Publications by authors named "Florent Allagnat"

Photobiomodulation (PBM) therapy, a therapeutic approach utilizing low-level light, has garnered significant attention for its potential to modulate various biological processes. This study aimed at optimizing and investigating the effects of PBM on angiogenesis and mitochondrial metabolic activity. In vitro experiments using human umbilical vein endothelial cells (HUVECs) and vascular smooth muscle cells (VSMCs) were performed to assess PBM's impacts on cell migration, proliferation, endogenous protoporphyrin IX production, mitochondrial membrane potential, Rhodamine 123 fluorescence lifetime, mitochondrial morphology, and oxygen consumption.

View Article and Find Full Text PDF

One-week protein restriction (PR) limits ischemia-reperfusion (IR) damages and improves metabolic fitness. Similarly, longer-term calory restriction results in increased lifespan, partly via reduced insulin-like growth factor (IGF)-1. However, the influence of short-term PR on IGF-1 and its impact on IR are unknown.

View Article and Find Full Text PDF

Dietary restriction of the sulfur-containing amino acids methionine and cysteine (SAAR) improves body composition, enhances insulin sensitivity, and extends lifespan; benefits seen also with endurance exercise. Yet, the impact of SAAR on skeletal muscle remains largely unexplored. Here we demonstrate that one week of SAAR in sedentary, young, male mice increases endurance exercise capacity.

View Article and Find Full Text PDF

Dietary restriction promotes resistance to surgical stress in multiple organisms. Counterintuitively, current medical protocols recommend short-term carbohydrate-rich drinks (carbohydrate loading) prior to surgery, part of a multimodal perioperative care pathway designed to enhance surgical recovery. Despite widespread clinical use, preclinical and mechanistic studies on carbohydrate loading in surgical contexts are lacking.

View Article and Find Full Text PDF

Background: In rodents, hydrogen sulfide (HS) reduces ischemia-reperfusion injury and improves renal graft function after transplantation. Here, we hypothesized that the benefits of HS are conserved in pigs, a more clinically relevant model.

Methods: Adult porcine kidneys retrieved immediately or after 60 min of warm ischemia (WI) were exposed to 100 µM sodium hydrosulfide (NaHS) (1) during the hypothermic ex vivo perfusion only, (2) during WI only, and (3) during both WI and ex vivo perfusion.

View Article and Find Full Text PDF

The saphenous vein is the conduit of choice for bypass grafting. Unfortunately, the hemodynamic stress associated with the arterial environment of the bypass vein graft leads to the development of intimal hyperplasia (IH), an excessive cellular growth and collagen deposition that results in restenosis and secondary graft occlusion. Hydrogen sulfide (HS) is a ubiquitous redox-modifying gasotransmitter that inhibits IH.

View Article and Find Full Text PDF

Peripheral artery disease (PAD) affects more than 230 million people worldwide. PAD patients suffer from reduced quality of life and are at increased risk of vascular complications and all-cause mortality. Despite its prevalence, impact on quality of life and poor long-term clinical outcomes, PAD remains underdiagnosed and undertreated compared to myocardial infarction and stroke.

View Article and Find Full Text PDF

Objective: Hydrogen sulfide is a proangiogenic gas produced primarily by the transsulfuration enzyme cystathionine-γ-lyase (CGL). CGL-dependent hydrogen sulfide production is required for neovascularization in models of peripheral arterial disease. However, the benefits of increasing endogenous CGL and its mechanism of action have not yet been elucidated.

View Article and Find Full Text PDF

Arterial occlusive disease is the leading cause of death in Western countries. Core contemporary therapies for this disease include angioplasties, stents, endarterectomies and bypass surgery. However, these treatments suffer from high failure rates due to re-occlusive vascular wall adaptations and restenosis.

View Article and Find Full Text PDF

Therapies to accelerate vascular repair are currently lacking. Pre-clinical studies suggest that hydrogen sulfide (HS), an endogenous gasotransmitter, promotes angiogenesis. Here, we hypothesized that sodium thiosulfate (STS), a clinically relevant source of HS, would stimulate angiogenesis and vascular repair.

View Article and Find Full Text PDF

Unlabelled: The ideal preservation temperature for donation after circulatory death kidney grafts is unknown. We investigated whether subnormothermic (22 °C) ex vivo kidney machine perfusion could improve kidney metabolism and reduce ischemia-reperfusion injury.

Methods: To mimic donation after circulatory death procurement, kidneys from 45-kg pigs underwent 60 min of warm ischemia.

View Article and Find Full Text PDF

Arterial occlusive disease is the narrowing of the arteries atherosclerotic plaque buildup. The major risk factors for arterial occlusive disease are age, high levels of cholesterol and triglycerides, diabetes, high blood pressure, and smoking. Arterial occlusive disease is the leading cause of death in Western countries.

View Article and Find Full Text PDF

Background: Intimal hyperplasia (IH) remains a major limitation in the long-term success of any type of revascularisation. IH is due to vascular smooth muscle cell (VSMC) dedifferentiation, proliferation and migration. The gasotransmitter Hydrogen Sulfide (HS), mainly produced in blood vessels by the enzyme cystathionine- γ-lyase (CSE), inhibits IH in pre-clinical models.

View Article and Find Full Text PDF

Background: Biological xenografts using tubulized porcine pericardium are an alternative to replace infected prosthetic graft. We recently reported an innovative technique using a stapled porcine pericardial bioconduit for immediate vascular reconstruction in emergency. The objective of this study is to compare the growth and adherence to grafts of bacteria and yeast incubated with stapled porcine pericardium, sutured or naked pericardium.

View Article and Find Full Text PDF

Objective: Hypertension is a major risk factor for intimal hyperplasia (IH) and re-stenosis following vascular and endovascular interventions. Preclinical studies suggest that hydrogen sulphide (HS), an endogenous gasotransmitter, limits re-stenosis. While there is no clinically available pure HS releasing compound, the sulfhydryl containing angiotensin converting enzyme inhibitor zofenopril is a source of HS.

View Article and Find Full Text PDF
Article Synopsis
  • NAD+ plays a crucial role in energy metabolism and is often deficient during acute kidney injury (AKI) and chronic kidney disease (CKD).
  • The study examined NAD+ biosynthesis in human kidney biopsies and used mouse models to simulate AKI and CKD, investigating the effects of nicotinamide riboside (NR) supplementation.
  • Results showed that NAD+ synthesis is impaired in AKI but NR supplementation helps in acute cases; however, it does not prevent progression in CKD models.
View Article and Find Full Text PDF

Connexin37 (Cx37) forms intercellular channels between endothelial cells (EC), and contributes to coordinate the motor tone of vessels. We investigated the contribution of this protein during physiological angiogenesis. We show that, compared to WT littermates, mice lacking Cx37 (Cx37 ) featured (i) a decreased extension of the superficial vascular plexus during the first 4 days after birth; (ii) an increased vascular density at the angiogenic front at P6, due to an increase in the proliferative rate of EC and in the sprouting of the venous compartment, as well as to a somewhat displaced position of tip cells; (iii) a decreased coverage of newly formed arteries and veins by mural cells; (iv) altered ERK-dependent endothelial cells proliferation through the EphB4 signaling pathway, which is involved in the specification of veins and arteries.

View Article and Find Full Text PDF

Currently available interventions for vascular occlusive diseases suffer from high failure rates due to re-occlusive vascular wall adaptations, a process called intimal hyperplasia (IH). Naturally occurring hydrogen sulfide (HS) works as a vasculoprotective gasotransmitter in vivo. However, given its reactive and hazardous nature, HS is difficult to administer systemically.

View Article and Find Full Text PDF

Background: Somatostatin analogs (SSAs) are first-line medical therapy for the treatment of acromegaly and neuroendocrine tumors that express somatostatin receptors (SSTR). Somatostatin suppresses secretion of a large number of hormones through the stimulation of the five SSTR. However, unbalanced inhibition of secretion as observed with the highly potent SSAs pasireotide causes hyperglycaemia mainly by inhibiting insulin secretion.

View Article and Find Full Text PDF

Type 1 diabetes (T1D) results from β-cell destruction due to concerted action of both innate and adaptive immune responses. Pro-inflammatory cytokines, such as interleukin-1β and interferon-γ, secreted by the immune cells invading islets of Langerhans, contribute to pancreatic β-cell death in T1D. Cytokine-induced endoplasmic reticulum (ER) stress plays a central role in β-cell demise.

View Article and Find Full Text PDF
Article Synopsis
  • Cx40 (Connexin40) is crucial for coordinating electrical conduction in the heart and vascular tone, and it plays a role in both tumoral and physiological angiogenesis, although its specific contribution to normal angiogenesis was previously unclear.
  • Research findings indicate that deleting Cx40 in mice leads to reduced vascular growth and capillary density, suggesting it is important for developing retinal blood vessels.
  • The study concludes that endothelial Cx40 is essential for early-stage physiological angiogenesis, making it a potential target for therapies aimed at treating abnormal eye blood vessel growth.
View Article and Find Full Text PDF

Aims: Intimal hyperplasia (IH) is an abnormal response to vessel injury characterized by the dedifferentiation, migration, and proliferation of quiescent vascular smooth muscle cells (VSMC) to form a neointima layer. Vascular connexins (Cx) are involved in the pathophysiology of various vascular diseases, and Cx43, the main Cx expressed in VSMC, has been shown to promote VSMC proliferation and IH. The aim of this study was to investigate the participation of another Cx, namely Cx37, in the formation of the neointima layer.

View Article and Find Full Text PDF

Normal plasma glucose level is ensured by the action of insulin, the major hypoglycemic hormone. Therefore, it is not surprising that insulin release from pancreatic β-cells of the islets of Langerhans is controlled by an array of balanced mechanisms in which glucose plays the leading role. Glucose triggers insulin secretion through the well-described pathway of ATP-driven closure of ATP-sensitive potassium channels (K), depolarization of the plasma membrane, and opening of the voltage-dependent Ca channels (VDCC).

View Article and Find Full Text PDF

Insulin-secreting pancreatic β-cells are extremely dependent on their endoplasmic reticulum (ER) to cope with the oscillatory requirement of secreted insulin to maintain normoglycemia. Insulin translation and folding rely greatly on the unfolded protein response (UPR), an array of three main signaling pathways designed to maintain ER homeostasis and limit ER stress. However, prolonged or excessive UPR activation triggers alternative molecular pathways that can lead to β-cell dysfunction and apoptosis.

View Article and Find Full Text PDF

Store-operated Ca(2+) channels (SOCs) are voltage-independent Ca(2+) channels activated upon depletion of the endoplasmic reticulum Ca(2+) stores. Early studies suggest the contribution of such channels to Ca(2+) homeostasis in insulin-secreting pancreatic β-cells. However, their composition and contribution to glucose-stimulated insulin secretion (GSIS) remains unclear.

View Article and Find Full Text PDF