Reelin links Apolipoprotein E4, Tau, and Amyloid-β in Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder that affects the cerebral cortex and hippocampus, and is characterised by progressive cognitive decline and memory loss. A recent report of a patient carrying a novel gain-of-function variant of RELN (H3447R, termed RELN-COLBOS) who developed resilience against presenilin-linked autosomal-dominant AD (ADAD) has generated enormous interest. The RELN-COLBOS variant enhances interactions with the apolipoprotein E receptor 2 (ApoER2) and very-low-density lipoprotein receptor (VLDLR), which are associated with delayed AD onset and progression. These findings were validated in a transgenic mouse model. Reelin is involved in neurodevelopment, neurogenesis, and neuronal plasticity. The evidence accumulated thus far has demonstrated that the Reelin pathway links apolipoprotein E4 (ApoE4), amyloid-β (Aβ), and tubulin-associated unit (Tau), which are key proteins that have been implicated in AD pathogenesis. Reelin and key components of the Reelin pathway have been highlighted as potential therapeutic targets and biomarkers for AD.

Passive immunotherapy for Alzheimer's disease: challenges & future directions

Passive immunotherapy with specific antibodies targeting Amyloid β (Aβ) peptide or tubulin-associated unit (tau) protein has emerged as a promising therapeutic approach in Alzheimer's disease (AD). However, in a recent phase III clinical study, Sperling et al. (N Engl J Med 10.1056/NEJMoa2305032, 2023) reported that solanezumab, a monoclonal antibody targeting Aβ peptide, failed to slow cognitive decline in AD patients. Previously, three other anti-Aβ antibodies, bapineuzumab, crenezumab, and gantenerumab, have also failed to show similar beneficial effects. In addition, three humanized antibodies targeting tau protein failed in their phase II trials. However, other anti-Aβ antibodies, such as lecanemab (a humanized mAb binds to soluble Aβ protofibrils), donanemab (a humanized mAb binds to insoluble, N-terminal truncated form of Aβ peptides) and aducanumab (a human mAb binds to the aggregated form of Aβ), have been shown to slow the decline of cognitive functions in early stage AD patients. The specific targets used in passive immunotherapy in these clinical trials may explain the divergent clinical outcomes. There are several challenges and limitations of passive immunotherapy using anti-Aβ antibodies and long term longitudinal studies are needed to assess their efficacy, side effects and cost effectiveness in a wider spectrum of subjects, from pre-dementia to more advanced dementia. A combination therapeutic approach using both anti-Aβ antibodies and other pharmaceutical agents should also be explored.

Tyrosine Hydroxylase Inhibitors and Dopamine Receptor Agonists Combination Therapy for Parkinson's Disease

There are currently no disease-modifying therapies for Parkinson's disease (PD), a progressive neurodegenerative disorder associated with dopaminergic neuronal loss. There is increasing evidence that endogenous dopamine (DA) can be a pathological factor in neurodegeneration in PD. Tyrosine hydroxylase (TH) is the key rate-limiting enzyme for DA generation. Drugs that inhibit TH, such as alpha-methyltyrosine (α-MT), have recently been shown to protect against neurodegeneration in various PD models. DA receptor agonists can activate post-synaptic DA receptors to alleviate DA-deficiency-induced PD symptoms. However, DA receptor agonists have no therapeutic effects against neurodegeneration. Thus, a combination therapy with DA receptor agonists plus TH inhibitors may be an attractive therapeutic approach. TH inhibitors can protect and promote the survival of remaining dopaminergic neurons in PD patients' brains, whereas DA receptor agonists activate post-synaptic DA receptors to alleviate PD symptoms. Additionally, other PD drugs, such as N-acetylcysteine (NAC) and anticholinergic drugs, may be used as adjunctive medications to improve therapeutic effects. This multi-drug cocktail may represent a novel strategy to protect against progressive dopaminergic neurodegeneration and alleviate PD disease progression.

Genetic Association Studies in Restless Legs Syndrome: Risk Variants & Ethnic Differences

BACKGROUND

Genetic association studies have not produced consistent results in restless legs syndrome (RLS).

OBJECTIVES

To conduct a systematic review on genetic association studies in RLS to highlight the common gene variants and ethnic differences.

METHODOLOGY

We conducted Pubmed, Embase, and Cochrane search using terms "Genetic association studies" and "restless legs syndrome" for candidate gene-based studies. Out of the initial 43 studies, 18 case control studies (from 2012 to 2022) were included. Thirteen studies including 10794 Caucasian subjects (4984 RLS cases and 5810 controls) and five studies involving 2009 Asian subjects (796 RLS cases and 1213 controls) were tabulated and analyzed. In addition, three Genome-Wide Association Studies (GWAS) in Asians and Europeans/Caucasians were included for comparisons.

RESULTS

In the Asian population, gene variants in BST1, SNCA Rep1, IL1B, BTBD9, and MAP2K5/SKOR1 increased the risk of RLS (odds ratio range 1.2-2.8). In Caucasian populations, examples of variants that were associated with an increased risk of RLS (odds ratio range 1.1-1.9) include those in GABRR3 TOX3, ADH1B, HMOX1, GLO1, DCDC2C, BTBD9, SKOR1, and SETBP1. Based on the meta-analysis of GWAS studies, the rs9390170 variant in UTRN gene was identified to be a novel genetic marker for RLS in Asian cohorts, whereas rs113851554 in MEIS1 gene was a strong genetic factor among the >20 identified gene variants for RLS in Caucasian populations.

CONCLUSION

Our systemic review demonstrates that multiple genetic variants modulate risk of RLS in Caucasians (such as MEIS1 BTBD9, MAP2K5) and in Asians (such as BTBD9, MAP2K5, and UTRN).

Role of dopamine in the pathophysiology of Parkinson's disease

A pathological feature of Parkinson's disease (PD) is the progressive loss of dopaminergic neurons and decreased dopamine (DA) content in the substantia nigra pars compacta in PD brains. DA is the neurotransmitter of dopaminergic neurons. Accumulating evidence suggests that DA interacts with environmental and genetic factors to contribute to PD pathophysiology. Disturbances of DA synthesis, storage, transportation and metabolism have been shown to promote neurodegeneration of dopaminergic neurons in various PD models. DA is unstable and can undergo oxidation and metabolism to produce multiple reactive and toxic by-products, including reactive oxygen species, DA quinones, and 3,4-dihydroxyphenylacetaldehyde. Here we summarize and highlight recent discoveries on DA-linked pathophysiologic pathways, and discuss the potential protective and therapeutic strategies to mitigate the complications associated with DA.

[Analysis of disease composition and primary surgical procedures in pediatric secondary glaucoma inpatients: a single-center study]

Objective: To analyze the disease composition and primary surgical procedures in pediatric inpatients with secondary glaucoma. Methods: A retrospective case series study was conducted. Clinical data of children aged≤16 years with secondary glaucoma who were admitted to the Zhongshan Ophthalmic Center, Sun Yat-sen University, between January 1, 2017, and December 31, 2021, were included. The patients were classified according to the Childhood Glaucoma Research Network (CGRN) classification system, and their diagnoses, underlying factors, gender, age of onset, affected eye(s), age and type of initial surgery, and ophthalmic examination data were analyzed. Statistical analysis was performed using Kruskal-Wallis rank sum test and χ2 test. Results: A total of 540 patients (744 eyes) were included in this study, comprising 319 males (59.1%) and 221 females (40.9%). Unilateral disease was observed in 336 cases (62.2%), while bilateral involvement was present in 204 cases (37.8%). The age of onset was 4.0 (0.0, 9.0) years, and the median age of the first anti-glaucoma surgery was 5.0 (0.7, 10.0) years. Among them, there were 195 cases (36.1%) of secondary glaucoma associated with non-acquired ocular anomalies (SCG-O), with a median age of onset of 0.0 (0.0, 4.0) years, and 97 of these cases (49.7%) were male. secondary glaucoma associated with non-acquired systemic disease or syndrome (SCG-S) were observed in 68 cases (12.6%), with a median age of glaucoma onset of 0.1 (0.0, 4.0) years, and 47 of these cases (69.1%) were male. Secondary glaucoma associated with acquired conditions (SCG-A) accounted for 192 cases (35.6%), with a median age of onset of 9.0 (5.0, 13.0) years, and 125 of these cases (65.1%) were male. There were 85 cases (15.7%) of secondary glaucoma following cataract surgery (SCG-C), with a median age of onset of 3.0 (0.8, 7.0) years, and 50 of these cases (58.8%) were male. Male patients were predominant in SCG-S and SCG-A, with 47 cases (69.1%) and 125 cases (65.1%), respectively (χ2=9.94, 17.52; P=0.002,<0.001). Except for SCG-O, all other types of pediatric secondary glaucoma predominantly affected only one eye: SCG-S in 52 cases (76.5%), SCG-A in 128 cases (66.7%), and SCG-C in 54 cases (63.5%) (χ2=19.06, 21.33, 6.22; all P<0.05). The highest proportion of SCG-O was attributed to congenital ectropion uveae (46 cases, 23.6%). Sturge-Weber syndrome was the most common SCG-S (45 cases, 66.3%), while SCG-A mostly resulted from trauma (59 cases, 30.8%) and corticosteroid use (56 cases, 29.2%). Trabeculectomy (211 eyes, 30.8%) and glaucoma drainage device implantation (197 eyes, 28.7%) were the most frequently performed primary surgical procedures. Conclusions: SCG-O and SCG-A were found to be common types of pediatric secondary glaucoma. The age of onset and the choice of primary anti-glaucoma surgical procedures varied among different types of pediatric secondary glaucoma. However, overall, trabeculectomy and glaucoma drainage device implantation were the primary surgical procedures predominantly employed.

Neurodegenerative Diseases: Molecular Mechanisms and Therapies

Neurodegenerative diseases are characterized by the progressive degeneration or death of neurons in the central or peripheral nervous system [...].

Targeting gasdermin E in neurodegenerative diseases

Neel et al. identified pathophysiologic clues linking gasdermin-E (GSDME) with frontotemporal dementia and amyotrophic lateral sclerosis.¹ Therapeutic studies targeting GSDME may provide a viable approach for neurodegenerative diseases.

The role of tyrosine hydroxylase-dopamine pathway in Parkinson's disease pathogenesis

BACKGROUND

Parkinson's disease (PD) is characterized by selective and progressive dopamine (DA) neuron loss in the substantia nigra and other brain regions, with the presence of Lewy body formation. Most PD cases are sporadic, whereas monogenic forms of PD have been linked to multiple genes, including Leucine kinase repeat 2 (LRRK2) and PTEN-induced kinase 1 (PINK1), two protein kinase genes involved in multiple signaling pathways. There is increasing evidence to suggest that endogenous DA and DA-dependent neurodegeneration have a pathophysiologic role in sporadic and familial PD.

METHODS

We generated patient-derived dopaminergic neurons and human midbrain-like organoids (hMLOs), transgenic (TG) mouse and Drosophila models, expressing both mutant and wild-type (WT) LRRK2 and PINK1. Using these models, we examined the effect of LRRK2 and PINK1 on tyrosine hydroxylase (TH)-DA pathway.

RESULTS

We demonstrated that PD-linked LRRK2 mutations were able to modulate TH-DA pathway, resulting in up-regulation of DA early in the disease which subsequently led to neurodegeneration. The LRRK2-induced DA toxicity and degeneration were abrogated by wild-type (WT) PINK1 (but not PINK1 mutations), and early treatment with a clinical-grade drug, α-methyl-L-tyrosine (α-MT), a TH inhibitor, was able to reverse the pathologies in human neurons and TG Drosophila models. We also identified opposing effects between LRRK2 and PINK1 on TH expression, suggesting that functional balance between these two genes may regulate the TH-DA pathway.

CONCLUSIONS

Our findings highlight the vital role of the TH-DA pathway in PD pathogenesis. LRRK2 and PINK1 have opposing effects on the TH-DA pathway, and its balance affects DA neuron survival. LRRK2 or PINK1 mutations can disrupt this balance, promoting DA neuron demise. Our findings provide support for potential clinical trials using TH-DA pathway inhibitors in early or prodromic PD.

[Observation on the clinical effect of self-designed modified rhomboid skin flap in facial wound repair]

Objective: To investigate the clinical effect of self-designed modified rhomboid flap in repairing rhomboid, round, and teardrop-shaped wounds on the face. Methods: A retrospective observational study was conducted. From August 2018 to April 2020, 30 patients with facial lesions admitted into Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine and the People's Hospital of Jianchuan County in Yunnan province met the inclusion criteria, including 16 males and 14 females, aged 23 to 88 years. The wound area ranged from 1.0 cm×1.0 cm to 7.0 cm×5.0 cm, with 10 cases of rhomboid wounds, 12 cases of round wounds, and 8 cases of teardrop-shaped wounds. The self-designed modified rhomboid flaps were applied to repair the wounds and after that, the patients were followed up for 1 to 18 months to record the survival of flaps, wound tension, scar formation and complications after surgery. Results: No necrosis or blackening was observed at the tip of the flaps after surgery. All the flaps survived and the wounds healed well with little tension, minimal scars, and no complications. Conclusions: The self-designed modified rhomboid flap is especially suitable for facial wounds with multiple important organs, multiple anatomical subunits, and areas with large changes in soft tissue tension, which can reduce not only the rotation of the flap, but also unnecessary excision of normal skin and soft tissue.

Oxidized nicotinamide adenine dinucleotide-dependent mitochondrial deacetylase sirtuin-3 as a potential therapeutic target of Parkinson's disease

Mitochondrial impairment is associated with progressive dopamine (DA) neuron degeneration in Parkinson's disease (PD). Recent findings highlight that Sirtuin-3 (SIRT3), a mitochondrial protein, is an oxidized nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase and a key modulator in maintaining integrity and functions of mitochondria. SIRT3 plays vital roles in regulation of mitochondrial functions, including mitochondrial ATP generation and energy metabolism, anti-oxidant defense, and cell death and proliferation. SIRT3 can deacetylate the transcriptional factors and crosstalk with different signaling pathways to cooperatively modulate mitochondrial functions and regulate defensive mitochondrial quality control (QC) systems. Down-regulated NAD+ level and decreased SIRT3 activity are related to aging process and has been pathologically linked to PD pathogenesis. Further, SIRT3 can bind and deacetylate PTEN-induced kinase 1 (PINK1) and PD protein 2 E3 ubiquitin protein ligase (Parkin) to facilitate mitophagy. Leucine Rich Repeat Kinase 2 (LRRK2)-G2019S mutation in PD is linked to SIRT3 impairment. Furthermore, SIRT3 is inversely associated with α-synuclein aggregation and DA neuron degeneration in PD. SIRT3 chemical activators and NAD+ precursors can up-regulate SIRT3 activity to protect against DA neuron degeneration in PD models. Taken together, SIRT3 is a promising PD therapeutic target and studies of SIRT3 functional modulators with neuroprotective capability will be of clinical interest.

The Therapeutic Implications of Tea Polyphenols Against Dopamine (DA) Neuron Degeneration in Parkinson's Disease (PD)

: Accumulative evidence indicated that the pathologically accumulated metal ions (iron species and Mn³⁺) and abnormally up-regulated monoamine oxidase B (MAOB) activity induced oxidation of endogenous dopamine (DA) can lead to mitochondria impairment, lysosome dysfunction, proteasome inhibition, and selective DA neuron vulnerability, which is implicated in the pathogenesis of Parkinson's disease (PD). The DA oxidation can generate deleterious reactive oxygen species (ROS) and highly reactive DA quinones (DAQ) to induce DA-related toxicity, which can be alleviated by DA oxidation suppressors, ROS scavengers, DAQ quenchers, and MAOB inhibitors. On the other hand, the nuclear factor erythroid 2-related factor 2 (Nrf2)-Keap1 and Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) anti-oxidative and proliferative signaling pathways play roles in anti-oxidative cell defense and mitochondria biogenesis, which is implicated in DA neuron protections. Therefore, agents with capabilities to suppress DA-related toxicity including inhibition of DA oxidation, scavenge of ROS, detoxification of DAQ, inhibition of MAOB, and modulations of anti-oxidative signaling pathways can be protective to DA neurons. Accumulative evidence shows that tea or coffee consumptions and smoking are related to deceased PD prevalence with unknown mechanisms. In this study, we investigate the protective capabilities of tea polyphenols and other PD relevant agents to inhibit DA-related toxicity and protect against environmental or genetic factors induced DA neuron degeneration in vitro and in vivo. We find that tea polyphenols can significantly suppress DA-related toxicity to protect DA neurons. The tea polyphenols can protect DA neurons via inhibition of DA oxidation, conjugation with DAQ, scavenge of ROS, inhibition of MAOB, and modulations of Nrf2-Keap1 and PGC-1α anti-oxidative signaling pathways. The tea polyphenols with more phenolic hydroxyl groups and ring structures have stronger protective functions. The protective capabilities of tea polyphenols is further strengthened by evidence that phenolic hydroxyl groups can directly conjugate with DAQ. However, GSH and other sulfhydyl groups containing agents have weaker capabilities to abrogate DA oxidation, detoxify ROS and DAQ and inhibit MAOB; whereas nicotine (NICO) and caffeine (CAF) can only modulate Nrf2-Keap1 and PGC-1α pathways to protect DA neurons weakly. The tea polyphenols are identified to protect against overexpression of mutant A30P α-synuclein (α-syn) induced DA neuron degeneration and PD-like symptoms in transgenic Drosophila. Based on achievements from current studies, the excellent and versatile protective capabilities of tea polyphenols are highlighted, which will contribute and benefit to future anti-PD therapy.

Molecular targets for modulating the protein translation vital to proteostasis and neuron degeneration in Parkinson's disease

Parkinson's disease (PD) is the most common neurodegenerative movement disorder, which is characterized by the progressive loss of dopaminergic neurons in the Substantia Nigra pars compacta concomitant with Lewy body formation in affected brain areas. The detailed pathogenic mechanisms underlying the selective loss of dopaminergic neurons in PD are unclear, and no drugs or treatments have been developed to alleviate progressive dopaminergic neuron degeneration in PD. However, the formation of α-synuclein-positive protein aggregates in Lewy body has been identified as a common pathological feature of PD, possibly stemming from the consequence of protein misfolding and dysfunctional proteostasis. Proteostasis is the mechanism for maintaining protein homeostasis via modulation of protein translation, enhancement of chaperone capacity and the prompt clearance of misfolded protein by the ubiquitin proteasome system and autophagy. Deregulated protein translation and impaired capacities of chaperone or protein degradation can disturb proteostasis processes, leading to pathological protein aggregation and neurodegeneration in PD. In recent years, multiple molecular targets in the modulation of protein translation vital to proteostasis and dopaminergic neuron degeneration have been identified. The potential pathophysiological and therapeutic significance of these molecular targets to neurodegeneration in PD is highlighted.

Pathophysiological mechanisms linking F-box only protein 7 (FBXO7) and Parkinson's disease (PD)

Mutations of F-box only protein 7 (FBXO7) gene are associated with a severe form of autosomal recessive juvenile Parkinson's disease (PD) (PARK15) with clinical features of Parkinsonian-Pyramidal syndrome (PPS). FBXO7 is an adaptor protein in SCF^FBXO7 ubiquitin E3 ligase complex that recognizes and mediates degradative or non-degradative ubiquitination of substrates. The FBXO7 protein can regulate cell cycle, proliferation, mitochondrial and proteasome functions via interactions with multiple target proteins. Five PARK15-linked FBXO7 gene mutations and several PD-associated single nucleotide polymorphisms (SNP) have been identified so far. WT FBXO7 proteins possess dual protective and deleterious functions, whereas PARK15-linked FBXO7 mutants are toxic. FBXO7 is a stress response protein and stress challenges can promote translocation of FBXO7 protein from nucleus into mitochondria and even form deleterious protein aggregate in mitochondria. FBXO7 mutants aggravate protein aggregation in mitochondria and inhibit mitophagy. The pathological mechanisms concerning FBXO7-relevant protein aggregation, mitochondria impairment, reactive oxygen species (ROS) generation and mitophagy modulation in PARK15 pathogenesis are highlighted and discussed in the current review.

Iron regulatory protein (IRP)-iron responsive element (IRE) signaling pathway in human neurodegenerative diseases

The homeostasis of iron is vital to human health, and iron dyshomeostasis can lead to various disorders. Iron homeostasis is maintained by iron regulatory proteins (IRP1 and IRP2) and the iron-responsive element (IRE) signaling pathway. IRPs can bind to RNA stem-loops containing an IRE in the untranslated region (UTR) to manipulate translation of target mRNA. However, iron can bind to IRPs, leading to the dissociation of IRPs from the IRE and altered translation of target transcripts. Recently an IRE is found in the 5′-UTR of amyloid precursor protein (APP) and α-synuclein (α-Syn) transcripts. The levels of α-Syn, APP and amyloid β-peptide (Aβ) as well as protein aggregation can be down-regulated by IRPs but are up-regulated in the presence of iron accumulation. Therefore, inhibition of the IRE-modulated expression of APP and α-Syn or chelation of iron in patient’s brains has therapeutic significance to human neurodegenerative diseases. Currently, new pre-drug IRE inhibitors with therapeutic effects have been identified and are at different stages of clinical trials for human neurodegenerative diseases. Although some promising drug candidates of chemical IRE inhibitors and iron-chelating agents have been identified and are being validated in clinical trials for neurodegenerative diseases, future studies are expected to further establish the clinical efficacy and safety of IRE inhibitors and iron-chelating agents in patients with neurodegenerative diseases.

Immature Midbrain Dopaminergic Neurons Derived from Floor-Plate Method Improve Cell Transplantation Therapy Efficacy for Parkinson's Disease

Recent reports have indicated human embryonic stem cells-derived midbrain dopamine (mDA) neurons as proper cell resources for use in Parkinson's disease (PD) therapy. Nevertheless, no detailed and systematic study has been conducted to identify which differentiation stages of mDA cells are most suitable for transplantation in PD therapy. Here, we transplanted three types of mDA cells, DA progenitors (differentiated in vitro for 16 days [D16]), immature DA neurons (D25), and DA neurons (D35), into PD mice and found that all three types of cells showed high viability and strong neuronal differentiation in vivo. Both D25 and D35 cells showed neuronal maturation and differentiation toward TH⁺ cells and, accordingly, satisfactory behavioral functional recovery. However, transplanted D16 cells were less capable of producing functional recovery. These findings provide a valuable guideline for standardizing the differentiation stage of the transplantable cells used in clinical cell therapy for PD. Stem Cells Translational Medicine 2017;6:1803-1814.

[Effects of transient exposure to high glucose on biological behaviors of human dermal microvascular endothelial cells]

Objective: To observe the effects of transient exposure to high glucose on biological behaviors of human dermal microvascular endothelial cells cultured in vitro. Methods: The dividing method and treatment of cells for the detection of all indexes in this study were as follows. Human dermal microvascular endothelial cells of the 4th passage were divided into 3 groups according to the random number table, with 12 wells in each group. Cells in control group (C) were cultured with complete culture solution containing 5 mmol/L D-glucose for 7 d. Cells in transient high glucose group (THG) were cultured with complete culture solution containing 30 mmol/L D-glucose for 2 d and complete culture solution containing 5 mmol/L D-glucose for 5 d. Cells in prolonged high glucose group (PHG) were cultured with complete culture solution containing 30 mmol/L D-glucose for 7 d. (1) The cell morphology in groups C and PHG on culture day 7 and that in group THG on culture day 2 and 7 was observed by inverted optical microscope. (2) On culture day 0, 2, 4, and 7, cell proliferation rate was determined by cell viability analyzing counter. (3) After culture day 2, the scratch experiment was performed, and the cells were further cultured. At post scratch hour (PSH) 0, 24, 48, 72, 96, and 120, the scratch area was measured, and the cell migration rates of the latter 5 time points were calculated. (4) On culture day 0, 2, 4, and 7, the cell apoptosis rate was determined by cell analyzer. (5) Cells were seeded into Matrigel to culture for 24 h after culture day 7. The formation of vessel-like structure was observed by inverted optical microscope. The length and number of branch point of vessel-like structure were calculated. (6) On culture day 2, 4, and 7, mRNA expression of vascularization-related gene tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) was determined with real-time fluorescent quantitative reverse transcription polymerase chain reaction. Data were processed with analysis of variance of factorial design, analysis of variance for repeated measurement, one-way analysis of variance, and LSD test. Results: (1) Cells in group C exhibited ovary shape in cobble stone order on culture day 7. Cells in group THG exhibited long ovary shape and lost cobble stone order on culture day 2 and kept the same changes on culture day 7. Cells in group PHG exhibited long ovary shape and lost cobble stone order on culture day 7. (2) On culture day 0, there was no significant difference in cell proliferation rate among the 3 groups (F=0.23, P>0.05). On culture day 2, cell proliferation rates in groups THG and PHG were similar (P>0.05), which were significantly lower than the cell proliferation rate in group C (with P values below 0.01). On culture day 4 and 7, the cell proliferation rates in groups THG and C were similar (with P values above 0.05), which were significantly higher than those in group PHG (with P values below 0.01). (3) At PSH 24-120, the cell migration rates in groups THG and PHG were similar (with P values above 0.05), which were significantly lower than those in group C (with P values below 0.01). (4) On culture day 0, there was no statistically significant difference in cell apoptosis rate among the 3 groups (F=0.78, P>0.05). On culture day 2, cell apoptosis rates in groups THG and PHG were similar (P>0.05), which were significantly higher than the cell apoptosis rate in group C (with P values below 0.01). On culture day 4 and 7, the cell apoptosis rates in groups THG and C were similar (with P values above 0.05), which were significantly lower than those in group PHG (with P values below 0.01). (5) The length of vessel-like structure of cells in group THG was (1.84±0.10)×10(5) μm, close to (1.82±0.11)×10(5) μm in group PHG (P>0.05), both significantly shorter than (2.75±0.23)×10(5) μm in group C (with P values below 0.01). The numbers of branch point of vessel-like structure of cells in groups THG and PHG were 43±5 and 46±8 respectively, which were close to each other (P>0.05) and both significantly less than 103±21 in group C (with P values below 0.01). (6) On culture day 2, 4, and 7, mRNA expressions of TIMP-3 of cells in groups THG and PHG were similar (with P values above 0.05), which were significantly lower than those in group C (with P values below 0.05). Conclusions: Transient exposure to high glucose can cause metabolic memory of morphology, migration, and angiogenesis in human dermal microvascular endothelial cells cultured in vitro, resulting in sustained changes in biological behaviors. The mechanism may be related to the changes of vascularization-related genes.

Diffusion-weighted imaging (DWI) of hepatocellular carcinomas: a retrospective analysis of the correlation between qualitative and quantitative DWI and tumour grade

AIM

To evaluate the application of qualitative and quantitative diffusion-weighted imaging (DWI) in predicting the histological grade of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Two hundred and fifty-four patients with pathologically confirmed HCC who underwent hepatic DWI on a 1.5-T platform (b = 0, 600 s/mm²) were evaluated retrospectively. HCCs were divided into well-, moderately, and poorly differentiated groups. The relationships between naked-eye signal intensity (SI), SI values, apparent diffusion coefficient (ADC) values on DWI, and the histopathological differentiation of HCC were analysed. Receiver operating characteristic (ROC) curves were drawn to determine the optimal operating points (OOPs) of the SI and ADC values to predict the tumour grade.

RESULTS

A weak negative correlation (r=-0.350, p<0.05) was obtained between naked-eye SI and histological grade. There was a significant difference in mean SI values between well- (68.32±31.71) and moderately (102.39±45.55)/poorly (114.55±32.15) differentiated HCC but not between moderately and poorly differentiated HCC. The OOP of the SI value by ROC curve analysis was 66.5 to predict well-differentiated HCC. The mean ADC values of well-, moderately, and poorly differentiated HCC were 1.67±0.13×10^-3, 1.31±0.16×10^-3, and 1.08±0.11×10^-3 mm²/s, respectively, with significant differences between any two combinations of groups. The OOPs of ADC to diagnose well- and poorly differentiated HCC were 1.5×10^-3 and 1.24×10^-3 mm²/s, respectively.

CONCLUSION

Qualitative and quantitative SI and ADC values at DWI may be useful to estimate the histological grade of HCC preoperatively and non-invasively.

Linking F-box protein 7 and parkin to neuronal degeneration in Parkinson's disease (PD)

Mutations of F-box protein 7 (FBXO7) and Parkin, two proteins in ubiquitin-proteasome system (UPS), are both implicated in pathogenesis of dopamine (DA) neuron degeneration in Parkinson's disease (PD). Parkin is a HECT/RING hybrid ligase that physically receives ubiquitin on its catalytic centre and passes ubiquitin onto its substrates, whereas FBXO7 is an adaptor protein in Skp-Cullin-F-box (SCF) SCF(FBXO7) ubiquitin E3 ligase complex to recognize substrates and mediate substrates ubiquitination by SCF(FBXO7) E3 ligase. Here, we discuss the overlapping pathophysiologic mechanisms and clinical features linking Parkin and FBXO7 with autosomal recessive PD. Both proteins play an important role in neuroprotective mitophagy to clear away impaired mitochondria. Parkin can be recruited to impaired mitochondria whereas cellular stress can promote FBXO7 mitochondrial translocation. PD-linked FBXO7 can recruit Parkin into damaged mitochondria and facilitate its aggregation. WT FBXO7, but not PD-linked FBXO7 mutants can rescue DA neuron degeneration in Parkin null Drosophila. A better understanding of the common pathophysiologic mechanisms of these two proteins could unravel specific pathways for targeted therapy in PD.

F-box protein 7 mutations promote protein aggregation in mitochondria and inhibit mitophagy

The mutations of F-box protein 7 (FBXO7) gene (T22M, R378G and R498X) are associated with a severe form of autosomal recessive juvenile-onset Parkinson's disease (PD) (PARK 15). Here we demonstrated that wild-type (WT) FBXO7 is a stress response protein and it can play both cytoprotective and neurotoxic roles. The WT FBXO7 protein is vital to cell mitophagy and can facilitate mitophagy to protect cells, whereas mutant FBXO7 inhibits mitophagy. Upon stress, the endogenous WT FBXO7 gets up-regulated, concentrates into mitochondria and forms FBXO7 aggregates in mitochondria. However, FBXO7 mutations aggravate deleterious FBXO7 aggregation in mitochondria. The FBXO7 aggregation and toxicity can be alleviated by Proline, glutathione (GSH) and coenzyme Q10, whereas deleterious FBXO7 aggregation in mitochondria can be aggravated by prohibitin 1 (PHB1), a mitochondrial protease inhibitor. The overexpression of WT FBXO7 could lead to FBXO7 protein aggregation and dopamine neuron degeneration in transgenic Drosophila heads. The elevated FBXO7 expression and aggregation were identified in human fibroblast cells from PD patients. FBXO7 can also form aggregates in brains of PD and Alzheimer's disease. Our study provides novel pathophysiologic insights and suggests that FBXO7 may be a potential therapeutic target in FBXO7-linked neuron degeneration in PD.

Mutant PINK1 upregulates tyrosine hydroxylase and dopamine levels, leading to vulnerability of dopaminergic neurons

PINK1 mutations cause autosomal recessive forms of Parkinson disease (PD). Previous studies suggest that the neuroprotective function of wild-type (WT) PINK1 is related to mitochondrial homeostasis. PINK1 can also localize to the cytosol; however, the cytosolic function of PINK1 has not been fully elucidated. In this study we demonstrate that the extramitochondrial PINK1 can regulate tyrosine hydroxylase (TH) expression and dopamine (DA) content in dopaminergic neurons in a PINK1 kinase activity-dependent manner. We demonstrate that overexpression of full-length (FL) WT PINK1 can downregulate TH expression and DA content in dopaminergic neurons. In contrast, overexpression of PD-linked G309D, A339T, and E231G PINK1 mutations upregulates TH and DA levels in dopaminergic neurons and increases their vulnerability to oxidative stress. Furthermore transfection of FL WT PINK1 or PINK1 fragments with the PINK1 kinase domain can inhibit TH expression, whereas kinase-dead (KD) FL PINK1 or KD PINK1 fragments upregulate TH level. Our findings highlight a potential novel function of extramitochondrial PINK1 in dopaminergic neurons. Deregulation of these functions of PINK1 may contribute to PINK1 mutation-induced dopaminergic neuron degeneration. However, deleterious effects caused by PINK1 mutations may be alleviated by iron-chelating agents and antioxidant agents with DA quinone-conjugating capacity.

Iron species-mediated dopamine oxidation, proteasome inhibition, and dopaminergic cell demise: implications for iron-related dopaminergic neuron degeneration

Iron species have been suggested to be highly involved in the pathogenesis of Parkinson disease. However, the detailed mechanism of iron-induced dopaminergic degeneration is still unclear. In this study, we demonstrate that free iron ions (trivalent or bivalent) and iron ions in stable complex with cyanide ions (K(4)Fe(CN)(6) and K(3)Fe(CN)(6)) can induce dopamine (DA) oxidation with different profiles and subsequently lead to proteasome inhibition and even dopaminergic MN9D cell demise via different mechanisms. The free iron ions could mediate extensive DA oxidation in an iron-DA complex-dependent manner. However, iron ions in stable complex with cyanide ions could not induce, or could induce only brief, DA oxidation. Deferoxamine, a specific iron ion chelator, could disrupt iron-DA complex formation and thus abrogate free iron ion-catalyzed DA oxidation and subsequent cell toxicity. Glutathione could neither disrupt iron-DA complex formation nor influence free iron ion-catalyzed DA oxidation but could protect against iron-mediated toxicity via detoxification of toxic by-products of iron-mediated DA oxidation. The resulting DA oxidation could inhibit chymotrypsin-like, trypsin-like, and caspase-like proteasome activities. However, we demonstrated that oxidative damage was not the major toxic mechanism of MN9D cell degeneration, but it was the DA quinones derived from iron-induced DA oxidation that contributed significantly to proteasome inhibition and even dopaminergic cell demise.

Dopamine (DA) induced irreversible proteasome inhibition via DA derived quinones

This study demonstrated that DA and its oxidative metabolites: H2O2 and aminochrome (AM), cyclized DA quinones, could all directly inhibit proteasome activity. DA and AM, especially AM, could induce intensive and irreversible proteasome inhibition, whereas proteasome inhibition induced by H2O2 was weaker and GSH reversible. It was concluded that DA induced irreversible proteasome inhibition via DA-derived quinones, rather than through small molecular weight ROS. The AM was also more toxic than H2O2 to dopaminergic MN9D cells. Furthermore the cytotoxicity and proteasome inhibition induced by DA, AM and H2O2 could be abrogated by GSH, ascorbic acid (AA), Vitamin E, SOD (superoxidase dismutase) or CAT (catalase) with different profiles. Only GSH was potent to abrogate DA, AM or H2O2-induced cell toxicity and proteasome inhibition, as well as to reverse H2O2-induced proteosome inhibition. Therefore, therapeutic strategies to increase GSH level or to use GSH substitutes should function to control PD onset and development.

Dopamine auto-oxidation aggravates non-apoptotic cell death induced by over-expression of human A53T mutant alpha-synuclein in dopaminergic PC12 cells

In this study, we demonstrated that transient transfection and over-expression of human mutant A53T alpha-synuclein (alpha-syn) could induce expression level- and time-dependent, non-apoptotic cell death in PC12 cells, while wild-type and mutant A30P alpha-syn could not. The non-apoptotic cell death induced by over-expression of A53T alpha-syn in PC12 cells was found to be dopamine (DA) related. It could be alleviated by nerve growth factor but not by chemicals that abrogate endoplasmic reticulum stress. Furthermore, PC12 cell death could be alleviated by N-acetyl-cysteine (NAC) as well as by L-cysteine; but not by cell permeable tyrosinase inhibitors. NAC could prevent DA auto-oxidation and tyrosinase-catalyzed DA oxidation, whereas L-cysteine could potently abrogate DA auto-oxidation but could not prevent tyrosinase-catalyzed DA oxidation. Both NAC and L-cysteine could increase the reduced and total GSH levels, and concurrently decrease the oxidized GSH level in PC12 cells. On the other hand, over-expression of human mutant A53T alpha-syn could decrease the reduced and total GSH levels, and increase the oxidized GSH level in the cells. Taken together, we concluded that auto-oxidation of endogenous DA aggravates non-apoptotic cell death induced by over-expression of human mutant A53T alpha-syn in PC12 cells.

Dopamine-related and caspase-independent apoptosis in dopaminergic neurons induced by overexpression of human wild type or mutant α-synuclein

Human wild type (WT) and mutant alpha-synuclein (alpha-syn) genes were overexpressed using a Tet-on expression system in stably transfected dopaminergic MN9D cells. Their overexpression induced caspase-independent and dopamine-related apoptosis not rescued by general caspase inhibitor Z-VAD-FMK. While apoptosis due to overexpression of WT alpha-syn was completely abrogated by a specific tyrosine hydroxylase (TH) inhibitor, alpha-methyl-p-tyrosine (alpha-MT), the inhibitor only partially rescued apoptosis caused by overexpression of alpha-syn mutants. In addition, overexpression of mutants enhanced the toxicity of 1-methyl-4-phenylpyridinium (MPP+) and 6-hydroxyldopamine (6-OHDA) to MN9D cells, whereas overexpression of WT protected MN9D cells against MPP+ toxicity, but not against 6-OHDA. We conclude that WT alpha-syn is beneficial to dopaminergic neurons but its overexpression in the presence of endogenous dopamine makes it a potential threat to the cells. In contrast, mutant alpha-syn not only caused the loss of WT protective function but also the gain-of-toxicity which becomes more serious in the presence of dopamine and neurotoxins.

Avoiding serious complications in laparoscopic cholecystectomy--lessons learned from an experience of 2428 cases

Over a three-and-a-half year period, we performed 2428 cases of laparoscopic cholecystectomy (LC) and encountered 11 cases of serious procedure-related complications, including bile duct injuries in 4 patients, postoperative bleeding requiring laparotomy and haemostasis in 3 patients, bile leakage from the cystic duct stump, jejunal injury related to puncture, intraoperative injury to the duodenum and subdiaphragmatic abscess in 1 patient each respectively. Six patients required re-hospitalisation including 2 patients with pancreatitis, 1 patient with Ascaris cholangitis, 1 patient with residual stone of the common bile duct (CBD) after laparoscopic CBD exploration, 1 patient with a stone in the CBD after LC, and 1 patient with bile leakage from the cystic duct stump and peritonitis. Of the 2428 patients treated, there was only 1 operative mortality. This patient developed frequent episodes of supraventricular tachycardia. She was found to have pnuemonia on the 21st postoperative day and she died. Apart from this, 1 other patient was found to have primary cancer of the liver 1 month after LC. Based on our experience, we think that LC is safe for patients with benign disease of the gallbladder.

[Serological survey on mycoplasma infection among three populations in Yunnan Province]

Mycoplasma infection in both female and male genital tract has attracted attention recently. 636 infertile and sterile cases together with 284 women with IUDs and 113 women with genital inflammatory complications after artificial abortion were detected through indirect hemagglutination test for serological survey on the frequency of ureaplasma urealyticum (Uu) and mycoplasma hominis (Mh) infection. Some of them were detected through isolated culture at the same time. Among the 636 infertile and sterile cases, the results showed that the antibody positive rate to mycoplasma was 26.10%. Among women with IUD, the antibody positive rate was 32.39%. However, the antibody positives rates among women with IUD shorter than three months were significantly higher than those prior to and three to twelve months after insertion of IUD (P < 0.01). Among the 113 women after abortion, the positive rate was 46.02%. The positive rates of the three groups were significantly different from the control group (P < 0.001), and the antibody titers to mycoplasma were significantly higher than that of the control group. It is suggested that mycoplasma infection is one of the important causes for infertility and causing complication of genital inflammatory symptoms after abortion.

[Laparoscopic cholecystectomy performed in 235 cases of cholecystitis with impacted gallstones]

During the past 2 years, 235 cases of cholecystitis with impacted gallstones were treated with laparoscopic technique. There were 221 chronic cases and 14 acute cases accounting altogether for 15.19% of a total of 1475 patients undergoing laparoscopic cholecystectomy during the same period. As a result, 9 of these patients were converted to open surgery. Severe adhesion around the gallbladder or/and in the Calot triangle in 7, acute impacted gallstone, gallbladder necrosis along with obscure anatomy in the calot triangle in 1, and gallstone impacted at the junction of the common hepatic and cystic duct in 1 were observed. Conversion rate was 3.8%. Postoperative bile leakage developed in 2 cases and healed spontaneously. There were no intraperitoneal sepsis and perioperative death in our patients. The diagnosis, classification, and management for acute or chronic impacted gallstone are discussed.

[Diagnosis and treatment of colonic wound. Analysis of 81 cases]

81 cases of colonic wound were treated in the last 10 years. In early diagnosis, attention was paid to clinical signs and a few untypical bu. specific signs of colonic injury. In the management of colonic injury, one stage operation must comply with 5 operative indications including correct approach to the dangerous factors affecting the result of the operation. Our cure rate of one stage operation was 97.5%. We preferred one stage surgery to two-staged operation because of the complications occurred following colonostomy. In this series the cure rate of two-stage procedure was 92.7%.