In diabetes mellitus, vascular complications such as atherosclerosis are a major cause of death. The key underlying pathomechanisms are unclear. However, hyperglycemic oxidative stress derived from ...NADPH oxidase (Nox), the only known dedicated enzyme to generate reactive oxygen species appears to play a role. Here we identify the Nox1 isoform as playing a key and pharmacologically targetable role in the accelerated development of diabetic atherosclerosis.
Human aortic endothelial cells exposed to hyperglycemic conditions showed increased expression of Nox1, oxidative stress, and proinflammatory markers in a Nox1-siRNA reversible manner. Similarly, the specific Nox inhibitor, GKT137831, prevented oxidative stress in response to hyperglycemia in human aortic endothelial cells. To examine these observations in vivo, we investigated the role of Nox1 on plaque development in apolipoprotein E-deficient mice 10 weeks after induction of diabetes mellitus. Deletion of Nox1, but not Nox4, had a profound antiatherosclerotic effect correlating with reduced reactive oxygen species formation, attenuation of chemokine expression, vascular adhesion of leukocytes, macrophage infiltration, and reduced expression of proinflammatory and profibrotic markers. Similarly, treatment of diabetic apolipoprotein E-deficient mice with GKT137831 attenuated atherosclerosis development.
These studies identify a major pathological role for Nox1 and suggest that Nox1-dependent oxidative stress is a promising target for diabetic vasculopathies, including atherosclerosis.
High-mobility group box protein 1 (HMGB1) is a DNA-binding protein and cytokine highly expressed in atherosclerotic lesions, but its pathophysiological role in atherosclerosis is unknown. We ...investigated its role in the development of atherosclerosis in ApoE-/- mice.
Apolipoprotein E-deficient (ApoE-/-) mice fed a high-fat diet were administered a monoclonal anti-HMGB1 neutralizing antibody, and the effects on lesion size, immune cell accumulation, and proinflammatory mediators were assessed using Oil Red O, immunohistochemistry, and real-time polymerase chain reaction. As with human atherosclerotic lesions, lesions in ApoE-/- mice expressed HMGB1. Treatment with the neutralizing antibody attenuated atherosclerosis by 55%. Macrophage accumulation was reduced by 43%, and vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1 expression was attenuated by 48% and 72%, respectively. CD11c+ dendritic cells were reduced by 65%, and the mature (CD83+) population was reduced by 60%. Treatment also reduced CD4+ cells by nearly 50%. mRNAs in lesions encoding tumor necrosis factor-α and interleukin-1β tended to be reduced. Mechanistically, HMGB1 stimulated macrophage migration in vitro and in vivo; in vivo, it markedly augmented the accumulation of F4/80+Gr-1(Ly-6C)+ macrophages and also increased F4/80+CD11b+ macrophage numbers.
HMGB1 exerts proatherogenic effects augmenting lesion development by stimulating macrophage migration, modulating proinflammatory mediators, and encouraging the accumulation of immune and smooth muscle cells.
Atherosclerosis is driven by inflammatory reactions that are shared with the innate immune system. Toll-like receptor-9 (TLR9) is an intracellular pattern recognition receptor of the innate immune ...system that is currently under clinical investigation as a therapeutic target in inflammatory diseases. Here, we investigated whether TLR9 has a role in the development of atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) mice.
Newly generated double-knockout ApoE(-/-):TLR9(-/-) mice and control ApoE(-/-) mice were fed a high-fat diet from 8 weeks and effects on lesion size, cellular composition, inflammatory status, and plasma lipids were assessed after 8, 12, 15, and 20 weeks. All 4 time points demonstrated exacerbated atherosclerotic lesion severity in ApoE(-/-):TLR9(-/-) mice, with a corresponding increase in lipid deposition and accumulation of macrophages, dendritic cells, and CD4(+) T cells. Although ApoE(-/-):TLR9(-/-) mice exhibited an increase in plasma very low-density lipoprotein/low-density-lipoprotein cholesterol, the very low-density lipoprotein/low-density lipoprotein:high-density lipoprotein ratio was unaltered because of a parallel increase in plasma high-density lipoprotein cholesterol. As a potential mechanism accounting for plaque progression in ApoE(-/-):TLR9(-/-) mice, CD4(+) T-cell accumulation was further investigated and depletion of these cells in ApoE(-/-):TLR9(-/-) mice significantly reduced lesion severity. As a final translational approach, administration of a TLR9 agonist (type B CpG oligodeoxynucleotide 1668) to ApoE(-/-) mice resulted in a reduction of lesion severity.
Genetic deletion of the innate immune receptor TLR9 exacerbated atherosclerosis in ApoE(-/-) mice fed a high-fat diet. CD4(+) T cells were identified as potential mediators of this effect. A type B CpG oligodeoxynucleotide TLR9 agonist reduced lesion severity, thus identifying a novel therapeutic approach in atherosclerosis.
Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide and is heterogeneous both morphologically and molecularly. In an era of personalized medicine, the greatest challenge is to ...predict individual response to therapy and distinguish patients likely to be cured with surgical resection of tumors and systemic therapy from those resistant or non-responsive to treatment. Patients would avoid futile treatments, including clinical trial regimes and ultimately this would prevent under- and over-treatment and reduce unnecessary adverse side effects. In this review, the potential of specific biomarkers will be explored to address two key questions-1) Can the prognosis of patients that will fare well or poorly be determined beyond currently recognized prognostic indicators? and 2) Can an individual patient's response to therapy be predicted and those who will most likely benefit from treatment/s be identified? Identifying and validating key prognostic and predictive biomarkers and an understanding of the underlying mechanisms of drug resistance and toxicity in CRC are important steps in order to personalize treatment. This review addresses recent data on biological prognostic and predictive biomarkers in CRC. In addition, patient cohorts most likely to benefit from currently available systemic treatments and/or targeted therapies are discussed in this review.
RAGE (receptor for advanced glycation end-products) is expressed on multiple cell types implicated in the progression of atherosclerosis and plays a role in DAA (diabetes-associated atherosclerosis). ...The aim of the present study was to determine the relative role of either BM (bone marrow)- or non-BM-derived RAGE in the pathogenesis of STZ (streptozotocin)-induced DAA. Male ApoE (apolipoprotein E)-null (ApoE-/-:RAGE+/+) and ApoE:RAGE-null (ApoE-/-:RAGE-/-) mice at 7 weeks of age were rendered diabetic with STZ. At 8 weeks of age, ApoE-/- and ApoE-/-:RAGE-/- control and diabetic mice received BM from either RAGE-null or RAGE-bearing mice, generating various chimaeras. After 10 and 20 weeks of diabetes, mice were killed and gene expression and atherosclerotic lesion formation were evaluated respectively. Deletion of RAGE in either the BM cells or non-BM cells both resulted in a significant attenuation in DAA, which was associated with reduced VCAM-1 (vascular cell adhesion molecule-1) expression and translated into reduced adhesion in vitro. In conclusion, the results of the present study highlight the importance of both BM- and non-BM-derived RAGE in attenuating the development of DAA.
Purpose
Patients with locally advanced rectal cancer who achieve pathologic complete response (pCR) following neoadjuvant therapy have better long-term outcomes and could be spared from the ...perioperative and long-term morbidity of rectal resection. The aim of this study was to identify factors that predict the ability to achieve pCR at completion of conventional neoadjuvant therapy, therefore determining their suitability for non-surgical management.
Methods
A retrospective analysis was performed on data obtained from a prospectively maintained colorectal neoplasia database. Patients treated for biopsy-proven primary rectal adenocarcinoma between January 1, 2010, and February 28, 2018, who received neoadjuvant radiotherapy or chemoradiotherapy and had undergone surgical resection, were included in this study. Five-year oncologic outcome data was also obtained for 144 patients. Clinicopathological tumour characteristics and treatment regimens were analysed for correlation to clinical outcome.
Results
Three hundred fifty-four patients met inclusion criteria for this study. We identified significant differences between patients achieving a pCR and those that did not for tumour type (adenocarcinoma vs. mucinous/signet ring;
p
= 0.008), pre-treatment serum CEA level (</≥ 2.5 μg/L;
p
= 0.003), neoadjuvant therapy type (short-course radiotherapy and long-course chemoradiotherapy;
p
= 0.008) and preoperative lymph node status (node-negative versus node-positive disease;
p
= 0.031). Additionally, this is the first report to our knowledge to identify a significant correlation with pCR and the degree of tumour fixity (mobile vs. fixed/tethered;
p
= 0.038).
Conclusions
This retrospective analysis identified factors that significantly impact a patients’ ability to achieve a pCR, which may prove useful for prospectively selecting patients suitable for non-surgical management of disease.
The hemodynamic and nonhemodynamic effects of angiotensin II on diabetic complications are considered to be primarily mediated by the angiotensin II type 1 receptor subtype. However, its biological ...and functional effect mediated through the angiotensin II type 2 receptor subtype is still unclear. Activation of the angiotensin II type 2 receptors has been postulated to oppose angiotensin II type 1 receptor-mediated actions and thus attenuate fibrosis. This study aimed to elucidate the reno-protective role of the novel selective angiotensin II type 2 receptor agonist, Compound 21, in an experimental model of type 1 diabetic nephropathy. Compound 21 treatment significantly attenuated diabetes mellitus-induced elevated levels of cystatin C, albuminuria, mesangial expansion, and glomerulosclerosis in diabetic mice. Moreover, Compound 21 markedly inhibited the expression of various proteins implicated in oxidative stress, inflammation, and fibrosis, in association with decreased extracellular matrix production. These findings demonstrate that monotherapy of Compound 21 is protective against the progression of experimental diabetic nephropathy by inhibiting renal oxidative stress, inflammation, and fibrosis.
Background and Aim
Colorectal cancer (CRC) is the second leading cause of cancer death worldwide. To improve outcomes for these patients, we need to develop new treatment strategies. Personalized ...cancer medicine, where patients are treated based on the characteristics of their own tumor, has gained significant interest for its promise to improve outcomes and reduce unnecessary side effects. The purpose of this study was to examine the potential utility of patient‐derived colorectal cancer organoids (PDCOs) in a personalized cancer medicine setting.
Methods
Patient‐derived colorectal cancer organoids were derived from tissue obtained from treatment‐naïve patients undergoing surgical resection for the treatment of CRC. We examined the recapitulation of key histopathological, molecular, and phenotypic characteristics of the primary tumor.
Results
We created a bio‐resource of PDCOs from primary and metastatic CRCs. Key histopathological features were retained in PDCOs when compared with the primary tumor. Additionally, a cohort of 12 PDCOs, and their corresponding primary tumors and normal sample, were characterized through whole exome sequencing and somatic variant calling. These PDCOs exhibited a high level of concordance in key driver mutations when compared with the primary tumor.
Conclusions
Patient‐derived colorectal cancer organoids recapitulate characteristics of the tissue from which they are derived and are a powerful tool for cancer research. Further research will determine their utility for predicting patient outcomes in a personalized cancer medicine setting.
Aims/hypothesis
Angiotensin II is well-recognised to be a key mediator in driving the pathological events of diabetes-associated atherosclerosis via signalling through its angiotensin II type 1 ...receptor (AT
1
R) subtype. However, its actions via the angiotensin II type 2 receptor (AT
2
R) subtype are still poorly understood. This study is the first to investigate the role of the novel selective AT
2
R agonist, Compound 21 (C21) in an experimental model of diabetes-associated atherosclerosis (DAA).
Methods
Streptozotocin-induced diabetic
Apoe
-knockout mice were treated with vehicle (0.1 mol/l citrate buffer), C21 (1 mg/kg per day), candesartan cilexetil (4 mg/kg per day) or C21 + candesartan cilexetil over a 20 week period. In vitro models of DAA using human aortic endothelial cells and monocyte cultures treated with C21 were also performed. At the end of the experiments, assessment of plaque content and markers of oxidative stress, inflammation and fibrosis were conducted.
Results
C21 treatment significantly attenuated aortic plaque deposition in a mouse model of DAA in vivo, in association with a decreased infiltration of macrophages and mediators of inflammation, oxidative stress and fibrosis. On the other hand, combination therapy with C21 and candesartan (AT
1
R antagonist) appeared to have a limited additive effect in attenuating the pathology of DAA when compared with either treatment alone. Similarly, C21 was found to confer profound anti-atherosclerotic actions at the in vitro level, particularly in the setting of hyperglycaemia. Strikingly, these atheroprotective actions of C21 were completely blocked by the AT
2
R antagonist PD123319.
Conclusions/interpretation
Taken together, these findings provide novel mechanistic and potential therapeutic insights into C21 as a monotherapy agent against DAA.
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