Aquaporin-4-dependent glymphatic solute transport in the rodent brain

The glymphatic system is a brain-wide clearance pathway; its impairment contributes to the accumulation of amyloid-β. Influx of cerebrospinal fluid (CSF) depends upon the expression and perivascular localization of the astroglial water channel aquaporin-4 (AQP4). Prompted by a recent failure to find an effect of Aqp4 knock-out (KO) on CSF and interstitial fluid (ISF) tracer transport, five groups re-examined the importance of AQP4 in glymphatic transport. We concur that CSF influx is higher in wild-type mice than in four different Aqp4 KO lines and in one line that lacks perivascular AQP4 (Snta1 KO). Meta-analysis of all studies demonstrated a significant decrease in tracer transport in KO mice and rats compared to controls. Meta-regression indicated that anesthesia, age, and tracer delivery explain the opposing results. We also report that intrastriatal injections suppress glymphatic function. This validates the role of AQP4 and shows that glymphatic studies must avoid the use of invasive procedures.

Blocking meningeal lymphatic drainage aggravates Parkinson's disease-like pathology in mice overexpressing mutated α-synuclein

Background

Abnormal aggregation of brain α-synuclein is a central step in the pathogenesis of Parkinson’s disease (PD), thus, it is reliable to promote the clearance of α-synuclein to prevent and treat PD. Recent studies have revealed an essential role of glymphatic system and meningeal lymphatic vessels in the clearance of brain macromolecules, however, their pathophysiological aspects remain elusive.

Method

Meningeal lymphatic drainage of 18-week-old A53T mice was blocked via ligating the deep cervical lymph nodes. Six weeks later, glymphatic functions and PD-like phenotypes were systemically analyzed.

Results

Glymphatic influx of cerebrospinal fluid tracer was reduced in A53T mice, accompanied with perivascular aggregation of α-synuclein and impaired polarization of aquaporin 4 expression in substantia nigra. Cervical lymphatic ligation aggravated glymphatic dysfunction of A53T mice, causing more severe accumulation of α-synuclein, glial activation, inflammation, dopaminergic neuronal loss and motor deficits.

Conclusion

The results suggest that brain lymphatic clearance dysfunction may be an aggravating factor in PD pathology.

Electronic supplementary material

The online version of this article (10.1186/s40035-019-0147-y) contains supplementary material, which is available to authorized users.

Persistent Malfunction of Glymphatic and Meningeal Lymphatic Drainage in a Mouse Model of Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular event that often is followed by permanent brain impairments. It is necessary to explore the pathogenesis of secondary pathological damages in order to find effective interventions for improving the prognosis of SAH. Blockage of brain lymphatic drainage has been shown to worsen cerebral ischemia and edema after acute SAH. However, whether or not there is persistent dysfunction of cerebral lymphatic drainage following SAH remains unclear. In this study, autologous blood was injected into the cisterna magna of mice to establish SAH model. One week after surgery, SAH mice showed decreases in fluorescent tracer drainage to the deep cervical lymph nodes (dcLNs) and influx into the brain parenchyma after injection into the cisterna magna. Moreover, SAH impaired polarization of astrocyte aquaporin-4 (AQP4) that is a functional marker of glymphatic clearance and resulted in accumulations of Tau proteins as well as CD3⁺, CD4⁺, and CD8⁺ cells in the brain. In addition, pathological changes, including microvascular spasm, activation of glial cells, neuroinflammation, and neuronal apoptosis were observed in the hippocampus of SAH mice. Present results demonstrate persistent malfunction of glymphatic and meningeal lymphatic drainage and related neuropathological damages after SAH. Targeting improvement of brain lymphatic clearance potentially serves as a new strategy for the treatment of SAH.

Regenerative medicine, organ bioengineering and transplantation

Background

Organ transplantation is predicted to increase as life expectancy and the incidence of chronic diseases rises. Regenerative medicine-inspired technologies challenge the efficacy of the current allograft transplantation model.

Methods

A literature review was conducted using the PubMed interface of MEDLINE from the National Library of Medicine. Results were examined for relevance to innovations of organ bioengineering to inform analysis of advances in regenerative medicine affecting organ transplantation. Data reports from the Scientific Registry of Transplant Recipient and Organ Procurement Transplantation Network from 2008 to 2019 of kidney, pancreas, liver, heart, lung and intestine transplants performed, and patients currently on waiting lists for respective organs, were reviewed to demonstrate the shortage and need for transplantable organs.

Results

Regenerative medicine technologies aim to repair and regenerate poorly functioning organs. One goal is to achieve an immunosuppression-free state to improve quality of life, reduce complications and toxicities, and eliminate the cost of lifelong antirejection therapy. Innovative strategies include decellularization to fabricate acellular scaffolds that will be used as a template for organ manufacturing, three-dimensional printing and interspecies blastocyst complementation. Induced pluripotent stem cells are an innovation in stem cell technology which mitigate both the ethical concerns associated with embryonic stem cells and the limitation of other progenitor cells, which lack pluripotency. Regenerative medicine technologies hold promise in a wide array of fields and applications, such as promoting regeneration of native cell lines, growth of new tissue or organs, modelling of disease states, and augmenting the viability of existing ex vivo transplanted organs.

Conclusion

The future of organ bioengineering relies on furthering understanding of organogenesis, in vivo regeneration, regenerative immunology and long-term monitoring of implanted bioengineered organs.

Early enriched physical environment reverses impairments of the hippocampus, but not medial prefrontal cortex, of socially-isolated mice

Early social isolation (SI) produces a variety of emotional, behavioral and cognitive abnormalities. Conversely, environmental enrichment (EE), a complicated social and physical construct, offers beneficial effects on brain plasticity and development. However, whether or not exclusive physical EE is sufficient to reverse the adverse consequences of early SI remains unclear. Here we reported that 1month-old solitary mice housed in the EE for 8weeks corrected spatial cognitive dysfunction, but did not ameliorate social interaction deficits and increased anxiety-like behavior. Pathological analyses revealed that the enriched environment decreased cellular apoptosis, synaptic protein loss, myelination defect and microglial activation in the hippocampus, but not medial prefrontal cortex (mPFC) of mice housed singly. Moreover, increased nuclear factor-kappaB and interleukin-1β levels, and downregulation of brain-derived neurotrophic factor signaling pathway were normalized in the hippocampus rather than mPFC of these animals. Our results revealed a brain region-specific effectiveness of physical EE in remediating brain impairment of adolescent SI mice, with a complete reversal of hippocampus-dependent cognitive dysfunctions, but without mitigation of mPFC associated anxiety and social interaction defects. This finding emphasizes the irreplaceable role of social life for the early brain development.

Enriched Physical Environment Attenuates Spatial and Social Memory Impairments of Aged Socially Isolated Mice

BACKGROUND

Social isolation in the elderly is one of the principal health risks in an aging society. Physical environmental enrichment is shown to improve sensory, cognitive, and motor functions, but it is unknown whether environmental enrichment can protect against brain impairments caused by social isolation.

METHODS

Eighteen-month-old mice were housed, either grouped or isolated, in a standard or enriched environment for 2 months, respectively. Behavioral tests were performed to evaluate cognitive functional and social interaction ability. Synaptic protein levels, myelination, neuroinflammation, brain derived neurotrophic factor, and NOD-like receptor protein 3 inflammasome signaling pathways were examined in the medial prefrontal cortex and hippocampus.

RESULTS

Isolated aged mice exhibited declines in spatial memory and social memory compared with age-matched littermates living within group housing. The aforementioned memory malfunctions were mitigated in isolated aged mice that were housed in a large cage with a running wheel and novel toys. Enriched housing prevented synaptic protein loss, myelination defects, and downregulation of brain derived neurotrophic factor, while also increasing interleukin 1 beta and tumor necrosis factor alpha in the medial prefrontal cortex and hippocampus of isolated mice. In addition, activation of glial cells and NOD-like receptor protein 3 inflammasomes was partially ameliorated in the hippocampus of isolated mice treated with physical environmental enrichment.

CONCLUSIONS

These results suggest that an enriched physical environment program may serve as a nonpharmacological intervention candidate to help maintain healthy brain function of elderly people living alone.

Sequence variation and genetic diversity in the giant panda

About 336-444 bp mitochondrial D-loop region and tRNA gene were sequenced for 40 individuals of the giant panda which were collected from Mabian, Meigu, Yuexi, Baoxing, Pingwu, Qingchuan, Nanping and Baishuijiang, respectively. 9 haplotypes were found in 21 founders. The results showed that the giant panda has low genetic variations, and that there is no notable genetic isolation among geographical populations. The ancestor of the living giant panda population perhaps appeared in the late Pleistocene, and unfortunately, might have suffered bottleneck attacks. Afterwards, its genetic diversity seemed to recover to some extent.

Dental abnormalities in eight captive giant pandas (Ailuropoda melanoleuca) in China

Dental data from eight adult giant pandas (Ailuropoda melanoleuca) (four females and four males) were collected at the Beijing Zoo from February 2009 to July 2010. Examination findings were recorded in dental charts. All the pandas had different degrees of tooth wear. Incisors, canines and second premolars had the most abnormalities. Five animals had caries; molars were the most affected. Chip fractures were found in seven teeth (incisor, canine and premolar) of five pandas; two had complicated fractures of their canines. Premolars and other teeth were missing in three pandas. Different degrees of dental plaque and calculus were found in all animals. Two pandas had mild gingivitis; the depth of periodontal pockets in all pandas was normal (0-2 mm). Five pandas had abnormal tooth mobility. Samples of dental plaque were collected for microbial culture. Two hundred and fifty-three bacterial strains belonging to 48 species of 23 genera were isolated. Streptococcus, Moraxella, Peptostreptococcus and Porphyromonas were the dominant genera. Further research with larger sample sizes of free-ranging and captive giant pandas will be required in order to demonstrate the absence of the premolar tooth, tooth fractures and the relatively low prevalence of periodontal disease in captive giant pandas.

Persistent Malfunction of Glymphatic and Meningeal Lymphatic Drainage in a Mouse Model of Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular event that often is followed by permanent brain impairments. It is necessary to explore the pathogenesis of secondary pathological damages in order to find effective interventions for improving the prognosis of SAH. Blockage of brain lymphatic drainage has been shown to worsen cerebral ischemia and edema after acute SAH. However, whether or not there is persistent dysfunction of cerebral lymphatic drainage following SAH remains unclear. In this study, autologous blood was injected into the cisterna magna of mice to establish SAH model. One week after surgery, SAH mice showed decreases in fluorescent tracer drainage to the deep cervical lymph nodes (dcLNs) and influx into the brain parenchyma after injection into the cisterna magna. Moreover, SAH impaired polarization of astrocyte aquaporin-4 (AQP4) that is a functional marker of glymphatic clearance and resulted in accumulations of Tau proteins as well as CD3+, CD4+, and CD8+ cells in the brain. In addition, pathological changes, including microvascular spasm, activation of glial cells, neuroinflammation, and neuronal apoptosis were observed in the hippocampus of SAH mice. Present results demonstrate persistent malfunction of glymphatic and meningeal lymphatic drainage and related neuropathological damages after SAH. Targeting improvement of brain lymphatic clearance potentially serves as a new strategy for the treatment of SAH.

[Effect of TUTF1 expression on the proliferation, apoptosis and prognosis of hepatocellular carcinoma cells]

Objective: To study the relationship between the expressions of tuftelin 1 (TUFT1) and the clinicopathological features of hepatocellular carcinoma and its effect on proliferation and apoptosis, and to explore the relationship between TUFT1 with the development of hepatocellular carcinoma. Methods: Immunohistochemistry was used to detect the expression of TUFT1 in 98 cases of hepatocellular carcinoma and 30 cases of adjacent normal tissues. Quantitative real-time PCR (qRT-PCR) was used to detect the expression of TUFT1 in HCC cell line. The expression of TUFT1 in SMMC-7221 cell lines was down-regulated by lentiviral vector. Cell proliferation assay, clonogenic assay, cell apoptosis assay and cell cycle assay were used to detect proliferation, apoptosis, and cell cycle changes of hepatocarcinoma cells after TUFT1-down-regulation. Statistics were performed using the χ2 test and the t-test. Results: Among the 98 cases of hepatocellular carcinoma, 65 cases (66.33%) were positive for TUFT1, and in 30 cases of adjacent normal tissues, 6 cases (16.67%) were positive for TUFT1, and the difference was statistically significant (χ (2) = 19.956, P < 0.05). The expression of TUFT1 in HCC tissues was related to tumor size, tumor stage, recurrence and metastasis (χ(2) = 6.214, 8.066, 14.400, P < 0.05). After lentiviral vector mediated downregulation of TUFT1 expression in SMMC -7221 cells, the cell proliferation rate [(18.62% ± 0.15%) vs. (67.91% ± 0.62%), P < 0.05], clonality [(8.10% ± 0.80%) vs. (50.80% ± 1.60%), P < 0.05] and G1 phase cells [(36.71% ± 0.69%) vs. (44.65% ± 0.73%), P < 0.05] were significantly decreased, whereas the G2 phase cells [ (15.44% ± 0.53%) vs. (22.31% ± 0.20%), P < 0.05] and the rate of apoptosis [(3.45% ± 0.18%) vs. (5.45% ± 0.06%), P < 0.05] was significantly increased compared with the control group of HCC cells, and the differences were statistically significant. Conclusion: The expression of TUFT1 is highly expressed in hepatocellular carcinoma tissues. Furthermore, the expression of TUFT1 promotes HCC cell proliferation, inhibits the apoptosis, and is poor prognostic factor of hepatocellular carcinoma.

[COVID-19 treated with oral Nirmatrelvir-Ritonavir in 3 children]

Objective: To summarize the application experience and the therapeutic effect of Nirmatrelvir-Ritonavir (trade name: Paxlovid) for COVID-19 in children. Methods: A retrospective analysis was performed on the clinical data, including collecting the clinical manifestations and clinical outcomes, dynamically monitoring the blood routine, hepatic and renal function and SARS-CoV-2 nucleic acid results, and observing the related side effects during the treatment, etc, of 3 cases with COVID-19 treated with Paxlovid admitted to Shanghai Children's Hospital (designated referral hospital for SARS-CoV-2 infection in Shanghai) from May 1^st to June 1^st, 2022. Results: The 3 cases were 12, 14, 17 years of age, among which 2 cases were males, 1 case was female. All 3 cases were mild cases with underlying diseases and risk of developing into severe COVID-19, with symptoms of high fever, sore throat and dry cough. The treatment of Paxlovid at 3^rd day of symptom onset contributed to the symptom-free after 1-2 days and negative results of SARS-CoV-2 nucleic acid after 2-4 days. All patients had no adverse manifestations of gastrointestinal tract and nervous system but a case had little skin rashes, which recovered after the withdrawal of Paxlovid. Three cases had normal hepatic and renal function during the Paxlovid treatment. At 3 months after discharge, no clinical manifestations of post-COVID syndrome were found in all 3 cases. Conclusion: Paxlovid was effective and relatively safe in the treatment of 3 children with COVID-19.

[Interaction between APOB gene polymorphism and risk factors in coronary heart disease patients without lipid-lowering treatment]

Objective: To investigate the association between APOB gene R532W polymorphism and the risk of coronary heart disease (CHD) in patients without lipid-lowering treatment and to analyze the interactions between the variation of R532W and different risk factors of CHD. Methods: CHD and non-CHD were diagnosed according to coronary artery angiography (CAG) and/or coronary computed tomography angiogram (CTA) results, as well as clinical features. Blood samples from 771 CHD patients and 772 age- and sex-matched non-CHD controls, who never accepted any lipid-lowering treatments, were collected. R532W was genotyped by HumanExome BeadChip at BGI and strict quality control was made. Firstly, the association between R532W polymorphism and the risk of CHD in 3 genetic models (GA+ AA vs.GG, AA vs. GG+ GA, AA vs. GA vs. GG) after adjusting confounding factors was explored. Then, the interactions between the variation of this loci and risk factors related to CHD were investigated. Results: (1) Total cholesterol (TC) levels were significantly lower in AA genotype than in GA genotype in the total cohort and non-CHD controls, but was similar among the 3 genotypes in CHD patients. (2) R532W GG, GA and AA distribution was 80.7%, 18.2% and 1.2% in CHD patients, and 74.6%, 23.8% and 1.6% in non-CHD controls (P<0.05). (3) R532 polymorphism was related to the incidence of CHD in the dominant model, and A-allele carriers were related to about 35% reduced risk of CHD (OR=0.653, 95% CI 0.502-0.849, P=0.001) after adjusting for confounding factors. (4) R532W polymorphism had positive interactions with hypertension (1.452) and smoke (1.077), while negative interaction with diabetes (0.553) in the occurrence of CHD. Conclusions: APOB gene R532W polymorphism is related to TC levels in Chinese north Han population. A-allele carries of R532W loci is linked with reduced risk of CHD in the absence of lipid-lowering treatment. R532W polymorphism has a positive additive interaction with hypertension and smoke, while a negative additive interaction with diabetes mellitus in the occurrence of CHD.

[Surgical diagnosis and treatment of adult huge undifferentiated embryonal sarcoma of the liver]

Objective: To investigate the clinical characteristics of adult undifferentiated embryonal sarcoma of the liver (UESL). Methods: A retrospective analysis was performed on the clinical data of 5 patients with UESL who underwent surgical resection and were pathologically confirmed from January 2005 to December 2020 at the First and the Second Affiliated Hospital of Anhui Medical University. All the patients were female aged from 49 to 77 years old. Preoperative CT showed a solid cystic mass with low density and a slight density of cord like septum. Imaging findings were misdiagnosed as hepatocellular carcinoma or cystadenocarcinoma. CA125 was higher in 3 patients,and AFP in all patients was normal. Results: All patients were treated by surgery. The mean diameter of tumor was 20.2 cm (range:15.0 to 30.0 cm). All five patients had vimentin expression in immunohistochemistry. Three cases underwent complete resection of the tumor and achieved R0 resection,2 of them had tumor free survival until the end of the follow-up (89 and 55 months),the other 1 case died from renal cell carcinoma 158 months later. The remaining 2 cases were radically resected,but the tumors were ruptured during operation,and relapsed after 2 months and 19 months respectively. The overall survival was 3 and 26 months respectively. Conclusions: Radical hepatectomy is the first choice for treatment of UESL. Intraoperative tumor rupture should be avoided and implant metastasis is a major factor affecting the prognosis of UESL.

[Cerebellar infarction due to vertebral artery dissection in a girl]

We report here a case of vertebral artery dissection, which is rare in childhood. A 12-year-old, previous healthy girl was admitted to our hospital with symptoms of vertigo, tinnitus, hearing loss, nausea and vomiting. Although there was neither higher cortical dysfunction, motor weakness, sensory disturbance nor slurred speech. She could not stand up because of severe vertigo. Cranial magnetic resonance imaging (MRI) revealed a subacute cerebellar infarct. A left vertebral artery angiogram on the hospital day 3 demonstrated a sharp narrowing at the C1-C2 level. After an anticoagulant therapy for about 2 weeks, all the symptoms disappeared except for mild tinnitus. Two months later, a left vertebral artery angiogram showed an abrupt occlusion at the C1 level. MRI T1-weighted images demonstrated a thrombus within the false lumen of the dissected vessels. A flow void revealed the patency of the residual true lumen. From these findings, we made a diagnosis of vertebral artery dissection, which was considered to have caused cerebellar infarction. The patient was mostly normal at discharge, and 100 mg/day of aspirin has been given until present.