Technological Advances in Renal Replacement Therapy

Market Consolidation and Innovation in US Dialysis

While patients with end-stage kidney disease have benefited from innovations in clinical therapeutics and care delivery, these changes have been primarily incremental and have not fundamentally transformed care delivery. Dialysis markets are highly concentrated, which may impede innovation. Unique features of the dialysis industry that have contributed to consolidation can help to explain links between consolidation and innovation. We discuss these unique features and then provide a framework for considering the effects of consolidation on innovation in dialysis that focuses on the following economic considerations: (1) industry characteristics, composition, and stage of consolidation, (2) innovation characteristics and relative profitability, (3) the role of government regulation, and (4) innovation from smaller providers and new entrants. We present examples of how these considerations have influenced the adoption of alternative dialysis technologies such as peritoneal dialysis and erythropoietin-stimulating agents, and we discuss how consolidated markets can both help and hinder recent policy initiatives to transform dialysis care delivery. Only by considering these important drivers of consolidation, future efforts can be successful in transforming end-stage kidney disease care.

End-Stage Renal Disease Models in the Americas: Optimizing Resources to Achieve Better Health Outcomes

End-stage renal disease, the last and most severe stage of chronic kidney disease, represents a major and rising concern for countries in Latin America, driven in large part by aging populations and the near-epidemic rises in diabetes, obesity, and hypertension. This places a great clinical, economic, and social burden on the region's health systems. During the ISPOR 6th Latin America Conference held in Sao Paulo, Brazil, in September 2017, an educational forum debated on value-based decision making in the treatment of end-stage renal disease in Latin America. We summarize the current state and how to build strategies and implement actions to move to a more patient-centered, outcomes-based approach for renal care in the region, taken from the discussions in the conference and also from a literature review. Models of renal care used in Ontario (Canada), Colombia, and a Chilean hospital stress the importance of empowering and supporting patients and their families, allowing for a better coordination between primary care providers and specialists, providing financial incentives to health units, and establishing an entity that holds insurers and providers accountable for health outcomes and costs of treatment. The study uses the framework of value-based health care for the evaluation of different dialysis options-peritoneal dialysis, hemodialysis, home dialysis, and so forth-and calls for the countries to adopt an integrated care model. We emphasize that countries in Latin America need to recognize the chronic kidney disease challenge and develop health systems and efficient renal care models to be able to reduce the burden of the disease.

The Evolving Ethics of Dialysis in the United States: A Principlist Bioethics Approach

Throughout the history of dialysis, four bioethical principles - beneficence, nonmaleficence, autonomy and justice - have been weighted differently based upon changing forces of technologic innovation, resource limitation, and societal values. In the 1960s, a committee of lay people in Seattle attempted to fairly distribute a limited number of maintenance hemodialysis stations guided by considerations of justice. As technology advanced and dialysis was funded under an amendment to the Social Security Act in 1972, focus shifted to providing dialysis for all in need while balancing the burdens of treatment and quality of life, supported by the concepts of beneficence and nonmaleficence. At the end of the last century, the importance of patient preferences and personal values became paramount in medical decisions, reflecting a focus on the principle of autonomy. More recently, greater recognition that health care financial resources are limited makes fair allocation more pressing, again highlighting the importance of distributive justice. The varying application and prioritization of these four principles to both policy and clinical decisions in the United States over the last 50 years makes the history of hemodialysis an instructive platform for understanding principlist bioethics. As medical technology evolves in a landscape of changing personal and societal values, a comprehensive understanding of an ethical framework for evaluating appropriate use of medical interventions enables the clinician to systematically negotiate and optimize difficult ethical situations.

Kidney care in Haiti--the role of partnerships

Establishing a programme for the prevention and treatment of acute kidney injury, chronic kidney disease and end-stage renal disease in a developing country involves unique challenges. We became involved in a collaborative effort to improve nephrology care in Haiti after participating in the emergency response to the 2010 earthquake. The focus of this ongoing project is overcoming barriers to implementation with the goal of improving training and resources for Haitian health-care workers and developing programmes for renal disease prevention and treatment in a setting of limited resources. Here, we offer practical advice for nephrologists who would like to help to advance medical care in developing countries. Rather than technical issues related to the prevention and treatment of renal disease, we focus on collaboration, education and the building of partnerships.

Impact of hemodialysis on exhaled volatile organic compounds in end-stage renal disease: a pilot study

Aim: To demonstrate the feasibility of nanomaterial-based sensors for identifying patterns of exhaled volatile organic compound of end-stage renal disease (ESRD) and study the impact of hemodialysis (HD) on these patterns. Patients & methods: Exhaled breath samples were collected from a group of 37 volunteers (26 ESRD HD patients; 11 healthy controls); a third of the samples were randomly blinded for determining the sensitivity/specificity of the method. Discriminant function analysis was used to build a model for discriminating ESRD patients and healthy controls (classification accuracy for blind samples: 80%), based on the signals of the nanomaterial sensors. Results & conclusion: The breath pattern of the ESRD patients approached the healthy pattern during the HD treatment, without reaching it completely. Gas chromatography/mass spectrometry identified four volatile organic compounds as potential ESRD biomarkers. Although this pilot study has yielded encouraging results, additional large-scale clinical studies are required to develop a fast, noninvasive breath test for monitoring HD adequacy in real time.

Original submitted 23 September 2012; Revised submitted 26 February 2013

Study of uremic toxin fluxes across nanofabricated hemodialysis membranes using irreversible thermodynamics

INTRODUCTION

The flux of uremic toxin middle molecules through currently used hemodialysis membranes is suboptimal, mainly because of the membranes' pore architecture.

AIM

Identifying the modifiable sieving parameters that can be improved by nanotechnology to enhance fluxes of uremic toxins across the walls of dialyzers' capillaries.

METHODS

We determined the maximal dimensions of endothelin, cystatin C, and interleukin - 6 using the macromolecular modeling software, COOT. We also applied the expanded Nernst-Plank equation to calculate the changes in the overall flux as a function of increased electro-migration and pH of the respective molecules.

RESULTS

In a high flux hemodialyzer, the effective diffusivities of endothelin, cystatin C, and interleukin - 6 are 15.00 x 10(-10) cm(2)/s, 7.7 x 10(-10) cm(2)/s, and 5.4 x 10(-10) cm(2)/s, respectively, through the capillaries' walls. In a nanofabricated membrane, the effective diffusivities of endothelin, cystatin C, and interleukin - 6 are 13.87 x 10(-7) cm(2)/s, 5.73 x 10(-7) cm(2)/s, and 3.45 x 10(-7) cm(2)/s, respectively, through a nanofabricated membrane. Theoretical modeling showed that a 96% reduction in the membrane's thickness and the application of an electric potential of 10 mV across the membrane could enhance the flux of endothelin, cystatin C, and interleukin - 6 by a factor of 25. A ΔpH of 0.07 altered the fluxes minimally.

CONCLUSIONS

Nanofabricated hemodialysis membranes with a reduced thickness and an applied electric potential can enhance the effective diffusivity and electro-migration flux of the respective uremic toxins by 3 orders of magnitude as compared to those passing through the high flux hemodialyzer.

Morphological Characterization of the Polyflux 210H Hemodialysis Filter Pores

Background. Morphological characterization of hemodialysis membranes is necessary to improve pore design. Aim. To delineate membrane pore structure of a high flux filter, Polyflux 210H. Methods. We used a Joel JSM-6010LV scanning electron microscope (SEM) and a SU6600 Hitachi field emission scanning electron microscope (FESEM) to characterize the pore and fiber morphology. The maximal diameters of selected uremic toxins were calculated using the macromolecular modeling Crystallographic Object-Oriented Toolkit (COOT) software. Results. The mean pore densities on the outermost and innermost surfaces of the membrane were 36.81% and 5.45%, respectively. The membrane exhibited a tortuous structure with poor connection between the inner and outer pores. The aperture's width in the inner surface ranged between 34 and 45 nm, which is 8.76-11.60 times larger than the estimated maximum diameter of β2-microglobulin (3.88 nm). Conclusion. The results suggest that the diameter size of inner pore apertures is not a limiting factor to middle molecules clearance, the extremely diminished density is. Increasing inner pore density and improving channel structure are strategies to improve clearance of middle molecules.

Tissue engineering and regenerative medicine: history, progress, and challenges

The past three decades have seen the emergence of an endeavor called tissue engineering and regenerative medicine in which scientists, engineers, and physicians apply tools from a variety of fields to construct biological substitutes that can mimic tissues for diagnostic and research purposes and can replace (or help regenerate) diseased and injured tissues. A significant portion of this effort has been translated to actual therapies, especially in the areas of skin replacement and, to a lesser extent, cartilage repair. A good amount of thoughtful work has also yielded prototypes of other tissue substitutes such as nerve conduits, blood vessels, liver, and even heart. Forward movement to clinical product, however, has been slow. Another offshoot of these efforts has been the incorporation of some new exciting technologies (e.g., microfabrication, 3D printing) that may enable future breakthroughs. In this review we highlight the modest beginnings of the field and then describe three application examples that are in various stages of development, ranging from relatively mature (skin) to ongoing proof-of-concept (cartilage) to early stage (liver). We then discuss some of the major issues that limit the development of complex tissues, some of which are fundamentals-based, whereas others stem from the needs of the end users.

Regenerative medicine of the kidney

End stage renal disease is a major health problem in this country and worldwide. Although dialysis and kidney transplantation are currently used to treat this condition, kidney regeneration resulting in complete healing would be a desirable alternative. In this review we focus our attention on current therapeutic approaches used clinically to delay the onset of kidney failure. In addition we describe novel approaches, like Tissue Engineering, Stem cell Applications, Gene Therapy, and Renal Replacement Therapy that may one day be possible alternative therapies for patients with the hope of delaying kidney failure or even stopping the progression of renal disease.

An improved kidney dissociation and reaggregation culture system results in nephrons arranged organotypically around a single collecting duct system

Methods for constructing engineered "tissues" from simple suspensions of cells are valuable for investigations into basic developmental biology and for tissue engineering. We recently published a method for producing embryonic renal tissues from suspensions of embryonic mouse renal cells. This method reproduced the anatomies and differentiation states of nephrons and stroma very well; it had the limitation, however, that what would, in normal development, be a single, highly branched collecting duct tree leading to a ureter developed, in the engineered system, as a multitude of very small collecting duct trees. These were isolated from each other and therefore would not be effective for draining urine to a common exit, were the tissue to be supplied with blood and physiologically active. Here, we report an improvement on the original method; it results in the formation of nephrons arranged around one single collecting duct tree as would happen in a normal kidney.