, has been shown to be a promising approach for combating PCa. In PCa patients, bone is one of the most common sites of metastases, and about 90% of patients develop bone metastases. This review focuses on (i) clinically translated theragnostic radionuclide pairs for the management of PCa, (ii) radionuclide therapy of bone metastases in PCa, and (iii) a special emphasis on emerging theragnostic radionuclide pair, Copper-64/Copper-67 (64Cu/67Cu) for managing the disease.
- Open Access
- 8 December 2019
- Published by BMJ in BMJ Open Diabetes Research & Care
- Vol. 7 (1) , e000881
In vivo investigation of the tissue response to commercial Teflon insulin infusion sets in large swine for 14 days: the effect of angle of insertion on tissue histology and insulin spread within the subcutaneous tissue
Objective: This study investigated the effects of the inflammatory tissue response (ITR) to an insulin infusion set (IIS) on insulin bolus spread over wear time, as well as the effect of cannula insertion angle on the ITR, bolus shape, and pump tubing pressure.Research design and methods: Angled or straight IISs were inserted every other day for 14 days into the subcutaneous tissue of 11 swine and insulin was delivered continuously. Prior to euthanasia, a 70 µL bolus of insulin/X-ray contrast agent was infused while recording a pressure profile (peak tubing pressure, pmax; area under the pressure curve, AUC), followed by the excision of the tissue-catheter specimen. Bolus surface area (SA) and volume (V) were assessed via micro-CT. Tissue was stained to analyze total area of inflammation (TAI) and inflammatory layer thickness (ILT) surrounding the cannula.Results: A bolus delivered through an angled IIS had a larger mean SA than a bolus delivered through a straight cannula (314.0±84.2 mm2vs 229.0±99.7 mm2, p3vs 145.0±65.9 mm3, p=0.001). Both decreased significantly over wear time, independent of angle. There was a significant difference in TAI (angled, 9.1±4.0 mm2vs straight, 14.3±8.6 mm2, pmax(p=0.005) and AUC (p=0.014) were lower using angled IIS. As ILT increased, pmaxincreased, while SA and V decreased.Conclusions: The progression of the ITR directly affected bolus shape and tubing pressure. Although straight insertion is clinically preferred, our data suggest that an angled IIS elicits lower grades of ITR and delivers a bolus with lower tubing pressure and greater SA and V. The subcutaneous environment plays a crucial role in IIS longevity, and the insertion angle needs to be considered in future IIS designs and clinical trials.
- 8 December 2019
- Published by BMJ in BMJ Open Diabetes Research & Care
- Vol. 7 (1) , e000881
Open AccessIn vivo investigation of the tissue response to commercial Teflon insulin infusion sets in large swine for 14 days: the effect of angle of insertion on tissue histology and insulin spread within the subcutaneous tissue
Objective: This study investigated the effects of the inflammatory tissue response (ITR) to an insulin infusion set (IIS) on insulin bolus spread over wear time, as well as the effect of cannula insertion angle on the ITR, bolus shape, and pump tubing pressure.Research design and methods: Angled or straight IISs were inserted every other day for 14 days into the subcutaneous tissue of 11 swine and insulin was delivered continuously. Prior to euthanasia, a 70 µL bolus of insulin/X-ray contrast agent was infused while recording a pressure profile (peak tubing pressure, pmax; area under the pressure curve, AUC), followed by the excision of the tissue-catheter specimen. Bolus surface area (SA) and volume (V) were assessed via micro-CT. Tissue was stained to analyze total area of inflammation (TAI) and inflammatory layer thickness (ILT) surrounding the cannula.Results: A bolus delivered through an angled IIS had a larger mean SA than a bolus delivered through a straight cannula (314.0±84.2 mm2vs 229.0±99.7 mm2, p3vs 145.0±65.9 mm3, p=0.001). Both decreased significantly over wear time, independent of angle. There was a significant difference in TAI (angled, 9.1±4.0 mm2vs straight, 14.3±8.6 mm2, pmax(p=0.005) and AUC (p=0.014) were lower using angled IIS. As ILT increased, pmaxincreased, while SA and V decreased.Conclusions: The progression of the ITR directly affected bolus shape and tubing pressure. Although straight insertion is clinically preferred, our data suggest that an angled IIS elicits lower grades of ITR and delivers a bolus with lower tubing pressure and greater SA and V. The subcutaneous environment plays a crucial role in IIS longevity, and the insertion angle needs to be considered in future IIS designs and clinical trials.
- 20 September 2019
- Published by Springer Nature in Clinical and Translational Imaging
- Vol. 7 (6) , 381-404
Advanced approaches to imaging primary breast cancer: an update
- 20 September 2019
- Published by Springer Nature in Clinical and Translational Imaging
- Vol. 7 (6) , 381-404
Advanced approaches to imaging primary breast cancer: an update
- 18 June 2019
- Published by Springer Nature in Molecular Imaging and Biology
- Vol. 22 (2) , 293-302
Targeting VPAC1 Receptors for Imaging Glioblastoma
Scintigraphic imaging of malignant glioblastoma (MG) continues to be challenging. We hypothesized that VPAC1 cell surface receptors can be targeted for positron emission tomography (PET) imaging of orthotopically implanted MG in a mouse model, using a VPAC1-specific peptide [64Cu]TP3805.
- 18 June 2019
- Published by Springer Nature in Molecular Imaging and Biology
- Vol. 22 (2) , 293-302
Targeting VPAC1 Receptors for Imaging Glioblastoma
Scintigraphic imaging of malignant glioblastoma (MG) continues to be challenging. We hypothesized that VPAC1 cell surface receptors can be targeted for positron emission tomography (PET) imaging of orthotopically implanted MG in a mouse model, using a VPAC1-specific peptide [64Cu]TP3805.
- Open Access
- 1 June 2019
- Published by Jaypee Brothers Medical Publishing in Research & Innovation in Anesthesia
- Vol. 4 (1) , 25-28
Iatrogenic Posterior Mediastinal Hematoma Secondary to Internal Jugular Vein Cannulation: A Case Report
- 1 June 2019
- Published by Jaypee Brothers Medical Publishing in Research & Innovation in Anesthesia
- Vol. 4 (1) , 25-28
Open AccessIatrogenic Posterior Mediastinal Hematoma Secondary to Internal Jugular Vein Cannulation: A Case Report
- Open Access
- 5 December 2018
- Published by Springer Nature in EMBO Molecular Medicine
- Vol. 11 (1) , e9540
Murine MPDZ‐linked hydrocephalus is caused by hyperpermeability of the choroid plexus
Though congenital hydrocephalus is heritable, it has been linked only to eight genes, one of which is MPDZ . Humans and mice that carry a truncated version of MPDZ incur severe hydrocephalus resulting in acute morbidity and lethality. We show by magnetic resonance imaging that contrast medium penetrates into the brain ventricles of mice carrying a Mpdz loss‐of‐function mutation, whereas none is detected in the ventricles of normal mice, implying that the permeability of the choroid plexus epithelial cell monolayer is abnormally high. Comparative proteomic analysis of the cerebrospinal fluid of normal and hydrocephalic mice revealed up to a 53‐fold increase in protein concentration, suggesting that transcytosis through the choroid plexus epithelial cells of Mpdz KO mice is substantially higher than in normal mice. These conclusions are supported by ultrastructural evidence, and by immunohistochemistry and cytology data. Our results provide a straightforward and concise explanation for the pathophysiology of Mpdz ‐linked hydrocephalus.
- 5 December 2018
- Published by Springer Nature in EMBO Molecular Medicine
- Vol. 11 (1) , e9540
Open AccessMurine MPDZ‐linked hydrocephalus is caused by hyperpermeability of the choroid plexus
Though congenital hydrocephalus is heritable, it has been linked only to eight genes, one of which is MPDZ . Humans and mice that carry a truncated version of MPDZ incur severe hydrocephalus resulting in acute morbidity and lethality. We show by magnetic resonance imaging that contrast medium penetrates into the brain ventricles of mice carrying a Mpdz loss‐of‐function mutation, whereas none is detected in the ventricles of normal mice, implying that the permeability of the choroid plexus epithelial cell monolayer is abnormally high. Comparative proteomic analysis of the cerebrospinal fluid of normal and hydrocephalic mice revealed up to a 53‐fold increase in protein concentration, suggesting that transcytosis through the choroid plexus epithelial cells of Mpdz KO mice is substantially higher than in normal mice. These conclusions are supported by ultrastructural evidence, and by immunohistochemistry and cytology data. Our results provide a straightforward and concise explanation for the pathophysiology of Mpdz ‐linked hydrocephalus.
- Open Access
Murine MPDZ -Linked Hydrocephalus is Caused by Hyperpermeability of the Choroid Plexus
Though congenital hydrocephalus is heritable, it has been linked only to eight genes, one of which is MPDZ . Humans and mice that carry a truncated version of MPDZ incur severe hydrocephalus resulting in acute morbidity and lethality. We show by magnetic resonance imaging that contrast-medium penetrates into the brain ventricles of mice carrying a Mpdz loss-of-function mutation, whereas none is detected in the ventricles of normal mice, implying that the permeability of the choroid plexus epithelial cell monolayer is abnormally high. Comparative proteomic analysis of the cerebrospinal fluid of normal and hydrocephalic mice revealed up to a 53-fold increase in protein concentration, suggesting that transcytosis through the choroid plexus epithelial cells of Mpdz KO mice is substantially higher than in normal mice. These conclusions are supported by ultrastructural evidence, and by immunohistochemistry and cytology data. Our results provide a straight-forward and concise explanation for the pathophysiology of Mpdz -linked hydrocephalus.
Open AccessMurine MPDZ -Linked Hydrocephalus is Caused by Hyperpermeability of the Choroid Plexus
Though congenital hydrocephalus is heritable, it has been linked only to eight genes, one of which is MPDZ . Humans and mice that carry a truncated version of MPDZ incur severe hydrocephalus resulting in acute morbidity and lethality. We show by magnetic resonance imaging that contrast-medium penetrates into the brain ventricles of mice carrying a Mpdz loss-of-function mutation, whereas none is detected in the ventricles of normal mice, implying that the permeability of the choroid plexus epithelial cell monolayer is abnormally high. Comparative proteomic analysis of the cerebrospinal fluid of normal and hydrocephalic mice revealed up to a 53-fold increase in protein concentration, suggesting that transcytosis through the choroid plexus epithelial cells of Mpdz KO mice is substantially higher than in normal mice. These conclusions are supported by ultrastructural evidence, and by immunohistochemistry and cytology data. Our results provide a straight-forward and concise explanation for the pathophysiology of Mpdz -linked hydrocephalus.