Mechanistic study of transcription factor Sox18 during heart development

Heart development is a delicate and complex process regulated by coordination of various signaling pathways. In this study, we investigated the role of sox18 in heart development by modulating Wnt/β-Catenin signaling pathways. Our spatiotemporal expression analysis revealed that sox18 is mainly expressed in the heart, branchial arch, pharyngeal arch, spinal cord, and intersegmental vessels at the tailbud stage of Xenopus tropicalis embryo. Overexpression of sox18 in the X. tropicalis embryos causes heart edema, while loss-of-function of sox18 can change the signal of developmental heart marker gata4 at different stages, suggesting that sox18 plays an essential role in the development of the heart. Knockdown of SOX18 in human umbilical vein endothelial cells suggests a link between Sox18 and β-CATENIN, a key regulator of the Wnt signaling pathway. Sox18 negatively regulates islet1 and tbx3, the downstream factors of Wnt/β-Catenin signaling, during the linear heart tube formation and the heart looping stage. Taken together, our findings highlight the crucial role of Sox18 in the development of the heart via inhibiting Wnt/β-Catenin signaling.

P–547 Single-cell RNA sequencing identifies molecular regulations associated with poor maturation performance on rescue in vitro matured oocytes

Study question

What is the transcriptome signature associated with rescuein vitro matured (rIVM) oocytes?

Summary answer

GATA–1/CREB1/WNT signaling axis was repressed in rIVM oocytes of poor quality.

What is known already

rIVM aims to produce mature oocytes (MII) for in vitro fertilization (IVF) through IVM of immature oocytes collected from stimulated ovaries. It is less popular due to limited success rate in infertility treatment. Genetic aberrations, cellular stress, and the absence of cumulus cell support in oocytes could account for the failure of rIVM.

Study design, size, duration

We applied single-cell RNA sequencing (scRNA-seq) to capture the transcriptomes of human in vivo (IVO) oocytes (n = 10) from 7 donors and rIVM oocytes (n = 10) from 10 donors, followed by studying the maternal age effect and ovarian responses on rIVM oocyte transcriptomes.

Participants/materials, setting, methods

Human oocytes were collected from donors aged 28–41 years with a body mass index of < 30. RNA extraction, cDNA generation, library construction and sequencing were performed in one preparation. scRNA-seq data were then processed and analyzed. Selected genes in therIVM vs. IVO comparison were validated by quantitative real-time PCR.

Main results and the role of chance

The transcriptome profiles of rIVM/IVO showed distinctive differences. A total of 1559 differentially expressed genes (DEGs, genes with at least two-fold change and adjusted p < 0.05) were found to be enriched in metabolic processes, biosynthesis, and oxidative phosphorylation. Among these DEGs, we identified a repression of WNT/β-catenin signaling in rIVM when compared with IVO oocytes. We found that estradiol level exhibited a significant age-independent correlation with the IVO mature oocyte ratio (MII ratio). rIVM oocytes with higher MII ratio showed over-represented cellular processes such as anti-apoptosis. To further identify targets that contribute to the poor outcomes of rIVM, we compared oocytes collected from young donors with high MII ratio versus donors of advanced maternal age and revealed CREB1was an important regulator in rIVM. Our study identified GATA–1/CREB1/WNT signaling was repressed in both rIVM condition and rIVM oocytes of low-quality.

Limitations, reasons for caution

In the rIVM oocytes of high- and low-quality comparison, the number of samples was limited after data filtering with stringent selection criteria. For the oocyte stage identification, we were unable to predict the presence of oocyte spindle so polar body extrusion was the only indicator.

Wider implications of the findings: This study showed that GATA–1/CREB1/WNT signaling and antioxidant actions were repressed in rIVM condition and was further downregulated in rIVM oocytes of low-quality, providing us the foundation of subsequent follow-up research on human subjects.

Trial registration number

Not applicable

Single-cell RNA sequencing identifies molecular targets associated with poor in vitro maturation performance of oocytes collected from ovarian stimulation

STUDY QUESTION

What is the transcriptome signature associated with poor performance of rescue IVM (rIVM) oocytes and how can we rejuvenate them?

SUMMARY ANSWER

The GATA-1/CREB1/WNT signalling axis was repressed in rIVM oocytes, particularly those of poor quality; restoration of this axis may produce more usable rIVM oocytes.

WHAT IS KNOWN ALREADY

rIVM aims to produce mature oocytes (MII) for IVF through IVM of immature oocytes collected from stimulated ovaries. It is not popular due to limited success rate in infertility treatment. Genetic aberrations, cellular stress and the absence of cumulus cell support in oocytes could account for the failure of rIVM.

STUDY DESIGN, SIZE, DURATION

We applied single-cell RNA sequencing (scRNA-seq) to capture the transcriptomes of human in vivo oocytes (IVO) (n = 10) from 7 donors and rIVM oocytes (n = 10) from 10 donors. The effects of maternal age and ovarian responses on rIVM oocyte transcriptomes were also studied. In parallel, we studied the effect of gallic acid on the maturation rate of mouse oocytes cultured in IVM medium with (n = 84) and without (n = 85) gallic acid.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human oocytes were collected from donors aged 28-41 years with a body mass index of <30. RNA extraction, cDNA generation, library construction and sequencing were performed in one preparation. scRNA-seq data were then processed and analysed. Selected genes in the rIVM versus IVO comparison were validated by quantitative real-time PCR. For the gallic acid study, we collected immature oocytes from 5-month-old mice and studied the effect of 10-μM gallic acid on their maturation rate.

MAIN RESULTS AND THE ROLE OF CHANCE

The transcriptome profiles of rIVM/IVO oocytes showed distinctive differences. A total of 1559 differentially expressed genes (DEGs, genes with at least 2-fold change and adjusted P < 0.05) were found to be enriched in metabolic processes, biosynthesis and oxidative phosphorylation. Among these DEGs, we identified a repression of WNT/β-catenin signalling in rIVM when compared with IVO oocytes. We found that oestradiol levels exhibited a significant age-independent correlation with the IVO mature oocyte ratio (MII ratio) for each donor. rIVM oocytes from women with a high MII ratio were found to have over-represented cellular processes such as anti-apoptosis. To further identify targets that contribute to the poor clinical outcomes of rIVM, we compared oocytes collected from young donors with a high MII ratio with oocytes from donors of advanced maternal age and lower MII ratio, and revealed that CREB1 is an important regulator. Thus, our study identified that GATA-1/CREB1/WNT signalling was repressed in both rIVM oocytes versus IVO oocytes and in rIVM oocytes of lower versus higher quality. Consequently we investigated gallic acid, as a potential antioxidant substrate in human rIVM medium, and found that it increased the mouse oocyte maturation rate by 31.1%.

LARGE SCALE DATA

Raw data from this study can be accessed through GSE158539.

LIMITATIONS, REASONS FOR CAUTION

In the rIVM oocytes of the high- and low-quality comparison, the number of samples was limited after data filtering with stringent selection criteria. For the oocyte stage identification, we were unable to predict the presence of oocyte spindle, so polar body extrusion was the only indicator.

WIDER IMPLICATIONS OF THE FINDINGS

This study showed that GATA-1/CREB1/WNT signalling was repressed in rIVM oocytes compared with IVO oocytes and was further downregulated in low-quality rIVM oocytes, providing us the foundation of subsequent follow-up research on human oocytes and raising safety concerns about the clinical use of rescued oocytes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Collaborative Research Fund, Research Grants Council, C4054-16G, and Research Committee Funding (Research Sustainability of Major RGC Funding Schemes), The Chinese University of Hong Kong. The authors have no conflicts of interest to declare.

Oblique lumbar interbody fusion in management of lumbar degenerative spinal stenosis in Chinese population

Purpose:

The purpose of this study was to assess the outcomes of a cohort of local Chinese patients who underwent oblique lumbar interbody fusion (OLIF) surgery for lumbar degenerative diseases.

Methods:

We adopted a minimally invasive anterior approach to the lumbar spine through retroperitoneal access. In the first part of the surgery, a 3- to 5-cm left lateral incision over the abdomen was made guided by imaging. L2–L5 disc space was approached via the corridor between the left psoas muscle and the great vessels. A specially designed interbody cage filled with bone substitute was utilized for interbody fusion. In the second part of the surgery, posterior instrumentation with or without decompression, was performed in a prone position. Efficacy and safety of the surgery were studied.

Results:

A total of 60 patients with the mean age of 68 years underwent OLIF at 83 surgical levels. Their mean operative time was 79 min, and the average blood loss was 84 ml for the OLIF part. The mean length of hospital stay was 5.5 days. Based on plain computed tomography scan obtained at post-operative 6 months, successful fusion was achieved in 82 of the 83 surgical levels. The Oswestry Disability Index for low back pain had a mean reduction of 22.3% after 6 months. Specific complications observed include transient thigh pain or numbness, retroperitoneal hematoma, post-operative ileus and Bone Morphogenetic Protein (BMP) osteolysis. None of the patients experienced infection, symptomatic pseudo-arthrosis, hardware failure, vascular injury, nerve injury, ureteral injury, bowel injury, incisional hernia or death.

Conclusion:

OLIF is an effective procedure to treat lumbar spinal stenosis and spondylolisthesis with excellent fusion rate and good functional outcome. Complications specific to this procedure are not uncommon, but majority are minor and self-recovery. Proper training is required to minimize potential surgical risks.

Non-canonical cyclic AMP SMAD1/5/8 signalling in human granulosa cells

Development of mammalian ovarian follicles is promoted by the combined action of endocrine cues and paracrine factors. Follicle stimulating hormone (FSH), through the action of cAMP drives follicular growth and development. The oocyte secretes powerful growth factors such as bone morphogenetic protein 15 (BMP15) to regulate granulosa cell proliferation, metabolism, steroidogenesis and differentiation through the activation of SMAD1/5/8. This study investigated the role of the cAMP signalling pathway on SMAD1/5/8 action in human granulosa cells. Cyclic AMP enhanced BMP15-induction of a SMAD1/5/8-specific BRE reporter. Moreover, in the absence of BMP ligand, cAMP also activated SMAD1/5/8-induced BRE activity. Cyclic AMP increased canonical downstream targets of BMP signalling such as inhibitor of differentiation (ID) mRNA expression. The observed effects were not mediated by secretion of BMPs as cAMP did not promote BMP ligand mRNA expression and a BMP extracellular antagonist, the BMP type II receptor ectodomain, did not affect cAMP-induced ID mRNA expression. Finally, the ERK1/2 pathway was shown to be required for the maintenance of cAMP-induced SMAD1/5/8 activity. Together our results suggest a novel and non-canonical pathway for cAMP signalling in human granulosa cells. Cyclic AMP appears to promote SMAD1/5/8 pathway activity intracellularly and has the ability to activate canonical SMAD1/5/8 downstream targets. Our results add another layer of complexity to the interactions between endocrine signalling and oocyte-secreted BMP ligands during folliculogenesis. Given the importance of both cAMP and SMAD1/5/8 pathways in follicular development, these interactions are likely required for the fine-tuning of oocyte paracrine signalling by endocrine stimuli.

Post-fracture care gap: a retrospective population-based analysis of Hong Kong from 2009 to 2012

INTRODUCTION

Patients who sustain an osteoporotic fracture are at increased risk of sustaining further osteoporotic fracture. The risk can be reduced by prescription of anti-osteoporosis medication. The aim of the present study was to determine the current practice in Hong Kong regarding secondary drug prevention of fragility fractures after osteoporotic hip fracture.

METHODS

Dispensation of anti-osteoporosis medication records from patients with new fragility hip fractures aged ≥65 years were retrieved using the Hospital Authority Clinical Data Analysis and Reporting System from 2009 to 2012. The intervention rate each year was determined from the percentage of patients receiving anti-osteoporosis medication within 1 year after hip fracture.

RESULTS

A total of 15 866 patients with osteoporotic hip fracture who met the criteria were included. The intervention rate differed each year from 2009 to 2012, ranging between 9% and 15%. Orthopaedic surgeons initiated 63% of anti-osteoporosis medication, whereas physicians initiated 37%. The anti-osteoporosis drugs being prescribed included alendronic acid (76%), ibandronic acid (12%), strontium ranelate (5%), and zoledronic acid (4%).

CONCLUSION

Most patients with hip fracture remained untreated for 1 year after the osteoporotic hip fracture. The Hospital Authority should allocate more resources to implement a best practice framework for treatment of patients with hip fracture at high risk of secondary fracture.

Operative outcome of Hong Kong centenarians with hip fracture

INTRODUCTION

International clinical guidelines recommend early surgical treatment for geriatric patients with hip fracture. There are, however, few data concerning the operative outcome of centenarians. This study aimed to report the epidemiology of hip fracture and postoperative mortality rate, and to discuss whether operation is justified in centenarians in Hong Kong.

METHODS

This observational study was carried out in all public hospitals of Hong Kong. All patients aged 100 years or above who underwent hip fracture surgery in any public hospital between 1 January 2010 and 31 December 2013 were included. Their postoperative mean and median survival time was recorded.

RESULTS

Of 114 centenarians, 96 (84%) were female. The age of patients ranged from 100 to 109 years, with the largest number (44%) aged 100 years. The follow-up interval ranged from 5 to 1619 days (median, 412 days; interquartile range, 683 days). The 1-month, 6-month, and 1-year mortalities were 8%, 25%, and 37%, respectively. By Kaplan-Meier analysis, the postoperative mean survival was 2 years 2 months (95% confidence interval, 680-936 days) and the median survival time was 2 years (interquartile range, 1234 days).

CONCLUSION

The 1-year mortality among Hong Kong centenarians with hip fracture was 37%, which is lower than the 41.1% in the general centenarian population in Japan. The median survival time after hip fracture surgery was 2 years, suggesting that surgery even at an extreme age is worthwhile to maintain quality of life. Extreme age should not be a barrier to operative treatment.

Risk and predictors of work disability in Chinese patients with systemic lupus erythematosus

The aim of this study is to determine the risk and predictive factors for work disability in patients with SLE. A cross-sectional questionnaire study was performed to evaluate the employment status of a sample of consecutive Chinese patients with SLE. Demographic, socioeconomic data (age, gender, marital status, years of education and household income), employment status, self-reported fatigue score and disease characteristics (SLE duration, organ damage and disease activity) were collected. Work disability was defined by the failure to work due to SLE. The cumulative incidence of work disability since the time of SLE diagnosis was studied by a Kaplan Meier's plot, and factors predictive of work disability were studied by Cox regression. A total of 147 patients with SLE were studied (mean age = 39.4 +/- 11.3 years; 95% women). Among 105 patients who were working at the time of SLE diagnosis, 39 (37%) lost their ability to work as a result of SLE after a mean disease duration of 10.0 +/- 6.1 years. Twenty-two (56%) patients lost their work ability within 2 years of diagnosis of SLE. The self-reported reasons for job loss were musculoskeletal pain (87%), skin disease (26%), renal problem (21%), fatigue (85%), memory deterioration (51%), anxiety or depressive symptoms (74%), too frequent sick leave (10%) and long-term hospitalisation (10%). The cumulative risk of work disability was 36% at 5 years after SLE diagnosis. In a Cox regression model, age (HR = 1.06 [1.02-1.11] per year; P = 0.008), self-reported fatigue score (HR = 1.06 [1.01-1.10] per point; P = 0.01) and mean disease activity score in the preceding two years (HR = 1.20 [1.02-1.42] per point; P = 0.03) were independently associated with working disability. In all, 37% of this group of patients with SLE lost their work ability after having the disease for 10 years. More than 50% of these patients developed work disability within the first 2 years of SLE diagnosis. Older age, fatigue and more active disease were independent predictors of work disability.

Long-term effects of angiotensin-converting enzyme inhibition and metabolic control in hypertensive type 2 diabetic patients

Long-term effects of angiotensin-converting enzyme inhibition and metabolic control in hypertensive type 2 diabetic patients.

BACKGROUND

In hypertensive type 2 diabetic patients, treatment with angiotensin-converting enzyme (ACE) inhibitors is associated with a lower incidence of cardiovascular events than those treated with calcium channel-blocking agents. However, the long-term renal effects of ACE inhibitors in these patients remain inconclusive. In 1989, we commenced a placebo-controlled, double-blind, randomized study to examine the anti-albuminuric effects of enalapril versus nifedipine (slow release) in 102 hypertensive, type 2 diabetic patients. These patients have been followed up for a mean trial duration of 5.5 +/- 2.2 years. We examined the determinants, including the effect of ACE inhibition on clinical outcomes in these patients.

METHODS

After a six-week placebo-controlled, run-in period, 52 patients were randomized double-blind to receive nifedipine (slow release) and 50 patients to receive enalapril. After the one-year analysis, which confirmed the superior anti-albuminuric effects of enalapril (-54%) over nifedipine (+11%), all patients were continued on their previously assigned treatment with informed consent. They were subdivided into normoalbuminuric (N = 43), microalbuminuric (N = 34), and macroalbuminuric (N = 25) groups based on two of three 24-hour urinary albumin excretion (UAE) measurements during the run-in period. Renal function was shown by the 24-hour UAE, creatinine clearance (CCr), and the regression coefficient of the yearly plasma creatinine reciprocal (beta-1/Cr). Clinical endpoints were defined as death, cardiovascular events, and/or renal events (need for renal replacement therapy or doubling of baseline plasma creatinine).

RESULTS

In the whole group, patients treated with enalapril were more likely to revert to being normoalbuminuric (23.8 vs. 15.4%), and fewer of them developed macroalbuminuria (19.1 vs. 30.8%) compared with the nifedipine-treated patients (P < 0.05). In the microalbuminuric group, treatment with enalapril (N = 21) was associated with a 13.0% (P < 0.01) reduction in 24-hour UAE compared with a 17.3% increase in the nifedipine group (N = 13). In the macroalbuminuric patients, enalapril treatment (N = 11) was associated with stabilization compared with a decline in renal function in the nifedipine group, as shown by the beta-1/Cr (0.65 +/- 4.29 vs. -1.93 +/- 2.35 1/micromol x 10-3, P < 0.05) after adjustment for baseline values. Compared with the normoalbuminuric and microalbuminuric patients, those with macroalbuminuria had the lowest mean CCr (75.5 +/- 24.1 vs. 63.5 +/- 21.3 vs. 41.9 +/- 18.5 mL/min, P < 0.001) and the highest frequency of clinical events (4.7 vs. 5.9 vs. 52%, P < 0. 001). On multivariate analysis, beta-1/Cr (R2 = 0.195, P < 0.001) was independently associated with baseline HbA1c (beta = -0.285, P = 0.004), whereas clinical outcomes (R2 = 0.176, P < 0.001) were independently related to the mean low-density lipoprotein cholesterol (beta = 2.426, P = 0.018), high-density lipoprotein cholesterol (beta = -8.797, P = 0.03), baseline UAE (beta = 0.002, P = 0.04), and mean CCr during treatment (beta = -0.211, P = 0.006).

CONCLUSION

In this prospective cohort analysis involving 102 hypertensive, type 2 diabetic patients with varying degrees of albuminuria followed up for a mean duration of five years, we observed the importance of good metabolic and blood pressure control on the progression of albuminuria and renal function. Treatment with enalapril was associated with a greater reduction in albuminuria than with nifedipine in the entire patient group, and especially in those with microalbuminuria. In the macroalbuminuric patients, the rate of deterioration in renal function was also attenuated by treatment with enalapril.

Mandibular osteomyelitis caused by Blastoschizomyces capitatus in a child with acute myelogenous leukemia

A 6-year-old girl with acute myelogenous leukemia (AML) developed fungal mandibular osteomyelitis during chemotherapy. Blastoschizomyces capitatus was recognized histologically by its yeast-like morphology and formation of annelloconidia, and was confirmed by culture. The fungal osteomyelitis of the mandible was treated successfully with prolonged antifungal medication, extensive surgical debridement and an oral care program, without interrupting leukemia chemotherapy. B. capitatus osteomyelitis of the mandible may occur during chemotherapy in AML patients with poor dental condition. Successful treatment can be achieved by careful management without interruption of antineoplastic chemotherapy.

Abnormal albuminuria as a predictor of mortality and renal impairment in Chinese patients with NIDDM

OBJECTIVE

Microalbuminuria predicts mortality in non-insulin-dependent diabetes mellitus (NIDDM), but its association with deterioration of renal function remains more controversial than in insulin-dependent diabetes mellitus (IDDM). Using albumin-to-creatinine ratios (ACRs) in random spot urine samples is a convenient method for evaluating albuminuria. We studied prospectively the predictive values of albuminuria in NIDDM when assessed by this urine measurement.

RESEARCH DESIGN AND METHODS

Between 1991 and 1992, we restudied the clinical and biochemical status of 403 Chinese NIDDM patients recruited in 1989 after a follow-up period of 26.6 +/- 3.2 months (mean +/- SD). Spot urine ACR was measured on two occasions and microalbuminuria was defined as a mean ACR between 5.6 and 38 mg/mmol.

RESULTS

From the original cohort, 29 patients had died mostly because of cardiovascular events with or without renal failure. The overall relative risk of death in patients with abnormal albuminuria was 7.1 (P < 0.001) (microalbuminuria: 3.7, P = 0.04; macroalbuminuria: 11, P < 0.001). On multivariate analysis, the independent predictive factors for mortality were plasma creatinine (wald = 12.1, P < 0.001) and glucose concentrations (wald = 10.4, P < 0.001) in the normo- and microalbuminuric patients (n = 11) and age (wald = 4.4, P = 0.03) and plasma creatinine (wald = 8.2, P < 0.01) in the macroalbuminuric group (n = 18). In the survivors (n = 374), baseline spot urine ACR was independently associated with 2-year spot urine ACR in the normo- (P < 0.001), micro- (P < 0.01), and macroalbuminuric groups (P = 0.01). In addition, baseline spot urine ACR was independently related to 2-year plasma creatinine (P = 0.01) in the macroalbuminuric group. The rates of change of the reciprocal of plasma creatinine ( delta [Cr]-1) were -27.3 +/- 62.5, -43.4 +/- 68.6, and -108.8 +/- 98.81.mumol01.month-1 in the normo-, micro-, and macroalbuminuric groups, respectively (P < 0.001). The delta [Cr]-1 was independently and inversely related to the baseline spot urine ACR (P < 0.001) and 2-year systolic blood pressure (P < 0.001).

CONCLUSIONS

Abnormal albuminuria as indicated by a random spot urine ACR > 5.6 mg/mmol predicts increased mortality and is associated with the progression of albuminuria and deterioration of renal function in Chinese NIDDM patients.