The Trajectory of the COVID-19 Vaccine Antibody Titers Over Time and the Association of Mycophenolate Mofetil in Solid Organ Transplant Recipients.

The COVID-19 vaccine will be safe and effective in solid organ transplant recipients (SOTs). However, the blunted antibody responses were also of concern. Few studies have reported prolonged serologic follow-up after 2 doses of BNT162b2 vaccine in SOTs. We performed a single-center, prospective observational study of 78 SOTs who received 2 doses of BNT162b2 vaccine. We identified the trajectory of antibody titers after vaccination among SOTs with or without mycophenolate mofetil (MMF) or withdrawn from MMF. We found low seroconversion rates (29/42: 69%) and low antibody titers in SOTs treated with MMF. An inverse linear relationship between neutralizing antibody titers and MMF concentration was confirmed in restricted cubic spline plots (P for effect < .01, P for nonlinearity = .08). For the trajectory of antibody responses, seroconversion and improved antibody titers were observed after withdrawal from MMF in SOTs who showed seronegative or low antibody titers at the first visit after 2 doses of vaccine (P for effect < .01, P for nonlinearity < .05, and P for interaction < .01). We identified increased B-cell counts after withdrawal from MMF (P < .01). The recovery of antibody responses was seen in SOTs withdrawn from MMF. The trajectories of antibody responses were modified by MMF administration.

Immediate postnatal central hypothyroidism caused by maternal Graves' disease: Importance of early screening.

This report illustrates a case of central hypothyroidism in a newborn immediately after birth caused by maternal Graves' disease. Infants from mothers with Graves' disease require careful examination without waiting for neonatal screening results, even though the mother's thyroid function is normal at birth or the newborn does not have goiter.

Transplantation of hematopoietic stem cells: intra-arterial versus intravenous administration impacts stroke outcomes in a murine model.

Based on results of hematopoietic stem cell transplantation in animal models of stroke, clinical trials with hematopoietic stem cells administered intra-arterially or intravenously have been initiated in patients. Although intra-arterial injection is expected to deliver transplanted cells more directly to the ischemic tissue, the optimal route for enhancing clinical outcomes has not been identified in the setting of stroke. In this study, we compared the therapeutic potential of intra-arterial versus intravenous injection of bone marrow derived-mononuclear cells (BM-MNCs) and CD133-positive (CD133(+)) cells in a murine stroke model. We have found that intra-arterial injection of BM-MNCs exaggerates inflammation with accompanying loss of microvascular structures in poststroke brain and no improvement in cortical function. In contrast, intravenous injection of BM-MNCs did not similarly enhance inflammation and improved cortical function. Our results indicate that the optimal route of cell transplantation can vary with different cell populations and highlight possible issues that might arise with intra-arterial cell administration for acute ischemic cerebrovascular disease.

Intravenous Autologous Bone Marrow Mononuclear Cell Transplantation for Stroke: Phase1/2a Clinical Trial in a Homogeneous Group of Stroke Patients.

The goal of this clinical trial was to assess the feasibility and safety of transplanting autologous bone marrow mononuclear cells into patients suffering severe embolic stroke. Major inclusion criteria included patients with cerebral embolism, age 20-75 years, National Institute of Health Stroke Scale (NIHSS) score displaying improvement of ≤ 5 points during the first 7 days after stroke, and NIHSS score of ≥ 10 on day 7 after stroke. Bone marrow aspiration (25 or 50 mL; N = 6 patients in each case) was performed 7-10 days poststroke, and bone marrow mononuclear cells were administrated intravenously. Mean total transplanted cell numbers were 2.5 × 10(8) and 3.4 × 10(8) cells in the lower and higher dose groups, respectively. No apparent adverse effects of administering bone marrow cells were observed. Compared with the lower dose, patients receiving the higher dose of bone marrow cells displayed a trend toward improved neurologic outcomes. Compared with 1 month after treatment, patients receiving cell therapy displayed a trend toward improved cerebral blood flow and metabolic rate of oxygen consumption 6 months after treatment. In comparison with historical controls, patients receiving cell therapy had significantly better neurologic outcomes. Our results indicated that intravenous transplantation of autologous bone marrow mononuclear cells is safe and feasible. Positive results and trends favoring neurologic recovery and improvement in cerebral blood flow and metabolism by cell therapy underscore the relevance of larger scale randomized controlled trials using this approach.

Improvement in PET/CT image quality in overweight patients with PSF and TOF.

OBJECTIVE: The aim of this study was to evaluate the effect of the point spread function (PSF) and time of flight (TOF) on PET/CT images of overweight patients in relation to the iteration number and the acquisition time. METHODS: This study consisted of a phantom study and a clinical study. The NEMA IEC body phantom and a 40 cm diameter large phantom (LG phantom) simulating an overweight patient were used in this study. Both phantoms were filled with (18)F solution with a sphere to background ratio of 4:1. The PET data were reconstructed with the baseline ordered-subsets expectation maximization (OSEM) algorithm, with the OSEM + PSF model, with the OSEM + TOF model and with the OSEM + PSF + TOF model. The clinical study was a retrospective analysis of 66 patients who underwent (18)F-FDG PET/CT. The image quality was evaluated using the background variability (coefficient of variance, CVphantom and CVliver) and the contrast (CONTHOT and SNR). RESULTS: In phantom study, the CVphantom of the LG phantom was higher than that of the NEMA phantom. The PSF decreased the CVphantom of the LG phantom to the NEMA phantom level. The TOF information accelerated the CVphantom plateau earlier. The best relationship between the CVphantom and the CONTHOT was observed for the OSEM + PSF + TOF. In clinical study, the combination of PSF and TOF decreased the CVliver for overweight patients to that for normal weight patients while it increased the SNR similarly between two patient groups. CONCLUSION: The combination of the PSF and TOF correction improved the image quality of the LG phantom and overweight patients.

Cilostazol add-on therapy in patients with mild dementia receiving donepezil: a retrospective study.

GOAL: Combinatorial therapy directed at both vascular and neurodegenerative aspects of dementia may offer a promising strategy for treatment of dementia, which often has a multifactorial basis in the elderly. We investigated whether the phosphodiesterase III inhibitor cilostazol, which is often used in the prevention of stroke and peripheral artery disease, may delay cognitive decline in the elderly receiving donepezil. METHODS: Medical records were retrospectively surveyed to identify patients who had received donepezil for more than one year and had undergone Mini-Mental State Examination (MMSE) at least at two time points. Those with an initial MMSE score of less than 27 points were subjected to analysis (n = 156), with a cut-point of 21/22 applied to assign them to mild (n = 70) and moderate/severe (n = 86) dementia. The change of total MMSE score per year was compared between patients who had received donepezil and those given both donepezil and cilostazol. FINDINGS: In patients with mild dementia who had received donepezil and cilostazol (n = 34; 77.2±6.8 years old), the annual change in MMSE score was -0.5±1.6 during an observational period of 28.6±11.7 months, with those receiving donepezil only (n = 36; 78.4±6.5 years old) scoring less (-2.2±4.1) during 30.4±12.8 months with a statistical intergroup difference (p = 0.022). Multivariate analysis showed that absence of cilostazol treatment was the only significant predictor of MMSE decline. A positive effect of cilostazol was found in three subscale scores of MMSE, orientation for time or place and delayed recall. By clear contrast, in patients with moderate/severe dementia, there were no intergroup differences in decrease of total or subscale MMSE scores between the two groups. CONCLUSIONS: These results suggest potential for cilostazol treatment in the suppression of cognitive decline in patients receiving donepezil with mild dementia but not in those with moderate/severe dementia.

Experimental evidence and early translational steps using bone marrow derived stem cells after human stroke.

Neurogenesis is principally restricted to the subventricular zone of the lateral ventricle wall and the subgranular zone of the hippocampal dentate gyrus in physiological situations. However, neuronal stem cells are known to be mobilized into the post- and peristroke area and we have demonstrated that appropriate support of these stem cells, achieved by therapeutic angiogenesis, enhances neuroregeneration followed by neuronal functional recovery in an experimental stroke model. We also found that neural stem cells are mobilized in patients after stroke, as well as in animal models. Based on these observations, we have started cell-based therapy using autologous bone marrow-derived stem/progenitor cells in patients after stroke. This review summarizes the findings of recent experimental and clinical studies that have focused on neurogenesis in the injured brain after cerebral infarction. We also refer to the challenges for future cell-based therapy, including regeneration of the aged brain.

A novel reproducible model of neonatal stroke in mice: comparison with a hypoxia-ischemia model.

Neonatal stroke occurs in 1/4000 live births and leaves life-long neurological impairments, such as cerebral palsy and epilepsy. Currently, the rodent models of neonatal stroke that are available exhibit significant inter-animal variability, which makes it difficult to accurately assess the mechanisms of brain injury and the efficacy of candidate treatments. We aimed to introduce a novel, highly reproducible model of stroke, middle cerebral artery occlusion (MCAO), in immature mice, and to evaluate the reproducibility of this model compared with a conventional hypoxia-ischemia (HI) model. Postnatal day 12 CB-17 mice underwent left MCAO by direct electrocoagulation. The MCAO model exhibited excellent long-term survival; 85% up to 8 weeks after the insult. Infarct was evident in every animal with MCAO (n=27) and was confined to the cortex, with the exception of some mild thalamic injury. While the % stroke volume 48 h after the insult was consistent in the MCAO group, range: 17.8-30.4% (minimum-maximum), it was substantially less consistent in the HI group, range: 3.0-70.1%. This contrasting variability between the two models was also evident in the cerebral blood flow, 24h after the insult, and in the ipsilateral hemispheric volume, as assessed at 8 weeks after the insult. Mice with MCAO exhibited significant neurofunctional deficits in the rotarod and open-field tests. Preclinical studies for neonatal stroke could become more reliable using this model, with even a potential reduction in the number of pups required for statistical significance. The contrasting variability between the two models may provide insights into the factors that contribute to inter-animal variability in brain injury.

A highly reproducible model of cerebral ischemia/reperfusion with extended survival in CB-17 mice.

To simulate the clinical and pathologic situation in patients with stroke, as well as to evaluate future potential therapeutic approaches, it is essential to have a highly reproducible model that displays long-term survival. Though a range of rodent models has been employed in the literature, there are questions regarding reproducibility, especially in terms of ischemic zone (i.e., degree of ischemia) and long-term survival. We have developed a highly reproducible stroke model that produces a consistent ischemic zone as a result of direct transient occlusion of the middle cerebral artery (MCA) in CB-17 (CB-17/Icr-+/+Jcl) mice. The model employs a thin monofilament to twist the artery resulting in complete interruption of blood flow. Transient ischemia can be induced for up to 240min and the survival rate at 7 days post-ischemia was more than 60%, even in mice subjected to 240min of transient ischemia resulting in hemorrhagic infarction in most animals. Our method can be used to model several pathologic conditions, such as reversible reperfusion injury, delayed neuronal death, necrotic brain injury and hemorrhagic infarction. We believe this preclinical model provides a step forward for testing future therapeutic approaches applicable to patients with ischemic brain injury.

Cilostazol improves cognitive function in patients with mild cognitive impairment: a retrospective analysis.

BACKGROUND AND PURPOSE: Cerebral ischemia and accumulation of amyloid ß (Aß) are major risk factors for the development of dementia, including vascular dementia and Alzheimer's disease. Cilostazol, an antiplatelet drug, has been shown to improve cerebral circulation and reduce accumulation of Aß. In this study, the long-term effect of cilostazol on cognitive function was investigated retrospectively. METHODS: Medical records at Sumotoitsuki Hospital were surveyed to find all patients treated with cilostazol and evaluated by the Mini-Mental State Examination (MMSE) during at least two visits separated by an interval of more than 6 months. Patients receiving anti-dementia drugs were excluded. Temporal changes in MMSE scores were compared between patients treated with cilostazol (n = 70) and those who ceased administration of this drug (n = 22). The mean follow-up period was 691 days. RESULTS: Decrease in MMSE score was significantly ameliorated by administration of cilostazol. Subgroup analysis revealed that cilostazol significantly improved MMSE score in patients with mild cognitive impairment, though no significant effect was observed in patients with normal cognitive function or dementia. CONCLUSIONS: Although there are limitations to such a retrospective study, these results significantly encourage undertaking a prospective cohort study to determine the effect of cilostazol on mild cognitive impairment where no treatments currently exist.

Human umbilical cord provides a significant source of unexpanded mesenchymal stromal cells.

BACKGROUND AIMS: Human mesenchymal stromal cells (MSC) have considerable potential for cell-based therapies, including applications for regenerative medicine and immune suppression in graft-versus-host disease (GvHD). However, harvesting cells from the human body can cause iatrogenic disorders and in vitro expansion of MSC carries a risk of tumorigenesis and/or expansion of unexpected cell populations. METHODS: Given these problems, we have focused on umbilical cord, a tissue obtained with few ethical problems that contains significant numbers of MSC. We have developed a modified method to isolate MSC from umbilical cord, and investigated their properties using flow cytometry, mRNA analysis and an in vivo GvHD model. RESULTS: Our study demonstrates that, using umbilical cord, large numbers of MSC can be safely obtained using a simple procedure without in vitro expansion, and these non-expanded MSC have the potential to suppress GvHD. CONCLUSIONS: Our results suggest that the combined banking of umbilical cord-derived MSC and identical cord blood-derived hematopoietic stem cell banking, where strict inspection of the infectious disease status of donors is performed, as well as further benefits of HLA-matched mesenchymal cells, could become one of the main sources of cells for cell-based therapy against various disorders.

Leptomeningeal-derived doublecortin-expressing cells in poststroke brain.

Increasing evidence indicates that neural stem/progenitor cells (NSPCs) reside in many regions of the central nervous system (CNS), including the subventricular zone (SVZ) of the lateral ventricle, subgranular zone of the hippocampal dentate gyrus, cortex, striatum, and spinal cord. Using a murine model of cortical infarction, we recently demonstrated that the leptomeninges (pia mater), which cover the entire cortex, also exhibit NSPC activity in response to ischemia. Pial-ischemia-induced NSPCs expressed NSPC markers such as nestin, formed neurosphere-like cell clusters with self-renewal activity, and differentiated into neurons, astrocytes, and oligodendrocytes, although they were not identical to previously reported NSPCs, such as SVZ astrocytes, ependymal cells, oligodendrocyte precursor cells, and reactive astrocytes. In this study, we showed that leptomeningeal cells in the poststroke brain express the immature neuronal marker doublecortin as well as nestin. We also showed that these cells can migrate into the poststroke cortex. Thus, the leptomeninges may participate in CNS repair in response to brain injury.

Cell-based therapy to promote angiogenesis in the brain following ischemic damage.

Cell-based therapies are a novel approach for regeneration of microvasculature. We have shown that administration of CD34-positive cells, the rich cell fraction of endothelial progenitor cells, after stroke induces angiogenesis that results in enhanced endogenous neurogenesis and functional recovery in a murine model. Moreover, injury-induced neurogenesis occurs in the human brain following a stroke during the acute to sub-acute period. Based on these observations, clinical trials of cell therapies that aim to regenerate micro-circulation in the brain following a stroke are ongoing worldwide. This review summarizes the current basic research findings about the link between angiogenesis and neurogenesis in the post-stroke brain and introduces the ongoing clinical trials of cell-based therapies for patients that have suffered a stroke.

Progesterone and allopregnanolone exacerbate hypoxic-ischemic brain injury in immature rats.

Progesterone and its metabolite, allopregnanolone, are neurosteroids that are present at high concentrations in fetal brains that decrease right after birth. Allopregnanolone is a potent positive modulator of γ-aminobutyric acid A (GABA(A)) receptor function. We examined the effect of exogenous administration of these steroids on hypoxic-ischemic encephalopathy in immature rats. Progesterone (10mg/kg), allopregnanolone (10mg/kg), or vehicle alone was intraperitoneally administered immediately before and then subcutaneously 6h and 24h after hypoxia-ischemia to postnatal day 7 (P7), day 14 (P14), and day 21 (P21) rats. The effects of the treatments were evaluated using histological analyses (hemispheric volumes and semi-quantitative scoring for neuropathologic injury). Both progesterone and allopregnanolone significantly exacerbated brain injury in P7 and P14 rats, but not in P21 rats. This detrimental effect was similar across the examined brain regions (the cortex, striatum, hippocampus, and thalamus) and showed no sex differences. Co-administration of the GABA(A) receptor antagonist, bicuculline, partially mitigated the exacerbating effect of allopregnanolone. Based on the similarity of the effects of these neurosteroids, we speculate that progesterone accentuates neuronal injury mainly via the activity of allopregnanolone. The present study indicates that the detrimental effects of allopregnanolone were, at least in part, mediated via GABAergic neuroexcitability. This is in line with the notion that GABA is excitatory for immature neurons, while it is inhibitory for mature neurons.

Cerebral blood flow during reperfusion predicts later brain damage in a mouse and a rat model of neonatal hypoxic-ischemic encephalopathy.

Children with severe neonatal hypoxic-ischemic encephalopathy (HIE) die or develop life-long neurological impairments such as cerebral palsy and mental retardation. Decreased regional cerebral blood flow (CBF) is believed to be the predominant factor that determines the level of tissue injury in the immature brain. However, the spatio-temporal profiles of CBF after neonatal HIE are not well understood. CB17 mouse and Wistar rat pups were exposed to a unilateral hypoxic-ischemic (HI) insult at eight or seven days of age. Laser speckle imaging sequentially measured the cortical surface CBF before the hypoxic exposure and until 24h after the hypoxic exposure. Seven days after the HI insult, brain damage was morphologically assessed by measuring the hemispheric volumes and by semi-quantitative scoring for neuropathologic injury. The mean CBF on the ipsilateral hemisphere in mice decreased after carotid artery ligation. After the end of hypoxic insult (i.e., the reperfusion phase), the mean CBF level gradually rose and nearly attained its pre-surgery level by 9h of reperfusion. It then decreased. The degree of reduced CBF during reperfusion was well correlated with the degree of later morphological brain damage. The correlation was the strongest when the CBF was measured in the ischemic core region at 24h of reperfusion in mice (R²=0.89). A similar trend in results was found in rats. These results suggest that the CBF level during reperfusion may be a useful predictive factor for later brain damage in immature mice. This may enable optimizing brain damage for detail analyses.

Cilostazol reduces the risk of hemorrhagic infarction after administration of tissue-type plasminogen activator in a murine stroke model.

BACKGROUND AND PURPOSE: Prior use of antiplatelet agents improves stroke outcome in patients undergoing thrombolytic therapy as shown by reduced arterial reocclusion, although the risk of cerebral hemorrhage can be increased. METHODS: The effect of cilostazol, an antiplatelet drug that improves endothelial function through upregulation of intracellular cAMP, on cerebral hemorrhage after thrombolytic therapy was investigated using a highly reproducible transient ischemia model. RESULTS: Treatment with cilostazol for 7 days before ischemia significantly suppressed the risk and severity of cerebral hemorrhage after injection of tissue-type plasminogen activator, although treatment with aspirin had no such protective effect compared with nontreated mice. Immunohistological analysis revealed that treatment with cilostazol suppressed disruption of the microvasculature in the ischemic area associated with reduced matrix metalloproteinase-9 activity. CONCLUSIONS: Our results suggest that patients treated with cilostazol before onset of stroke could have a lower risk of cerebral hemorrhage after thrombolytic therapy and might also have a longer therapeutic time window for thrombolysis. Furthermore, the risk of cerebral hemorrhage can be significantly altered by prestroke therapies, and analysis of the effects of multiple drugs on tissue-type plasminogen activator-induced cerebral hemorrhage in animal models is essential for the extending safe and effective thrombolytic therapy to a wider group of patients.

Reduced ischemic brain injury by partial rejuvenation of bone marrow cells in aged rats.

Circulating bone marrow-derived immature cells, including endothelial progenitor cells, have been implicated in homeostasis of the microvasculature. Decreased levels of circulating endothelial progenitor cells, associated with aging and/or cardiovascular risk factors, correlate with poor clinical outcomes in a range of cardiovascular diseases. Herein, we transplanted bone marrow cells from young stroke-prone spontaneously hypertensive rats (SHR-SP) into aged SHR-SP, the latter not exposed to radiation or chemotherapy. Analysis of recipient peripheral blood 28 days after transplantation revealed that 5% of circulating blood cells were of donor origin. Cerebral infarction was induced on day 30 posttransplantation. Animals transplanted with bone marrow from young SHR-SP displayed an increase in density of the microvasculature in the periinfarction zone, reduced ischemic brain damage and improved neurologic function. In vitro analysis revealed enhanced activation of endothelial nitric oxide synthase and reduced activation p38 microtubule-associated protein (MAP) kinase, the latter associated with endothelial apoptosis, in cultures exposed to bone marrow-derived mononuclear cells from young animals versus cells from aged counterparts. Our findings indicate that partial rejuvenation of bone marrow from aged rats with cells from young animals enhances the response to ischemic injury, potentially at the level of endothelial/vascular activation, providing insight into a novel approach ameliorate chronic vascular diseases.

[Cell based therapy for patients after cerebral embolism].

Neuronal stem cells are mobilized after cerebral infarction. We had shown that appropriate support of these stem cells, achieved by therapeutic angiogenesis, enhances neurological recovery in experimental stroke model. Based on these observations, we started cell based therapy using autologous bone marrow mononuclear cells for patients after cerebral embolism as phase 1/2a clinical trial. We have treated 6 patients in low dose group (harvest 25 ml of bone marrow cells) and none of them showed treatment-related adverse effects. We are now recruiting another 6 patients in high dose group (harvest 50 ml of bone marrow cells) and are planning to evaluate the effectiveness and safety of the therapy after obtaining the results of all 12 patients.

A Reproducible and Simple Model of Permanent Cerebral Ischemia in CB-17 and SCID Mice.

In order to evaluate novel stroke therapies, it is essential to utilize a highly reproducible model of focal cerebral ischemia. Though a range of rodent stroke models has been employed in the literature, there are persistent issues regarding reproducibility of the ischemic zone, as there is considerable inter-animal and inter-laboratory variation. We have developed a highly reproducible model of stroke that involves direct electrocoagulation of the MCA in SCID (CB-17/lcr-scid/scidJcl) and CB-17 (CB-17/lcr-+/+Jcl) mice. Using a modification of the Tamura method, our results demonstrate reproducible cortical infarction with high survival in the chronic period (up to 180 days) in SCID and CB-17, but not in C57BL/6, mice. We believe that our preclinical model represents a step forward for testing future therapeutic methods potentially applicable to patients with stroke.