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A major barrier to adeno-associated virus (AAV) gene therapy is the inability to re-dose patients due to formation of vector-induced neutralizing antibodies (Nabs). Tolerogenic nanoparticles encapsulating rapamycin (ImmTOR) provide long-term and specific suppression of adaptive immune responses, allowing for vector re-dosing. Moreover, co-administration of hepatotropic AAV vectors and ImmTOR leads to an increase of transgene expression even after the first dose. ImmTOR and AAV Anc80 encoding the methylmalonyl-coenzyme A (CoA) mutase (MMUT) combination was tested in a mouse model of methylmalonic acidemia, a disease caused by mutations in the MMUT gene. Repeated co-administration of Anc80 and ImmTOR was well tolerated and led to nearly complete inhibition of immunoglobulin (Ig)G antibodies to the Anc80 capsid. A more profound decrease of plasma levels of the key toxic metabolite, plasma methylmalonic acid (pMMA), and disease biomarker, fibroblast growth factor 21 (FGF21), was observed after treatment with the ImmTOR and Anc80-MMUT combination. In addition, there were higher numbers of viral genomes per cell (vg/cell) and increased transgene expression when ImmTOR was co-administered with Anc80-MMUT. These effects were dose-dependent, with the higher doses of ImmTOR providing higher vg/cell and mRNA levels, and an improved biomarker response. Combining of ImmTOR and AAV can not only block the IgG response against capsid, but it also appears to potentiate transduction and enhance therapeutic transgene expression in the mouse model., Graphical abstract, Kishimoto and colleagues extend their earlier findings showing that combining ImmTOR rapamycin-encapsulated nanoparticles with hepatotropic AAV vector leads to increased transduction, transgene expression, and suppression of IgG responses and therefore enables effective therapeutic AAV vector re-dosing in a mouse model of methylmalonic acidemia, an inborn metabolic disease.

BACKGROUND: Aberrant microRNA (miRNA) expression affects biologic processes and downstream genes that are crucial to CKD initiation or progression. The miRNA miR-204-5p is highly expressed in the kidney but whether miR-204-5p plays any role in the development of chronic renal injury is unknown. METHODS: We used real-time PCR to determine levels of miR-204 in human kidney biopsies and animal models. We generated Mir204 knockout mice and used locked nucleic acid–modified anti-miR to knock down miR-204-5p in mice and rats. We used a number of physiologic, histologic, and molecular techniques to analyze the potential role of miR-204-5p in three models of renal injury. RESULTS: Kidneys of patients with hypertension, hypertensive nephrosclerosis, or diabetic nephropathy exhibited a significant decrease in miR-204-5p compared with controls. Dahl salt-sensitive rats displayed lower levels of renal miR-204-5p compared with partially protected congenic SS.13(BN26) rats. Administering anti–miR-204-5p to SS.13(BN26) rats exacerbated interlobular artery thickening and renal interstitial fibrosis. In a mouse model of hypertensive renal injury induced by uninephrectomy, angiotensin II, and a high-salt diet, Mir204 gene knockout significantly exacerbated albuminuria, renal interstitial fibrosis, and interlobular artery thickening, despite attenuation of hypertension. In diabetic db/db mice, administering anti–miR-204-5p exacerbated albuminuria and cortical fibrosis without influencing blood glucose levels. In all three models, inhibiting miR-204-5p or deleting Mir204 led to upregulation of protein tyrosine phosphatase SHP2, a target gene of miR-204-5p, and increased phosphorylation of signal transducer and activator of transcription 3, or STAT3, which is an injury-promoting effector of SHP2. CONCLUSIONS: These findings indicate that the highly expressed miR-204-5p plays a prominent role in safeguarding the kidneys against common causes of chronic renal injury.

SUMMARY Primary cilia are sensory organelles that protrude from the cell membrane. Defects in the primary cilium cause ciliopathy disorders, with retinal degeneration as a prominent phenotype. Here, we demonstrate that the retinal pigment epithelium (RPE), essential for photoreceptor development and function, requires a functional primary cilium for complete maturation and that RPE maturation defects in ciliopathies precede photoreceptor degeneration. Pharmacologically enhanced ciliogenesis in wild-type induced pluripotent stem cells (iPSC)-RPE leads to fully mature and functional cells. In contrast, ciliopathy patient-derived iPSC-RPE and iPSC-RPE with a knockdown of ciliary-trafficking protein remain immature, with defective apical processes, reduced functionality, and reduced adult-specific gene expression. Proteins of the primary cilium regulate RPE maturation by simultaneously suppressing canonical WNT and activating PKCδ pathways. A similar cilium-dependent maturation pathway exists in lung epithelium. Our results provide insights into ciliopathy-induced retinal degeneration, demonstrate a developmental role for primary cilia in epithelial maturation, and provide a method to mature iPSC epithelial cells for clinical applications., Graphical Abstract, In Brief May-Simera et al. show that primary cilia regulate the maturation and polarization of human iPSC-RPE, mouse RPE, and human iPSC-lung epithelium through canonical WNT suppression and PKCδ activation. RPE cells derived from ciliopathy patients exhibit defective structure and function. These results provide insights into ciliopathy-induced retinal degeneration.

Background Diabetes mellitus places a substantial burden on society worldwide. Diabetic foot ulcers are a challenging problem for clinicians. Seven generally accepted detriments to healing of diabetic foot ulcers were identified: infection, glycaemic control, vascular supply, smoking, nutrition, deformity and offloading. The aim of this paper is to present a comprehensive evidence based review of the literature available on detriments to healing of diabetic foot ulcers. Method A research question was generated for each of the detriments to healing and a comprehensive review of the literature was performed using the Pubmed database in July 2014. All articles were assessed for relevancy and a level of evidence was assigned. An analysis of the total body of literature was used to assign a grade of recommendation to each detriment. Results Grade A recommendation was assigned to offloading as there was good evidence supporting this intervention. Grade B recommendation was assigned to deformity as there was fair evidence consistent with the hypothesis. Infection and vascular supply had poor quality evidence supporting the research question and grade C recommendation was assigned. Grade I recommendation was assigned to glycaemic control, smoking and nutrition as there was insufficient and conflicting evidence available. Conclusion Our literature review revealed good evidence for some factors and insufficient literature on others. Further studies are needed to provide quality evidence regarding detriments to healing of diabetic ulcers.

Neuropathic and dysvascular feet can present challenges to the treating orthopedic surgeon and should be managed by a multidisciplinary team focusing on patient education and prevention of injury. The most common pathology revolves around diabetic complications and development of the Charcot neuropathic joint. Neuropathic ulcers need to be prevented with diligent care, because ulceration is prognostic for amputation in these patients. The goal of treatment for these patients is to maintain a viable limb that can support weight bearing and ambulation with an off-the-shelf orthosis. The first stage of treatment for neuropathic ulceration typically consists of a total contact cast, which allows off-loading of the affected area to promote wound healing. Once healing has started, the patient can be transitioned to off-loading orthotics such as an orthotic dynamic splint or, classically, the Charcot Restraint Orthotic Walker (CROW). After wounds are completely healed, future injuries can be prevented with appropriately fitting shoewear and accomodative inserts. Ulcers and wounds caused by venous vascular disease may benefit from treatment with compressive stockings, whereas wounds caused by arterial deficiency require consultation with a vascular surgeon for appropriate treatment.

For effective treatment, induced pluripotent stem cell (iPSC)-retinal pigment epithelium (RPE) must recapitulate the physiology of native human RPE cells. A set of physiologically relevant functional assays that assess the polarized functional activity and maturation state of the intact RPE monolayer is provided. The study data show that donor-to-donor variability exceeds the tissue-to-tissue variability for a given donor and provides, for the first time, criteria necessary to identify iPSC-RPE cells most suitable for clinical application., Induced pluripotent stem cells (iPSCs) can be efficiently differentiated into retinal pigment epithelium (RPE), offering the possibility of autologous cell replacement therapy for retinal degeneration stemming from RPE loss. The generation and maintenance of epithelial apical-basolateral polarity is fundamental for iPSC-derived RPE (iPSC-RPE) to recapitulate native RPE structure and function. Presently, no criteria have been established to determine clonal or donor based heterogeneity in the polarization and maturation state of iPSC-RPE. We provide an unbiased structural, molecular, and physiological evaluation of 15 iPSC-RPE that have been derived from distinct tissues from several different donors. We assessed the intact RPE monolayer in terms of an ATP-dependent signaling pathway that drives critical aspects of RPE function, including calcium and electrophysiological responses, as well as steady-state fluid transport. These responses have key in vivo counterparts that together help determine the homeostasis of the distal retina. We characterized the donor and clonal variation and found that iPSC-RPE function was more significantly affected by the genetic differences between different donors than the epigenetic differences associated with different starting tissues. This study provides a reference dataset to authenticate genetically diverse iPSC-RPE derived for clinical applications. Significance The retinal pigment epithelium (RPE) is essential for maintaining visual function. RPE derived from human induced pluripotent stem cells (iPSC-RPE) offer a promising cell-based transplantation therapy for slowing or rescuing RPE-induced visual function loss. For effective treatment, iPSC-RPE must recapitulate the physiology of native human RPE. A set of physiologically relevant functional assays are provided that assess the polarized functional activity and maturation state of the intact RPE monolayer. The present data show that donor-to-donor variability exceeds the tissue-to-tissue variability for a given donor and provides, for the first time, criteria necessary to identify iPSC-RPE most suitable for clinical application.

Considerable progress has been made in testing stem cell-derived retinal pigment epithelium (RPE) as a potential therapy for age-related macular degeneration (AMD). However, the recent reports of oncogenic mutations in induced pluripotent stem cells (iPSCs) underlie the need for robust manufacturing and functional validation of clinical-grade iPSC-derived RPE before transplantation. Here, we developed oncogenic mutation-free clinical-grade iPSCs from three AMD patients and differentiated them into clinical-grade iPSC-RPE patches on biodegradable scaffolds. Functional validation of clinical-grade iPSC-RPE patches revealed specific features that distinguished transplantable from nontransplantable patches. Compared to RPE cells in suspension, our biodegradable scaffold approach improved integration and functionality of RPE patches in rats and in a porcine laser-induced RPE injury model that mimics AMD-like eye conditions. Our results suggest that the in vitro and in vivo preclinical functional validation of iPSC-RPE patches developed here might ultimately be useful for evaluation and optimization of autologous iPSC-based therapies.

Primary cilia are sensory organelles that protrude from the cell membrane. Cilia defects cause ciliopathy disorders with retinal degeneration as a prominent phenotype. Here, we demonstrate that the retinal pigment epithelium (RPE), essential for photoreceptor development and function, requires a functional primary cilium for complete maturation, and RPE maturation defects in ciliopathies precede photoreceptor development. Pharmacologically enhanced ciliogenesis in wildtype induced pluripotent stem cells (iPSCs)-RPE leads to fully-mature and functional cells. Whereas, ciliopathy patient-derived iPSCs-RPE and wildtype iPSC-RPE with a knockdown of ciliary-trafficking protein remain immature, with defective apical processes, reduced functionality, and reduced adult-specific gene expression. Primary cilia proteins regulate RPE maturation by simultaneously suppressing canonical-WNT and activating PKC-δ pathways. A similar cilia-dependent maturation pathway exists in lung epithelium. Our results provide novel insights into ciliopathy-induced retinal degeneration, demonstrate a developmental role for primary cilia in epithelial maturation, and provide a method to mature iPSC-epithelial cells for clinical applications.

Safe medication management is a major focus of all of the stakeholders in the surgical ambulatory and hospital service arena. There are key elements which must be in place according to contemporary standards and regulatory and/or accrediting bodies. Adverse drug events cause substantial morbidity and mortality, yet they remain underappreciated and misunderstood. The terminology to describe errors and patient harm associated with medications causes much confusion. Medication errors are the number one cause of preventable adverse events, including death. System checks should be designed into the medication administration process to prevent or reduce chances of inadvertent drug/vial swap. There needs to be, among other expectations, prudent formulary management, closely managed controlled drug systems, ongoing focused education of staff, due diligence in purchasing in general and compounding pharmacy selection in specific, and unwavering support for safe injection practices. Also emphasized are the role and rationale for meaningful documentation of adverse drug events and the role of the pharmacist, along with an outline of the types of events that should be reported to regulatory agencies, pivotal in the goal of safe medication management. This chapter will be divided into two parts: Part I deals with managing adverse medication events in the operating room based upon a real event and Part II addresses ambulatory medication safety and regulatory oversight.

Background Recombinant human bone morphogenetic protein-2 (rhBMP-2) is particularly effective in improving osteogenesis in patients with diminished bone healing capabilities, such as individuals with type 1 diabetes mellitus (T1DM) who have impaired bone healing capabilities and increased risk of developing osteoporosis. This study measured the effects of rhBMP-2 treatment on osteogenesis by observing the dose-dependent effect of localized delivery of rhBMP-2 on biomechanical parameters of bone using a hydroxyapatite/tri-calcium phosphate (HA/TCP) carrier in a T1DM-related osteoporosis animal model. Materials and methods Two different doses of rhBMP-2 (LD low dose, HD high dose) with a HA/TCP carrier were injected into the femoral intramedullary canal of rats with T1DM-related osteoporosis. Two more diabetic rat groups were injected with saline alone and with HA/TCP carrier alone. Radiographs and micro-computed tomography were utilized for qualitative assessment of bone mineral density (BMD). Biomechanical testing occurred at 4- and 8-week time points; parameters tested included torque to failure, torsional rigidity, shear stress, and shear modulus. Results At the 4-week time point, the LD and HD groups both exhibited significantly higher BMD than controls; at the 8-week time point, the HD group exhibited significantly higher BMD than controls. Biomechanical testing revealed dose-dependent, higher trends in all parameters tested at the 4- and 8-week time points, with minimal significant differences. Conclusions Groups treated with rhBMP-2 demonstrated improved bone mineral density at both 4 and 8 weeks compared to control saline groups, in addition to strong trends towards improvement of intrinsic and extrinsic biomechanical properties when compared to control groups. Data revealed trends toward dose-dependent increases in peak torque, torsional rigidity, shear stress, and shear modulus 4 weeks after rhBMP-2 treatment. Level of evidence Not applicable.

This study investigated the effects of local delivery of manganese chloride (MnCl2), an insulin-mimetic compound, upon fracture healing using a rat femoral fracture model. Mechanical testing, histomorphometry, and immunohistochemistry were performed to assess early and late parameters of fracture healing. At 4 weeks post-fracture, maximum torque to failure was 70% higher (P

This study evaluated the efficacy of using calcium sulfate (CaSO4) as a carrier for intramedullary delivery of an organic vanadium salt, vanadyl acetylacetonate (VAC) after femoral fracture. VAC can act as an insulin-mimetic and can be used to accelerate fracture healing in rats. A heterogenous mixture of VAC and CaSO4 was delivered to the fracture site of BB Wistar rats, and mechanical testing, histomorphometry, micro-computed tomography (micro-CT) were performed to measure healing. At 4 weeks after fracture, maximum torque to failure, effective shear modulus, and effective shear stress were all significantly higher (p

The advent of improved glucose control with insulin and oral medications has allowed for the diabetic population to live longer and healthier lives. Unfortunately diabetes remains a worldwide epidemic with multiple health implications. Specifically, its affects upon fracture healing have been well studied and shown to have negative effects on bone mineral density, biomechanical integrity, and fracture healing. Multiple animal models have been used for research purposes to gain further insight into the effects and potential treatments of this disease process. The diabetic BB Wistar rat is one model that replicates a close homology to human type-1 diabetes and has been used as a fracture model to study the effects of diabetes on bone integrity and healing. In particular, the effects of tight glucose control, ultrasound therapy, platelet-rich plasma (PRP), platelet-derived growth factor (PDGF), bone morphogenetic protein 2 (BMP-2), and allograft bone incorporation have been studied extensively. We present a review of the literature using the BB Wistar rat to elucidate the implications of diabetes on fracture healing.

Local insulin delivery has been shown to improve osseous healing in diabetic animals. The purpose of this study was to quantify the effects of local intramedullary delivery of saline or Ultralente insulin (UL) on various fracture healing parameters using an in vivo non-diabetic BB Wistar rat model. Quantitation of local insulin levels showed a rapid release of insulin from the fractured femora, demonstrating complete release at 2 days. RT-PCR analysis revealed that the expression of early osteogenic markers (Col1α2, osteopontin) was significantly enhanced with UL treatment when compared with saline controls (p

A significant number of lower extremity fractures result in mal-union necessitating effective treatments to restore ambulation. Prior research in diabetic animal fracture models demonstrated improved healing following local insulin application to the fracture site and indicated that local insulin therapy can aid bone regeneration, at least within an insulin-dependent diabetic animal model. This study tested whether local insulin therapy could accelerate femur fracture repair in normal, non-diabetic rats. High (20 units) and low (10 units) doses of insulin were delivered in a calcium sulfate carrier which provided sustained release of the exogenous insulin for 7 days after fracture. Histomorphometry, radiographic scoring, and torsional mechanical testing were used to measure fracture healing. The fracture calluses from rats treated with high-dose insulin had significantly more cartilage than untreated rats after 7 and 14 days of healing. After 4 weeks of healing, femurs from rats treated with low-dose insulin had significantly higher radiographic scores and mechanical strength (p

Nonunion after tibial shaft fracture and hindfoot arthrodesis remains a major problem. Known risk factors include advanced age, immunosuppression, smoking, and diabetes. Several factors must be considered in the fracture healing process. This review evaluates the efficacy of orthobiologics in improving union rates after fracture or arthrodesis. Use of compounds have shown increased cellular proliferation experimentally. Percutaneous autologous bone marrow has shown increased cellular proliferation. Matrix supplementation has shown significant improvements in bone healing. Several studies have highlighted the importance of adequate graft fill over graft type. Patients at increased risk for nonunion would benefit most from these adjuvant therapies.

Background: Nonunion, an important complication following foot and ankle arthrodesis, causes substantial morbidity and disability. In patients undergoing hindfoot and ankle arthrodesis, autogenous bone graft (autograft) or a suitable alternative is often used to promote osseous fusion across the joint. This study assessed the importance of adequate graft material in the fusion space to achieve joint fusion during ankle and hindfoot arthrodesis. Methods: This study used data from a previously published clinical trial of grafting material (recombinant human platelet-derived growth factor-BB with beta-tricalcium phosphate [rhPDGF-BB/β-TCP] or autograft) for healing in hindfoot and ankle arthrodesis to correlate the amount of graft fill at 9 weeks with ultimate healing. Patients who received supplemental graft material for ankle or hindfoot arthrodesis for end-stage ankle or hindfoot arthritis were stratified according to nonunion risk factors and surgical fusion site. Patients underwent arthrodesis using standard rigid internal fixation. Graft fill was defined as “adequate” if the material occupied ≥50% of the cross-sectional area of the fusion space on a computed tomography (CT) scan made at 9 weeks. Fusion was defined as osseous bridging of ≥50% of each articulation on a CT scan made at 24 weeks. Three hundred and seventy-nine patients with 573 joints (383 managed with rhPDGF-BB/β-TCP and 190 managed with autograft) that underwent arthrodesis had complete follow-up with 9-week and 24-week CT scans available. Results: Overall, 472 (82%) of 573 joints had adequate graft fill; of those, 383 (81%) were successfully fused at 24 weeks compared with 21 (21%) of 101 joints without adequate graft fill (p < 0.0001). Absolute fusion rate differences (joints with adequate fill minus those without adequate fill) were consistent across joints (61% to 63%) and for graft materials. The overall odds ratio (OR) of successful fusion in joints with adequate graft fill compared with those without adequate graft fill was 16.4 (95% confidence interval, 9.6 to 27.9). Conclusions: This study demonstrates an association between the amount of graft material and successful hindfoot and ankle arthrodesis. Graft material filling of ≥50% of the fusion space at 9 weeks, regardless of type or origin, was associated with significantly higher fusion rates at 24 weeks. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Background: Electromagnetic bone growth stimulators have been found to biologically enhance the bone healing environment, with upregulation of numerous growth factors. The purpose of the study was to quantify the effect, in vivo, of pulsed electromagnetic fields (PEMFs) on growth factor expression and healing time in fifth metatarsal nonunions. Methods: This was a prospective, randomized, double-blind trial of patients, cared for by 2 fellowship-trained orthopedic foot and ankle surgeons. Inclusion criteria consisted of patients between 18 and 75 years old who had been diagnosed with a fifth metatarsal delayed or nonunion, with no progressive signs of healing for a minimum of 3 months. Eight patients met inclusion criteria and were randomized to receive either an active stimulation or placebo PEMF device. Each patient then underwent an open biopsy of the fracture site and was fitted with the appropriate PEMF device. The biopsy was analyzed for messenger-ribonucleic acid (mRNA) levels using quantitative competitive reverse transcription polymerase chain reaction (QT-RT-PCR). Three weeks later, the patient underwent repeat biopsy and open reduction and internal fixation of the nonunion site. The patients were followed at 2- to 4-week intervals with serial radiographs and were graded by the number of cortices of healing. Results: All fractures healed, with an average time to complete radiographic union of 14.7 weeks and 8.9 weeks for the inactive and active PEMF groups, respectively. A significant increase in placental growth factor (PIGF) level was found after active PEMF treatment ( P = .043). Other factors trended higher following active PEMF including brain-derived neurotrophic factor (BDNF), bone morphogenetic protein (BMP) -7, and BMP-5. Conclusion: The adjunctive use of PEMF for fifth metatarsal fracture nonunions produced a significant increase in local placental growth factor. PEMF also produced trends toward higher levels of multiple other factors and faster average time to radiographic union compared to unstimulated controls. Level of Evidence: Level I, prospective randomized trial.

This article provides a summary of new research pertaining to orthopaedic foot and ankle surgery, from May 2014 to July 2015. The studies included were published in The Journal of Bone & Joint Surgery and Foot and Ankle International, and some were also presented at Specialty Day at the Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS), March 24-28, 2015, in Las Vegas, Nevada, or at the Annual Meeting of the American Orthopaedic Foot & Ankle Society (AOFAS), July 15-18, 2015, in Long Beach, California. The Ponseti method is an effective treatment for clubfoot, as evidenced by the decreasing rate of surgery for clubfoot1-3. However, even among successfully treated patients, continued muscle imbalance can cause relapse. Depending on the pathomechanics involved, repeat cast application or tibialis anterior tendon transfer may be warranted. Identifying the specific aberrations in walking mechanics is important to help guide treatment. In a recent study, Mindler et al. used three-dimensional gait analysis, including the Oxford foot model, to compare the gait mechanics of children who had undergone Ponseti treatment with cast application with those of age-matched controls4. They demonstrated slight deviations from normal in the treated group. Moreover, the use of the Oxford foot model provided biomechanical information that can help clinicians to decide whether additional cast treatment is indicated prior to tendon transfer. Holt et al. corroborated the long-term efficacy of tendon transfer among patients who underwent the procedure for relapse of clubfoot deformity5. After a mean follow-up of 47 years, they found no impairment of function and no relapses requiring additional procedures. Ankle fractures are frequently encountered. The primary indication for operative fixation of ankle fractures is an unstable mortise. Instability is implied in the setting of bimalleolar fractures, or in lateral malleolar fractures …

Exploration into the molecular aspects of the healing process has led to the development of autologous and recombinant biologic agents. These products, collectively known as orthobiologics, have the potential to optimize favorable outcomes with respect to bone and soft-tissue restoration and to maximize the natural healing response. These orthobiologics include platelet-derived growth factor, bone morphogenetic proteins, and platelet-rich plasma. Although the usefulness of these growth factors is well described in various fields of surgery, few data exist to support or oppose the specific application of growth factors in foot and ankle surgery.

This study quantified the effects of local intramedullary delivery of an organic vanadium salt, which may act as an insulin-mimetic on fracture healing. Using a BB Wistar rat femoral fracture model, local vanadyl acetylacetonate (VAC) was delivered to the fracture site and histomorphometry, mechanical testing, and immunohistochemistry were performed. Callus percent cartilage was 200% higher at day 7 (p < 0.05) and 88% higher at day 10 (p < 0.05) in the animals treated with 1.5 mg/kg of VAC. Callus percent mineralized tissue was 37% higher at day 14 (p < 0.05) and 31% higher at day 21 (p < 0.05) in the animals treated with 1.5 mg/kg of VAC. Maximum torque to failure was 104% and 154% higher at 4 weeks post-fracture (p < 0.05) for the healing femurs from the VAC-treated (1.5 and 3.0 mg/kg) animals. Animals treated with other VAC doses demonstrated increased mechanical parameters at 4 weeks (p < 0.05). Immunohistochemistry detected 62% more proliferating cells at days 7 (p < 0.05) and 94% more at day 10 (p < 0.05) in the animals treated with 1.5 mg/kg VAC. Results showed 100% more vascular endothelial growth factor-C (VEGF-C) positive cells and 80% more blood vessels at day 7 (p < 0.05) within the callus subperiosteal region of VAC-treated animals (1.5 mg/kg) compared to controls. The results suggest that local VAC treatment affects chondrogenesis and angiogenesis within the first 7-10 days post-fracture, which leads to enhanced mineralized tissue formation and accelerated fracture repair as early as 3-4 weeks post-fracture.

Diabetes mellitus is a metabolic disorder associated with several complications, including impaired healing. Bone, as important skeletal structure in the body, is affected by the diabetic condition, particularly during fracture healing processes. In this review, we discuss the normal fracture process, as well as mechanical, histological, and molecular negative changes that take place during diabetic fracture repair. Although diabetes affects cartilages and bones from anabolic aspects, our studies have shed light on the impact of diabetes on the catabolic aspect as well. Several underlying proposed mechanisms involved in impaired diabetic fracture healing were also reviewed. Current potential therapeutic agents, which may improve the healing process, were reviewed based on the current understanding of diabetes’ impact on the various stages of fracture healing.

Impaired soft tissue regeneration and delayed osseous healing are known complications associated with diabetes mellitus with regard to orthopedic surgery, making the management and treatment of diabetic patients undergoing foot and ankle surgery more complex and difficult. At the moment several options are available to address the known issues that complicate the clinical outcomes in these high-risk patients. Using a multifaceted approach, with close attention to intraoperative and perioperative considerations including modification of surgical technique to supplement fixation, local application of orthobiologics, tight glycemic control, administration of supplementary oxygen, and biophysical stimulation via low-intensity pulsed ultrasound and electrical bone stimulation, the impediments associated with diabetic healing can potentially be overcome, to yield improved clinical results for diabetic patients after acute or elective foot and ankle surgery.

Diabetes mellitus is a common systemic disease that has been associated with poor fracture healing outcomes. The mechanism through which diabetes impairs bone regeneration is unknown. One possible mechanism may be related to either decreased or uncoordinated release of local growth factors at the fracture site. Indeed, previous studies have found reduced platelet-derived growth factor (PDGF) levels in the fracture callus of diabetic rats, suggesting that local application of PDGF may overcome the negative effects of diabetes and promote fracture healing. To test this hypothesis, low (22 microg) and high (75 ug) doses of recombinant human PDGF-BB (rhPDGF-BB) were applied directly to femur fracture sites in BB Wistar diabetic rats that were then compared to untreated or vehicle-treated animals. rhPDGF-BB treatment significantly increased early callus cell proliferation compared to that in control specimens. Low dose rhPDGF-BB treatment significantly increased callus peak torque values (p < 0.05) at 8 weeks after fracture as compared to controls. High dose rhPDGF-BB treatment increased callus bone area at 12 weeks postfracture. These data indicate that rhPDGF-BB treatment ameliorates the effects of diabetes on fracture healing by promoting early cellular proliferation that ultimately leads to more bone formation. Local application of rhPDGF-BB may be a new therapeutic approach to treat diabetes-impaired fracture healing.

Advances in understanding age-related changes in articular cartilage, joint homeostasis, the natural healing process after cartilage injury, and improved standards for evaluation of a joint surface made the ultimate goal of cartilage repair a possibility. New strategies for enhancement of articular cartilages' limited healing potential and biologic regeneration include advances in tissue engineering and the use of electromagnetic fields. This article reviews developments in basic science and clinical research made with these emerging technologies concerning treatment of articular cartilage defects and treatment of osteoarthritis of the ankle.

BACKGROUND Because hair restoration surgery (HRS) has changed so significantly, the International Society of Hair Restoration Surgery (ISHRS) presents the recently developed Core Curriculum for Hair Restoration Surgery (CCHRS). Physician competence in HRS demands a sound understanding of all of the alternate pathologic causes of hair loss, as well as their risks and treatments. OBJECTIVE The CCHRS defines the knowledge, didactic information, medical insights, and surgical techniques that are essential to physician competence in the correct diagnoses and treatment of hair loss problems, in a manner consistent with patient safety and sound esthetic results. The ISHRS hopes that all existing surgical and dermatology training programs that teach HRS procedures will find the CCHRS useful in developing their curriculum relative to HRS and that this will facilitate the development of a new standard of training within the profession. METHODS Developed and reviewed by a committee of experienced hair restoration surgeons. RESULTS The CCCHRS clearly defines the diagnosis and treatment of hair loss as a multidimensional specialty requiring knowledge of several medical disciplines, including genetics, endocrinology, dermatology, and surgery. CONCLUSION The ISHRS believes that the CCHRS is an important contribution to physician education in HRS and that a clearly defined core curriculum will facilitate achieving contemporary results and higher patient satisfaction.

Venous thromboembolic disease (VTED) can be fatal, particularly in orthopaedic surgical patients.14,15 Clinicians and researchers continue to struggle to define, from a riskbenefit perspective, which subset of foot and ankle patients would benefit from prophylaxis and which treatment is appropriate for a given patient. Efforts have focused on preventing the most common and most dangerous sequelae of VTED: proximal and distal deep venous thrombosis (DVT), post-thrombotic syndrome, pulmonary hypertension, and particularly the potentially fatal pulmonary embolism (PE).55 This current concepts review examines the pertinent literature that identifies the pathophysiology and treatment issues associated with venous thromboembolic disease in foot and ankle surgery.

Age-related macular degeneration (AMD) is the major cause of blindness for people over 60. In the “wet” form of AMD compounds targeting growth factor signaling pathways such as VEGF have been a major focus for therapeutic interventions. In a previously developed rat model of CNV, we utilized two receptor tyrosine kinase inhibitors (RTKi) to block VEGFR-1, VEGFR-2 and PDGFR signaling following the establishment of CNV. AAV-VEGF 165 was injected into the subretinal space of rats at postnatal days 15-17. Six weeks later, a suspension of RTK inhibitors, AG013764 or AG013711, was injected intraperitoneally (IP, twice daily) or intravitreally (every five days) over a two week period. FITC-dextran whole-mounts of RPE-choroid-sclera were prepared after the animals were sacrificed. CNV area was quantified using Neurolucida to measure the hyperfluorescence on FITC-dextran whole-mounts. Histology and immunohistochemistry were performed as described previously. VEGF expression in control and treated eyes was confirmed by immunohistochemistry and histological sections indicated recovery of retinal morphology and CNV reduction in treated eyes. In the animals IP injected with AG013764 or AG013711 the mean CNV level was reduced by 25 to 33% compared to control, but this effect did not achieve statistical significance. Intravitreal injections of AG013764 or AG013711 reduced the level of CNV by approximately 60% compared to control (p< 0.005 or p< 0.05, respectively). These data show that two RTK inhibitors, AG013764 or AG013711, delivered intravitreally, significantly reduce blood vessel proliferation in this AAV-VEGF 165 model of CNV.

We performed a linear regression analysis on demographic, memory performance, and amygdala activity during memory recall on 23 unmedicated participants remitted from major depressive disorder. Amygdala activity during positive memory recall, and the percent of specific positive memories recalled were the variables that explained the most variance in residual depressive symptoms. This model was not significant in control or currently depressed participants. Longitudinal follow up is necessary to assess whether these variables predict relapse.

Several studies have documented that diabetes impairs bone healing clinically and experimentally. Systemic insulin treatment has been shown to ameliorate impaired diabetic bone healing. However, these studies failed to distinguish between a direct and a systemic effect of insulin upon bone healing. A novel intramedullary insulin delivery system was used in the diabetic BB Wistar femur fracture model to investigate the potential direct effects of insulin on bone healing. Insulin delivery at the fracture site normalized the early (cellular proliferation and chondrogenesis) and late (mineralized tissue, cartilage content and mechanical strength) parameters of diabetic fracture healing without affecting the systemic parameters of blood glucose. These results suggest a critical role for insulin in directly mediating fracture healing and that decreased systemic insulin levels in the diabetic state lead to reduced localized insulin levels at fracture site with concomitant increases in diabetic fracture healing time.

The scalp may be involved in traumatic injury, resulting in significant disfigurement and psychologic morbidity. Scarring alopecia is seen after burn injuries, avulsion injuries, accidents, and treatment of tumors. Historically, hair restoration procedures have included scalp reduction, pedicle flaps, expanders, and hair transplantation. This article describes the special techniques required to restore a patient's appearance when treating these injuries, while emphasizing the versatility of scalp expansion, advancement flaps, and follicular unit hair transplantation.

Several clinical series, analyzing fracture healing in patients with diabetes mellitus (DM). demonstrated significant incidence of delayed union, non-union, and pseudarthrosis. In this study, analysis was performed to evaluate the effects of blood glucose (BG) control on fracture healing in the DM BB Wistar rat, a rat strain that represents a close homology to Type I DM in man. Our study showed decreased cell proliferation at the fracture site as well as decreased mechanical stiffness and bony content in the poorly controlled DM rats. To determine the effect of BG control, DM rats were treated with insulin sufficient to maintain physiologic BG levels throughout the course of the study. Values of cellular proliferation, biomechanical properties and callus bone content in tightly controlled DM animals were not significantly different from values of non-DM control values. This study suggests that insulin treatment with resultant improved BG control will ameliorate the impaired early and late parameters of DM fracture healing.

These clinical practice guidelines summarize the recommendations of the American Association of Clinical Endocrinologists for the diagnostic evaluation of hyperthyroidism and hypothyroidism and for treatment strategies in patients with these disorders. The sensitive thyroid-stimulating hormone (TSH or thyrotropin) assay has become the single best screening test for hyperthyroidism and hypothyroidism, and in most outpatient clinical situations, the serum TSH is the most sensitive test for detecting mild thyroid hormone excess or deficiency. Therapeutic options for patients with Graves' disease include thyroidectomy (rarely used now in the United States), antithyroid drugs (frequently associated with relapses), and radioactive iodine (currently the treatment of choice). In clinical hypothyroidism, the standard treatment is levothyroxine replacement, which must be tailored to the individual patient. Awareness of subclinical thyroid disease, which often remains undiagnosed, is emphasized, as is a system of care that incorporates regular follow-up surveillance by one physician as well as education and involvement of the patient.

To best inform evidence-based patient care, it is often desirable to compare competing therapies. We performed a network meta-analysis to indirectly compare low intensity pulsed ultrasonography (LIPUS) with electrical stimulation (ESTIM) for fracture healing.We searched the reference lists of recent reviews evaluating LIPUS and ESTIM that included studies published up to 2011 from 4 electronic databases. We updated the searches of all electronic databases up to April 2012. Eligible trials were those that included patients with a fresh fracture or an existing delayed union or nonunion who were randomized to LIPUS or ESTIM as well as a control group. Two pairs of reviewers, independently and in duplicate, screened titles and abstracts, reviewed the full text of potentially eligible articles, extracted data and assessed study quality. We used standard and network meta-analytic techniques to synthesize the data.Of the 27 eligible trials, 15 provided data for our analyses. In patients with a fresh fracture, there was a suggested benefit of LIPUS at 6 months (risk ratio [RR] 1.17, 95% confidence interval [CI] 0.97-1.41). In patients with an existing nonunion or delayed union, ESTIM had a suggested benefit over standard care on union rates at 3 months (RR 2.05, 95% CI 0.99-4.24). We found very low-quality evidence suggesting a potential benefit of LIPUS versus ESTIM in improving union rates at 6 months (RR 0.76, 95% CI 0.58-1.01) in fresh fracture populations.To support our findings direct comparative trials with safeguards against bias assessing outcomes important to patients, such as functional recovery, are required.Pour mieux orienter les soins fondés sur des données probantes, il est souvent souhaitable de comparer des traitements entre eux. Nous avons procédé à une méta-analyse réseau pour comparer indirectement l’effet des ultrasons pulsés de faible intensité (UPFI) et de l’électrostimulation (ÉS) sur la guérison des fractures.Nous avons interrogé les listes bibliographiques de revues récentes ayant évalué les UPFI et l’ÉS, en incluant des études publiées jusqu'en 2011 à partir de 4 bases de données électroniques. Nous avons actualisé les interrogations de toutes les bases de données électroniques jusqu’à avril 2012. Les essais admissibles étaient ceux qui incluaient des patients victimes d’une fracture récente ou présentant un retard de soudure ou une non soudure de fracture ayant été assignés aléatoirement aux UPFI ou à l’ÉS ou à un groupe témoin. Deux paires d’examinateurs ont passé en revue indépendamment et en duplicata les titres, les résumés et les textes complets des articles potentiellement admissibles. Ils en ont extrait les données et ont évalué la qualité des études. Nous avons utilisé des techniques de méta-analyse standard et réseau pour synthétiser les données.Parmi les 27 essais admissibles, 15 ont fourni des données pour notre analyse. Chez les patients présentant une fracture récente, les UPFI auraient produit un avantage à 6 mois (risque relatif [RR] 1,17, intervalle de confiance [IC] de 95 % 0,97–1,41). Chez les patients qui présentaient un problème de non soudure ou de retard de soudure osseuse et par rapport aux soins classiques, l’ÉS aurait conféré un avantage sur les taux de soudure osseuse à 3 mois (RR 2,05, IC de 95 % 0,99–4,24), et nous avons noté des preuves de très faible qualité selon lesquelles les UPFI conféreraient un avantage potentiel par rapport à l’ÉS pour ce qui est d’améliorer les taux de soudure osseuse à 6 mois (RR 0,76, IC de 95% 0,58–1,01) chez les populations dont les fractures étaient récentes.Pour confirmer nos conclusions, il faudra procéder à des essais comparatifs directs en veillant à écarter tout biais lors de l’évaluation des paramètres importants liés aux patients, tels que le rétablissement fonctionnel.

Biomedical advances in vision research have been greatly facilitated by the clinical accessibility of the visual system, its ease of experimental manipulation, and its ability to be functionally monitored in real time with noninvasive imaging techniques at the level of single cells and with quantitative end-point measures. A recent example is the development of stem cell-based therapies for degenerative eye diseases including AMD. Two phase I clinical trials using embryonic stem cell-derived RPE are already underway and several others using both pluripotent and multipotent adult stem cells are in earlier stages of development. These clinical trials will use a variety of cell types, including embryonic or induced pluripotent stem cell-derived RPE, bone marrow- or umbilical cord-derived mesenchymal stem cells, fetal neural or retinal progenitor cells, and adult RPE stem cells-derived RPE. Although quite distinct, these approaches, share common principles, concerns and issues across the clinical development pipeline. These considerations were a central part of the discussions at a recent National Eye Institute meeting on the development of cellular therapies for retinal degenerative disease. At this meeting, emphasis was placed on the general value of identifying and sharing information in the so-called "precompetitive space.'' The utility of this behavior was described in terms of how it could allow us to remove road blocks in the clinical development pipeline, and more efficiently and economically move stem cell-based therapies for retinal degenerative diseases toward the clinic. Many of the ocular stem cell approaches we discuss are also being used more broadly, for nonocular conditions and therefore the model we develop here, using the precompetitive space, should benefit the entire scientific community.

Ankle fractures in patients with diabetes mellitus (DM) have long been recognized as a challenge to practicing clinicians in terms of delays in fracture healing, difficulties with wound healing, and the development of Charcot arthropathy. Significant controversy exists as to whether diabetic ankle fractures are best treated noninvasively or by open reduction and internal fixation (ORIF). Despite these well-known management difficulties of ankle fractures in diabetic patients, clinical series regarding the treatment of ankle fractures in patients with DM are few. The existing series are reviewed in this article, followed by a discussion of the basic science behind delayed fracture healing and impaired wound healing in diabetics as well as Charcot arthropathy.

Iliac crest bone grafting and K wire fixation was used to fuse the arthritic intertarsal articulations of sixteen patients with post-traumatic or primary degenerative disease. Using pre-and post-operative AOFAS scores, foot function indices (FFI), and a subjective scoring system, functional and subjective outcome was critically evaluated. The AOFAS score improved an average of 41 points, the FFI decreased from 64 to 24, and 81 percent of patients rated their results as good or excellent. Fusion of the 4th and 5th TMT joints was associated with significantly poorer functional scores, and people with worker's compensation claims had poorer subjective scores. The authors demonstrated comparable results to previously published series using other methods of fixation.

Acute traumatic compartment syndrome of the foot is a sequelae of serious injury to the foot, which, if unrecognized, may result in significant motor and sensory deficits, pain, stiffness, and deformity. It is nearly always associated with fractures, dislocations, and crush injuries to the foot. Vascular injuries and coagulopathic states are also risk factors for the development of an acute foot compartment syndrome. In children, the presentation of an acute foot compartment syndrome may be masked by the pain and edema caused by associated fractures and dislocations. A high index of suspicion is warranted in children presenting with foot injuries that are associated with foot compartment syndrome. Recognition of the signs and symptoms of compartment syndrome in the emergency room are paramount; the diagnosis is best confirmed by multiple compartment pressure readings. The urgency of diagnosis of a compartment syndrome must be underscored, as the complications of a missed foot compartment syndrome includes contractures, claw toe deformity, sensory loss, stiffness, and chronic pain. Prompt orthopaedic consultation is mandatory; urgent compartment fasciotomies are associated with a good clinical outcome.

Interphalangeal (IP) ulcerations of the great toe are frequently encountered in neuropathic diabetic feet. While total contact casting is usually effective as a first line treatment, recalcitrant ulcers continue to present substantial management challenges. The authors retrospectively reviewed the results of Keller arthroplasty employed to accelerate ulcer resolution with total contact casting in fourteen patients with neuropathic ulcers under the great toe interphalangeal (IP) joint that were resistant to casting alone. These data were compared to a group of similar patients whose ulcers were successfully treated by non-operative measures. No operative complications were observed, and all ulcers healed within twenty-four days with no recurrence documented at an average follow-up of 26 weeks. In cases of resistant great toe IP plantar ulcers associated with hallux rigidus that have failed casting trials, this treatment method can be effective.

Interdigital neuroma requires thorough clinical evaluation to ensure an accurate diagnosis. For cases refractory to conservative treatment, a neurectomy and release of the transverse metatarsal ligament is performed through a dorsal approach. Recurrent pain is a common complication, but its incidence may be minimized by diagnostic precision and meticulous surgical technique.

Elevated levels of Na and Cl in airway surface liquid may play a major role in the airway pathology of cystic fibrosis (CF) (J. J. Smith, S. M. Travis, E. P. Greenberg, and M. J. Welsh. Cell85: 229–236, 1996) and could be caused by block of transcellular Cl absorption due to lack of a functional CF transmembrane conductance regulator (CFTR). To test for transcellular absorption of Cl across non-CF epithelium, we studied how fluid absorption was affected by the opening and closing of Cl channels. Forskolin (an activator of CFTR) tripled fluid absorption across primary cultures of bovine tracheal epithelium but had no effect on human cells. However, in both species, fluid absorption was markedly inhibited by 5-nitro-2-(3-phenylpropylamino)benzoate, a blocker of CFTR. Microelectrode studies suggested that the magnitude of the absorptive response to forskolin in bovine cells depended on the size of an inwardly directed electrochemical driving force for Cl movement across the apical membrane. Patch-clamp measurements of bovine cells revealed CFTR in the apical membrane and a cAMP-activated, inwardly rectifying Cl channel in the basolateral membrane. We conclude that a significant fraction of absorbed Cl passes transcellularly in bovine tracheal epithelial cultures, with CFTR as the path of entry in the apical membrane and a novel cAMP-activated Cl channel as the exit route in the basolateral membrane. Our data further indicate that a similar pathway may exist in non-CF human tracheal epithelium.

Background: The sustentacular fragment in displaced intra-articular calcaneal fractures has historically been portrayed as a “constant fragment,” bound to the talus by the interosseous and deltoid ligament complex. Operative treatment typically occurs through a lateral approach, with the remaining calcaneus being reconstructed back to the sustentaculum. We hypothesized that the sustentacular fragment in displaced intra-articular calcaneal fractures does not maintain its relationship to the talus. The purpose of this study was to characterize the frequency, magnitude, and mode of displacement of the sustentacular fragment. Methods: Computed tomographic (CT) scans of eighty-eight patients with 100 displaced intra-articular calcaneal fractures admitted to our level-I trauma center over a five-year period were retrospectively reviewed. Basic patient demographics and mechanisms of injury were recorded. CT scans were graded according to the Sanders classification, and associated injuries were noted. Angulation and translation of the sustentacular fragment as well as gapping and intra-articular fractures of the middle facet were examined. Angulation exceeding 10° and translation of more than 3 mm were considered diagnostic of displacement. Results: Overall, the sustentacular fragment was displaced in forty-two of the 100 fractures. Twenty-five of one hundred calcanei had sustentacular fragment angulation of >10°, twenty-four had sustentacular translation >3 mm, twenty had fracture diastasis of the middle facet, and twenty-one had a displaced intra-articular fracture of the calcaneal middle facet. Fractures involving greater than 50% of the posterior facet (consistent with Sanders Type-B and Type-C fracture lines) demonstrated a significant increase in relative risk of angulation and translation of the sustentacular fragment as well as gapping and intra-articular fractures of the middle facet. Three-part or four-part fractures also showed a significant association with overall displacement of the sustentaculum. Conclusions: This study is the first to our knowledge to quantify in a detailed manner the displacement of the sustentacular fragment as occurring with calcaneal fractures. This displacement disproves the “constant” theory of the sustentacular fragment, and it may alter the quality of the fracture reduction and affect patient outcome. An alternative surgical approach may be indicated for the treatment of certain calcaneal fracture patterns with sustentacular displacement. Level of Evidence: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

We recently discovered that chronic high fructose intake by lactating rats prevented adaptive increases in rates of active intestinal Ca2+ transport and in levels of 1,25-(OH)2D3, the active form of vitamin D. Since sufficient Ca2+ absorption is essential for skeletal growth, our discovery may explain findings that excessive consumption of sweeteners compromises bone integrity in children. We tested the hypothesis that 1,25-(OH)2D3 mediates the inhibitory effect of excessive fructose intake on active Ca2+ transport. First, compared with those fed glucose or starch, growing rats fed fructose for 4 wk had a marked reduction in intestinal Ca2+ transport rate as well as in expression of intestinal and renal Ca2+ transporters that was tightly associated with decreases in circulating levels of 1,25-(OH)2D3, bone length, and total bone ash weight but not with serum parathyroid hormone (PTH). Dietary fructose increased the expression of 24-hydroxylase (CYP24A1) and decreased that of 1α-hydroxylase (CYP27B1), suggesting that fructose might enhance the renal catabolism and impair the synthesis, respectively, of 1,25-(OH)2D3. Serum FGF23, which is secreted by osteocytes and inhibits CYP27B1 expression, was upregulated, suggesting a potential role of bone in mediating the fructose effects on 1,25-(OH)2D3 synthesis. Second, 1,25-(OH)2D3 treatment rescued the fructose effect and normalized intestinal and renal Ca2+ transporter expression. The mechanism underlying the deleterious effect of excessive fructose intake on intestinal and renal Ca2+ transporters is a reduction in serum levels of 1,25-(OH)2D3. This finding is significant because of the large amounts of fructose now consumed by Americans increasingly vulnerable to Ca2+ and vitamin D deficiency.

In order to clinically assess the efficacy of tissue extension applied to scalp reduction, a prospective study was performed on 24 patients who underwent tissue extension between scalp reductions in the treatment of male pattern baldness. The accelerated rate of reduction provided by tissue extension was found to be most efficient when the extension was performed for 31 days or less after scalp reduction. The complication rate was low, while patient acceptance was high. Tissue extension is a valuable technique in scalp reduction for male pattern baldness with potential clinical applications to other situations where the harvesting of surrounding local tissue is indicated.

Between 1993 and 1995, 93 neuropathic diabetes mellitus patients with foot ulcers underwent a total contact cast (TCC) protocol. A randomly chosen group of 21 patients (Group I) demonstrated ulcer healing in a mean time of 43.5 days. Despite 9 weeks of TCC, 15 patients (Group II) with forefoot ulcers failed to heal. Physical examination of Group I revealed plantarflexion/dorsiflexion range of motion of the ankle of 33.871.9° compared to 32.3°/-10.5° of Group II, demonstrating an ankle equinus deformity and limited joint motion. Group II patients underwent a correction of the equinus deformity with percutaneous tendo-Achilles lengthening (TAL), followed by a TCC. All but one ulcer (93.3%) healed within 39.4 days. Four (19.0%) ulcers recurred (at the same site) in Group I, compared to none in Group II at the latest follow up of 17.3 months. Surgical correction with percutaneous TAL and TCC results in healing of forefoot ulcer and helps prevent ulcer recurrence.

In cystic fibrosis (CF), absence or dysfunction of a phosphorylation-regulated chloride channel [CF transmembrane conductance regulator (CFTR)] leads to the loss or reduction of chloride secretion into the airways. Active sodium absorption is also increased in CF, and both of these ion transport changes could alter fluid transport across the airways. Under baseline conditions, cultured human airway epithelia from normal individuals absorbed fluid, and this absorption was increased in epithelia from patients with CF. In normal and CF epithelial cultures fluid absorption was inhibited by amiloride. Adenosine 3',5'-monophosphate stimulated fluid secretion in normal epithelial cultures but not in cultures from individuals with CF. In contrast, fluid secretion induced by nucleotide triphosphates (uridine triphosphate or adenosine triphosphate) was unaltered in cultures of epithelia from patients with CF, suggesting an approach to the treatment of CF.

We have developed a robust and well-defined primary cell culture model of human fetal retinal pigment epithelium (hfRPE). This model was used to analyze how metabolic waste products produced in the retina can be disposed of by CO2/HCO3 and lactate transporters in the apical and basolateral cell membranes. It was also used to analyze RPE antioxidant mechanisms protective against disease processes, such as age-related macular degeneration or uveitis, and to define the impact of cytokines and, in particular, interferon gamma, on RPE function and physiology.