Pleiotropic effects of double filtration plasmapheresis

Double filtration plasmapheresis (DFPP) is a semi-selective blood purification modality derived from the plasma exchange modality. DFPP can be applied to a variety of refractory disorders including metabolic disorders, organ transplants, rheumatic disorders, neurological disorders, and dermatologic disorders. Familial hypercholesterolemia and lipoprotein (a) hyperlipoproteinemia are major chronic metabolic disorders. Lipoprotein apheresis (LA) is applied for those patients to remove low-density lipoprotein cholesterol (LDL-C) and lipoprotein (a) (Lp(a)). DFPP is used as one of the modalities in LA. In addition to removing LDL-C and Lp(a), DFPP has pleiotropic effects such as removal of lipid metabolism-related substances, C-reactive protein lowering effect, removal of adhesion molecules, removal of inflammatory cytokines, and anti-oxidative effect. This article summarizes the pleiotropic effects of DFPP based on recent clinical articles.

Heparin-Mediated Extracorporeal Low-Density Lipoprotein Precipitation Apheresis for Treating Peripheral Arterial Disease in Patients with Chronic Kidney Disease

Patients with chronic kidney disease (CKD), particularly those with end-stage renal disease (ESRD), have a high prevalence of cardiovascular disease and peripheral arterial disease (PAD). Medical treatment is mainly based on risk factor management, and the surgical approach remains the gold standard treatment in specific conditions. Heparin-mediated extracorporeal low-density lipoprotein precipitation (H.E.L.P.) apheresis is effective in reducing circulating lipoprotein, fibrinogen, inflammatory mediators and procoagulant factors, thereby reducing cardiovascular risk in patients with familial hypercholesterolemia and hypertriglyceridemia. These activities may be effective in reducing symptoms and ischemic vascular lesions even in patients with severe PAD. We reported the application of a treatment protocol with H.E.L.P. apheresis in an ESRD patient with severe PAD without clinical improvement after severe revascularization who was not suitable for further surgical approaches, despite normal LDL cholesterol and lipoprotein (a). The H.E.L.P. protocol was characterized by an intensive first phase with weekly treatments followed by a single session every 10-15 days for 6 months of treatment. The overall clinical condition, foot lesions and walking distance improved significantly after the first 2 months of treatment, and foot amputation was avoided. Here, we review the main pathogenetic mechanisms through which LDL apheresis improves microcirculation and clinical outcomes. Its wider application may represent an optimal therapeutic option for patients unresponsive to standard treatment.

Current status of low-density lipoprotein apheresis treatment for patients with peripheral artery disease and chronic kidney disease in Japanese clinical database

INTRODUCTION

Patients with peripheral arterial disease (PAD) have a poorer prognosis than those without PAD. PAD complications worsen the prognosis of patients with chronic kidney disease (CKD), especially those on maintenance dialysis. Although low-density lipoprotein apheresis (LDL-A) is expected to be effective in treating severe PAD, there are no large-scale reports on the prognosis of patients undergoing LDL-A.

METHODS

We obtained a clinical database from April 2008 to August 2021 and selected 924 238 patients with CKD. We selected patients with disease codes of lower limb arteriosclerosis obliterans, arteriosclerosis obliterans, and critical limb ischemia or foot ulcer. Patients who were prescribed antithrombotic medications were included. Patients who used steroids were excluded. Among these patients, those undergoing blood purification considered LDL-A were selected, and their current status was investigated.

RESULTS

We included 147 patients (113 males and 34 females). The mean patient age was 70 ± 10 years. Diabetes mellitus was present in 86%, ischemic heart disease in 34%, and stroke in 48%. Maintenance dialysis patients accounted for 86% of the patients. Statins were administered to 40% of the patients, and bypass surgery was performed in 2.7%. The median observation period was 812 days, and the mortality rate was 41%.

CONCLUSION

LDL-A was performed in a small population of patients with CKD with the most severe form of PAD. The prognosis for these patients is extremely poor. Therefore, strategies to improve prognosis are important.

Short term-efficacy and tolerability of Rheocarna, a novel direct hemoperfusion adsorptive column, for chronic limb-threatening ischemia in dialysis patients: A single-center case series

INTRODUCTION

With population aging and lifestyle changes, the number of patients with chronic limb-threatening ischemia (CLTI) is increasing, and refractory or recurrent lesions are more common, especially in chronic dialysis patients. In March 2021, a new type of adsorptive cellulose bead column immobilized with dextran sulfate and L-tryptophan for direct hemoperfusion (DHP) was approved by Japan's medical insurance system as a treatment for CLTI.

METHODS

We retrospectively analyzed 17 cases of CLTI in dialysis patients treated with DHP using the novel column (Rheocarna) (DHP-R) at our hospital from May 2021 to October 2022. The short-term of efficacy of DHP-R was judged qualitatively by the foot care team every 2 weeks based on the assessment of skin color, warmth, ulcer epithelialization or shrinkage of the ulcer area, and foot pain. The final judgment of efficacy was made after the final DHP-R session.

RESULTS

The median age of patients was 66 years, the median dialysis duration was 10 years, 15 cases (88%) were male, and 15 cases (88%) had diabetes. The median total number of sessions was eight. In comparing the groups in which DHP-R was effective and ineffective, there was no significant difference in any factors including patient background data (i.e., age, diabetes, low-density lipoprotein cholesterol, hemoglobin, dialysis duration, etc.), type of anticoagulants, and presence of episodes of blood pressure drop or circuit clotting during session. Three cases with symptomatic hypotension during the session and two cases with circuit clotting that did not improve with increased heparin dose all resolved immediately after changing the anticoagulant from heparin to nafamostat mesylate (NM).

CONCLUSION

Identification of patients' characteristics in which DHP-R is favorable and some reliable index that allow a rapid decision to continue DHP-R are needed. In addition, validating whether the use of NM as anticoagulant affects the efficacy of DHP-R for CTLI treatment remains a challenge to resolve.

The Characteristics of Dialysis Membranes: Benefits of the AN69 Membrane in Hemodialysis Patients

Patients undergoing hemodialysis (HD) experience serious cardiovascular complications, through malnutrition, inflammation, and atherosclerosis. Amputation for peripheral arterial disease (PAD) is more prevalent in patients undergoing HD than in the general population. In addition, revascularization procedures in dialysis patients are often associated with subsequent amputation and high mortality rates. To improve the prognosis of dialysis patients, malnutrition and inflammation must be properly treated, which necessitates a better understanding of the characteristics of dialysis membranes. Herein, the characteristics of several dialysis membranes were studied, with a special reference to the AN69 membrane, noting several similarities to low-density lipoprotein (LDL)-apheresis, which is also applicable for the treatment of PAD. Both systems (LDL-apheresis and AN69) have anti-inflammatory and anti-thrombogenic effects because they use a negatively charged surface for extracorporeal adsorptive filtration from the blood/plasma, and contact phase activation. The concomitant use of both these therapeutic systems may have additive therapeutic benefits in HD patients. Here, we reviewed the characteristics of dialysis membranes and benefits of the AN69 membrane in dialysis patients.

A Case of Refractory Heel Ulcer Complicated by Moderate Osteomyelitis and Cellulitis Successfully Treated with Rheocarna

Revascularization surgery was first considered for the treatment of ulcers in patients with critical limb ischemia (CLI). However, it may not be indicated for patients with severe infections or peripheral vascular occlusions. Although blood purification therapy is adjuvant therapy for such patients, it is not yet widely used due to insurance coverage. We report a case of a refractory heel ulcer with moderate osteomyelitis and cellulitis that was not amenable to revascularization. Treatment with the adsorptive blood purifier rheocarna® (Kaneka Corporation; Osaka, Japan) resulted in complete epithelialization of the ulcer and control of inflammation. Although this case required careful follow-up, we believe rheocarna might be a promising treatment option for patients with CLI who do not respond to revascularization. Rheocarna could improve peripheral blood flow and control inflammation by improving antibiotic drug delivery.

Low-density-lipoprotein apheresis-mediated endothelial activation therapy to severe-peripheral artery disease study: Rationale and study design

A novel approach is required for standard therapy-resistant peripheral arterial disease (PAD). This is a single-center, single-arm, interventional study (LDL Apheresis-Mediated Endothelial Activation Therapy to Severe-Peripheral Artery Disease study), which aims to evaluate the efficacy and safety of lipoprotein apheresis (LA) with a dextran sulfate cellulose column in PAD with controlled serum cholesterol levels. The study participants have standard therapy-resistant PAD with controlled serum cholesterol levels. A total of 35 patients undergo 10 sessions of LA therapy. The ankle-brachial index and vascular quality of life questionnaire are assessed before and after the treatment period as primary outcomes. Registration of patients began in November 2015 and is planned to be concluded in October 2020.

Homozygous familial hypercholesterolemia with stenosis of the left anterior descending coronary artery successfully treated with weekly low-density lipoprotein apheresis for 16 years without percutaneous coronary intervention

We successfully treated a patient with homozygous familial hypercholesterolemia (HoFH) with stable coronary arterial disease using optimal medical therapy and low-density lipoprotein (LDL) apheresis for 16 years without percutaneous coronary intervention or bypass surgery. Intensive LDL lowering using apheresis and medication protected the patient from coronary atherosclerotic progression even in HoFH.

Familial Hypercholesterolemia and Lipoprotein Apheresis

Lipoprotein apheresis has been developed as the treatment for refractory familial hypercholesterolemia (FH) to remove low-density lipoprotein (LDL), which is the main pathogenic factor. Currently, three procedures are available in Japan, including the plasma exchange, double-membrane filtration, and selective LDL adsorption. Selective LDL adsorption, which was developed in Japan, has been one of the most common treatment methods in the world. Lipoprotein apheresis enabled the prevention of atherosclerosis progression even in homozygous FH (HoFH) patients. However, in our observational study, HoFH patients who started lipoprotein apheresis in adulthood had a poorer prognosis than those who started in childhood. Therefore, HoFH patients need to start lipoprotein apheresis as early as possible. Although the indication for lipoprotein apheresis in heterozygous FH (HeFH) patients has been decreasing with the advent of strong statins, our observational study showed that HeFH patients who discontinued lipoprotein apheresis had a poorer prognosis than patients who continued apheresis therapy. These results suggest that it is beneficial for very-high-risk HeFH patients to be treated by lipoprotein apheresis even if their LDL cholesterol is controlled well by lipid-lowering agents. Since launching a new class of lipid-lowering agents, proprotein convertase subtilisin/kexin type 9 (PCSK9) antibody and microsome triglyceride transfer protein inhibitors, the indication for lipoprotein apheresis in FH has been changing. However, despite the development of these drugs, lipoprotein apheresis is still an option with a high therapeutic effect for FH patients with severe atherosclerotic cardiovascular disease.

Plasma nitric oxide level is correlated with microvascular functions in the peripheral arterial disease

At present there is no widely accepted biomarker for monitoring of vascular functions. The purpose of this prospective study was to investigate the association of some blood biomarkers with vascular reactivity in patients with peripheral arterial diseases (PAD). A prospective evaluation was made of 3 groups comprising a control group of healthy individuals, and patients with PAD caused by either atherosclerosis or Buerger's disease. Microvascular perfusion was examined using laser Doppler imaging of cutaneous erythrocyte flux after iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP). The correlation of microvascular reactivity with endothelium-related biomarkers was assessed. ACh-induced and SNP-induced vasodilations were significantly diminished in the PAD groups. The plasma nitric oxide (NO) levels of PAD patients were significantly higher than those of the control group, but asymmetric dimethylarginine, total antioxidant capacity and hydrogen sulphide levels were similar. Plasma NO level was negatively correlated with ACh and SNP-stimulated microvascular flow increase, whereas a positive correlation was detected with blood glucose and glycated hemoglobin (HbA1c) levels in all groups. These results indicate that a high plasma level of NO in PAD patients is associated with diminished endothelium-dependent and independent flow increase in the microvascular bed. An excessive amount of NO-induced nitrosative stress in an inflammatory condition that might be a reason for vascular dysfunction should be taken into consideration in the diagnostic and therapeutic approaches to PAD.

Oxidative DNA Damage Mediated by Intranuclear MMP Activity Is Associated with Neuronal Apoptosis in Ischemic Stroke

Evidence of the pathological roles of matrix metalloproteinases (MMPs) in various neurological disorders has made them attractive therapeutic targets. MMPs disrupt the blood-brain barrier and cause neuronal death and neuroinflammation in acute cerebral ischemia and are critical for angiogenesis during recovery. However, some challenges have to be overcome before MMPs can be further validated as drug targets in stroke injury. Identifying in vivo substrates of MMPs should greatly improve our understanding of the mechanisms of ischemic injury and is critical for providing more precise drug targets. Recent works have uncovered nontraditional roles for MMPs in the cytosol and nucleus. These have shed light on intracellular targets and biological actions of MMPs, adding additional layers of complexity for therapeutic MMP inhibition. In this review, we discussed the recent advances made in understanding nuclear location of MMPs, their regulation of intranuclear sorting, and their intranuclear proteolytic activity and substrates. In particular, we highlighted the roles of intranuclear MMPs in oxidative DNA damage, neuronal apoptosis, and neuroinflammation at an early stage of stroke insult. These novel data point to new putative MMP-mediated intranuclear actions in stroke-induced pathological processes and may lead to novel approaches to treatment of stroke and other neurological diseases.