Peptide-coated liposomal fasudil enhances site specific vasodilation in pulmonary arterial hypertension

Catheterization of Pulmonary and Carotid Arteries for Concurrent Measurement of Mean Pulmonary and Systemic Arterial Pressure in Rat Models of Pulmonary Arterial Hypertension

Pulmonary hypertension (PH) is a group of pulmonary vascular disorders in which mean pulmonary arterial pressure (mPAP) becomes abnormally high because of various pathological conditions, including remodeling of the pulmonary arteries, lung and heart disorders, or congenital conditions. Various animal models, including mouse and rat models, have been used to recapitulate elevated mPAP observed in PH patients. However, the measurement and recording of mPAP and mean systemic arterial pressure (mSAP) in small animals require microsurgical procedures and a sophisticated data acquisition system. In this paper, we describe the surgical procedures for right heart catheterizations (RHC) to measure mPAP in rats. We also explain the catheterization of the carotid artery for simultaneous measurement of mPAP and mSAP using the PowerLab Data Acquisition system. We enumerate the surgical steps involved in exposing the jugular vein and the carotid artery for catheterizing these two blood vessels. We list the tools used for microsurgery in rats, describe the methods for preparing catheters, and illustrate the process for inserting the catheters in the pulmonary and carotid arteries. Finally, we delineate the steps involved in the calibration and setup of the PowerLab system for recording both mPAP and mSAP. This is the first protocol wherein we meticulously explain the surgical procedures for RHC in rats and the recording of mPAP and mSAP. We believe this protocol will be essential for PH research. Investigators with little training in animal handling can reproduce this microsurgical procedure for RHC in rats and measure mPAP and mSAP in rat models of PH. Further, this protocol is likely to help master RHC in rats that are performed for other conditions, such as heart failure, congenital heart disease, heart valve disorders, and heart transplantation.

Nanomedicine-mediated therapeutic approaches for pulmonary arterial hypertension

Nanomedicine has emerged as a field in which there are opportunities to improve the diagnosis, treatment and prevention of incurable diseases. Pulmonary arterial hypertension (PAH) is known as a severe and fatal disease affecting children and adults. Conventional treatments have not produced optimal effectiveness in treating this condition. Several reasons for this include drug instability, poor solubility of the drug and a shortened duration of pharmacological action. The present review focuses on new approaches for delivering anti-PAH drugs using nanotechnology with the aim of overcoming these shortcomings and increasing their efficacy. Solid-lipid nanoparticles, liposomes, metal-organic frameworks and polymeric nanoparticles have demonstrated advantages for the potential treatment of PAH, including increased drug bioavailability, drug solubility and accumulation in the lungs.

Advanced Microparticulate/Nanoparticulate Respirable Dry Powders of a Selective RhoA/Rho Kinase (Rock) Inhibitor for Targeted Pulmonary Inhalation Aerosol Delivery

Pulmonary hypertension (PH) is a progressive disease that eventually leads to heart failure and potentially death for some patients. There are many unique advantages to treating pulmonary diseases directly and non-invasively by inhalation aerosols and dry powder inhalers (DPIs) possess additional unique advantages. There continues to be significant unmet medical needs in the effective treatment of PH that target the underlying mechanisms. To date, there is no FDA-approved DPI indicated for the treatment of PH. Fasudil is a novel RhoA/Rho kinase (ROCK) inhibitor that has shown great potential in effectively treating pulmonary hypertension. This systematic study is the first to report on the design and development of DPI formulations comprised of respirable nanoparticles/microparticles using particle engineering design by advanced spray drying. In addition, comprehensive physicochemical characterization, in vitro aerosol aerosol dispersion performance with different types of human DPI devices, in vitro cell-drug dose response cell viability of different human respiratory cells from distinct lung regions, and in vitro transepithelial electrical resistance (TEER) as air-interface culture (AIC) demonstrated that these innovative DPI fasudil formulations are safe on human lung cells and have high aerosol dispersion performance properties.

Integrated weighted gene co-expression network analysis uncovers STAT1(signal transducer and activator of transcription 1) and IFI44L (interferon-induced protein 44-like) as key genes in pulmonary arterial hypertension

Despite the multiple diagnostic and therapeutic strategies implemented in clinical practice, the mortality rate of patients with pulmonary arterial hypertension (PAH) remains high. Understanding the mechanisms and key genes involved could provide insight into the drivers of the pathogenesis of PAH. In this research, we aimed to examine the mechanisms underlying PAH and identify key genes with potential usefulness as clinical biomarkers of PAH and thereby establish therapeutic targets for PAH. The datasets GSE117261, GSE113439, and GSE53408 were downloaded from the Gene Expression Omnibus (GEOs) database. We used weighted gene coexpression network analysis (WGCNA) to identify networks and the most relevant modules in PAH. Functional enrichment analysis was performed for the selected clinically relevant modules. The least absolute shrinkage and selection operator (LASSO) was applied to identify key genes in lung samples from patients with PAH. The genes were validated in a monocrotaline-induced PAH rat model. Three clinically relevant modules were identified through average linkage hierarchical clustering. The genes in the clinically relevant modules were related to endothelial cell differentiation, inflammation, and autoimmunity. Seven genes were screened as key genes significantly associated with PAH. Interferon-induced protein 44-like (IFI44L) and signal transducer and activator of transcription 1 (STAT1) were expressed at higher levels in the lung tissues of the PAH rat model than in those of the controls. Our findings reveal the novel pathological mechanisms underlying PAH and indicate that STAT1 and IFI44L may represent potential therapeutic targets in PAH.

Selective Targeting and Tissue Penetration to the Retina by a Systemically Administered Vascular Homing Peptide in Oxygen Induced Retinopathy (OIR)

Pathological angiogenesis is the hallmark of ischemic retinal diseases among them retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (PDR). Oxygen-induced retinopathy (OIR) is a pure hypoxia-driven angiogenesis model and a widely used model for ischemic retinopathies. We explored whether the vascular homing peptide CAR (CARSKNKDC) which recognizes angiogenic blood vessels can be used to target the retina in OIR. We were able to demonstrate that the systemically administered CAR vascular homing peptide homed selectively to the preretinal neovessels in OIR. As a cell and tissue-penetrating peptide, CAR also penetrated into the retina. Hyperoxia used to induce OIR in the retina also causes bronchopulmonary dysplasia in the lungs. We showed that the CAR peptide is not targeted to the lungs in normal mice but is targeted to the lungs after hyperoxia-/hypoxia-treatment of the animals. The site-specific delivery of the CAR peptide to the pathologic retinal vasculature and the penetration of the retinal tissue may offer new opportunities for treating retinopathies more selectively and with less side effects.

Protein and peptide delivery to lungs by using advanced targeted drug delivery

The challenges and difficulties associated with conventional drug delivery systems have led to the emergence of novel, advanced targeted drug delivery systems. Therapeutic drug delivery of proteins and peptides to the lungs is complicated owing to the large size and polar characteristics of the latter. Nevertheless, the pulmonary route has attracted great interest today among formulation scientists, as it has evolved into one of the important targeted drug delivery platforms for the delivery of peptides, and related compounds effectively to the lungs, primarily for the management and treatment of chronic lung diseases. In this review, we have discussed and summarized the current scenario and recent developments in targeted delivery of proteins and peptide-based drugs to the lungs. Moreover, we have also highlighted the advantages of pulmonary drug delivery over conventional drug delivery approaches for peptide-based drugs, in terms of efficacy, retention time and other important pharmacokinetic parameters. The review also highlights the future perspectives and the impact of targeted drug delivery on peptide-based drugs in the coming decade.

Systemically Administered Homing Peptide Targets Dystrophic Lesions and Delivers Transforming Growth Factor-β (TGFβ) Inhibitor to Attenuate Murine Muscular Dystrophy Pathology

Muscular dystrophy is a progressively worsening and lethal disease, where accumulation of functionality-impairing fibrosis plays a key pathogenic role. Transforming growth factor-β1 (TGFβ1) is a central signaling molecule in the development of fibrosis in muscular dystrophic humans and mice. Inhibition of TGFβ1 has proven beneficial in mouse models of muscular dystrophy, but the global strategies of TGFβ1 inhibition produce significant detrimental side effects. Here, we investigated whether murine muscular dystrophy lesion-specific inhibition of TGFβ1 signaling by the targeted delivery of therapeutic decorin (a natural TGFβ inhibitor) by a vascular homing peptide CAR (CARSKNKDC) would reduce skeletal muscle fibrosis and pathology and increase functional characteristics of skeletal muscle. We demonstrate that CAR peptide homes to dystrophic lesions with specificity in two muscular dystrophy models. Recombinant fusion protein consisting of CAR peptide and decorin homes selectively to sites of skeletal muscle damage in mdxDBA2/J and gamma-sarcoglycan deficient DBA2/J mice. This targeted delivery reduced TGFβ1 signaling as demonstrated by reduced nuclear pSMAD staining. Three weeks of targeted decorin treatment decreased both membrane permeability and fibrosis and improved skeletal muscle function in comparison to control treatments in the mdxD2 mice. These results show that selective delivery of decorin to the sites of skeletal muscle damage attenuates the progression of murine muscular dystrophy.

Decorin in the Tumor Microenvironment

The tumor microenvironment plays a determining role in cancer development through a plethora of interactions between the extracellular matrix and tumor cells. Decorin is a prototype member of the SLRP family found in a variety of tissues and is expressed in the stroma of various forms of cancer. Decorin has gained recognition for its essential roles in inflammation, fibrotic disorders, and cancer, and due to its antitumor properties, it has been proposed to act as a "guardian from the matrix." Initially identified as a natural inhibitor of transforming growth factor-β, soluble decorin is emerging as a pan-RTK inhibitor targeting a multitude of RTKs, including EGFR, Met, IGF-IR, VEGFR2, and PDGFR. Besides initiating signaling, decorin/RTK interaction can induce caveosomal internalization and receptor degradation. Decorin also triggers cell cycle arrest and apoptosis and evokes antimetastatic and antiangiogenic processes. In addition, as a novel regulatory mechanism, decorin was shown to induce conserved catabolic processes, such as endothelial cell autophagy and tumor cell mitophagy. Therefore, decorin is a promising candidate for combatting cancer, especially the cancer types heavily dependent on RTK signaling.

Novel Molecular Mechanisms of Pulmonary Hypertension: A Search for Biomarkers and Novel Drug Targets-From Bench to Bed Site

Pulmonary hypertension (PH) is defined as increased mean pulmonary artery pressure (mPAP) above 25 mmHg, measured at rest by right heart catheterization. The exact global prevalence of PH is difficult to estimate, mainly due to the complex aetiology, and its spread may be underestimated. To date, numerous studies on the aetiology and pathophysiology of PH at molecular level were conducted. Simultaneously, some clinical studies have shown potential usefulness of well-known and widely recognized cardiovascular biomarkers, but their potential clinical usefulness in diagnosis and management of PH is poor due to their low specificity accompanied with numerous other cardiovascular comorbidities of PH subjects. On the other hand, a large body of basic research-based studies provides us with novel molecular pathomechanisms, biomarkers, and drug targets, according to the evidence-based medicine principles. Unfortunately, the simple implementation of these results to clinical practice is impossible due to a large heterogeneity of the PH pathophysiology, where the clinical symptoms constitute only a common denominator and a final result of numerous crosstalking metabolic pathways. Therefore, future studies, based mostly on translational medicine, are needed in order to both organize better the pathophysiological classification of various forms of PH and define precisely the optimal diagnostic markers and therapeutic targets in particular forms of PH. This review paper summarizes the current state of the art regarding the molecular background of PH with respect to its current classification. Novel therapeutic strategies and potential biomarkers are discussed with respect to their limitations in use in common clinical practice.

Newer approaches and novel drugs for inhalational therapy for pulmonary arterial hypertension

Introduction: Pulmonary arterial hypertension (PAH) is a progressive disease characterized by remodeling of small pulmonary arteries leading to increased pulmonary arterial pressure. Existing treatments acts to normalize vascular tone via three signaling pathways: the prostacyclin, the endothelin-1, and the nitric oxide. Although over the past 20 years, there has been considerable progress in terms of treatments for PAH, the disease still remains incurable with a disappointing prognosis.Areas covered: This review summarizes the pathophysiology of PAH, the advantages and disadvantages of the inhalation route, and assess the relative advantages various inhaled therapies for PAH. The recent studies concerning the development of controlled-release drug delivery systems loaded with available anti-PAH drugs have also been summarized.Expert opinion: The main obstacles of current pharmacotherapies of PAH are their short half-life, stability, and formulations, resulting in reducing the efficacy and increasing systemic side effects and unknown pathogenesis of PAH. The pulmonary route has been proposed for delivering anti-PAH drugs to overcome the shortcomings. However, the application of approved inhaled anti-PAH drugs is limited. Inhalational delivery of controlled-release nanoformulations can overcome these restrictions. Extensive studies are required to develop safe and effective drug delivery systems for PAH patients.

Systemically Administered, Target-Specific, Multi-Functional Therapeutic Recombinant Proteins in Regenerative Medicine

Growth factors, chemokines and cytokines guide tissue regeneration after injuries. However, their applications as recombinant proteins are almost non-existent due to the difficulty of maintaining their bioactivity in the protease-rich milieu of injured tissues in humans. Safety concerns have ruled out their systemic administration. The vascular system provides a natural platform for circumvent the limitations of the local delivery of protein-based therapeutics. Tissue selectivity in drug accumulation can be obtained as organ-specific molecular signatures exist in the blood vessels in each tissue, essentially forming a postal code system ("vascular zip codes") within the vasculature. These target-specific "vascular zip codes" can be exploited in regenerative medicine as the angiogenic blood vessels in the regenerating tissues have a unique molecular signature. The identification of vascular homing peptides capable of finding these unique "vascular zip codes" after their systemic administration provides an appealing opportunity for the target-specific delivery of therapeutics to tissue injuries. Therapeutic proteins can be "packaged" together with homing peptides by expressing them as multi-functional recombinant proteins. These multi-functional recombinant proteins provide an example how molecular engineering gives to a compound an ability to home to regenerating tissue and enhance its therapeutic potential. Regenerative medicine has been dominated by the locally applied therapeutic approaches despite these therapies are not moving to clinical medicine with success. There might be a time to change the paradigm towards systemically administered, target organ-specific therapeutic molecules in future drug discovery and development for regenerative medicine.

In vitro Permeability and Bioavailability Enhancement of Curcumin by Nanoemulsion via Pulmonary Administration

Background:

Curcumin has shown considerable pharmacological activity, including antiinflammatory activity. Nevertheless, the pharmacological effect of curcumin may be limited because of poor water solubility, metabolizing rapidly and systemic elimination.

Objective:

In the current research, a novel curcumin nanoemulsion (Cur-NE) was developed for improving in vitro permeability and bioavailability via pulmonary administration.

Methods:

The Cur-NE was prepared by a modified emulsification-evaporation method and its surfac morphology, particles size and distribution, and encapsulation efficiencies of drug in NE were characterized. In vitro transmembrane transport experiment was performed to investigate the transport profile of curcumin across Xenopus alveolar membrane. The pharmacokinetics of Cur-NE in rabbits was evaluated.

Results:

The average particles size, zeta potential, polydispersity index of Cur-NE were 234.8±1.08 nm, -19.5±0.2 mV and 0.10, respectively. Xenopus alveolar membrane was used in the transmembrane transport study, the cumulative amount of curcumin was 6.6% for curcumin suspensions, but nearly 50% for Cur-NE at the time of 8 h (P<0.05). The pharmacokinetic study in rabbits, the absolute bioavailability of curcumin for Cur-NE was 24.11%.

Conclusion:

Thus, a novel Cur-NE for pulmonary drug delivery was developed for improving in vitro permeability and bioavailability, which can be an alternate to the oral administration.

CAR, a Homing Peptide, Prolongs Pulmonary Preferential Vasodilation by Increasing Pulmonary Retention and Reducing Systemic Absorption of Liposomal Fasudil

Here, we sought to elucidate the role of CAR (a cyclic peptide) in the accumulation and distribution of fasudil, a drug for pulmonary arterial hypertension (PAH), in rat lungs and in producing pulmonary specific vasodilation in PAH rats. As such, we prepared liposomes of fasudil and CAR-conjugated liposomal fasudil and assessed the liposomes for CAR conjugation, physical properties, entrapment efficiencies, in vitro release profiles, and stabilities upon incubation in cell culture media, storage, and aerosolization. We also studied the cellular uptake of fasudil in different formulations, quantified heparan sulfate (HS) in pulmonary arterial smooth muscle cells (PASMCs), and investigated the distribution of the liposomes in the lungs of PAH rats. We assessed the drug accumulation in a close and recirculating isolated perfused rat lung model and studied the pharmacokinetics and pharmacological efficacy of the drug and formulations in Sugen/hypoxia-induced PAH rats. The entrapment efficiency of the liposomal fasudil was 95.5 ± 4.5%, and the cumulative release was 93.95 ± 6.22%. The uptake of CAR liposomes by pulmonary arterial cells and their distribution and accumulation in the lungs were much greater than those of no-CAR-liposomes. CAR-induced increase in the cellular uptake was associated with an increase in HS expression by rat PAH-PASMCs. CAR, when conjugated with liposomal fasudil and given via an intratracheal instillation, extended the elimination half-life of the drug by four-fold compared with fasudil-in-no-CAR-liposomes given via the same route. CAR-conjugated liposomal fasudil, as opposed to fasudil-in-no-CAR-liposomes and CAR pretreatment followed by fasudil-in-no-CAR-liposomes, reduced the mean pulmonary arterial pressure by 40-50% for 6 h, without affecting the mean systemic arterial pressure. On the whole, this study suggests that CAR aids in concentrating the drug in the lungs, increasing the cellular uptake, extending the half-life of fasudil, and eliciting a pulmonary-specific vasodilation when the peptide remains conjugated on the liposomal surface, but not when CAR is given as a pretreatment or alone as an admixture with the drug.

Inhaled combination of sildenafil and rosiglitazone improves pulmonary hemodynamics, cardiac function, and arterial remodeling

Currently, dual- or triple-drug combinations comprising different vasodilators are the mainstay for the treatment of pulmonary arterial hypertension (PAH). However, the patient outcome continues to be disappointing because the existing combination therapy cannot restrain progression of the disease. Previously, we have shown that when given as a monotherapy, long-acting inhaled formulations of sildenafil (a phosphodiesterase-5 inhibitor) and rosiglitazone (a peroxisome proliferator receptor-γ agonist) ameliorate PAH in rats. Thus, with a goal to develop a new combination therapy, we prepared and characterized poly(lactic-co-glycolic acid) (PLGA)-based long-acting inhalable particles of sildenafil and rosiglitazone. We then assessed the efficacy of the combinations of sildenafil and rosiglitazone, given in plain forms or as PLGA particles, in reducing mean pulmonary arterial pressure (mPAP) and improving pulmonary arterial remodeling and right ventricular hypertrophy (RVH) in Sugen 5416 plus hypoxia-induced PAH rats. After intratracheal administration of the formulations, we catheterized the rats and measured mPAP, cardiac output, total pulmonary resistance, and RVH. We also conducted morphometric studies using lung tissue samples and assessed the degree of muscularization, the arterial medial wall thickening, and the extent of collagen deposition. Compared with the plain drugs, given via the pulmonary or oral route as a single or dual combination, PLGA particles of the drugs, although given at a longer dosing interval compared with the plain drugs, caused more pronounced reduction in mPAP without affecting mean systemic pressure, improved cardiac function, slowed down right heart remodeling, and reduced arterial muscularization. Overall, PLGA particles of sildenafil and rosiglitazone, given as an inhaled combination, could be a viable alternative to currently available vasodilator-based combination therapy for PAH.

Generation of a multi-functional, target organ-specific, anti-fibrotic molecule by molecular engineering of the extracellular matrix protein, decorin

Extracellular matrix (ECM) molecules play important roles in regulating processes such as cell proliferation, migration, differentiation and survival. Decorin is a proteoglycan that binds to ('decorates') collagen fibrils in the ECM. Decorin also interacts with many growth factors and their receptors, the most notable of these interactions being its inhibitory activity on TGF-β, the growth factor responsible for fibrosis formation. We have generated a recombinant, multi-functional, fusion-protein consisting of decorin as a therapeutic domain and a vascular homing and cell-penetrating peptide as a targeting vehicle. This recombinant decorin (CAR-DCN) accumulates at the sites of the targeted disease at higher levels and, as a result, has substantially enhanced biological activity over native decorin. CAR-DCN is an example of how molecular engineering can give a compound the ability to seek out sites of disease and enhance its therapeutic potential. CAR-DCN will hopefully be used to treat severe human diseases. LINKED ARTICLES: This article is part of a themed section on Translating the Matrix. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.1/issuetoc.

Nanotherapeutics for Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a devastating and fatal chronic lung disease. While current pharmacotherapies have improved patient quality of life, PAH drugs suffer from limitations in the form of short-term pharmacokinetics, instability, and poor organ specificity. Traditionally, nanotechnology-based delivery strategies have proven advantageous at increasing both circulation lifetimes of chemotherapeutics and accumulation in tumors due to enhanced permeability through fenestrated vasculature. Importantly, increased nanoparticle (NP) accumulation in diseased tissues has been observed pre-clinically in pathologies characterized by endothelial dysfunction and remodeled vasculature, including myocardial infarction and heart failure. Recently, this phenomenon has also been observed in preclinical models of PAH, leading to the exploration of NP-based drug delivery as a therapeutic modality in PAH. Herein, we discussed the advantages of NPs for efficacious treatment of PAH, including heightened therapeutic delivery to diseased lungs for increased drug bioavailability, as well as highlighted innovative nanotherapeutic approaches for PAH.

Anti-RSV Peptide-Loaded Liposomes for the Inhibition of Respiratory Syncytial Virus

Although respiratory syncytial virus (RSV) is one of the leading causes of acute respiratory tract infection in infants and adults, effective treatment options remain limited. To circumvent this issue, there is a novel approach, namely, the development of multifunctional liposomes for the delivery of anti RSV-peptides. While most of the peptides that are used for loading with the particulate delivery systems are the penetrating peptides, an alternative approach is the development of liposome-peptide systems, which are loaded with an RSV fusion peptide (RF-482), which has been designed to inhibit the RSV fusion and block infection. The results of this work have revealed that the liposomes themselves can serve as potential RSV inhibitors, whilst the anti-RSV-peptide with liposomes can significantly increase the RSV inhibition when compared with the anti-RSV peptide alone.

Fasudil and DETA NONOate, Loaded in a Peptide-Modified Liposomal Carrier, Slow PAH Progression upon Pulmonary Delivery

We investigated the feasibility of a combination therapy comprising fasudil, a Rho-kinase inhibitor, and DETA NONOate (diethylenetriamine NONOate, DN), a long-acting nitric oxide donor, both loaded in liposomes modified with a homing peptide, CAR (CARSKNKDC), in the treatment of pulmonary arterial hypertension (PAH). We first prepared and characterized unmodified and CAR-modified liposomes of fasudil and DN. Using individual drugs alone or a mixture of fasudil and DN as controls, we studied the efficacy of the two liposomal preparations in reducing mean pulmonary arterial pressure (mPAP) in monocrotaline (MCT) and SUGEN-hypoxia-induced PAH rats. We also conducted morphometric studies (degree of muscularization, arterial medial wall thickness, and collagen deposition) after treating the PAH rats with test and control formulations. When the rats were treated acutely and chronically, the reduction in mPAP was more pronounced in the liposomal formulation-treated rats than in plain drug-treated rats. CAR-modified liposomes were more selective in reducing mPAP than unmodified liposomes of the drugs. Both drugs, formulated in CAR-modified liposomes, reduced the degree of muscularization, medial arterial wall thickness, and collagen deposition more than the combination of plain drugs did. As seen with the in vivo data, CAR-modified liposomes of fasudil or DN increased the levels of the vasodilatory signaling molecule, cGMP, in the smooth muscle cells of PAH-afflicted human pulmonary arteries. Overall, fasudil and DN, formulated in liposomes, could be used as a combination therapy for a better management of PAH.

Pulmonary arterial hypertension: pathogenesis and clinical management

Pulmonary hypertension is defined as a resting mean pulmonary artery pressure of 25 mm Hg or above. This review deals with pulmonary arterial hypertension (PAH), a type of pulmonary hypertension that primarily affects the pulmonary vasculature. In PAH, the pulmonary vasculature is dynamically obstructed by vasoconstriction, structurally obstructed by adverse vascular remodeling, and pathologically non-compliant as a result of vascular fibrosis and stiffening. Many cell types are abnormal in PAH, including vascular cells (endothelial cells, smooth muscle cells, and fibroblasts) and inflammatory cells. Progress has been made in identifying the causes of PAH and approving new drug therapies. A cancer-like increase in cell proliferation and resistance to apoptosis reflects acquired abnormalities of mitochondrial metabolism and dynamics. Mutations in the type II bone morphogenetic protein receptor (BMPR2) gene dramatically increase the risk of developing heritable PAH. Epigenetic dysregulation of DNA methylation, histone acetylation, and microRNAs also contributes to disease pathogenesis. Aberrant bone morphogenetic protein signaling and epigenetic dysregulation in PAH promote cell proliferation in part through induction of a Warburg mitochondrial-metabolic state of uncoupled glycolysis. Complex changes in cytokines (interleukins and tumor necrosis factor), cellular immunity (T lymphocytes, natural killer cells, macrophages), and autoantibodies suggest that PAH is, in part, an autoimmune, inflammatory disease. Obstructive pulmonary vascular remodeling in PAH increases right ventricular afterload causing right ventricular hypertrophy. In some patients, maladaptive changes in the right ventricle, including ischemia and fibrosis, reduce right ventricular function and cause right ventricular failure. Patients with PAH have dyspnea, reduced exercise capacity, exertional syncope, and premature death from right ventricular failure. PAH targeted therapies (prostaglandins, phosphodiesterase-5 inhibitors, endothelin receptor antagonists, and soluble guanylate cyclase stimulators), used alone or in combination, improve functional capacity and hemodynamics and reduce hospital admissions. However, these vasodilators do not target key features of PAH pathogenesis and have not been shown to reduce mortality, which remains about 50% at five years. This review summarizes the epidemiology, pathogenesis, diagnosis, and treatment of PAH.

Effects of fasudil on pulmonary hypertension in clinical practice

Pulmonary hypertension (PH) is a pathophysiologic disorder that may involve multiple clinical conditions and can complicate the majority of cardiovascular and respiratory diseases. The presence of PH is associated with worse outcomes, but the efficacy of current therapy is still unsatisfactory. Because Rho-kinase (ROCK) plays an important role in the pathogenesis of PH, the ROCK inhibitor fasudil is expected to contribute to PH treatment. In animal models of PH, fasudil reduced pulmonary artery pressure (PAP) and improved survival. Furthermore, the short-term efficacy and safety of fasudil in the treatment of PH are demonstrated in clinical trials. Both PAP and pulmonary vascular resistance in patients with PH are significantly decreased by intravenous or inhaled fasudil without apparent side effect. However, no clinical trial has assessed the long-term efficacy of fasudil in the treatment of PH. Limited data suggest that the mid-term use of fasudil could improve exercise capacity and reduce in-hospital mortality. We also discuss the combined use of fasudil and other drugs for PH treatment. However, these combinations have not yet been evaluated in a clinical trial. According to animal studies, the combination of fasudil with beraprost or sildenafil shows synergistic effects, whereas the combination of fasudil with bosentan has no additional ameliorating effects on PH development.

Cocktail of Superoxide Dismutase and Fasudil Encapsulated in Targeted Liposomes Slows PAH Progression at a Reduced Dosing Frequency

Currently, two or more pulmonary vasodilators are used to treat pulmonary arterial hypertension (PAH), but conventional vasodilators alone cannot reverse disease progression. In this study, we tested the hypothesis that a combination therapy comprising a vasodilator plus a therapeutic agent that slows pulmonary arterial remodeling and right heart hypertrophy is an efficacious alternative to current vasodilator-based PAH therapy. Thus, we encapsulated a cocktail of superoxide dismutase (SOD), a superoxide scavenger, and fasudil, a specific rho-kinase inhibitor, into a liposomal formulation equipped with a homing peptide, CAR. We evaluated the effect of the formulations on pulmonary hemodynamics in monocrotaline-induced PAH rats (MCT-induced PAH) and assessed the formulation's efficacy in slowing the disease progression in Sugen-5416/hypoxia-induced PAH rats (SU/hypoxia-induced PAH). For acute studies, we monitored both mean pulmonary and systemic arterial pressures (mPAP and mSAP) for 2 to 6 h after a single dose of the plain drugs or formulations. In chronic studies, PAH rats received plain drugs every 48 h and the formulations every 72 h for 21 days. In MCT-induced PAH rats, CAR-modified liposomes containing fasudil plus SOD elicited a more pronounced, prolonged, and selective reduction in mPAP than unmodified liposomes and plain drugs did. In SU/hypoxia-induced PAH rats, the formulation produced a >50% reduction in mPAP and slowed right ventricular hypertrophy. When compared with individual plain drugs or combination, CAR-modified-liposomes containing both drugs reduced the extent of collagen deposition, muscularization of arteries, increased SOD levels in the lungs, and decreased the expression of pSTAT-3 and p-MYPT1. Overall, CAR-modified-liposomes of SOD plus fasudil, given every 72 h, was as efficacious as plain drugs, given every 48 h, suggesting that the formulation can reduce the total drug intake, systemic exposures, and dosing frequency.

Finding New Tricks for Old Drugs: Tumoricidal Activity of Non-Traditional Antitumor Drugs

Chemotherapy, a traditional method, plays an important role in tumor therapy. Currently, common clinical antitumor drugs have several defects like poor efficacy, side effects, etc. Furthermore, developing new antitumor drugs takes a long time and requires many resources. Recent studies have found that oldies are newbies for the oncologist, such as flavonoid, metformin, aspirin, etc. These non-traditional antitumor drugs (NTADs) are widely used in management of non-cancer diseases, which gained FDA approval for treatment of patients. Increasingly, studies about antitumor action of NTADs have attracted many researchers' interests. A giant amount of studies showed a decrease in cancer incidence in NTAD-treated patients. Several reports outlined a direct inhibitory effect of NTADs on cancer cell growth and antitumoral actions. This review summarized the research progress on antitumor effects of ten NTADs. Retrospective and meta-analyses of trials also showed that these NTADs had preventive effects against cancer in vitro and in vivo. These drugs represent a promising option for cancer treatment, which have clear benefits including clinical safety, obvious curative effect, and saving medical and health resources. Judged from previous reports, future studies will yield valuable data about the profitable effects of these drugs. With a better understanding of its mechanisms of antitumor activity, NTADs may become available for combination with chemotherapy or targeted therapy in clinic.

Liposomal Aerosols of Nitric Oxide (NO) Donor as a Long-Acting Substitute for the Ultra-Short-Acting Inhaled NO in the Treatment of PAH

PURPOSE

This study seeks to develop a liposomal formulation of diethylenetriamine NONOate (DN), a long acting nitric oxide (NO) donor, with a goal to replace inhaled NO (iNO) in the treatment of pulmonary arterial hypertension (PAH).

METHODS

Liposomal formulations were prepared by a lipid film hydration method and modified with a cell penetrating peptide, CAR. The particles were characterized for size, polydispersity index (PDI), zeta potential, entrapment efficiency, storage and nebulization stability, and in-vitro release profiles. The cellular uptake and transport were assessed in rat alveolar macrophages (NR8383) and transforming growth factor β (TGF-β) activated rat pulmonary arterial smooth muscle cells (PASMCs). The fraction of the formulation that enters the systemic circulation, after intratracheal administration, was determined in an Isolated Perfused Rat Lung (IPRL) model. The safety of the formulations were assessed using an MTT assay and by measuring injury markers in the bronchoalveolar lavage (BAL) fluid; the pharmacological efficacy was evaluated by monitoring the changes in the mean pulmonary arterial (mPAP) and systemic pressure (mSAP) in a monocrotaline (MCT) induced-PAH rat model

RESULTS

Liposome size, zeta potential, and entrapment efficiency were 171 ± 4 nm, -37 ± 3 mV, and 46 ± 5%, respectively. The liposomes released 70 ± 5% of the drug in 8 h and were stable when stored at 4°C. CAR-conjugated-liposomes were taken up more efficiently by PASMCs than liposomes-without-CAR; the uptake of the formulations by rat alveolar macrophages was minimal. DN-liposomes did not increase lung weight, protein quantity, and levels of injury markers in the BAL fluid. Intratracheal CAR-liposomes reduced the entry of liposomes from the lung to blood; the formulations produced a 40% reduction in mPAP for 180 minutes.

CONCLUSION

This study establishes the proof-of-concept that peptide modified liposomal formulations of long-acting NO donor can be an alternative to short-acting iNO.

Decorin: A Growth Factor Antagonist for Tumor Growth Inhibition

Decorin (DCN) is the best characterized member of the extracellular small leucine-rich proteoglycan family present in connective tissues, typically in association with or “decorating” collagen fibrils. It has substantial interest to clinical medicine owing to its antifibrotic, anti-inflammatory, and anticancer effects. Studies on DCN knockout mice have established that a lack of DCN is permissive for tumor development and it is regarded as a tumor suppressor gene. A reduced expression or a total disappearance of DCN has been reported to take place in various forms of human cancers during tumor progression. Furthermore, when used as a therapeutic molecule, DCN has been shown to inhibit tumor progression and metastases in experimental cancer models. DCN affects the biology of various types of cancer by targeting a number of crucial signaling molecules involved in cell growth, survival, metastasis, and angiogenesis. The active sites for the neutralization of different growth factors all reside in different parts of the DCN molecule. An emerging concept that multiple proteases, especially those produced by inflammatory cells, are capable of cleaving DCN suggests that native DCN could be inactivated in a number of pathological inflammatory conditions. In this paper, we review the role of DCN in cancer.

Systemically Administered, Target Organ-Specific Therapies for Regenerative Medicine

Growth factors and other agents that could potentially enhance tissue regeneration have been identified, but their therapeutic value in clinical medicine has been limited for reasons such as difficulty to maintain bioactivity of locally applied therapeutics in the protease-rich environment of regenerating tissues. Although human diseases are treated with systemically administered drugs in general, all current efforts aimed at enhancing tissue repair with biological drugs have been based on their local application. The systemic administration of growth factors has been ruled out due to concerns about their safety. These concerns are warranted. In addition, only a small proportion of systemically administered drugs reach their intended target. Selective delivery of the drug to the target tissue and use of functional protein domains capable of penetrating cells and tissues could alleviate these problems in certain circumstances. We will present in this review a novel approach utilizing unique molecular fingerprints (“Zip/postal codes”) in the vasculature of regenerating tissues that allows target organ-specific delivery of systemically administered therapeutic molecules by affinity-based physical targeting (using peptides or antibodies as an “address tag”) to injured tissues undergoing repair. The desired outcome of targeted therapies is increased local accumulation and lower systemic concentration of the therapeutic payload. We believe that the physical targeting of systemically administered therapeutic molecules could be rapidly adapted in the field of regenerative medicine.

Agents with vasodilator properties in acute heart failure: how to design successful trials

Agents with vasodilator properties (AVDs) are frequently used in the treatment of acute heart failure (AHF). AVDs rapidly reduce preload and afterload, improve left ventricle to aorta and right ventricle to pulmonary artery coupling, and may improve symptoms. Early biomarker changes after AVD administration have suggested potentially beneficial effects on cardiac stretch, vascular tone, and renal function. AVDs that reduce haemodynamic congestion without causing hypoperfusion might be effective in preventing worsening organ dysfunction. Existing AVDs have been associated with different results on outcomes in randomized clinical trials, and observational studies have suggested that AVDs may be associated with a clinical outcome benefit. Lessons have been learned from past AVD trials in AHF regarding preventing hypotension, selecting the optimal endpoint, refining dyspnoea measurements, and achieving early randomization and treatment initiation. These lessons have been applied to the design of ongoing pivotal clinical trials, which aim to ascertain if AVDs improve clinical outcomes. The developing body of evidence suggests that AVDs may be a clinically effective therapy to reduce symptoms, but more importantly to prevent end-organ damage and improve clinical outcomes for specific patients with AHF. The results of ongoing trials will provide more clarity on the role of AVDs in the treatment of AHF.

Novel therapeutic approaches for pulmonary arterial hypertension: Unique molecular targets to site-specific drug delivery

Pulmonary arterial hypertension (PAH) is a cardiopulmonary disorder characterized by increased blood pressure in the small arterioles supplying blood to lungs for oxygenation. Advances in understanding of molecular and cellular biology techniques have led to the findings that PAH is indeed a cascade of diseases exploiting multi-faceted complex pathophysiology, with cellular proliferation and vascular remodeling being the key pathogenic events along with several cellular pathways involved. While current therapies for PAH do provide for amelioration of disease symptoms and acute survival benefits, their full therapeutic potential is hindered by patient incompliance and off-target side effects. To overcome the issues related with current therapy and to devise a more selective therapy, various novel pathways are being investigated for PAH treatment. In addition, inability to deliver anti-PAH drugs to the disease site i.e., distal pulmonary arterioles has been one of the major challenges in achieving improved patient outcomes and improved therapeutic efficacy. Several novel carriers have been explored to increase the selectivity of currently approved anti-PAH drugs and to act as suitable carriers for the delivery of investigational drugs. In the present review, we have discussed potential of various novel molecular pathways/targets including RhoA/Rho kinase, tyrosine kinase, endothelial progenitor cells, vasoactive intestinal peptide, and miRNA in PAH therapeutics. We have also discussed various techniques for site-specific drug delivery of anti-PAH therapeutics so as to improve the efficacy of approved and investigational drugs. This review will provide gainful insights into current advances in PAH therapeutics with an emphasis on site-specific drug payload delivery.