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Noncommunicable diseases, including cardiovascular disease, diabetes, chronic respiratory disease, and cancer, are the leading cause of death in the world. The cost, both monetary and time, of developing therapies to prevent, treat, or manage these diseases has become unsustainable. A contributing factor is inefficient and ineffective preclinical research, in which the animal models utilized do not replicate the complex physiology that influences disease. An ideal preclinical animal model is one that responds similarly to intrinsic and extrinsic influences, providing high translatability and concordance of preclinical findings to humans. The overwhelming genetic, anatomical, physiological, and pathophysiological similarities to humans make miniature swine an ideal model for preclinical studies of human disease. Additionally, recent development of precision gene-editing tools for creation of novel genetic swine models allows the modeling of highly complex pathophysiology and comorbidities. As such, the utilization of swine models in early research allows for the evaluation of novel drug and technology efficacy while encouraging redesign and refinement before committing to clinical testing. This review highlights the appropriateness of the miniature swine for modeling complex physiologic systems, presenting it as a highly translational preclinical platform to validate efficacy and safety of therapies and devices.

T hirteen percent of global mortality has been associated with arterial hypertension. Approximately 34% of the total adult population worldwide is hypertensive, and 13% of this segment of the population is further categorized as having resistant hypertension (RHTN).1 Criteria for the diagnosis of RHTN are the following: any patient requiring ≥3 antihypertensive drugs, including a diuretic, and still maintaining a blood pressure (BP) >140/90 mm Hg.2 RHTN has been previously described as a multifactorial phenomenon involving multiple biological mechanisms; however, the hyperactivity of the sympathetic nervous system plays a paramount role in the onset, maintenance, and progression of RHTN. 3 The renal sympathetic nervous system, composed of afferent and efferent nerves, courses immediately adjacent to the wall of the renal artery. 4 The afferent renal sensory nerves, with neuronal cell bodies located in the ipsilateral dorsal root ganglia, modulate the central sympathetic outflow by providing sensory information from mechanoreceptors and chemoreceptors in the renal tissue. Renal injuries (ie, hypoxia) increase afferent sensory signals, resulting in an increase in efferent sympathetic nerve activity, peripheral arterial vasoconstriction, and subsequent increase in arterial BP. The efferent renal sympathetic nerves transmit signals from the central sympathetic nervous system to the kidneys (ie, renal vasculature, tubules, and juxtaglomerular apparatus). Efferent renal sympathetic activity is moderated by an inhibitory renorenal reflex and central sympathetic nervous system outflow. Elevated efferent renal sympathetic activity increases sodium reabsorption and renin release and causes renal arterial vasoconstriction, leading to hypertension. Catheter-based ablation of afferent and efferent sympathetic nerves surrounding the renal arteries has been proposed Background-Renal denervation (RDN) emerged as a therapeutic option for resistant hypertension. Nerve regrowth after RDN has been questioned. We aimed to characterize the nerve response after RDN. Methods and Results-Swine underwent bilateral RDN and were followed up for 7, 30, and 90 days and evaluated with S100 (Schwann cell), tyrosine hydroxylase (TH; efferent nerves), and growth-associated protein 43 (neurite regeneration) markers. At 7 days, nerve changes consisted of necrosis associated with perineurial fibrosis and distal atrophy with inflammation. At 30 days changes were substituted by healing changes (ie, fibrosis). This response progressed through 90 days resulting in prominent neuroma formation. Immunohistochemistry at 7 days: TH staining was strongly decreased in treated nerves. Early regenerative attempts were observed with strongly TH and growth-associated protein 43 positive and weak S100 disorganized nerve sprouts within the thickened perineurium. Distal atrophic nerves show weak staining for all 3 markers. At 30 days, affected nerves show a weak TH and S100 staining. Evident growth-associated protein 43+ disorganized neuromatous tangles in the thick...

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ObjectivesTo evaluate the biological effect of a paclitaxel‐coated balloon (PCB) technology on vascular drug distribution and healing in drug eluting stent restenosis (DES‐ISR) swine model.BackgroundThe mechanism of action and healing response via PCB technology in DES‐ISR is not completely understood.MethodsA total of 27 bare metal stents were implanted in coronary arteries and 30 days later the in‐stent restenosis was treated with PCB. Treated segments were harvested at 1 hr, 14 days and 30 days post treatment for the pharmacokinetic analysis. In addition, 24 DES were implanted in coronary arteries for 30 days, then all DES‐ISRs were treated with either PCB (n = 12) or uncoated balloon (n = 12). At day 60, vessels were harvested for histology following angiography and optical coherence tomography (OCT).ResultsThe paclitaxel level in neointimal tissue was about 18 times higher (P = 0.0004) at 1 hr C max, and retained about five times higher (P = 0.008) at day 60 than that in vessel wall. A homogenous distribution of paclitaxel in ISR was demonstrated by using fluorescently labeled paclitaxel. Notably, in DES‐ISR, both termination OCT and quantitative coronary angioplasty showed a significant neointimal reduction and less late lumen loss (P = 0.05 and P = 0.03, respectively) post PCB versus post uncoated balloon. The PES‐ISR + PCB group displayed higher levels of peri‐strut inflammation and fibrin scores compared to the ‐limus DES‐ISR + PCB group.ConclusionsIn ISR, paclitaxel is primarily deposited in neointimal tissue and effectively retained over time following PCB use. Despite the presence of metallic struts, a uniform distribution was characterized. PCB demonstrated an equivalent biological effect in DES‐ISR without significantly increasing inflammation. © 2015 Wiley Periodicals, Inc.