High risk factors of atrial fibrillation in type 2 diabetes: results from the Chinese Kailuan study

BACKGROUND

The pathophysiological mechanisms for atrial fibrillation (AF) vulnerability in diabetic patients are largely unclear.

AIM

To investigate the high risk factors of AF in Chinese Kailuan diabetes.

DESIGN

A retrospective review of AF in Chinese Kailuan diabetes.

METHODS

Research and statistic analysis on the clinical data of 9050 diabetic patients from Kailuan Coal Mine Group Corporation who participated in a health survey from July 2006 to October 2007.

RESULTS

Sixty diabetic patients (50 males and 10 females) were diagnosed with AF during the health checkup, with a prevalence of 0.66% (0.67% in males and 0.62% in females). Univariate analysis showed that patients with AF were older and had higher levels of serum uric acid (UA), pulse pressure, serum c-reactive protein and anti-hypertensive medication usage, but lower levels of fasting blood glucose and triglycerides (TG). Multivariate analysis indicated that older age (OR = 1.09; 95% CI: 1.06-1.12), increased UA (OR = 1.01; 95% CI: 1.00-1.01) and decreased TG (OR = 0.71; 95% CI: 0.55-0.92) were independent predictive factors of AF after adjusting for other variables. After gender stratification, age and UA remained as independent predictive factors of AF in both male and female patients. However, TG had an independent inverse association with AF in male patients only.

CONCLUSIONS

Age and UA are independent predictive factors of AF in both male and female diabetic patients. TG is inversely correlated with AF in male diabetic patients only.

Once daily ledipasvir/sofosbuvir fixed-dose combination with ribavirin in patients with inherited bleeding disorders and hepatitis C genotype 1 infection

AIM

People with inherited bleeding disorders have been disproportionally affected by HCV. We assessed the fixed-dose combination of the NS5A inhibitor ledipasvir (LDV) with the NS5B polymerase inhibitor sofosbuvir (SOF) with ribavirin (RBV) in patients with genotype 1 HCV and inherited bleeding disorders.

METHODS

To be eligible, patients had to be over 18 years of age and have an inherited bleeding disorder. HCV treatment-naïve and -experienced patients could enrol. All patients received LDV 90 mg per SOF 400 mg once daily and weight-based RBV in a divided dose for 12 weeks. The primary efficacy endpoint was sustained virologic response (SVR), defined as HCV RNA below the limit of detection (15 IU mL^-1 ) 12 weeks after the end of treatment (SVR12).

RESULTS

Of the 14 patients enrolled, 8 (57%) had haemophilia A, 3 (21%) had haemophilia B and 2 (14%) had von Willebrand disease, and 1 (7%) had factor XIII deficiency. All 14 patients (100%, 95% CI: 77-100%) achieved SVR12. Treatment was well tolerated: all patients completed therapy, with mostly mild adverse events. No specific safety concerns associated with the patient's underlying bleeding disorders were noted.

CONCLUSION

These results appear to suggest that people with HCV and inherited bleeding disorders can be safely and effectively treated with 12 weeks of LDV/SOF plus RBV.

Harpagoside ameliorates the amyloid-β-induced cognitive impairment in rats via up-regulating BDNF expression and MAPK/PI3K pathways

So far, no effective disease-modifying therapies for Alzheimer's disease (AD) aiming at protecting or reversing neurodegeneration of the disease have been established yet. The present work aims to elucidate the effect of Harpagoside (abbreviated HAR), an iridoid glycosides purified from the Chinese medicinal herb Scrophularia ningpoensis, on neurodegeneration induced by β-amyloid peptide (Aβ) and the underlying molecular mechanism. Here we show that HAR exerts neuroprotective effects against Aβ neurotoxicity. Rats injected aggregated Aβ₁₋₄₀ into the bilateral hippocampus displayed impaired spatial learning and memory ability in a Y-maze test and novel object recognition test, while HAR treatment ameliorated Aβ₁₋₄₀-induced behavioral deficits. Moreover, administration of HAR increased the expression levels of brain-derived neurotrophic factor (BDNF) and activated the extracellular-regulated protein kinase (ERK) and the phosphatidylinositol 3-kinase (PI3-kinase) pathways both in the cerebral cortex and hippocampus of the Aβ₁₋₄₀-insulted rat model. Furthermore, in cultured primary cortical neurons, Aβ₁₋₄₂ induced significant decrease of choline acetyltransferase (ChAT)-positive neuron number and neurite outgrowth length, both of which were dose dependently increased by HAR. In addition, HAR pretreatment also significantly attenuated the decrease of cell viability in Aβ₁₋₄₂-injured primary cortical neurons. Finally, when K252a, an inhibitor of Trk tyrosine kinases, and a BDNF neutralizing antibody were added to the culture medium 2 h prior to HAR addition, the protective effect of HAR on Aβ₁₋₄₂-induced neurodegeneration in the primary cortical neuron was almost inhibited. Taken together, HAR exerting neuroprotection effect and ameliorating learning and memory deficit appears to be associated, at least in part, with up-regulation of BDNF content as well as activating its downstream signaling pathways, e.g., MAPK/PI3K pathways. It raises the possibility that HAR has potential to be a therapeutic agent against AD.

Characterizations, relationship, and potential sources of outdoor and indoor particulate matter bound polycyclic aromatic hydrocarbons (PAHs) in a community of Tianjin, Northern China

Polycyclic aromatic hydrocarbons (PAHs) are among the most toxic air pollutants in China. However, because there are unsubstantial data on indoor and outdoor particulate PAHs, efforts in assessing inhalation exposure and cancer risk to PAHs are limited in China. This study measured 12 individual PAHs in indoor and outdoor environments at 36 homes during the non-heating period and heating period in 2009. Indoor PAH concentrations were comparable with outdoor environments in the non-heating period, but were lower in the heating period. The average indoor/outdoor ratios in both sampling periods were lower than 1, while the ratios in the non-heating period were higher than those in the heating period. Correlation analysis and coefficient of divergence also verified the difference between indoor and outdoor PAHs, which could be caused by high ventilation in the non-heating period. To support this conclusion, linear and robust regressions were used to estimate the infiltration factor to compare outdoor PAHs to indoor PAHs. The calculated infiltration factors obtained by the two models were similar in the non-heating period but varied greatly in the heating period, which may have been caused by the influence of ventilation. Potential sources were distinguished using a diagnostic ratio and a mixture of coal combustion and traffic emission, which are major sources of PAHs.

Properties of different selection signature statistics and a new strategy for combining them

Identifying signatures of recent or ongoing selection is of high relevance in livestock population genomics. From a statistical perspective, determining a proper testing procedure and combining various test statistics is challenging. On the basis of extensive simulations in this study, we discuss the statistical properties of eight different established selection signature statistics. In the considered scenario, we show that a reasonable power to detect selection signatures is achieved with high marker density (>1 SNP/kb) as obtained from sequencing, while rather small sample sizes (~15 diploid individuals) appear to be sufficient. Most selection signature statistics such as composite likelihood ratio and cross population extended haplotype homozogysity have the highest power when fixation of the selected allele is reached, while integrated haplotype score has the highest power when selection is ongoing. We suggest a novel strategy, called de-correlated composite of multiple signals (DCMS) to combine different statistics for detecting selection signatures while accounting for the correlation between the different selection signature statistics. When examined with simulated data, DCMS consistently has a higher power than most of the single statistics and shows a reliable positional resolution. We illustrate the new statistic to the established selective sweep around the lactase gene in human HapMap data providing further evidence of the reliability of this new statistic. Then, we apply it to scan selection signatures in two chicken samples with diverse skin color. Our analysis suggests that a set of well-known genes such as BCO2, MC1R, ASIP and TYR were involved in the divergent selection for this trait.

Association between the rs189037 single nucleotide polymorphism in the ATM gene promoter and cognitive impairment

The aim of this study was to explore the existence of a relationship between the rs189037 single nucleotide polymorphism (SNP) of the ataxia telangiectasia mutated (ATM) gene and cognitive impairment in the elderly (aged 60 years and above). In a cohort, 505 residents of Suinung City were consecutively recruited and their cognitive function was measured using a 30-point Mini-Mental State Examination (MMSE). The subjects were divided into cognitive impairment group and control group on the basis of MMSE scores. Presence of the rs189037 SNP variant was examined using polymerase chain reaction-restriction fragment length polymorphism. The prevalence rates of cognitive impairment were 32.7% in the whole sample. The genotype frequencies of the rs189037 polymorphism were 33.5% (CC), 50.7% (CT), and 15.8% (TT); the C and T allele frequencies were 58.8 and 41.2%, respectively. No significant differences in the frequency distributions of the CC, CT and TT genotypes were observed between cognitively impaired and control groups. We found that the rs189037 SNP was not directly correlated with cognitive impairment among the elderly Chinese Han population.

Which is more suitable for kidney transplantation at the early post-transplantation phase in China - low dosing or standard dosing of enteric-coated mycophenolate sodium?

AIMS

To investigate the pharmacokinetics of enteric-coated mycophenolate sodium (EC-MPS) and the clinical outcome in kidney transplant recipients in the early post-transplantation phase. Then explain which regimen is more suitable for Chinese renal transplant recipients.

METHODOLOGY

In total, 60 de novo kidney transplant recipients treated with tacrolimus and steroids were randomised to receive EC-MPS at standard dose (SD; 1440 mg/day; n = 28) or low dose (LD; 1080 mg/day; n = 32). Efficacy parameters, safety and tolerability were assessed over a 6-month study period. Full mycophenolic acid (MPA) areas under the curve (AUCs) were completed on days 3 and 5, whereas a three-point limited sampling strategy (LSS) was utilised for MPA AUC assessments at 2 weeks and months 1, 3 and 6 (the LSS for three-time-point MPA AUC 0-12 h (mg h/l) = 15.99 + 0.87C1 h  + 0.68C2 h  + 7.85C4 h ; r(2)  = 0.8670.

RESULTS

The mean AUC levels at day 3 and day 5 in the SD group were significantly higher than in the LD group (57.4 mg·h/l vs. 38.2 mg·h/l and 59.3 mg·h/l vs. 44.8 mg·h/l, respectively, p < 0.01). There was a trend for fewer clinically diagnosed acute rejections in the SD group vs. the LD group at 6 months (7.1% vs. 12.5%). This trend was also present when acute rejection was analysed as biopsy-proven cases. There were significantly more acute rejections (all definitions) in patients with MPA AUC levels < 30 mg·h/l compared with those with MPA AUC levels ≥ 30 mg·h/l within 6 months (p < 0.05). Renal function, incidence of infection and haematological disorders were not significantly different in either study group.

CONCLUSIONS

Early adequate MPA exposure in renal transplant recipients can be achieved with a higher starting dose. In addition, a SD regimen was as well-tolerated as a LD regimen. Furthermore, early adequate MPA exposure significantly lowered the rate of acute rejection without compromising safety and tolerability.

Effects of down-regulated steroidogenic factor-1 on ACTH and potassium chloride-induced steroid synthesis in H295R cells

The prevalence of adrenal diseases in the cortex is more common than that in the medulla in the form of hormone disorder or neoplasm. Steroidogenic factor&mdash;1 (SF&mdash;1) is important in regulating aldosterone synthase (CYP11B2) and cortisol synthase (CYP11B1). SF&mdash;1 is increased in aldosterone&mdash;producing adenoma (APA) and cortisol&mdash;producing adenoma (CPA). Overexpression of SF&mdash;1 has been extensively studied, but the available in&mdash;depth information regarding the effects of downregulated SF&mdash;1 on CYP11B2/CYP11B1 and their regulators is limited. In this paper, we attempted to investigate the effects of downregulated SF&mdash;1 on aldosterone to adrenocorticotropic hormone (ACTH) and potassium chloride (KCl) stimulation and those on cortisol to ACTH stimulation through RNA interference in acute and chronic phases. Downregulated SF&mdash;1 decreased the sensitivity of aldosterone to ACTH/KCl and that of cortisol to ACTH stimulation. This study provides new insights into the influence of SF&mdash;1 on adrenocortical diseases by considering the effects of SF&mdash;1 on regulation.

Estimation of the rate of tooth wear in permanent incisors: a cross-sectional digital radiographic study

This study used conventional digital radiography to estimate the rate of tooth wear (TW) of maxillary and mandibular central incisors based on a cross-sectional study design. The crown length of 1239 permanent maxillary and mandibular central incisors from 346 persons (age groups: 10, 25, 40, 55 and 70 years ± 3) were measured by three calibrated dentists. Study teeth were intact incisally, had clearly visible incisal edges and cementoenamel junctions and had natural tooth antagonists. Measures were based on digital radiographic images (N = 666) archived in MiPACS within the electronic health record (axiUm(®)) from the College of Dentistry patient database. Incisor crown length decreased at a linear rate in both arches over the 60 years represented by the age groups. The average crown length for maxillary incisors in the youngest age group was 11.94 mm, which decreased by an average of 1.01 mm by median age 70. For mandibular incisors, the average crown length in the youngest age group was 9.58 mm, which decreased by an average of 1.46 mm in the oldest age group. Males and females showed similar rates of TW. Regardless of age, females demonstrated smaller mean crown height for maxillary incisors than males (P < 0.0001). Measures by the examiners demonstrated good agreement, with an interclass correlation coefficient of 0.869 and an average intra-examiner correlation of 99.5%, based on repeated measurements (n = 100). TW was estimated to average 1.01 mm for maxillary central incisors and 1.46 mm for mandibular central incisors by age 70 years.

Imputation of missing genotypes from low- to high-density SNP panel in different population designs

Imputation of missing genotypes, in particular from low density to high density, is an important issue in genomic selection and genome-wide association studies. Given the marker densities, the most important factors affecting imputation accuracy are the size of the reference population and the relationship between individuals in the reference (genotyped with high-density panel) and study (genotyped with low-density panel) populations. In this study, we investigated the imputation accuracies when the reference population (genotyped with Illumina BovineSNP50 SNP panel) contained sires, halfsibs, or both sires and halfsibs of the individuals in the study population (genotyped with Illumina BovineLD SNP panel) using three imputation programs (fimpute v2.2, findhap v2, and beagle v3.3.2). Two criteria, correlation between true and imputed genotypes and missing rate after imputation, were used to evaluate the performance of the three programs in different scenarios. Our results showed that fimpute performed the best in all cases, with correlations from 0.921 to 0.978 when imputing from sires to their daughters or between halfsibs. In general, the accuracies of imputing between halfsibs or from sires to their daughters were higher than were those imputing between non-halfsibs or from sires to non-daughters. Including both sires and halfsibs in the reference population did not improve the imputation performance in comparison with when only including halfsibs in the reference population for all the three programs.

Gas tamponade combined with laser photocoagulation therapy for congenital optic disc pit maculopathy

PURPOSE

To evaluate the long-term clinical efficacy and safety of gas tamponade combined with laser photocoagulation for optic disc pit maculopathy.

METHODS

Seven consecutive patients with unilateral maculopathy associated with optic disc pit and one patient with bilateral optic disc pit maculopathy were given octafluoropropane (C3F8) tamponade combined with focal laser photocoagulation treatment. Patients were followed up for 21-62 months after treatment. Main outcomes were determined by optical coherence tomography (OCT) and best-corrected visual acuity (BCVA).

RESULTS

Treatment with C3F8 tamponade followed by laser photocoagulation in ODP maculopathy patients resulted in resolution of sub-retinal and/or intra-retinal fluid in six out of eight patients. The remaining two patients had significant reduction in fluid, as determined by OCT, and funduscopy, as well as an improvement in anatomical architecture. Visual acuity improved obviously in seven eyes and remained stable in two eyes. Central visual field loss after photocoagulation was not clinically appreciable by visual field examination. No post-operative complications of maculopathy occurred during the follow-up period.

CONCLUSIONS

Although repeated treatment was needed in some patients, C3F8 tamponade combined with laser photocoagulation is still a simple, effective, minimally invasive, and economic therapy for optic disc pit maculopathy.

A supported liquid extraction-LC-MS/MS method for determination of GDC-0980 (Apitolisib), a dual small-molecule inhibitor of class 1A phosphoinositide 3-kinase and mammalian target of rapamycin, in human plasma

A liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method for the determination of GDC-0980 (Apitolisib) concentrations in human plasma has been developed and validated to support clinical development. Supported liquid extraction (SLE) was used to extract plasma samples (80μL) and the resulting samples were analyzed using reverse-phase chromatography and mass spectrometry coupled with a turbo-ionspray interface. The mass analysis of GDC-0980 was performed using multiple reaction monitoring (MRM) transitions in positive ionization mode. The method was validated over the calibration curve range 0.0500-25.0ng/mL using linear regression and 1/x(2) weighting. Within-run relative standard deviation (%RSD) ranged from 0.4 to 3.9%, while the between-run %RSD varied from 1.1 to 1.5% for QCs. The accuracy ranged from 96.1% to 106.7% of nominal for within-run and 96.7-106.7% of nominal for between-run at all concentrations including the LLOQ quality control at 0.0500ng/mL. Extraction recovery of GDC-0980 was between 72.4% and 75.5%. Stability of GDC-0980 was established in human plasma for 547 days at -20°C and -70°C and established in reconstituted sample extracts for 146h when stored at 2-8°C. Stable-labeled internal standard was used to minimize matrix effects. Mean pharmacokinetic parameters determined using this method for the day 1 control group in a phase I trial were: Cmax=11.1ng/mL, AUC0-inf=108ngh/mL, and T1/2=13.1h.

The role of testicular nuclear receptor 4 in chemo-resistance of docetaxel in castration-resistant prostate cancer

Docetaxel-based therapy is one of the first-line options for castration-resistant prostate cancer (CRPC). However, a large proportion of CRPC patients show different extents of docetaxel resistance. The current study aims to investigate the role of testicular nuclear receptor 4 (TR4) in docetaxel resistance in CRPC. TR4 expression level in prostate biopsy samples from CRPC patients treated with docetaxel was measured by immunohistochemistry (IHC). Alternation of TR4 expression in prostate cancer (PCa) cell line PC3 was applied to find out the influence of TR4 on half-maximal inhibitory concentration (IC50), cell viability and cell apoptosis. Patients who failed to achieve prostate-specific antigen (PSA) response (<50% PSA reduction from baseline) after docetaxel-based chemotherapy had a comparatively higher TR4 expression than those who achieved PSA response (⩾50% PSA reduction from baseline). Knocking down TR4 in PC3 cells led to a lower IC50 dose, poorer cell viability and more cell apoptosis when treated with docetaxel, whereas overexpression of TR4 in PC3 led to a higher IC50 dose, better cell viability and less cell apoptosis. TR4 enhances the chemo-resistance of docetaxel in CRPC. It may serve as a biomarker to determine the prognosis of docetaxel-based therapy and as a potential therapy target to combine with docetaxel to better suppress CRPC.

Increasing imputation and prediction accuracy for Chinese Holsteins using joint Chinese-Nordic reference population

This study investigated the effect of including Nordic Holsteins in the reference population on the imputation accuracy and prediction accuracy for Chinese Holsteins. The data used in this study include 85 Chinese Holstein bulls genotyped with both 54K chip and 777K (HD) chip, 2862 Chinese cows genotyped with 54K chip, 510 Nordic Holstein bulls genotyped with HD chip, and 4398 Nordic Holstein bulls genotyped with 54K chip and with deregressed proofs for five milk production traits. Based on these data, the accuracy of imputation from 54K to HD marker data and the accuracy of genomic predictions in Chinese Holstein were assessed. The allele correct rate increased around 2.7 and 1.7% in imputation from the 54K to the HD marker data for Chinese Holstein bulls and cows, respectively, when the Nordic HD-genotyped bulls were included in the reference data for imputation. However, the prediction accuracy was improved slightly when using the marker data imputed based on the combined HD reference data, compared with using the marker data imputed based on the Chinese HD reference data only. On the other hand, when using the combined reference population including 4398 Nordic Holstein bulls, the accuracy of genomic predictions increased 6.5 percentage points together with a reduction of prediction bias. The HD markers did not outperform the 54K markers in genomic prediction based on the present data. The results indicate that for Chinese Holsteins, it is necessary to genotype more individuals with 54K chip to increase reference population rather than increasing marker density.

Effectiveness of continuous and pulsed ultrasound for the management of knee osteoarthritis: a systematic review and network meta-analysis

BACKGROUND

To investigate the efficacy of continuous and pulsed ultrasound (US) in the management of knee osteoarthritis (OA).

DESIGN

This systematic review and network meta-analysis covered 12 trials in total. Electronic databases including MEDLINE, Embase and Cochrane Library were searched through to identify randomized controlled trials comparing the two modes of US with control interventions (sham or blank) or with each other. Bayesian network meta-analysis was used to integrate both the direct and indirect evidences on treatment effectiveness.

RESULTS

Pulsed US (PUS) is more effective in both pain relief and function improvement when compared with the control group; but for continuous US (CUS), there is only a significant difference in pain relief in comparison with the control group. In addition, no matter in terms of pain intensity or function at the last follow-up time point, PUS always exhibited a greater probability of being the preferred mode. However, the evidence of heterogeneity and the limitation in sample size of some studies could be a potential threat to the validity of results.

CONCLUSIONS

Our findings indicated that PUS, with a greater probability of being the preferred mode, is more effective in both pain relief and function improvement when compared with the control group. However, CUS could only be considered as a pain relief treatment in the management of knee OA. The findings also confirmed that none of these modes is dangerous.

LEVEL OF EVIDENCE

Level II, systematic review and network meta-analysis of randomized controlled trials.

Patterns in default-mode network connectivity for determining outcomes in cognitive function in acute stroke patients

OBJECT

To investigate whether resting-state functional connectivity (FC) differed in the default mode network (DMN) in stroke patients with and without post-stroke cognitive impairment (PSCI vs. Non-PSCI) and to explore the relationship between DMN connectivity and the cognitive performance in stroke patients.

METHODS

We totally enrolled twenty healthy controls and 18 stroke patients. The stroke patients were divided into two subgroups on the basis of the cognitive assays. Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) scores were recorded 10 days and 3 months after the stroke. Independent component analysis was used to isolate the DMN. One-way analysis of variance was performed to detect different FC among groups. Pearson correlation analyses were conducted to determine the relationships between FC strength and the MoCA and MMSE scores.

RESULTS

Compared to healthy controls, both Non-PSCI patients and PSCI patients showed significantly decreased FC in the posterior cingulate cortex/precuneus (PCC/PCu), as well as increased FC in the medial prefrontal cortex (MPFC) and left hippocampus. However, Non-PSCI patients showed more significantly increased FC in the MPFC and hippocampus than PSCI patients did. The FC in the PCC/PCu was related to the MoCA score measured at a 10-day follow-up, and the FC in the left hippocampus predicted the MoCA score measured at 3 months follow-up.

CONCLUSIONS

Our findings may be helpful for facilitating further understanding of the potential mechanism underlying PSCI, and suggests that resting-state DMN connectivity could serve as neuroimaging biomarkers for future interventional studies.

Epidemiological characteristics of motor neuron disease in Chinese patients

BACKGROUND

The epidemiology, diagnosis, and treatment of motor neuron disease (MND) in Chinese patients are ill known.

METHODS

A registered study of 461 MND patients was conducted across 10 facilities in 7 Chinese cities from February 2009 to March 2010.

RESULTS

Patients were classified as amyotrophic lateral sclerosis (ALS) (84.4%), progressive bulbar palsy (PBP) (4.1%), progressive muscular atrophy (PMA) (10.4%), or primary lateral sclerosis (PLS) (0.9%). MND was predominant in men (men/women; 1.6:1.0). Mean onset age was 52.6 years, with the highest incidence being observed between 51 and 60 years. Notably, 26.0% of MND patients were employed in forestry, fishery, or animal husbandry industries. Ten cases (2.7%) reported family history of MND, and 54.2% exhibited cervical onset. MND was also associated with head/neck trauma. Non-invasive positive pressure ventilation was the most common supportive therapy.

CONCLUSION

As a novel comprehensive report of a Chinese population, this study reveals that epidemiological characteristics of MND patients were similar to those observed in international populations. MND is age-related, male gender predominant, and may be associated with both environmental and genetic risk factors.

Activation of mTOR pathway in myeloid-derived suppressor cells stimulates cancer cell proliferation and metastasis in lal(-/-) mice

Inflammation critically contributes to cancer metastasis, in which myeloid-derived suppressor cells (MDSCs) are an important participant. Although MDSCs are known to suppress immune surveillance, their roles in directly stimulating cancer cell proliferation and metastasis currently remain unclear. Lysosomal acid lipase (LAL) deficiency causes systemic expansion and infiltration of MDSCs in multiple organs and subsequent inflammation. In the LAL-deficient (lal^−/−) mouse model, melanoma metastasized massively in allogeneic lal^−/− mice, which was suppressed in allogeneic lal^+/+ mice due to immune rejection. Here we report for the first time that MDSCs from lal^−/− mice directly stimulated B16 melanoma cell in vitro proliferation, and in vivo growth and metastasis. Cytokines i.e., IL-1β and TNFα from MDSCs are required for B16 melanoma cell proliferation in vitro. Myeloid-specific expression of human LAL (hLAL) in lal^−/− mice rescues these malignant phenotypes in vitro and in vivo. The tumor-promoting function of lal^−/− MDSCs is mediated, at least in part, through over-activation of the mammalian target of rapamycin (mTOR) pathway. Knockdown of mTOR, Raptor or Rictor in lal^−/− MDSCs suppressed their stimulation on proliferation of cancer cells, including B16 melanoma, LLC and Tramp-C2 cancer cells. Our results indicate that LAL plays a critical role in regulating MDSCs ability to directly stimulate cancer cell proliferation, and overcome immune rejection of cancer metastasis in allogeneic mice through modulation of the mTOR pathway, which provides a mechanistic basis for targeting MDSCs to reduce the risk of cancer metastasis. Therefore, MDSCs possess dual functions to facilitate cancer metastasis: suppress immune surveillance, and stimulate cancer cell proliferation and growth.