Mary Anna Venneri

Chronic Inhibition of PDE5 Limits Pro-Inflammatory Monocyte-Macrophage Polarization in Streptozotocin-Induced Diabetic Mice

Diabetes mellitus is characterized by changes in endothelial cells that alter monocyte recruitment, increase classic (M1-type) tissue macrophage infiltration and lead to self-sustained inflammation. Our and other groups recently showed that chronic inhibition of phosphodiesterase-5 (PDE5i) affects circulating cytokine levels in patients with diabetes; whether PDE5i also affects circulating monocytes and tissue inflammatory cell infiltration remains to be established. Using murine streptozotocin (STZ)-induced diabetes and in human vitro cell-cell adhesion models we show that chronic hyperglycemia induces changes in myeloid and endothelial cells that alter monocyte recruitment and lead to self-sustained inflammation. Continuous PDE5i with sildenafil (SILD) expanded tissue anti-inflammatory TIE2-expressing monocytes (TEMs), which are known to limit inflammation and promote tissue repair. Specifically, SILD: 1) normalizes the frequency of circulating pro-inflammatory monocytes triggered by hyperglycemia (53.7 ± 7.9% of CD11b+Gr-1+ cells in STZ vs. 30.4 ± 8.3% in STZ+SILD and 27.1 ± 1.6% in CTRL, P<0.01); 2) prevents STZ-induced tissue inflammatory infiltration (4-fold increase in F4/80+ macrophages in diabetic vs. control mice) by increasing renal and heart anti-inflammatory TEMs (30.9 ± 3.6% in STZ+SILD vs. 6.9 ± 2.7% in STZ, P <0.01, and 11.6 ± 2.9% in CTRL mice); 3) reduces vascular inflammatory proteins (iNOS, COX2, VCAM-1) promoting tissue protection; 4) lowers monocyte adhesion to human endothelial cells in vitro through the TIE2 receptor. All these changes occurred independently from changes of glycemic status. In summary, we demonstrate that circulating renal and cardiac TEMs are defective in chronic hyperglycemia and that SILD normalizes their levels by facilitating the shift from classic (M1-like) to alternative (M2-like)/TEM macrophage polarization. Restoration of tissue TEMs with PDE5i could represent an additional pharmacological tool to prevent end-organ diabetic complications.

Endothelial dysfunction markers as a therapeutic target for Sildenafil treatment and effects on metabolic control in type 2 diabetes

Objective: Endothelial dysfunction (ED) plays a role in diabetic cardiovascular complications. Hyperglycemia increases cytockines involved in vascular inflammation. Inhibition of phosphodiesterase type 5 (PDE5) exerts a relaxation on corpora cavernosa and has cardioprotective properties. The effect of chronic sildenafil treatment, on ED markers and metabolic parameters in a non-randomized study on men with type 2 diabetes (T2DM), was investigated. Research design and methods: Twenty-eight T2DM patients (61.2 ± 7.8 years, hemoglobin A1c (HbA1c) 7.9 ± 1.3%, duration of diabetes 11.5 ± 7.8 years) were treated with sildenafil 100 mg/d for 3 months. Baseline and postprandial glycemia, insulin, HbA1c, HOMA index, lipids, glomerular filtration rate, homocysteine were assessed at each visit. P-selectin (CD62P), CD14/42b, CD14/41, ICAM (CD54), PECAM (CD31) and CD11b/CD18, were evaluated, after monocyte isolation with flow-cytometry, before and after treatment. Results: After 3 months, sildenafil decreased P-selectin (p < 0.05), post-prandial glycemia (p < 0.01), HbA1c (p < 0.01), low-density lipoprotein cholesterol (p < 0.01) and increased high-density lipoprotein (p < 0.05). Conclusions: PDE5 inhibition, in T2DM patients, reduces the endothelial function marker P-selectin and exerts a beneficial effect on glycometabolic control.

Effect of once-daily, modified-release hydrocortisone versus standard glucocorticoid therapy on metabolism and innate immunity in patients with adrenal insufficiency (DREAM): a single-blind, randomised controlled trial

BACKGROUND Conventional treatment of patients with adrenal insufficiency involves administration of glucocorticoids multiple times a day and has been associated with weight gain and metabolic impairment. The optimal glucocorticoid replacement therapy for these patients is highly debated because of the scarcity of evidence from randomised trials. We aimed to establish whether the timing and pharmacokinetics of glucocorticoid replacement therapy affect the metabolism and immune system of patients with adrenal insufficiency. METHODS We did a single-blind randomised controlled trial at two reference university hospitals in Italy. Eligible patients (aged 18-80 years) with adrenal insufficiency were on conventional glucocorticoid therapy and had been stable for at least 3 months before enrolment. Patients were randomly assigned (1:1) with a computer-generated random sequence stratified by type of adrenal insufficiency and BMI to continue conventional glucocorticoid therapy (standard treatment group) or to switch to an equivalent dose of once-daily, modified-release oral hydrocortisone (switch treatment group). Outcome assessors were masked to treatment allocation. The primary outcome was bodyweight change from baseline to 24 weeks. Secondary outcomes included immune cell profiles, susceptibility to infections, and quality of life. Efficacy analyses included all patients who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, NCT02277587. FINDINGS Between March 1, 2014, and June 30, 2016, 89 patients with adrenal insufficiency were randomly assigned to continue standard glucocorticoid therapy (n=43) or to switch to once-daily, modified-release hydrocortisone (n=46). At 24 weeks, bodyweight reduction was superior in patients in the once-daily hydrocortisone group compared with those in the standard treatment group (-2·1 kg [95% CI -4·0 to -0·3] vs 1·9 kg [-0·1 to 3·9]; treatment difference -4·0 kg, 95% CI -6·9 to -1·1; p=0·008). Additionally, patients in the once-daily hydrocortisone group had more normal immune cell profiles, reduced susceptibility to infections, and improved quality of life compared with the standard glucocorticoid therapy group. We observed no difference in frequency or severity of adverse events between the two intervention groups, although a lower cumulative number of recurrent upper respiratory tract infections was observed with once-daily hydrocortisone than with standard treatment (17 vs 38; p=0·016). Most adverse events were mild; three serious adverse events occurred in each group, of which one adverse advent (arthritis) in the switch treatment group could be considered drug related. INTERPRETATION Patients with adrenal insufficiency on conventional glucocorticoid replacement therapy multiple times a day exhibit a pro-inflammatory state and weakened immune defence. Restoration of a more physiological circadian glucocorticoid rhythm by switching to a once-daily, modified-release regimen reduces bodyweight, normalises the immune cell profile, reduces recurrent infections, and improves the quality of life of patients with adrenal insufficiency. FUNDING Italian Ministry of University and Research.

Angiopoietin-1 and Angiopoietin-2 in metabolic disorders: therapeutic strategies to restore the highs and lows of angiogenesis in diabetes

AbstractThe morbidity and mortality of diabetes mellitus are mostly attributed to cardiovascular complications. Despite tremendous advancement in glycemic control, anti-diabetic medications have failed to revert vascular impairment once triggered by the metabolic disorder. The angiogenic growth factors, Angiopoietin-1 (Ang1) and Angiopoietin-2 (Ang2), are crucial regulators of vessel formation and maintenance starting with embryonic development and continuing through life. In mature vessels, angiopoietins control vascular permeability, inflammation and remodeling. A crucial role of angiopoietins is to drive vascular inflammation from the active to the quiescent state, enabling restoration of tissue homeostasis. The mechanism is of particular importance for healing and repair after damage, two conditions typically impaired in metabolic disorders. There is an emerging body of evidences suggesting that the imbalance of Ang1 and Ang2 regulation, leading to an increased Ang2/Ang1 ratio, represents a culprit of the vascular alterations of patients with type-2 diabetes mellitus. Pharmacological modulation of Ang1 or Ang2 actions may help prevent or delay the onset of diabetic vascular complications by restoring vessel function, favoring tissue repair and maintaining endothelial quiescence. In this review, we present a summary of the role of Ang1 and Ang2, their involvement in diabetic complications, and novel therapeutic strategies targeting angiopoietins to ameliorate vascular health in metabolic disorders.

Everything you ever wanted to know about phosphodiesterase 5 inhibitors and the heart (but never dared ask): How do they work?

IntroductionPhosphodiesterase 5 inhibitors (PDE5i) were developed while investigating novel treatments for coronary artery disease, but their andrological side effects shifted their indication toward the management of erectile dysfunction. Although PDE5i are now also indicated for pulmonary arterial hypertension and there are mounting preclinical and clinical evidences about their potentially beneficial cardiac effects, their use remains controversial and the involved mechanisms remain unclear.Materials and methodsThis review aimed to analyze the effects of PDE5i administration in various animal and humans models of cardiovascular diseases.ResultsAnimal studies have shown that PDE5i have protective effects in several models of cardiac disease. In humans, some studies showed that PDE5i improves microvascular and endothelial dysfunction and exerts positive effects in different samples of cardiovascular (CV) impairment. In contrast, other studies found no benefit (and no harm) in heart failure with preserved ejection fraction. The discrepancies in these findings are likely related to the fact that the mechanisms targeted by PDE5i in human disease are still poorly understood and the target population not yet identified. The mechanisms of actions herein reviewed suggest that hypertrophy, microvascular impairment, and inflammation, should be variably present for PDE5i to work. All these conditions frequently coexist in diabetes. A gender responsiveness has also been recently proposed.ConclusionsContinuous PDE5 inhibition may exert cardioprotective effects, improving endothelial function and counteracting cardiac remodeling in some but not all conditions. A better patient selection could help to clarify the controversies on PDE5i use for CV disorders.

PDE5 Inhibition Ameliorates Visceral Adiposity Targeting the miR-22/SIRT1 Pathway: Evidence From the CECSID Trial

CONTEXT Visceral adiposity plays a significant role in cardiovascular risk. PDE5 inhibitors (PDE5i) can improve cardiac function and insulin sensitivity in type 2 diabetes patients. OBJECTIVE To investigate whether PDE5i affect visceral adipose tissue (VAT), specifically epicardial fat (epicardial adipose tissue [EAT]), and what mechanism is involved, using microarray-based profiling of pharmacologically modulated microRNA (miRNAs). DESIGN Randomized, double-blind, placebo-controlled study in type 2 diabetes. PATIENTS AND INTERVENTION A total of 59 diabetic patients were randomized to receive 100-mg/d sildenafil or placebo for 12 weeks. Fat biopsies were collected in a subgroup of patients. In a parallel protocol, db/db mice were randomized to 12 weeks of sildenafil or vehicle, and VAT was collected. MAIN OUTCOME AND MEASURES Anthropometric and metabolic parameters, EAT quantification through cardiac magnetic resonance imaging, array of 2005 circulating miRNAs, quantitative PCR, and flow cytometry of VAT. RESULTS Compared with placebo, sildenafil reduced waist circumference (P = .024) and EAT (P = .045). Microarray analysis identified some miRNAs differentially regulated by sildenafil, including down-regulation of miR-22-3p, confirmed by real-time quantitative PCR (P < .001). Sildenafils modulation of miR-22-3p expression was confirmed in vitro in HL1 cardiomyocytes. Up-regulation of SIRT1, a known target of miR-22-3p, was found in both serum and sc fat in sildenafil-treated subjects. Compared with vehicle, 12-week sildenafil treatment down-regulated miR-22-3p and up-regulated Sirtuin1 (SIRT1) gene expression in VAT from db/db mice, shifting adipose tissue cell composition toward a less inflamed profile. CONCLUSIONS Treatment with PDE5i in humans and murine models of diabetes improves VAT, targeting SIRT1 through a modulation of miR-22-3p expression.

Phosphodiesterase-5 inhibition preserves renal hemodynamics and function in mice with diabetic kidney disease by modulating miR-22 and BMP7

Diabetic Nephropathy (DN) is the leading cause of end-stage renal disease. Preclinical and experimental studies show that PDE5 inhibitors (PDE5is) exert protective effects in DN improving perivascular inflammation. Using a mouse model of diabetic kidney injury we investigated the protective proprieties of PDE5is on renal hemodynamics and the molecular mechanisms involved. PDE5i treatment prevented the development of DN-related hypertension (P < 0.001), the increase of urine albumin creatinine ratio (P < 0.01), the fall in glomerular filtration rate (P < 0.001), and improved renal resistive index (P < 0.001) and kidney microcirculation. Moreover PDE5i attenuated the rise of nephropathy biomarkers, soluble urokinase-type plasminogen activator receptor, suPAR and neutrophil gelatinase-associated lipocalin, NGAL. In treated animals, blood vessel perfusion was improved and vascular leakage reduced, suggesting preserved renal endothelium integrity, as confirmed by higher capillary density, number of CD31+ cells and pericyte coverage. Analysis of the mechanisms involved revealed the induction of bone morphogenetic protein-7 (BMP7) expression, a critical regulator of angiogenesis and kidney homeostasis, through a PDE5i-dependent downregulation of miR-22. In conclusion PDE5i slows the progression of DN in mice, improving hemodynamic parameters and vessel integrity. Regulation of miR-22/BMP7, an unknown mechanism of PDE5is in nephrovascular protection, might represent a novel therapeutic option for treatment of diabetic complications.

Circadian rhythm of glucocorticoid administration entrains clock genes in immune cells: a DREAM trial ancillary study.

Context Adrenal insufficiency (AI) requires lifelong glucocorticoid (GC) replacement. Conventional therapies do not mimic the endogenous cortisol circadian rhythm. Clock genes are essential components of the machinery controlling circadian functions and are influenced by GCs. However, clock gene expression has never been investigated in patients with AI. Objective To evaluate the effect of the timing of GC administration on circadian gene expression in peripheral blood mononuclear cells (PBMCs) of patients from the Dual Release Hydrocortisone vs Conventional Glucocorticoid Replacement in Hypocortisolism (DREAM) trial. Design Outcome assessor-blinded, randomized, active comparator clinical trial. Participants and Intervention Eighty-nine patients with AI were randomly assigned to continue their multiple daily GC doses or switch to an equivalent dose of once-daily modified-release hydrocortisone and were compared with 25 healthy controls; 65 patients with AI and 18 controls consented to gene expression analysis. Results Compared with healthy controls, 19 of the 68 genes were found modulated in patients with AI at baseline, 18 of which were restored to control levels 12 weeks after therapy was switched: ARNTL [BMAL] (P = 0.024), CLOCK (P = 0.016), AANAT (P = 0.021), CREB1 (P = 0.010), CREB3 (P = 0.037), MAT2A (P = 0.013); PRKAR1A, PRKAR2A, and PRKCB (all P < 0.010) and PER3, TIMELESS, CAMK2D, MAPK1, SP1, WEE1, CSNK1A1, ONP3, and PRF1 (all P < 0.001). Changes in WEE1, PRF1, and PER3 expression correlated with glycated hemoglobin, inflammatory monocytes, and CD16+ natural killer cells. Conclusions Patients with AI on standard therapy exhibit a dysregulation of circadian genes in PBMCs. The once-daily administration reconditions peripheral tissue gene expression to levels close to controls, paralleling the clinical outcomes of the DREAM trial (NCT02277587).

USPIO-labeling in M1 and M2-polarized macrophages: An in vitro study using a clinical magnetic resonance scanner

Aim of the study was to evaluate USPIO labeling in different macrophage populations using a clinical 3.0T MR unit with optical and electron microscopy as the gold standard. Human monocytic cell line THP‐1 cells were differentiated into macrophages. Afterwards, M0 macrophages were incubated with IL‐4 and IL‐13 in order to obtain M2 polarized macrophages or with IFN‐gamma and LPS for classical macrophage activation (M1). These groups were incubated with USPIO‐MR contrast agent (P904) for 36 hr; M0, M0 + P904, M1 +  P904, and M2 + P904 were analyzed in gel phantoms with a 3.0T MR scanner. m‐RNA of M1 and M2 markers confirmed the polarization of THP‐1‐derived macrophages. M2 + P904 showed a much higher T1 signal (p <  0.0001), a significantly lower (p < 0.0001) T2* signal, and significantly higher R* (p < 0.0001) compared to the other populations. Hystological analysis confirmed higher iron content in the M2‐polarized population compared to both M1‐polarized (p = 0.04) and M0‐P904 (p = 0.003). Ultrastructure analysis demonstrated ubiquitous localization of P904 within the cellular compartments. Our results demonstrate that a selective USPIO‐labeling of different macrophage populations can be detected in vitro using the 3.0T clinical scanner.

Chronic phosphodiesterase type 5 inhibition has beneficial effects on subcutaneous adipose tissue plasticity in type 2 diabetic mice: FIORE et al.

Different adipose tissue (AT) depots are associated with multiple metabolic risks. Phosphodiesterase type 5 (PDE5) is involved in adipocyte physiology and PDE5 inhibition may affect adipogenesis and ameliorate white AT quality. The aim of this study is to investigate the distribution of AT and the composition of the stroma‐vascular fraction (SVF) of subcutaneous AT (SAT) in type 2 diabetic mice after prolonged treatment with a PDE5 inhibitor, Sildenafil. 18 db/db mice were treated with Sildenafil or vehicle for 12 weeks. AT distribution was monitored and SAT was processed for isolation of SVF by flow cytometry. Sildenafil induced an overall reduction in AT, mainly in visceral AT (VAT), compared with SAT. In Sildenafil‐treated mice, the mean change in body weight from baseline positively correlated with VAT, but not with SAT. Characterization of SVF of SAT showed an increase in the frequency of M2 macrophages and endothelial cells in treated mice. Sildenafil improved the maintenance of SAT homeostasis and distribution.