Characterization of human dermal sheath cells reveals CD36-expressing perivascular cells associated with capillary blood vessel formation in hair follicles.

Dermal sheath (DS) is located at the outermost border of hair follicles, comprising the connective tissue sheath of these follicles; DS cells are known to contribute to hair cycling and follicle neogenesis. However, the mechanisms by which DS cells contribute to hair formation are currently unclear. We investigated the global transcriptional profile of human DS cells in early passaged culture, compared with those of human dermal papilla cells (DP cells) and dermal fibroblasts. Vascular related genes were highly expressed in DS cells, and expression of the multi-ligand receptor, CD36, was significantly higher in DS cells than in DP cells. Further analyses with whole-mount imaging technique showed that dense networks of blood capillaries were formed in the DS of human anagen hair follicles, whereas regression of blood capillaries was observed in telogen and catagen hair follicles. We found that CD36-expressing cells were present in populations of DS cells, but were rarely observed in populations of DP cells and fibroblasts. Furthermore, our results indicated that CD36-expressing DS cells may participate in angiogenesis. Therefore, we concluded that CD36-expressing DS cells may modulate blood capillaries in hair follicles, in association with hair cycling.

Wnt activator CHIR99021-stimulated human dermal papilla spheroids contribute to hair follicle formation and production of reconstituted follicle-enriched human skin.

The aim of the present study was to accomplish de novo generation of reconstituted human skin with enriched hair follicles. Dermal papillae (DP) are known to play a crucial organizing role in hair follicle induction. However, generation of enriched human hair follicles using cultured DP cells has not been accomplished because DP cells easily lose their hair-inducing ability with culturing. To enhance the hair-inducing ability of DP cells, Wnt signaling pathway activation or three-dimensional (3D) spheroid culture methods were employed in previous studies. Herein, we assessed effects of the canonical Wnt/ß-catenin signaling activator CHIR99021 and found that it enhanced the expression of DP signature genes associated with hair-inducing ability. Further comparison of three different 3D culture methods revealed the highest expression of DP signature genes in spheroids generated by a floating drop method compared with other methods. CHIR99021 synergistically increased expression of DP signature genes in combination with floating drop culture. "Reconstituted skin assay" prepared using the most promising CHIR99021-stimulated 3D spheroids showed enrichment for human hair follicles. Labeled DP spheroids and derived cells were primarily found to be DP and dermal sheath cup (DSC) cells, implying organization of hair formation by DP spheroids. Finally, to evaluate the functional features of generated human skin and hair follicles, we injected human DSC cells, which reportedly show DP precursor behavior, and exhibit hair-inducing ability through incorporation into hair follicles, into mice. Histological studies revealed injected DSC cells in dermal sheath of hair follicles, consistent with a previous report, thus verifying the functionality of generated skin and hair follicles. Collectively, our findings demonstrate that DP spheroids synergistically stimulated by CHIR99021 and 3D culture contributed to hair follicle formation, thus making it possible to generate reconstituted hair follicle-enriched human skin with functional features.

Gene Expression Profiling of the Intact Dermal Sheath Cup of Human Hair Follicles.

Cells that constitute the dermal papillae of hair follicles might be derived from the dermal sheath, the peribulbar component of which is the dermal sheath cup. The dermal sheath cup is thought to include the progenitor cells of the dermal papillae and possesses hair inductive potential; however, it has not yet been well characterized. This study investigated the gene expression profile of the intact dermal sheath cup, and identified dermal sheath cup signature genes, including extracellular matrix components and bone morphogenetic protein-binding molecules, as well as transforming frowth factor beta 1 as an upstream regulator. Among these, gremilin-2, a member of the bone morphogenetic protein antagonists, was found by in situ hybridization to be highly specific to the dermal sheath cup, implying that gremlin-2 is a key molecule contributing to maintenance of the properties of the dermal sheath cup.

Differentiation of myocardial ischemia and infarction assessed by dynamic computed tomography perfusion imaging and comparison with cardiac magnetic resonance and single-photon emission computed tomography.

OBJECTIVES: To evaluate the feasibility of myocardial blood flow (MBF) by computed tomography from dynamic CT perfusion (CTP) for detecting myocardial ischemia and infarction assessed by cardiac magnetic resonance (CMR) or single-photon emission computed tomography (SPECT). METHODS: Fifty-three patients who underwent stress dynamic CTP and either SPECT (n = 25) or CMR (n = 28) were retrospectively selected. Normal and abnormal perfused myocardium (ischemia/infarction) were assessed by SPECT/CMR using 16-segment model. Sensitivity and specificity of CT-MBF (mL/g/min) for detecting the ischemic/infarction and severe infarction were assessed. RESULTS: The abnormal perfused myocardium and severe infarction were seen in SPECT (n = 90 and n = 19 of 400 segments) and CMR (n = 223 and n = 36 of 448 segments). For detecting the abnormal perfused myocardium, sensitivity and specificity were 80 % (95 %CI, 71-90) and 86 % (95 %CI, 76-91) in SPECT (cut-off MBF, 1.23), and 82 % (95 %CI, 76-88) and 87 % (95 %CI, 80-92) in CMR (cut-off MBF, 1.25). For detecting severe infarction, sensitivity and specificity were 95 % (95 %CI, 52-100) and 72 % (95 %CI, 53-91) in SPECT (cut-off MBF, 0.92), and 78 % (95 %CI, 67-97) and 80 % (95 %CI, 58-86) in CMR (cut-off MBF, 0.98), respectively. CONCLUSIONS: Dynamic CTP has a potential to detect abnormal perfused myocardium and severe infarction assessed by SPECT/CMR using comparable cut-off MBF. KEY POINTS: • CT-MBF accurately reflects the severity of myocardial perfusion abnormality. • CT-MBF provides good diagnostic accuracy for detecting myocardial perfusion abnormalities. • CT-MBF may assist in stratifying severe myocardial infarction in abnormal perfusion myocardium.

Voxel-based correlation between whole-brain CT perfusion with 320-row area detector ct and iodine 123 iodoamphetamine brain perfusion spect in patients with cerebrovascular disease.

OBJECTIVE: We compared cerebral blood flow (CBF) measured using computed tomographic (CT) perfusion (CTP) and N-isopropyl-p-[(123) I]-iodoamphetamine cerebral perfusion single-photon emission computed tomography (SPECT). METHODS: We used a 320-row area detector CT and N-isopropyl-p-[(123) I]-iodoamphetamine cerebral perfusion SPECT under similar conditions in patients with chronic cerebrovascular disease. Images were automatically aligned 3-dimensionally for voxel-by-voxel comparisons. RESULTS: Linear positive correlations were observed between CTP-CBF including high-blood-flow areas and SPECT-CBF over the whole brain (r = 0.001-0.6, P < 0.01), superior cerebral level (r = 0.45-0.93, P < 0.01), basal ganglia level (r = 0.44-0.77, P < 0.01), and skull base (r = 0.02-0.66, P < 0.01). Correlations between CTP-CBF excluding high-blood-flow areas were significantly higher (P < 0.0001). CONCLUSIONS: Computed tomographic perfusion overestimated CBF compared with SPECT and showed poor correlation at the skull base. Computed tomographic perfusion CTP excluding high-blood-flow areas improved the correlation over the whole brain in patients with chronic cerebrovascular disease.

Development of software for measuring brain amyloid accumulation using 18 F-florbetapir PET and calculating global Centiloid scale and regional Z-score values.

BACKGROUND AND PURPOSE: Quantitative measures have been proposed to aid the visual interpretation of amyloid PET. Our objective was to develop and validate quantitative software that enables calculation of the Centiloid (CL) scale and Z-score for amyloid PET with 18 F-florbetapir. METHODS: This software was developed as a toolbox in statistical parametric mapping 12 running on MATLAB Runtime. For each participant's amyloid PET, this software calculates the CL scale using the standard MRI-guided pipeline proposed by the Global Alzheimer's Association Interactive Network (GAAIN) and generates a Z-score map for comparison with a new amyloid-negative database constructed from 20 healthy controls. In 23 cognitively impaired patients with suspected Alzheimer's disease, Z-score values for a target cortical area from the new database were compared with those from the GAAIN database constructed from 13 healthy controls. The CL values obtained using low-dose CT of PET/CT equipment were then compared with those obtained using MRI. RESULTS: The CL calculation was validated with the 18 F-florbetapir dataset in the GAAIN repository. Z-score values obtained from the new database were significantly higher (mean ± standard deviation, 1.05 ± 0.77; p < .0001) than those obtained from the GAAIN database. The use of low-dose CT provided CL scales that were highly correlated with those obtained with MRI (R2  = .992) but showed a slight yet significant underestimation (-2.1 ± 4.2; p = .013). CONCLUSIONS: Our quantification software provides the CL scale and Z-score for measuring overall and local amyloid accumulation with the use of MRI or low-dose CT.

Perivascular localization of dermal stem cells in human scalp.

In mammalian skin, the existence of stem cells in the dermis is still poorly understood. Previous studies have indicated that mesenchymal stem cells (MSCs) are situated as pericytes in various mammalian tissues. We speculated that the human adult dermis also contains MSC-like cells positive for CD34 at perivascular sites similar to adipose tissue. At first, stromal cells from adult scalp skin tissues showed colony-forming ability and differentiated into mesenchymal lineages (osteogenic, chondrogenic and adipogenic). Three-dimensional analysis of scalp skin with a confocal microscope clearly demonstrated that perivascular cells were positive for not only NG2, but also CD34, immunoreactivity. Perivascular CD34-positive cells were abundant around follicular portions. Furthermore, CD34-positive cell fractions collected with magnetic cell sorting were capable of differentiating into mesenchymal lineages. This study suggests that dermal perivascular sites act as a niche of MSCs in human scalp skin, which are easily accessible and useful in regenerative medicine.

Hair-inducing ability of human dermal papilla cells cultured under Wnt/ß-catenin signalling activation.

It is well known that dermal papilla cells (DPCs) play crucial roles in hair follicle induction. In this study, we examined whether Wnt/ß-catenin activation results in maintenance of the hair-inducing ability of human DPCs. Expression of DPC marker genes was maintained under Wnt/ß-catenin signalling stimulation by GSK-3ß inhibition. Furthermore, human DPCs showed constant hair induction when transplanted with murine epidermal cell fraction. Alu-positive human DPCs were essentially detected adjacent to the reconstructing epidermal structure positive for P-cadherin immunoreactivity. The transplanted human DPCs were abundant in the surrounding dermal sheath portion of the fully regenerated hair follicles. These results support the importance of Wnt/ß-catenin signalling in hair follicle induction. This study may provide valuable information to establish a culture method of human DPCs for cell-based therapy.

Evaluation of lung perfusion by using lung perfusion SPECT and lung CT with breathing synchronization software.

BACKGROUND: Lung perfusion using 99mTc-macroaggregated albumin single-photon emission computed tomography (SPECT) and lung computed tomography (CT) is a useful modality for identifying patients with pulmonary artery embolism. However, conformity between SPECT and CT at the bottom of the lung is generally low. This study aims to investigate the progression of conformity between lung perfusion SPECT and lung CT using a breathing synchronization software. METHODS: Among 95 consecutive patients who underwent lung perfusion SPECT and lung CT within 14 days because of suspected pulmonary embolism between June 2019 and August 2020 in department of cardiovascular medicine, we identified 28 patients (73 ± 10 years) who had normal pulmonary artery on contrast lung CT. We compared lung volumes calculated using lung perfusion SPECT and lung CT as gold standard. Visual conformity between lung SPECT and lung CT was scored 0-4 (0: 0-25%, 1: 25-50%, 2: 50-75%, 3: 75-90%, 4: > 90%) by two specialists in nuclear medicine and assessed. RESULTS: The lung volume calculated from lung CT was 3749 ± 788 ml. The lung volume calculated from lung perfusion SPECT without using the breathing synchronization software was 3091 ± 610 ml. There was a significant difference between the lung volume calculated from CT and SPECT without using the breathing synchronization software (P < 0.01). The lung volume calculated from lung perfusion SPECT using the breathing synchronization software was 3435 ± 686 ml, and there was no significant difference between the lung volume calculated from CT and SPECT using the breathing synchronization software. The visual score improved with the use of breathing synchronization software (without software; 1.9 ± 0.6 vs. with software; 3.4 ± 0.7, P < 0.001). CONCLUSION: This study demonstrated that the breathing synchronization software could improve conformity between lung perfusion SPECT and lung CT.

Identification of novel hair-growth inducers by means of connectivity mapping.

The aim of this study was to identify novel inducers of hair growth using gene expression profiling at various stages of hair-growth induction. First, we analyzed gene expression at the onset of hair growth in mice induced by cyclosporin A (CsA), a well-known hair-growth inducer, using DNA microarray analysis. The results unveiled genes involved in the step-by-step progression of hair growth, including increases in melanin biosynthesis and decreases in immune response at d 2 and the subsequent stimulation of cell proliferation at d 4, followed by the up-regulation of hair specific keratins at d 7 after CsA treatment. With the use of the connectivity map (Cmap), agents that had a similar "gene signature" to that of the profiles of CsA-treated mice were identified. Several agents, including CsA, were identified by the Cmap and were evaluated for hair induction activity in vivo. One of the proposed agents, fluphenazine (from the d 2 signature) actually induced hair growth in vivo (ED(50): 2 mM for single application), and the subsequent application of 5 mM iloprost (from the d 4 signature) significantly enhanced the hair-growth effect of fluphenazine. From these results, Cmap analysis was proven to be a useful method that connects gene expression profiles of complicated biological processes, such as hair-growth induction, to effective agents.

Cerebral perfusion changes in chronic dizziness: A single-photon emission computed tomography study.

BACKGROUND AND PURPOSE: Dizziness may persist even after the causative vestibular imbalance subsides. Although the precise mechanism of chronic dizziness is unknown, various cerebral activity changes associated with it have been reported. To understand its mechanism in the absence of the causative vestibular imbalance, we compared cerebral changes in chronic dizziness with and without persistent vestibular imbalance. METHODS: Between September 2014 and March 2020, we examined regional cerebral blood flow (rCBF) in 12 patients having chronic post-lateral medullary infarction dizziness with persistent brainstem vestibular imbalance and 23 patients having chronic dizziness without currently active vestibular imbalance using single-photon emission computed tomography (SPECT) with 99m Technetium-ethyl cysteinate dimer. Further, we analyzed the SPECT images using a voxel-based group comparison. RESULTS: We observed a decreased rCBF in the occipital lobe and increased rCBF in the medial and inferior parts of the temporal lobe in patients having chronic dizziness with and without active vestibular imbalance compared to healthy controls. However, only patients having chronic dizziness without active vestibular imbalance exhibited increased rCBF in the frontal lobe, including the orbitofrontal cortex. CONCLUSION: This is the first study to highlight the difference in rCBF changes between patients having chronic dizziness with and without active vestibular imbalance. Decreased occipital lobe activity and increased medial and inferior temporal lobe activity may be related to keeping dizziness perception triggered regardless of the presence or absence of active vestibular imbalance, whereas increased frontal lobe activity may explain the dizziness background to persist after the disappearance of vestibular imbalance.

Changes after behavior therapy among responsive and nonresponsive patients with obsessive-compulsive disorder.

Neuroimaging studies have suggested that behavior therapy (BT) might change abnormal activity in the frontal-subcortical circuits of the brain in patients with obsessive-compulsive disorder (OCD). However, the results of these studies have been rather inconsistent. The aim of the present study was to use statistical parametric mapping (SPM) analysis to explore the effects of successful BT on regional cerebral blood flow (rCBF) in patients with OCD. Forty-five OCD patients who were treatment-resistant to a single serotonin reuptake inhibitor (SRI) trial were examined. Single photon emission computed tomography (SPECT) using 99mTc-ECD was performed before and after the completion of 12 weeks of BT. Although no significant differences in pre-treatment rCBF were observed between responders and nonresponders to BT, the post-treatment rCBF values in the left medial prefrontal cortex (Brodmann area 10) and bilateral middle frontal gyri (Brodmann area 10) were significantly lower in the responders than in the nonresponders. Furthermore, the baseline rCBF in the bilateral orbitofrontal cortex (OFC) was significantly correlated with the change in the Y-BOCS score among the responders. Our results support the hypothesis that while the OFC may be associated with the BT response, BT may result in changes in rCBF in the medial and middle frontal cortex.

Marked Changes in Lamellar Granule and Trans-Golgi Network Structure Occur during Epidermal Keratinocyte Differentiation.

Epidermal lamellar granules transport various lipids, proteins, and protein inhibitors from the trans-Golgi network to the extracellular space, and play an important role in skin barrier formation. We elucidated the 3-dimensional structure of lamellar granules and the trans-Golgi network in normal human skin by focused ion beam scanning electron microscopy. Reconstructed focused ion beam scanning electron microscopy 3-dimensional images revealed that the overall lamellar granule structure changed from vesicular to reticular within the second layer of the stratum granulosum. Furthermore, the trans-Golgi network was well developed within this layer and spread through the cytoplasm with branched, tubular structures that connected to lamellar granules. Our study reveals the unique overall 3-dimensional structure of lamellar granules and the trans-Golgi network within the cells of the epidermis, and provides the basis for an understanding of the skin barrier formation.

Pattern of FDG and MET Distribution in High- and Low-Grade Gliomas on PET Images.

PURPOSE OF THE REPORT: This study aimed to determine the most effective metabolic index of FDG-PET and MET-PET to differentiate high- and low-grade gliomas, and then to characterize tumor metabolism according to the 2016 WHO classification. We also developed a new calculation method of potential infiltrative tumor volume to overcome the current limitations of tumor evaluation according to metabolic index, which focuses solely on tumor core area. MATERIALS AND METHODS: Patients who underwent both FDG-PET and MET-PET, as well as surgical treatment, were retrospectively identified. All tumors were diagnosed histologically and included 44 high-grade and 19 low-grade gliomas. Metabolic indices of tumor-to-normal (T/N) ratio and maximum value within the tumor itself were compared between high- and low-grade tumors. A calculation method for potential infiltrative tumor volume was developed and compared between these 2 grades. RESULTS: T/N, calculated as tumor value divided by normal cortex value, was the most effective (area under the curve, 0.800 for FDG-PET; area under the curve, 0.773 for MET-PET) for differentiating high- and low-grade gliomas. Potential infiltrative volume effectively distinguished between high- and low-grade glioma (43.8 ± 30.2 mL vs 14.0 ± 12.6 mL; P = 0.005 [t test]). A combination of T/N, with a cutoff value of 0.9 or higher on FDG-PET and/or 3.0 or higher on MET-PET, and potential infiltrative volume, with a cutoff value of 20.0 mL or higher, provided a diagnostic accuracy of 89% in distinguishing high- from low-grade gliomas. CONCLUSIONS: Evaluation of potential infiltrative volume surrounding the tumor core area, in addition to the T/N ratio of the tumor core, may help distinguish between high- and low-grade gliomas.

SPECT-identified neuroanatomical predictor of the cognitive effects of donepezil treatment in patients with Alzheimer's disease.

BACKGROUND/OBJECTIVE: We attempted to determine whether the pretreatment regional cerebral blood flow (rCBF) might predict cognitive changes in response to donepezil treatment, as assessed in terms of the Alzheimer Disease Assessment Scale cognitive subscale (ADAS-cog), and in relation to the severity of subcortical hyperintensities (SH). METHOD: Forty-one patients with Alzheimer's disease (AD) were treated with donepezil at baseline. All the patients underwent a single photon emission computed tomography examination before donepezil therapy. They also completed the ADAS-cog at baseline and after 24 weeks of donepezil therapy. SH were assessed semiquantitatively using a recently developed visual rating scale. We analyzed the correlation between the baseline rCBF and changes in the ADAS-cog score using statistical parametric mapping, including the severity of the SH as a covariate. RESULTS: Lower pretreatment rCBF levels in the right orbitofrontal cortex (OFC) predicted a better improvement in the ADAS-cog score in response to donepezil therapy. The severity of SH did not appear to influence this correlation. CONCLUSIONS: This effect may reflect the choline acetyltransferase activity associated with the OFC. The presence of SH did not appear to influence the effect of donepezil therapy on the cognitive function as assessed by ADAS-cog.

Behaviors of cost functions in image registration between 201Tl brain tumor single-photon emission computed tomography and magnetic resonance images.

OBJECTIVE: We studied the behaviors of cost functions in the registration of thallium-201 (201Tl) brain tumor single-photon emission computed tomography (SPECT) and magnetic resonance (MR) images, as the similarity index of image positioning. METHODS: A marker for image registration [technetium-99m (99mTc) point source] was attached at three sites on the heads of 13 patients with brain tumor, from whom 42 sets of 99mTc-201Tl SPECT (the dual-isotope acquisition) and MR images were obtained. The 201Tl SPECT and MR images were manually registered according to the markers. From the positions where the two images were registered, the position of the 201Tl SPECT was moved to examine the behaviors of the three cost functions, i.e., ratio image uniformity (RIU), mutual information (MI), and normalized MI (NMI). RESULTS: The cost functions MI and NMI reached the maximum at positions adjacent to those where the SPECT and MR images were manually registered. As for the accuracy of image registration in terms of the cost functions MI and NMI, on average, the images were accurately registered within 3 degrees of rotation around the X-, Y-, and Z-axes, and within 1.5 mm (within 2 pixels), 3 mm (within 3 pixels), and 4 mm (within 1 slice) of translation to the X-, Y-, and Z-axes, respectively. In terms of rotation around the Z-axis, the cost function RIU reached the minimum at positions where the manual registration of the two images was substantially inadequate. CONCLUSIONS: The MI and NMI were suitable cost functions in the registration of 201Tl SPECT and MR images. The behavior of the RIU, in contrast, was unstable, being unsuitable as an index of image registration.

Comparison of regional brain volume and glucose metabolism between patients with mild dementia with lewy bodies and those with mild Alzheimer's disease.

UNLABELLED: The aim of this study was to investigate regional differences between morphologic and functional changes in patients with mild dementia with Lewy bodies (DLB) compared with those with Alzheimer's disease (AD). METHODS: Twenty patients with very mild DLB (mean age, 74.5 y; mean Mini-Mental State Examination [MMSE] score, 24.0), 20 patients with very mild AD (mean age, 74.1 y; mean MMSE score, 24.0), and 20 age- and sex-matched healthy volunteers (normal controls [NC]) underwent both (18)F-FDG PET and 3-dimensional spoiled gradient echo MRI. Fully automatic volumetry of the MRI data was used to obtain whole brain, hippocampal, occipital, and striatal volumes, which were compared with the results of a similar analysis of glucose metabolic data. RESULTS: In DLB patients, volumetric data indicated a significant volume decrease in the striatum, whereas (18)F-FDG PET showed significant glucose metabolic reductions in the temporal, parietal, and frontal areas--including in the occipital lobe--compared with those in the NC group. In contrast, in AD patients, both the hippocampal volume and glucose metabolism were significantly decreased, whereas the occipital volume and metabolism were preserved. CONCLUSION: Comparison of very mild DLB and AD revealed different morphologic and metabolic changes occurring in the medial temporal lobes and the occipital lobe, demonstrating characteristic pathophysiologic differences between these 2 diseases.

[A paper sheet phantom for scintigraphic planar imaging: usefulness of pouch-laminated paper source].

In order to perform experimental measurements for evaluation of imaging device's performance, data acquisition technique, and clinical images on scintigraphic imaging, many kinds of phantoms are employed. However, since these materials are acrylic and plastic, the thickness and quality of those materials cause attenuation and scatter in itself. We developed a paper sheet phantom sealed with a pouch laminator, which can be a true radioactive source in air. In this study, the paper sheet phantom was compared to the acrylic liver phantom, with the thickness of 2 cm, which is commercially available. The results showed that although some scatter counts were contained within the image of the acrylic liver phantom, there were few scattered photons in the paper sheet phantom image. Furthermore, this laminated paper sheet phantom made handling of the source and its waste easier. If the paper sheet phantom will be designed more sophisticatedly, it becomes a useful tool for planar imaging experiments.