Effects of decreased insulin-like growth factor-1 stimulation on hypoxia inducible factor 1-alpha protein synthesis and function during cutaneous repair in diabetic mice

Deciphering the Dysregulating IGF-1-SP1-CD248 Pathway in Fibroblast Functionality during Diabetic Wound Healing

Reduced fibroblast activity is a critical factor in the progression of diabetic ulcers. CD248, a transmembrane glycoprotein prominently expressed in activated fibroblasts, plays a pivotal role in wound healing. However, the role of CD248 in diabetic wound healing and the CD248 regulatory pathway remains largely unexplored. Our study shows that CD248 expression is significantly reduced in skin wounds from both diabetic patients and mice. Single-cell transcriptome data analyses reveal a marked reduction of CD248-enriched secretory-reticular fibroblasts in diabetic wounds. We identify insulin-like growth factor-1 (IGF-1) as a key regulator of CD248 expression through the Akt/mTOR signaling pathway and the Sp1 transcription factor. Overexpression of CD248 enhances fibroblast motility, elucidating the underrepresentation of CD248-enriched fibroblasts in diabetic wounds. Immunohistochemical staining of diabetic wound samples further confirm low SP1 expression and fewer CD248-positive secretory-reticular fibroblasts. Further investigation reveals that elevated tumor necrosis factor α (TNFα) levels in diabetic environment promotes IGF-1 resistance, and inhibiting IGF-1-induced CD248 expression. In summary, our findings underscore the critical role of the IGF1-SP1-CD248 axis in activating reticular fibroblasts during wound-healing processes. Targeting this axis in fibroblasts could help develop a therapeutic regimen for diabetic ulcers.

Platelet-rich plasma: a comparative and economical therapy for wound healing and tissue regeneration

Rise in the incidences of chronic degenerative diseases with aging makes wound care a socio-economic burden and unceasingly necessitates a novel, economical, and efficient wound healing treatment. Platelets have a crucial role in hemostasis and thrombosis by modulating distinct mechanistic phases of wound healing, such as promoting and stabilizing the clot. Platelet-rich plasma (PRP) contains a high concentration of platelets than naïve plasma and has an autologous origin with no immunogenic adverse reactions. As a consequence, PRP has gained significant attention as a therapeutic to augment the healing process. Since the past few decades, a robust volume of research and clinical trials have been performed to exploit extensive role of PRP in wound healing/tissue regeneration. Despite these rigorous studies and their application in diversified medical fields, efficacy of PRP-based therapies is continuously questioned owing to the paucity of large samplesizes, controlled clinical trials, and standard protocols. This review systematically delineates the process of wound healing and involvement of platelets in tissue repair mechanisms. Additionally, emphasis is laid on PRP, its preparation methods, handling, classification,application in wound healing, and PRP as regenerative therapeutics combined with biomaterials and mesenchymal stem cells (MSCs).

Single Dose of N-Acetylcysteine in Local Anesthesia Increases Expression of HIF1α, MAPK1, TGFβ1 and Growth Factors in Rat Wound Healing

In this study, we aimed to investigate the influence of N-acetylcysteine (NAC) on the gene expression profile, neoangiogenesis, neutrophils and macrophages in a rat model of incisional wounds. Before creating wounds on the backs of 24 Sprague-Dawley rats, intradermal injections were made. Lidocaine-epinephrin solutions were supplemented with 0.015%, 0.03% or 0.045% solutions of NAC, or nothing (control group). Scars were harvested on the 3rd, 7th, 14th and 60th day post-surgery. We performed immunohistochemical staining in order to visualize macrophages (anti-CD68), neutrophils (anti-MPO) and newly formed blood vessels (anti-CD31). Additionally, RT-qPCR was used to measure the relative expression of 88 genes involved in the wound healing process. On the 14th day, the number of cells stained with anti-CD68 and anti-CD31 antibodies was significantly larger in the tissues treated with 0.03% NAC compared with the control. Among the selected genes, 52 were upregulated and six were downregulated at different time points. Interestingly, NAC exerted a significant effect on the expression of 45 genes 60 days after its administration. In summation, a 0.03% NAC addition to the pre-incisional anesthetic solution improves neovasculature and increases the macrophages' concentration at the wound site on the 14th day, as well as altering the expression of numerous genes that are responsible for the regenerative processes.

Bioactive Medications for the Delivery of Platelet Derivatives to Skin Wounds

Chronic wounds are the result of alterations in the complex series of events of physiological wound healing. In particular, the prolonged inflammation results in increased protease activity, in the deg-radation of extracellular matrix (ECM) and of growth factors (GFs). The relevance of platelet GFs in maintaining and restoring the complex equilibrium of different moments in wound healing is well recog-nized. Moreover, the observed decrease of their levels in chronic wounds suggested a possible therapeutic role of the external application to the wounds. It has been also pointed out that tissue regeneration can be more efficiently obtained by the synergic use of different GFs. Platelet derivatives such as platelet-rich plasma (PRP) and platelet lysate (PL) are able to release GFs in a balanced pool. Their therapeutic use in regenerative medicine and wound healing has been therefore more and more frequently proposed in clini-cal trials and in the literature. The development of a suitable formulation able to control the GFs release rate, to protect the GFs, and to assure their prolonged contact with the wound site, is of paramount im-portance for the therapeutic success. The present review considers some formulation approaches for PRP and PL application to wounds

Von Hippel-Lindau (VHL) Protein Antagonist VH298 Improves Wound Healing in Streptozotocin-Induced Hyperglycaemic Rats by Activating Hypoxia-Inducible Factor- (HIF-) 1 Signalling

AIMS

The purpose of the present research is to investigate the effects of the VHL protein antagonist, VH298, on functional activities of fibroblasts and vascular endothelial cells and the effects on the wound healing process in a streptozotocin-induced hyperglycaemic rat model.

METHODS

HIF-1α and hydroxy-HIF-1α protein levels in VH298-treated rat fibroblasts (rFb) were measured by immunoblotting, rFb proliferation was detected by the CCK-8 assay, and mRNA levels of related genes were measured by quantitative RT-PCR. In vitro wound healing was simulated by the scratch test; angiogenesis was measured by the human umbilical vein endothelial cell (hUVEC) tube formation assay. VH298 or PBS was locally injected into wounds in rat models with streptozotocin- (STZ-) induced hyperglycaemia, the wound tissues were harvested, and haematoxylin-eosin (HE) and Masson trichrome staining and immunohistochemical processes were conducted.

RESULTS

HIF-1α and hydroxy-HIF-1α levels increased in VH298-treated rFb, in a time- and dose-dependent manner. Thirty micromolar VH298 could significantly increase cell proliferation, angiogenesis, and gene expression of type I collagen-α1 (Col1-α1), vascular endothelial growth factor A (VEGF-A), and insulin-like growth factor 1 (IGF-1). The VH298-treated wound had a better healing pattern, activation of HIF-1 signalling, and vascularization.

CONCLUSIONS

Taken together, VH298 activated the HIF-1 signalling pathway by stabilizing both HIF-1α and hydroxy-HIF-1α. VH298 enhanced rFb functions, promoted hUVEC angiogenesis, and accelerated wound healing in the rat model mimicking diabetes mellitus.

Platelet Rich Plasma: New Insights for Cutaneous Wound Healing Management

The overall increase of chronic degenerative diseases associated with ageing makes wound care a tremendous socioeconomic burden. Thus, there is a growing need to develop novel wound healing therapies to improve cutaneous wound healing. The use of regenerative therapies is becoming increasingly popular due to the low-invasive procedures needed to apply them. Platelet-rich plasma (PRP) is gaining interest due to its potential to stimulate and accelerate the wound healing process. The cytokines and growth factors forming PRP play a crucial role in the healing process. This article reviews the emerging field of skin wound regenerative therapies with particular emphasis on PRP and the role of growth factors in the wound healing process.

Wound-healing markers after autologous and allogeneic epithelial-like stem cell treatment

BACKGROUND AIMS

Several cytokines and growth factors play an essential role in skin regeneration and epithelial-like stem cells (EpSCs) have beneficial effects on wound healing in horses. However, there are no reports available on the expression of these growth factors and cytokines after EpSC therapy.

METHODS

Wounds of 6 cm(2) were induced in the gluteus region of 6 horses and treated with (i) autologous EpSCs, (ii) allogeneic EpSCs, (iii) vehicle treatment or (iv) untreated control. Real time polymerase chain reaction was performed on tissue biopsies taken 1 and 5 weeks after these treatments to evaluate mRNA expression of interferon (IFN)-γ, interleukin (IL)-6, vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), insulin-like growth factor (IGF)-1 and epidermal keratin (eKER).

RESULTS

One week after treatments, mRNA levels of IL-6 (P = 0.012) and VEGF (P = 0.008) were higher in allogeneic EpSC-treated wounds compared with controls. Also, mRNA levels of IGF-1 were higher at 1 week in both autologous (P = 0.027) and allogeneic (P = 0.035) EpSC-treated wounds. At week 5, all EpSC- and vehicle-treated wounds demonstrated significantly higher IFN-γ, VEGF and eKER mRNA expression compared with controls and compared with their respective levels at week 1.

CONCLUSIONS

Equine wounds treated with allogeneic EpSCs demonstrate a significant increase in mRNA expression of IL-6, VEGF and IGF-1 in the acute phase. In the longer term, an increase in IFN-γ, VEGF and eKER mRNA was detected in the wounds treated with allogenic EpSCs, autologous EpSCs or their vehicle.

Levels of Serum 25(OH)VD3, HIF-1α, VEGF, vWf, and IGF-1 and Their Correlation in Type 2 Diabetes Patients with Different Urine Albumin Creatinine Ratio

OBJECTIVE

To investigate changes in serum 25(OH)VD3, HIF-1α, VEGF, vWf, IGF-1, and their correlation in type 2 diabetes patients at different stages of diabetic kidney disease (DKD).

METHODS

502 type 2 diabetes patients were divided into three groups: Normoalbuminuric group (201 patients), Microalbuminuric group (171 patients), and Macroalbuminuric group (130 patients). Serum 25-hydroxyvitamin D3 [25(OH)VD3] was measured by chemiluminescence. Serum hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), von Willebrand factor (vWf), and insulin-like growth factor-1 (IGF-1) were determined by enzyme-linked immunosorbent assay. We detected the aforementioned serum factors in all cases and 224 control subjects.

RESULTS

Serum HIF-1α, VEGF, vWf, and IGF-1 in type 2 diabetes patients were significantly higher than those in the control group and increased with the increase of Ln(ACR), respectively (P < 0.001). Serum 25(OH)VD3 was significantly lower in type 2 diabetes patients and decreased with the increase of Ln(ACR) (P < 0.001). Ln(ACR) was positively correlated with duration, HbA1c, Scr, BUN, TC, LDL, TG, UA, HIF-1α, VEGF, IGF-1, vWf, and Fg and negatively correlated with 25(OH)VD3 and eGFR.

CONCLUSION

Serum HIF-1α, VEGF, vWf, and IGF-1 may be involved in DKD process through inflammation, angiogenesis, and endothelial injury. Serum 25(OH)VD3 may have protective effects on DKD partly by inhibiting inflammation, abnormal angiogenesis, and vascular endothelial dysfunction.

The effects of insulin-like growth factor-1 gene therapy and cell transplantation on rat acute wound model

BACKGROUND

Wound healing is a complex process. Different types of skin cells, extracellular matrix and variety of growth factors are involved in wound healing. The use of recombinant growth factors in researches and production of skin substitutes are still a challenge.

OBJECTIVES

Much research has been done on the effects of gene therapy and cell therapy on wound healing. In this experimental study, the effect of insulin-like growth factor (IGF-1) gene transfer in fibroblast cells was assessed on acute dermal wound healing.

MATERIALS AND METHODS

Fibroblasts were cultured and transfected with IGF-1. Lipofectamine 2000 was used as a reagent of transfection. Transgene expression levels were measured by the enzyme linked immunosorbent assay (ELISA). To study in vivo, rats (weighing 170-200 g) were randomly divided into three groups (five/group) and full-thickness wounds were created on the dorsum region. Suspensions of transfected fibroblast cells were injected into the wound and were compared with wounds treated with native fibroblast cells and normal saline. For the microscopic examination, biopsy was performed on day seven.

RESULTS

In vitro, the maximum expression of IGF1 (96.95 pg/mL) in transfected fibroblast cells was 24 hours after gene transfer. In vivo, it was clear that IGF-1 gene therapy caused an increase in the number of keratinocyte cells during the wound healing process (mean of group A vs. group B with P value = 0.01, mean of group A vs. group C with P value = 0.000). Granulation of tissue formation in the transfected fibroblast group was more organized when compared with the normal saline group and native fibroblast cells.

CONCLUSIONS

This study indicated that the optimization of gene transfer increases the expression of IGF-1. High concentrations of IGF-1, in combination with cell therapy, have a significant effect on wound healing.

Understanding regulatory pathways of neovascularization in diabetes

Diabetes mellitus and its associated comorbidities represent a significant health burden worldwide. Vascular dysfunction is the major contributory factor in the development of these comorbidities, which include impaired wound healing, cardiovascular disease and proliferative diabetic retinopathy. While the etiology of abnormal neovascularization in diabetes is complex and paradoxical, the dysregulation of the varied processes contributing to the vascular response are due in large part to the effects of hyperglycemia. In this review, we explore the mechanisms by which hyperglycemia disrupts chemokine expression and function, including the critical hypoxia inducible factor-1 axis. We place particular emphasis on the therapeutic potential of strategies addressing these pathways; as such targeted approaches may one day help alleviate the healthcare burden of diabetic sequelae.

Reduction of ARNT in myeloid cells causes immune suppression and delayed wound healing

Aryl hydrocarbon receptor nuclear translocator (ARNT) is a transcription factor that binds to partners to mediate responses to environmental signals. To investigate its role in the innate immune system, floxed ARNT mice were bred with lysozyme M-Cre recombinase animals to generate lysozyme M-ARNT (LAR) mice with reduced ARNT expression. Myeloid cells of LAR mice had altered mRNA expression and delayed wound healing. Interestingly, when the animals were rendered diabetic, the difference in wound healing between the LAR mice and their littermate controls was no longer present, suggesting that decreased myeloid cell ARNT function may be an important factor in impaired wound healing in diabetes. Deferoxamine (DFO) improves wound healing by increasing hypoxia-inducible factors, which require ARNT for function. DFO was not effective in wounds of LAR mice, again suggesting that myeloid cells are important for normal wound healing and for the full benefit of DFO. These findings suggest that myeloid ARNT is important for immune function and wound healing. Increasing ARNT and, more specifically, myeloid ARNT may be a therapeutic strategy to improve wound healing.

Myeloid cell dysfunction and the pathogenesis of the diabetic chronic wound

Diabetes can promote a state of chronic inflammation associated with serious complications that are difficult to treat, including ulceration of the lower extremities and chronic wounds. Chronic wounds are often incurable and contribute to both a reduced quality of life for patients and an enormous burden for healthcare services. In diabetes, the inflammatory response early in wound healing is inappropriately amplified and prolonged, leading to the persistent presence in the wound of vastly elevated numbers of dysfunctional, hyperpolarised macrophages that fail to transition to a pro-healing phenotype. Recent evidence suggests that systemic chronic inflammation induces intrinsic defects in monocytes via chromatin modifications that may pre-programme monocytes to a pro-inflammatory phenotype, while the local wound environment inhibits differentiation to a pro-healing phenotype. Current understanding remains incomplete, and careful dissection of how local and systemic inflammation combine to negatively influence myeloid cell development will be key to developing effective therapies aimed at healing the diabetic wound.

Adenoviral-mediated gene transfer of insulin-like growth factor 1 enhances wound healing and induces angiogenesis

BACKGROUND

Chronic wounds are characterized by a wound healing and neovascularization deficit. Strategies to increase neovascularization can significantly improve chronic wound healing. Insulin-like growth factor (IGF)-1 is reported to be a keratinocyte mitogen and is believed to induce angiogenesis via a vascular endothelial growth factor (VEGF)-dependent pathway. Using a novel ex vivo human dermal wound model and a diabetic-impaired wound healing murine model, we hypothesized that adenoviral overexpression of IGF-1 (Ad-IGF-1) will enhance wound healing and induce angiogenesis through a VEGF-dependent pathway.

METHODS

Ex vivo: 6-mm full-thickness punch biopsies were obtained from normal human skin, and 3-mm full-thickness wounds were created at the center. Skin explants were maintained at air liquid interface. Db/db murine model: 8-mm full-thickness dorsal wounds in diabetic (db/db) mice were created. Treatment groups in both human ex vivo and in vivo db/db wound models include 1×10(8) particle forming units of Ad-IGF-1 or Ad-LacZ, and phosphate buffered saline (n=4-5/group). Cytotoxicity (lactate dehydrogenase) was quantified at days 3, 5, and 7 for the human ex vivo wound model. Epithelial gap closure (hematoxylin and eosin; Trichrome), VEGF expression (enzyme-linked immunosorbent assay), and capillary density (CD 31+CAPS/HPF) were analyzed at day 7.

RESULTS

In the human ex vivo organ culture, the adenoviral vectors did not demonstrate any significant difference in cytotoxicity compared with phosphate buffered saline. Ad-IGF-1 overexpression significantly increases basal keratinocyte migration, with no significant effect on epithelial gap closure. There was a significant increase in capillary density in the Ad-IGF-1 wounds. However, there was no effect on VEGF levels in Ad-IGF-1 samples compared with controls. In db/db wounds, Ad-IGF-1 overexpression significantly improves epithelial gap closure and granulation tissue with a dense cellular infiltrate compared with controls. Ad-IGF-1 also increases capillary density, again with no significant difference in VEGF levels in the wounds compared with control treatments.

CONCLUSIONS

In two different models, our data demonstrate that adenoviral-mediated gene transfer of IGF-1 results in enhanced wound healing and induces angiogenesis via a VEGF-independent pathway. Understanding the underlying mechanisms of IGF-1 effects on angiogenesis may help produce novel therapeutics for chronic wounds or diseases characterized by a deficit in neovascularization.

Adenoviral-mediated gene transfer of insulin-like growth factor 1 enhances wound healing and induces angiogenesis

BACKGROUND

Chronic wounds are characterized by a wound healing and neovascularization deficit. Strategies to increase neovascularization can significantly improve chronic wound healing. Insulin-like growth factor (IGF)-1 is reported to be a keratinocyte mitogen and is believed to induce angiogenesis via a vascular endothelial growth factor (VEGF)-dependent pathway. Using a novel ex vivo human dermal wound model and a diabetic-impaired wound healing murine model, we hypothesized that adenoviral overexpression of IGF-1 (Ad-IGF-1) will enhance wound healing and induce angiogenesis through a VEGF-dependent pathway.

METHODS

Ex vivo: 6-mm full-thickness punch biopsies were obtained from normal human skin, and 3-mm full-thickness wounds were created at the center. Skin explants were maintained at air liquid interface. Db/db murine model: 8-mm full-thickness dorsal wounds in diabetic (db/db) mice were created. Treatment groups in both human ex vivo and in vivo db/db wound models include 1×10(8) particle forming units of Ad-IGF-1 or Ad-LacZ, and phosphate buffered saline (n=4-5/group). Cytotoxicity (lactate dehydrogenase) was quantified at days 3, 5, and 7 for the human ex vivo wound model. Epithelial gap closure (hematoxylin and eosin; Trichrome), VEGF expression (enzyme-linked immunosorbent assay), and capillary density (CD 31+CAPS/HPF) were analyzed at day 7.

RESULTS

In the human ex vivo organ culture, the adenoviral vectors did not demonstrate any significant difference in cytotoxicity compared with phosphate buffered saline. Ad-IGF-1 overexpression significantly increases basal keratinocyte migration, with no significant effect on epithelial gap closure. There was a significant increase in capillary density in the Ad-IGF-1 wounds. However, there was no effect on VEGF levels in Ad-IGF-1 samples compared with controls. In db/db wounds, Ad-IGF-1 overexpression significantly improves epithelial gap closure and granulation tissue with a dense cellular infiltrate compared with controls. Ad-IGF-1 also increases capillary density, again with no significant difference in VEGF levels in the wounds compared with control treatments.

CONCLUSIONS

In two different models, our data demonstrate that adenoviral-mediated gene transfer of IGF-1 results in enhanced wound healing and induces angiogenesis via a VEGF-independent pathway. Understanding the underlying mechanisms of IGF-1 effects on angiogenesis may help produce novel therapeutics for chronic wounds or diseases characterized by a deficit in neovascularization.

Diabetes induces stable intrinsic changes to myeloid cells that contribute to chronic inflammation during wound healing in mice

Acute inflammation in response to injury is a tightly regulated process by which subsets of leukocytes are recruited to the injured tissue and undergo behavioural changes that are essential for effective tissue repair and regeneration. The diabetic wound environment is characterised by excessive and prolonged inflammation that is linked to poor progression of healing and, in humans, the development of diabetic foot ulcers. However, the underlying mechanisms contributing to excessive inflammation remain poorly understood. Here we show in a murine model that the diabetic environment induces stable intrinsic changes in haematopoietic cells. These changes lead to a hyper-responsive phenotype to both pro-inflammatory and anti-inflammatory stimuli, producing extreme M1 and M2 polarised cells. During early wound healing, myeloid cells in diabetic mice show hyperpolarisation towards both M1 and M2 phenotypes, whereas, at late stages of healing, when non-diabetic macrophages have transitioned to an M2 phenotype, diabetic wound macrophages continue to display an M1 phenotype. Intriguingly, we show that this population predominantly consists of Gr-1⁺ CD11b⁺ CD14⁺ cells that have been previously reported as ‘inflammatory macrophages’ recruited to injured tissue in the early stages of wound healing. Finally, we show that this phenomenon is directly relevant to human diabetic ulcers, for which M2 polarisation predicts healing outcome. Thus, treatments focused at targeting this inflammatory cell subset could prove beneficial for pathological tissue repair.

ROS constitute a convergence nexus in the development of IGF1 resistance and impaired wound healing in a rat model of type 2 diabetes

An indolent non-healing wound and insulin and/or insulin-like growth factor (IGF1) resistance are cardinal features of diabetes, inflammation and hypercortisolemia. Little is known about why these phenomena occur in so many contexts. Do the various triggers that induce insulin and/or IGF1 resistance and retard wound healing act through a common mechanism? Cultured dermal fibroblasts from rats and full-thickness excisional wounds were used as models to test the premise that reactive oxygen species (ROS) play a causal role in the development of IGF1 resistance and impaired wound healing under different but pathophysiologically relevant clinical settings, including diabetes, dexamethasone-induced hypercortisolemia and TNFα-induced inflammation. In normal fibroblasts, IGF1 initiated a strong degree of phosphorylation of insulin receptor substrate 1 (IRS1) (Tyr612) and Akt (Ser473), concomitantly with increased PI3K activity. This phenomenon seemed to be attenuated in fibroblasts that had phenotypic features of diabetes, inflammation or hypercortisolemia. Notably, these cells also exhibited an increase in the activity of the ROS–phospho-JNK (p-JNK)–p-IRS1 (Ser307) axis. The above-mentioned defects were reflected functionally by attenuation in IGF1-dependent stimulation of key fibroblast functions, including collagen synthesis and cell proliferation, migration and contraction. The effects of IGF1 on glucose disposal and cutaneous wound healing were also impaired in diabetic or hypercortisolemic rats. The ROS suppressors EUK-134 and α-lipoic acid, or small interfering RNA (siRNA)-mediated silencing of JNK expression, restored IGF1 sensitivity both in vitro and in vivo, and also ameliorated the impairment in IGF1-mediated wound responses during diabetes, inflammation and hypercortisolemia. Our data advance the notion that ROS constitute a convergence nexus for the development of IGF1 resistance and impaired wound healing under different but pathophysiologically relevant clinical settings, with a proof of concept for the beneficial effect of ROS suppressors.

IGF-1 and atherothrombosis: relevance to pathophysiology and therapy

IGF-1 (insulin-like growth factor-1) plays a unique role in the cell protection of multiple systems, where its fine-tuned signal transduction helps to preserve tissues from hypoxia, ischaemia and oxidative stress, thus mediating functional homoeostatic adjustments. In contrast, its deprivation results in apoptosis and dysfunction. Many prospective epidemiological surveys have associated low IGF-1 levels with late mortality, MI (myocardial infarction), HF (heart failure) and diabetes. Interventional studies suggest that IGF-1 has anti-atherogenic actions, owing to its multifaceted impact on cardiovascular risk factors and diseases. The metabolic ability of IGF-1 in coupling vasodilation with improved function plays a key role in these actions. The endothelial-protective, anti-platelet and anti-thrombotic activities of IGF-1 exert critical effects in preventing both vascular damage and mechanisms that lead to unstable coronary plaques and syndromes. The pro-survival and anti-inflammatory short-term properties of IGF-1 appear to reduce infarct size and improve LV (left ventricular) remodelling after MI. An immune-modulatory ability, which is able to suppress 'friendly fire' and autoreactivity, is a proposed important additional mechanism explaining the anti-thrombotic and anti-remodelling activities of IGF-1. The concern of cancer risk raised by long-term therapy with IGF-1, however, deserves further study. In the present review, we discuss the large body of published evidence and review data on rhIGF-1 (recombinant human IGF-1) administration in cardiovascular disease and diabetes, with a focus on dosage and safety issues. Perhaps the time has come for the regenerative properties of IGF-1 to be assessed as a new pharmacological tool in cardiovascular medicine.

Apoptotic, regenerative, and immune-related signaling in human islets from type 2 diabetes individuals

Islet dysfunction is a primary cause of developing type 2 diabetes mellitus (T2DM). Events leading to islet failure are still poorly defined due to the complexity of the disease and scarcity of human T2DM islets. The aim of the present study was to identify cellular mechanisms involved in the T2DM pathophysiology by protein profiling islets obtained from T2DM individuals and age- and weight-matched controls using liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry and surface enhanced laser desorption/ionization time-of-flight mass spectrometry. In T2DM islets, multiple differentially expressed proteins correlated with insulin secretion. When these T2DM islet proteins were analyzed for differential pathway activation, three of the five most activated pathways were pathways of cell arrest and apoptosis (p53, caspase, stress-activated), one represented immune-response (Fas), and the most activated pathway was connected with proliferation and regeneration (E2F). Among the inactivated pathways, three out of five were pathways of proliferation and regeneration (insulin, PRL, PDGF). The present study is the first to report differential activation of specific pathways during T2DM islet deterioration. The information about alterations in pathway signaling patterns may open new ways to develop strategies aimed at restoring islet cell function and survival.