Non-adherence to cardiometabolic medication as assessed by LC-MS/MS in urine and its association with kidney and cardiovascular outcomes in type 2 diabetes mellitus

AIMS/HYPOTHESIS

Non-adherence to medication is a frequent barrier in the treatment of patients with type 2 diabetes mellitus, potentially limiting the effectiveness of evidence-based treatments. Previous studies have mostly relied on indirect adherence measures to analyse outcomes based on adherence. The aim of this study was to use LC-MS/MS in urine-a non-invasive, direct and objective measure-to assess non-adherence to cardiometabolic drugs and analyse its association with kidney and cardiovascular outcomes.

METHODS

This cohort study includes 1125 participants from the PROVALID study, which follows patients with type 2 diabetes mellitus at the primary care level. Baseline urine samples were tested for 79 cardiometabolic drugs and metabolites thereof via LC-MS/MS. An individual was classified as totally adherent if markers for all drugs were detected, partially non-adherent when at least one marker for one drug was detected, and totally non-adherent if no markers for any drugs were detected. Non-adherence was then analysed in the context of cardiovascular (composite of myocardial infarction, stroke and cardiovascular death) and kidney (composite of sustained 40% decline in eGFR, sustained progression of albuminuria, kidney replacement therapy and death from kidney failure) outcomes.

RESULTS

Of the participants, 56.3% were totally adherent, 42.0% were partially non-adherent, and 1.7% were totally non-adherent to screened cardiometabolic drugs. Adherence was highest to antiplatelet and glucose-lowering agents and lowest to lipid-lowering agents. Over a median (IQR) follow-up time of 5.10 (4.12-6.12) years, worse cardiovascular outcomes were observed with non-adherence to antiplatelet drugs (HR 10.13 [95% CI 3.06, 33.56]) and worse kidney outcomes were observed with non-adherence to antihypertensive drugs (HR 1.98 [95% CI 1.37, 2.86]).

CONCLUSIONS/INTERPRETATION

This analysis shows that non-adherence to cardiometabolic drug regimens is common in type 2 diabetes mellitus and negatively affects kidney and cardiovascular outcomes.

International Variability of Renal and Cardiovascular Outcomes and Mortality in Patients with Type 2 Diabetes Mellitus in Europe

INTRODUCTION

Type 2 diabetes and its complications represent a huge burden to public health. With this prospective, observational cohort study, we aimed to estimate and to compare the incidence rate (IR) of renal and cardiovascular outcomes and all-cause mortality in patients with type 2 diabetes in different European countries.

METHODS

The renal endpoint was a composite of a sustained decline in estimated GFR of at least 40%, a sustained increase in albuminuria of at least 30% including a transition in albuminuria class, progression to kidney failure with replacement therapy, or death from renal causes. The cardiovascular endpoint was a composite of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke.

RESULTS

3,131 participants from four European countries (Austria, Hungary, The Netherlands, and Scotland) with a median follow-up time of 4.4 years were included. IRs were adjusted for several risk factors including sex, age, estimated GFR, albuminuria, HbA1c, blood pressure, and duration of type 2 diabetes. Across countries, the adjusted IR for the renal endpoint was significantly higher in Hungary and Austria, and the adjusted IR for the cardiovascular endpoint was significantly higher in Scotland and Austria. All-cause mortality was significantly higher in Scotland compared to all other countries.

CONCLUSION

Our findings show how the longitudinal outcome of patients with type 2 diabetes varies significantly across European countries even after accounting for the distribution of underlying risk factors.

Clonal hematopoiesis of indeterminate potential and diabetic kidney disease: a nested case-control study

Introduction

The disease trajectory of diabetic kidney disease (DKD) shows a high interindividual variability not sufficiently explained by conventional risk factors. Clonal hematopoiesis of indeterminate potential (CHIP) is a proposed novel cardiovascular risk factor. Increased kidney fibrosis and glomerulosclerosis were described in mouse models of CHIP. Here, we aim to analyze whether CHIP affects the incidence or progression of DKD.

Methods

A total of 1419 eligible participants of the PROVALID Study were the basis for a nested case-control (NCC) design. A total of 64 participants who reached a prespecified composite endpoint within the observation period (initiation of kidney replacement therapy, death from kidney failure, sustained 40% decline in estimated glomerular filtration rate or sustained progression to macroalbuminuria) were identified and matched to 4 controls resulting in an NCC sample of 294 individuals. CHIP was assessed via targeted amplicon sequencing of 46 genes in peripheral blood. Furthermore, inflammatory cytokines were analyzed in plasma via a multiplex assay.

Results

The estimated prevalence of CHIP was 28.91% (95% CI 22.91%–34.91%). In contrast to other known risk factors (albuminuria, hemoglobin A1c, heart failure, and smoking) and elevated microinflammation, CHIP was not associated with incident or progressive DKD (hazard ratio [HR] 1.06 [95% CI 0.57–1.96]).

Conclusions

In this NCC study, common risk factors as well as elevated microinflammation but not CHIP were associated with kidney function decline in type 2 diabetes mellitus.

A porcine model of hemodialyzer reactions: roles of complement activation and rinsing back of extracorporeal blood

Hemodialysis reactions (HDRs) resemble complement-activation-related pseudoallergy (CARPA) to certain i.v. drugs, for which pigs provide a sensitive model. On this basis, to better understand the mechanism of human HDRs, we subjected pigs to hemodialysis using polysulfone (FX CorDiax 40, Fresenius) or cellulose triacetate (SureFlux-15UX, Nipro) dialyzers, or Dialysis exchange-set without membranes, as control. Experimental endpoints included typical biomarkers of porcine CARPA; pulmonary arterial pressure (PAP), blood cell counts, plasma sC5b-9 and thromboxane-B2 levels. Hemodialysis (60 min) was followed by reinfusion of extracorporeal blood into the circulation, and finally, an intravenous bolus injection of the complement activator zymosan. The data indicated low-extent steady rise of sC5b-9 along with transient leukopenia, secondary leukocytosis and thrombocytopenia in the two dialyzer groups, consistent with moderate complement activation. Surprisingly, small changes in baseline PAP and plasma thromboxane-B2 levels during hemodialysis switched into 30%-70% sharp rises in all three groups resulting in synchronous spikes within minutes after blood reinfusion. These observations suggest limited complement activation by dialyzer membranes, on which a membrane-independent second immune stimulus was superimposed, and caused pathophysiological changes also characteristic of HDRs. Thus, the porcine CARPA model raises the hypothesis that a second "hit" on anaphylatoxin-sensitized immune cells may be a key contributor to HDRs.

Impact of the first wave of COVID-19 pandemic on the Hungarian university students' social and health behaviour

BACKGROUND

The COVID-19 pandemic brought quick, severe and unexpected changes to our everyday life and also changed the traditional education pattern of Semmelweis University in the middle of academic year 2019-2020. We explored adaptive changes in Hungarian students' behaviour and their time-budget in order to determine whether quarantine and/or fear of infection were responsible for these changes.

METHODS

A self-administered online questionnaire was distributed to all students in the Hungarian language program (N = 7436) of Semmelweis University. Information was collected on basic demographic data, knowledge and attitude about COVID-19, methods of prevention as well as the students' behaviour before, during and after the first wave of the pandemic. Statistical analyses were processed using the IBM-SPSS 25.0 software package.

RESULTS

The overall response rate was 11% (N = 816). Only complete responses were processed (55%, N = 447). Among these responders, 83% did not fear the pandemic. Those who greatly feared COVID-19 infection strictly kept all regulations. The number of non-smokers increased by the end of the first wave. The nutrition of 100 students (21%) became healthier and the lockdown reduced the level of physical activity.

CONCLUSION

Social and health-related behaviour of medical students changed basically during the first wave of the pandemic and some changes remained after it in tobacco smoking, nutrition and sleeping habits. Time-budget of students changed significantly during the pandemic and did not return to the baseline values. Results of this study justify future multiple systematic research to analyse and better understand the short- and long-term effects of the current crisis.

U100: An Innovative USERN Platform for Education and Research Without Borders

The article's abstract is no available.

Can chlorine dioxide prevent the spreading of coronavirus or other viral infections? Medical hypotheses

Motivation

Viruses have caused many epidemics throughout human history. The novel coronavirus [10] is just the latest example. A new viral outbreak can be unpredictable, and development of specific defense tools and countermeasures against the new virus remains time-consuming even in today's era of modern medical science and technology. In the lack of effective and specific medication or vaccination, it would be desirable to have a nonspecific protocol or substance to render the virus inactive, a substance/protocol, which could be applied whenever a new viral outbreak occurs. This is especially important in cases when the emerging new virus is as infectious as SARS-CoV-2 [4].

Aims and structure of the present communication

In this editorial, we propose to consider the possibility of developing and implementing antiviral protocols by applying high purity aqueous chlorine dioxide (ClO2) solutions. The aim of this proposal is to initiate research that could lead to the introduction of practical and effective antiviral protocols. To this end, we first discuss some important properties of the ClO2 molecule, which make it an advantageous antiviral agent, then some earlier results of ClO2 gas application against viruses will be reviewed. Finally, we hypothesize on methods to control the spread of viral infections using aqueous ClO2 solutions.

Bedside placement of peritoneal dialysis catheters - a single-center experience from Hungary

Objectives: The successful implantation of peritoneal dialysis (PD) catheters is a critical skill procedure with the potential to impact both the short- and long-term success of renal replacement therapy and the patients’ survival.

Methods: We retrospectively reviewed our single-center experience with nephrologist-placed minimally invasive, double-cuffed PD catheters (PDCs).

Results: The recruitment period was March 2014 through December 2015. The follow-up period lasted until 2016. The mean age of the subjects was 60 ± 18 years and indications for the PD were diuretic resistant acutely decompensated chronic heart failure in seven patients (47%) and end-stage renal disease in eight (53%) patients. Comorbid conditions included diabetes (27%), ischemic heart disease (47%), advanced liver failure (27%), and a history of hypertension (73%). The cohort had a high mortality with five subjects only in severe heart failure group (33%) passing away during the index hospitalization; of the rest, two (13%) had heart transplantation, three (20%) changed modality to hemodialysis, and only five (33%) continued with maintenance PD beyond 1 month. Acute technical complications within the first month were infrequent: one catheter (6%) had drainage problems and one (6%) was lost due to extrusion. There were no serious complications (e.g., organ damage, peritonitis, etc.).

Conclusions: In selected cases, particularly in severe diuretic refractory heart failure, PDC placement placed by a nephrologist is feasible with a low rate of complications even in a low-volume center setting. The catheters we placed were all functioning with only minor complications and PD could be started immediately.

The association of overhydration with megafistulas in hemodialysis patients

Objectives: Diffuse enlargements of arteriovenous dialysis fistulas customarily attributed to either excessive arterial inflow or central outflow stenosis. The relationship between volume status and clinically enlarged (arteriovenous) fistula (CEF) formation in end-stage renal disease (ESRD) patients is not well understood.

Methods: We assessed the pre-dialysis bioimpedance spectroscopy-measured percentage of overhydration (OH%) in 13 prevalent dialysis patients with CEF development and negative angiography and compared the results with those of 52 control dialysis patients (CONTR). All patients were prevalent ESRD patients receiving thrice-weekly maintenance hemodiafiltration at an academic outpatient dialysis unit.

Results: 10/13 CEF patients had OH% ≥15% as compared to 20/52 control patients (Chi square p: .02). The degree of OH% was 20.2 ± 7.4% among the CEF vs. 14.4 ± 7.1% in the control group (Student’s t-test p: .01), representing 4.2 ± 3.2 vs. 2.8 ± 1.6 L of excess fluid pre-dialysis (p: .03). Patients with CEF development took an average of 1.7 ± 1.4 vs. 0.8 ± 0.8 (p: .002) antihypertensive medications compared to the CONTR patients, yet their blood pressure was higher: 156/91 vs. 141/78 mmHg (systolic/diastolic p: .03<.0001). We found no difference in fistula vintage, body mass index, age, diabetes status, or diuretic use. The odds ratio of having a CEF in patients with ≥15% OH status was 5.3 (95% CI: 1.3–21.7; p: .01), the Number Needed to Harm with overhydration was 4.

Conclusions: There is an association between bioimpedance spectroscopy-measured overhydrated clinical state and the presence of CEF; either as an increased volume capacitance or as a potential cause.

Pseudo-anaphylaxis to Polyethylene Glycol (PEG)-Coated Liposomes: Roles of Anti-PEG IgM and Complement Activation in a Porcine Model of Human Infusion Reactions

Polyethylene glycol (PEG)-coated nanopharmaceuticals can cause mild to severe hypersensitivity reactions (HSRs), which can occasionally be life threatening or even lethal. The phenomenon represents an unsolved immune barrier to the use of these drugs, yet its mechanism is poorly understood. This study showed that a single i.v. injection in pigs of a low dose of PEGylated liposomes (Doxebo) induced a massive rise of anti-PEG IgM in blood, peaking at days 7-9 and declining over 6 weeks. Bolus injections of PEG-liposomes during seroconversion resulted in anaphylactoid shock (pseudo-anaphylaxis) within 2-3 min, although similar treatments of naı̈ve animals led to only mild hemodynamic disturbance. Parallel measurement of pulmonary arterial pressure (PAP) and sC5b-9 in blood, taken as measures of HSR and complement activation, respectively, showed a concordant rise of the two variables within 3 min and a decline within 15 min, suggesting a causal relationship between complement activation and pulmonary hypertension. We also observed a rapid decline of anti-PEG IgM in the blood within minutes, increased binding of PEGylated liposomes to IgM⁺ B cells in the spleen of immunized animals compared to control, and increased C3 conversion by PEGylated liposomes in the serum of immunized pigs. These observations taken together suggest rapid binding of anti-PEG IgM to PEGylated liposomes, leading to complement activation via the classical pathway, entailing anaphylactoid shock and accelerated blood clearance of liposome-IgM complexes. These data suggest that complement activation plays a causal role in severe HSRs to PEGylated nanomedicines and that pigs can be used as a hazard identification model to assess the risk of HSRs in preclinical safety studies.

Therapeutic Targeting of Fibrotic Epithelial-Mesenchymal Transition-An Outstanding Challenge

Back in 1995, a landmark paper was published, which shaped the fibrosis literature for many years to come. During the characterization of a fibroblast-specific marker (FSP1) in the kidneys, an observation was made, which gave rise to the hypothesis that “fibroblasts in some cases arise from the local conversion of epithelium.” In the following years, epithelial-mesenchymal transition was in the spotlight of fibrosis research, especially in the kidney. However, the hypothesis came under scrutiny following some discouraging findings from lineage tracing experiments and clinical observations. In this review, we provide a timely overview of the current position of the epithelial-mesenchymal transition hypothesis in the context of fibrosis (with a certain focus on renal fibrosis) and highlight some of the potential hurdles and pitfalls preventing therapeutic breakthroughs targeting fibrotic epithelial-mesenchymal transition.

The association of overhydration with chronic inflammation in chronic maintenance hemodiafiltration patients

INTRODUCTION

Achieving euvolemia is one of the major challenges when treating end-stage renal disease (ESRD) patients receiving maintenance renal replacement therapy. Fluid overload is recognized as an independent predictor of mortality in ESRD, but its association with chronic inflammation is less well explored especially in chronic maintenance hemodiafiltration.

METHODS

We performed a cross-sectional study of 87 prevalent ESRD patients receiving chronic maintenance hemodiafiltration (vintage 66.5 ± 57.1 months) with bioimpedance analysis to characterize the degree of percent overhydration (OH%). We also compared the levels of inflammatory markers, including C-reactive protein (CRP), serum albumin, neutrophil/lymphocyte ratio (NLR), and hemoglobin red cell distribution width (RDW) for the overhydrated (OH% ≥ 15%) versus euvolemic (OH% < 15%) groups. Linear regression analysis was performed to explore relationships between the degree of OH and inflammatory indicators.

FINDINGS

The cohort represented an all-European population with a mean age of 60.9 ± 14.7 years and prevalence of diabetes mellitus of 27%. The entire cohort's OH% was 14.9% ± 5.1% (range -11.1% to 39.0%); further, the <15% group of patients' OH% was 8.0% ± 8.5% versus 20.9% ± 5.1% in the OH% ≥ 15% group (P < 0.0001). Forty-seven patients (53%) were overhydrated by traditional criteria (OH% ≥15%) and 20 patients (23%) were severely overhydrated (OH% > 20%). The euvolemic (OH% <15%) versus severely overhydrated (OH% > 20%) groups had significant differences in markers of inflammation: CRP (9.8 ± 10.6 vs. 21.5 ± 21.6 mg/L, P < 0.006), serum albumin (37.6 ± 02.9 vs. 34.5 ± 5.3 g/L, P < 0.004), and NLR (3.06 ± 1.25 vs. 3.92 ± 2.04; P < 0.004). On linear regression, significant correlations were found between OH% and CRP (r = 0.2899, P < 0.006), serum albumin (r = -0.3670; P < 0.0005), RDW (r = 0.2992; P < 0.005), and NLR (r = 0.2900; P < 0.006).

DISCUSSION

In a prevalent hemodiafiltration cohort, OH was common and correlated with several inflammatory markers.

Acute physiological changes caused by complement activators and amphotericin B-containing liposomes in mice

Purpose

Undesirable complement (C) activation by nanomedicines can entail an adverse immune reaction known as C activation-related pseudoallergy (CARPA) in sensitive patients. The syndrome includes cardiopulmonary, hemodynamic, and a variety of other physiological changes that have been well described in man, pigs, dogs, and rats. However, the information on CARPA is scarce and ambiguous in mice, a species widely used in preclinical studies. The present study aimed to fill this gap by exploring signs of CARPA in mice following i.v. administration of AmBisome and Abelcet, which are nano-formulations of Amphotericin B with high risk to cause CARPA.

Materials and methods

Anesthetized NMRI mice were intravenously injected with liposomal amphotericin B (Abelcet and AmBisome; 30–300 mg phospholipid/kg), drug-free high cholesterol multilamellar vesicles (HC-MLV), and positive controls, cobra venom factor (CVF) and zymosan, followed by the measurement of blood pressure (BP), heart rate, white blood cell, and platelet counts and plasma thromboxane B2 (TXB2) levels. C activation was assessed by C3a ELISA, a C3 consumption assay (PAN-C3) and a modified sheep red blood cell hemolytic assay.

Results

All test agents, except HC-MLV, caused transient hypertension, thrombocytopenia, and elevation of plasma TXB2, which were paralleled by significant rises of plasma C3a in CVF and zymosan-treated animals, wherein the initial hypertension turned into hypotension and shock. Abelcet and AmBisome caused minor, delayed rise of C3a that was not associated with hypertension. The C3a receptor inhibitor SB-290157 attenuated the hypertension caused by Abelcet and decreased the BP thereafter.

Conclusion

The parallelism between C3a anaphylatoxin production and severity of physiological changes caused by the different agents is consistent with CARPA underlying these changes. Although the reactive dose of liposomal phospholipids was substantially higher than that in other species (pigs, dogs), the mouse seems suitable for studying the mechanism of hypersensitivity reactions to liposomal formulations of amphotericin B, a frequent side effect of these drugs.

[The savior of mothers and newborns, whom we shall always be proud of: Ignác Semmelweis (1818-1865). One who defeated the disease, yet could not convince the people, Doctor of Medical Sciences and Surgery, Master of Obstetrics, Professor of Theoretical and Practical Obstetrics at the Pest Royal Hungarian University of Sciences]

Semmelweis finally achieved results from his persistent research work. Those being the scientific analysis of clinical statistical data and his animal experiments, which recognized the dreadful disease of puerperal fever and its prevention. "He not only discovered the real cause of puerperal fever but he also created antiseptic prophylaxis, which he introduced in obstetrics and laid the foundations of modern surgery (asepsis). The theory and practice of asepsis stemmed from the discovery of the etiology of puerperal fever and therefore originating from the genius idea of Semmelweis. The discoveries of bacteriology by Lister, Pasteur and Koch only provided a scientific proof of the intuitive statements of Semmelweis." Semmelweis was a pioneer of clinical etiological research whose findings were aggressively disapproved by his colleagues due to earlier medical misunderstandings. Semmelweis is given due respect by posterity as a remuneration, to all the bitterness that he had suffered throughout his life. Semmelweis is considered the savior of mothers and infants. The Hungarian nation is very proud of him as he is one of our models whose oeuvre is acknowledged not only in Hungary but throughout the world. The message of his short, tragic yet effective life is eternal. The figure of Ignác Semmelweis is depicted as a statue and is placed in Chicago among the statues of the most innovative doctors and health care professionals of the world. The statue of Semmelweis is next to the statues of Louis Pasteur and Wilhelm Conrad Röntgen. "Semmelweis reflex" is a new expression which appeared and spread in English speaking countries. The word does not relate to a medical phenomenon but describes a social phenomenon when experts or the whole society automatically rejects discoveries and new recognitions without examination or justification. This phenomenon frequently occurs, even in our times. Orv Hetil. 2018; 159(26): 1041-1054.

Cinaciguat ameliorates glomerular damage by reducing ERK1/2 activity and TGF-ß expression in type-1 diabetic rats

Decreased soluble guanylate cyclase activity and cGMP levels in diabetic kidneys were shown to influence the progression of nephropathy. The regulatory effects of soluble guanylate cyclase activators on renal signaling pathways are still unknown, we therefore investigated the renal molecular effects of the soluble guanylate cyclase activator cinaciguat in type-1 diabetic (T1DM) rats. Male adult Sprague-Dawley rats were divided into 2 groups after induction of T1DM with 60 mg/kg streptozotocin: DM, untreated (DM, n = 8) and 2) DM + cinaciguat (10 mg/kg per os daily, DM-Cin, n = 8). Non-diabetic untreated and cinaciguat treated rats served as controls (Co (n = 10) and Co-Cin (n = 10), respectively). Rats were treated for eight weeks, when renal functional and molecular analyses were performed. Cinaciguat attenuated the diabetes induced proteinuria, glomerulosclerosis and renal collagen-IV expression accompanied by 50% reduction of TIMP-1 expression. Cinaciguat treatment restored the glomerular cGMP content and soluble guanylate cyclase expression, and ameliorated the glomerular apoptosis (TUNEL positive cell number) and podocyte injury. These effects were accompanied by significantly reduced TGF-ß overexpression and ERK1/2 phosphorylation in cinaciguat treated diabetic kidneys. We conclude that the soluble guanylate cyclase activator cinaciguat ameliorated diabetes induced glomerular damage, apoptosis, podocyte injury and TIMP-1 overexpression by suppressing TGF-ß and ERK1/2 signaling.

Sustained hyperosmolarity increses TGF-ß1 and Egr-1 expression in the rat renal medulla

BACKGROUND

Although TGF-ß and the transcription factor Egr-1 play an important role in both kidney fibrosis and in response to acute changes of renal medullary osmolarity, their role under sustained hypo- or hyperosmolar conditions has not been elucidated. We investigated the effects of chronic hypertonicity and hypotonicity on the renal medullary TGF-ß and Egr-1 expression.

METHODS

Male adult Sprague Dawley rats (n = 6/group) were treated with 15 mg/day furosemide, or the rats were water restricted to 15 ml/200 g body weight per day. Control rats had free access to water and rodent chow. Kidneys were harvested after 5 days of treament. In cultured inner medullary collecting duct (IMCD) cells, osmolarity was increased from 330 mOsm to 900 mOsm over 6 days. Analyses were performed at 330, 600 and 900 mOsm.

RESULTS

Urine osmolarity has not changed due to furosemide treatment but increased 2-fold after water restriction (p < 0.05). Gene expression of TGF-ß and Egr-1 increased by 1.9-fold and 7-fold in the hypertonic medulla, respectively (p < 0.05), accompanied by 6-fold and 2-fold increased c-Fos and TIMP-1 expression, respectively (p < 0.05) and positive immunostaining for TGF-ß and Egr-1 (p < 0.05). Similarly, hyperosmolarity led to overexpression of TGF-ß and Egr-1 mRNA in IMCD cells (2.5-fold and 3.5-fold increase from 330 to 900 mOsm, respectively (p < 0.05)) accompanied by significant c-Fos and c-Jun overexpressions (p < 0.01), and increased Col3a1 and Col4a1 mRNA expression.

CONCLUSION

We conclude that both TGF-ß and Egr-1 are upregulated by sustained hyperosmolarity in the rat renal medulla, and it favors the expression of extracellular matrix components.

Simple, readily available clinical indices predict early and late mortality among patients with ANCA-associated vasculitis

Background

The early identification of patients with ANCA-associated vasculitis (AAV) who are at increased risk for inferior clinical outcome at the time of diagnosis might help to optimize the immunosuppressive therapy. In this study we wanted to determine the predictive value of simple clinical characteristics, which may be applicable for early risk-stratification of patients with AAV.

Methods

We retrospectively analyzed the outcome of 101 consecutive patients with AAV receiving a protocolized immunosuppressive therapy. Baseline Birmingham Vasculitis Activity Score (BVAS) and non-vasculitic comorbidities were computed, then predictors of early (<90 days) and late (>90 days) mortality, infectious death, relapse and end stage kidney disease (ESKD) were evaluated.

Results

The baseline comorbidity score independently predicted early mortality (HR 1.622, CI 1.006–2.614), and showed association with infectious mortality (HR 2.056, CI 1.247–3.392). Patients with BVAS at or above median (=21) had worse early mortality in univariable analysis (HR 3.57, CI 1.039–12.243) (p = 0.031), and had more frequent relapses (p = 0.01) compared to patients with BVAS below median.

Conclusions

Assessing baseline comorbidities, beside clinical indices characterizing the severity and extension of AAV, might help clinicians in risk-stratification of patients. Future prospective studies are needed to investigate whether therapies based on risk-stratification could improve both short term and long term survival.

Volume-related weight gain as an independent indication for renal replacement therapy in the intensive care units

Attempts to identify specific therapies to reverse acute kidney injury (AKI) have been unsuccessful in the past; only modifying risk profile or addressing the underlying disease processes leading to AKI proved efficacious. The current thinking on recognizing AKI is compromised by a "kidney function percent-centered" viewpoint, a paradigm further reinforced by the emergence of serum creatinine-based automated glomerular filtration reporting over the last two decades. Such thinking is, however, grossly corrupted for AKI and poorly applicable in critically ill patients in general. Conventional indications for renal replacement therapy (RRT) may have limited applicability in critically ill patients and there has been a relative lack of progress on RRT modalities in these patients. AKI in critically ill patients is a highly complex syndrome and it may be counterproductive to produce complex clinical practice guidelines, which are labor and resource-intensive to maintain, difficult to memorize or may not be immediately available in all settings all over the world. Additionally, despite attempts to develop reliable and reproducible biomarkers to replace serum creatinine as a guide to therapy such biomarkers failed to materialize. Under such circumstances, there is an ongoing need to reassess the practical value of simple measures, such as volume-related weight gain (VRWG) and urine output, both for prognostic markers and clinical indicators for the need for RRT. This current paper reviews the practical utility of VRWG as an independent indication for RRT in face of reduced urine output and hemodynamic instability.

Clinical Utility of Potassium-Sparing Diuretics to Maintain Normal Serum Potassium in Peritoneal Dialysis Patients

♦ BACKGROUND: Hypokalemia is a vexing problem in end-stage renal disease patients on peritoneal dialysis (PD), and oral potassium supplements (OPS) have limited palatability. Potassium-sparing diuretics (KSD) (spironolactone, amiloride) may be effective in these patients. ♦ METHODS: We performed a cross-sectional review of 75 current or past (vintage > 6 months) PD patients with regard to serum potassium (K+), OPS, and KSD utilization. We reviewed charts for multiple clinical and laboratory variables, including dialysis adequacy, residual renal function, nutritional status and co-existing medical therapy. ♦ RESULTS: The cohort was middle-aged with a mean age of 49.2 years (standard deviation [SD] = 14.7) and overweight with a body mass index of 29.5 (6.7) kg/m². Of all the participants, 57.3% were female, 73.3% African-American, and 48% diabetic with an overall PD vintage of 28.2 (24.3) months at the time of enrollment. Weekly Kt/V was 2.12 (0.43), creatinine clearance was 73.5 (33.6) L/week/1.73 m² with total daily exchange volume of 10.8 (2.7) L. Residual urine output (RUO) measured at 440 (494) mL (anuric 30.6%). Three-month averaged serum K⁺ measured at 4 (0.5) mmol/L with 36% of the participants receiving K⁺ supplements (median: 20 [0;20] mmol/day) and 41.3% KSD (spironolactone dose: 25 - 200 mg/day; amiloride dose: 5 - 10 mg/day). Serum K⁺ correlated positively with weekly Kt/V (r = 0.239; p = 0.039), PD vintage (r = 0.272; p = 0.018) but not with PD modality, daily exchange volume, RUO, or KSD use. However, KSD use was associated with decreased use of OPS (r = -0.646; p < 0.0001). ♦ CONCLUSIONS: Potassium-sparing diuretics were effective in this cohort of PD patients and decreased the need for OPS utilization.

Diagnosis and treatment of early renal disease in patients with type 2 diabetes mellitus: what are the clinical needs?

Renal disease is prevalent in patients with diabetes mellitus type 2. Aggressive metabolic control and lowering of systemic and/or intraglomerular blood pressure are effective interventions but not without side effects. Thus a better, early identification of patients at risk for incidence or progression to end-stage renal failure by the use of new, validated biomarkers is highly desirable. In the majority of patients, hypertension and hyperglycaemia are pathogenetically important pathways for the progression of renal disease. Nonetheless even aggressive therapy targeting these factors does not eliminate the risk of end-stage renal failure and experimental evidence suggests that many other pathways (e.g. tubulointerstitial hypoxia or inflammation etc.) also contribute. As their individual importance might vary from patient to patient, interventions which interfere are likely not to be therapeutically effective in all subjects. In this situation, an option to preserve the statistical power of clinical trials is to rely on biomarkers that reflect individual pathophysiology. In current clinical practice, albuminuria is the biomarker that has been best evaluated to guide stratified/personalized therapy but there is a clear need to expand our diagnostic abilities.

When the endothelium scores an own goal: endothelial cells actively augment metastatic extravasation through endothelial-mesenchymal transition

Endothelial-mesenchymal transition (EndMT) is an important mechanism during organ development and in certain pathological conditions. For example, EndMT contributes to myofibroblast formation during organ fibrosis, and it has been identified as an important source of cancer-associated fibroblasts, facilitating tumor progression. Recently, EndMT was proposed to modulate endothelial function during intravasation and extravasation of metastatic tumor cells. Evidence suggests that endothelial cells are not passive actors during transendothelial migration (TEM) of cancer cells, as there are profound changes in endothelial junctional protein expression, signaling, permeability, and contractility. This review describes these alterations in endothelial characteristics during TEM of metastatic tumor cells and discusses them in the context of EndMT. EndMT could play an important role during metastatic intravasation and extravasation, a novel hypothesis that may lead to new therapeutic approaches to tackle metastatic disease.

Expression of Vascular Endothelial Growth Factor Has a Regulatory Role in Gingival Venules in Experimental Diabetes

BACKGROUND

In the present study, the possible localization and role of vascular endothelial growth factor receptor type 2 (VEGFR2) in the regulation of gingival venules in a rat model of experimental diabetes are examined.

METHODS

Six weeks after streptozotocin premedication, Wistar male rats presenting blood sugar levels >20 mmol/L were selected for investigation. The VEGFR2 antagonist ZM323881 [5-((7-benzyloxyquinazolin-4-yl)amino)-4-fluoro-2-methylphenol-hydrochloride] (20 μg/mL) was dripped onto the gingiva between the mandibular incisors. Changes in diameter of the selected gingival venule were measured by vital microscopy combined with digital photography at specified times. Immunohistochemical staining was used to localize VEGFR2. For controls, the same protocol was used on animals with normal blood sugar levels and healthy gingiva.

RESULTS

There was a significant difference between the baseline venule diameter of the diabetic and the control groups (47 ± 1 and 28 ± 2 μm, respectively). After 15, 30, and 60 minutes of local application of ZM323881, significant vasoconstriction was observed in the venules of diabetic rats compared with the baseline (81.4% ± 4.6%, 81.8% ± 4.4%, and 80.6% ± 5.1%, respectively). The control group showed no change in the venule diameter. The immunohistochemical analysis showed significantly increased VEGFR2 expression in the mast cells along the venules in the diabetic group, whereas mast cells were rarely found in the control group.

CONCLUSIONS

The findings suggest that VEGF expression is increased in gingiva in experimentally induced diabetes. After VEGFR2 activation, the mast cell-derived vasodilatory and inflammatory mediators may contribute markedly to the concomitant changes in the microcirculation.

Endothelial-mesenchymal transition of brain endothelial cells: possible role during metastatic extravasation

Cancer progression towards metastasis follows a defined sequence of events described as the metastatic cascade. For extravasation and transendothelial migration metastatic cells interact first with endothelial cells. Yet the role of endothelial cells during the process of metastasis formation and extravasation is still unclear, and the interaction between metastatic and endothelial cells during transendothelial migration is poorly understood. Since tumor cells are well known to express TGF-β, and the compact endothelial layer undergoes a series of changes during metastatic extravasation (cell contact disruption, cytoskeletal reorganization, enhanced contractility), we hypothesized that an EndMT may be necessary for metastatic extravasation. We demonstrate that primary cultured rat brain endothelial cells (BEC) undergo EndMT upon TGF-β1 treatment, characterized by the loss of tight and adherens junction proteins, expression of fibronectin, β1-integrin, calponin and α-smooth muscle actin (SMA). B16/F10 cell line conditioned and activated medium (ACM) had similar effects: claudin-5 down-regulation, fibronectin and SMA expression. Inhibition of TGF-β signaling during B16/F10 ACM stimulation using SB-431542 maintained claudin-5 levels and mitigated fibronectin and SMA expression. B16/F10 ACM stimulation of BECs led to phosphorylation of Smad2 and Smad3. SB-431542 prevented SMA up-regulation upon stimulation of BECs with A2058, MCF-7 and MDA-MB231 ACM as well. Moreover, B16/F10 ACM caused a reduction in transendothelial electrical resistance, enhanced the number of melanoma cells adhering to and transmigrating through the endothelial layer, in a TGF-β-dependent manner. These effects were not confined to BECs: HUVECs showed TGF-β-dependent SMA expression when stimulated with breast cancer cell line ACM. Our results indicate that an EndMT may be necessary for metastatic transendothelial migration, and this transition may be one of the potential mechanisms occurring during the complex phenomenon known as metastatic extravasation.

Endothelial-mesenchymal transition of brain endothelial cells: possible role during metastatic extravasation

Cancer progression towards metastasis follows a defined sequence of events described as the metastatic cascade. For extravasation and transendothelial migration metastatic cells interact first with endothelial cells. Yet the role of endothelial cells during the process of metastasis formation and extravasation is still unclear, and the interaction between metastatic and endothelial cells during transendothelial migration is poorly understood. Since tumor cells are well known to express TGF-β, and the compact endothelial layer undergoes a series of changes during metastatic extravasation (cell contact disruption, cytoskeletal reorganization, enhanced contractility), we hypothesized that an EndMT may be necessary for metastatic extravasation. We demonstrate that primary cultured rat brain endothelial cells (BEC) undergo EndMT upon TGF-β1 treatment, characterized by the loss of tight and adherens junction proteins, expression of fibronectin, β1-integrin, calponin and α-smooth muscle actin (SMA). B16/F10 cell line conditioned and activated medium (ACM) had similar effects: claudin-5 down-regulation, fibronectin and SMA expression. Inhibition of TGF-β signaling during B16/F10 ACM stimulation using SB-431542 maintained claudin-5 levels and mitigated fibronectin and SMA expression. B16/F10 ACM stimulation of BECs led to phosphorylation of Smad2 and Smad3. SB-431542 prevented SMA up-regulation upon stimulation of BECs with A2058, MCF-7 and MDA-MB231 ACM as well. Moreover, B16/F10 ACM caused a reduction in transendothelial electrical resistance, enhanced the number of melanoma cells adhering to and transmigrating through the endothelial layer, in a TGF-β-dependent manner. These effects were not confined to BECs: HUVECs showed TGF-β-dependent SMA expression when stimulated with breast cancer cell line ACM. Our results indicate that an EndMT may be necessary for metastatic transendothelial migration, and this transition may be one of the potential mechanisms occurring during the complex phenomenon known as metastatic extravasation.

Rodent models of complement activation-related pseudoallergy: Inducers, symptoms, inhibitors and reaction mechanisms

Complement activation-related pseudoallergy (CARPA) is a hypersensitivity reaction to intravenous administration of nanoparticle-containing medicines (nanomedicines). This review focuses on CARPA in rodent models: rats, mice, guinea pigs and rabbits. Information on all aspects of hypersensitivity reactions caused by known complement activators (zymosan, cobra venom factor) and different nanomedicines (liposomes, other drug carrier nanocarriers) in these species has been compiled and analyzed, trying to highlight the similarities and differences. What is most common in all species’ reactions to i.v. complement activators, liposomes and other nanoparticles is a dose-dependent hemodynamic and cardiopulmonary disturbance manifested in acute, reversible rise or fall of blood pressure and respiratory distress that can lead to shock. Other symptoms include heart rate changes, leukopenia followed by leukocytosis, thrombocytopenia, hemoconcentration due to fluid extravasation (rise of hematocrit) and rise of plasma thromboxane B2. The results of a recent rat study are detailed, which show that rats are 2–3 orders of magnitude less sensitive to liposome-induced CARPA than pigs or hypersensitive humans. It is concluded that CARPA can be studied in rodent models, but they do not necessarily mimic the human reactions in terms of symptom spectrum and sensitivity.

Pulmonary intravascular macrophages: prime suspects as cellular mediators of porcine CARPA

Pigs provide a highly sensitive and quantitative in vivo model for complement (C) activation-related pseudoallergy (CARPA), a hypersensitivity reaction caused by some state-of-art nanomedicines. In an effort to understand the mechanism of the pigs’ unique sensitivity for CARPA, this review focuses on pulmonary intravascular macrophages (PIMs), which are abundantly present in the lung of pigs. These cells represent a macrophage subpopulation whose unique qualities explain the characteristic symptoms of CARPA in this species, most importantly the rapidly (within minutes) developing pulmonary vasoconstriction, leading to elevation of pulmonary arterial pressure. The unique qualities of PIM cells include the following; 1) they are strongly adhered to the capillary walls via desmosome-like intercellular adhesion plaques, which secure stable and lasting direct exposition of the bulk of these cells to the blood stream; 2) their ruffled surface engaged in intense phagocytic activity ensures efficient binding and phagocytosis of nanoparticles; 3) PIM cells express anaphylatoxin receptors, this way C activation can trigger these cells, 4) they also express pattern recognition molecules on their surface, whose engagement with certain coated nanoparticles may also activate these cells or act in synergy with anaphylatoxins and, finally 5) their high metabolic activity and capability for immediate secretion of vasoactive mediators upon stimulation explain the circulatory blockage and other robust physiological effects that their stimulation may cause. These qualities taken together with reports on liposome uptake by PIM cells during CARPA and the possible presence of these cells in human lung suggests that PIM cells may be a potential therapeutic target against CARPA.

Paradoxical rise of hemolytic complement in the blood of mice during zymosan- and liposome-induced CARPA: a pilot study

The complement (C) activating effect of zymosan and liposomal drugs (AmBisome, Caelyx) leads to significant C consumption in rats, dogs, pigs and other species in vivo, as reflected by a fall in hemolytic complement activity (HCA) of their plasma. However, the acute C activating effect of zymosan and liposomal drugs is unclear in the mouse. Therefore, using sheep red blood cells, we assayed the HCA of plasma obtained from apolipoprotein E-deficient (ApoE) as well as from background C57BL/6 (BL6) mice. Intravenous (i.v.) administration of C activators led to a significant rise (up to 40%) in HCA of the plasma. The HCA steadily rose up to 30 min in ApoE mice, while it peaked at 3 min in BL6 mice, returning to baseline thereafter. The elevated HCA after IV injection of C activators is “paradoxical” in mice, since it implies an increase rather than a decrease in C levels in the blood. One possible explanation of the phenomenon is hemoconcentration due to anaphylatoxin-induced capillary leakage, resulting in an apparent rise of HCA. In conclusion, these preliminary observations highlight, for the first time, a species-dependent opposing impact of C activation and the resulting anaphylatoxin actions on hemolytic complement activity.

LPS-induced delayed preconditioning is mediated by Hsp90 and involves the heat shock response in mouse kidney

Introduction

We and others demonstrated previously that preconditioning with endotoxin (LPS) protected from a subsequent lethal LPS challenge or from renal ischemia-reperfusion injury (IRI). LPS is effective in evoking the heat shock response, an ancient and essential cellular defense mechanism, which plays a role in resistance to, and recovery from diseases. Here, by using the pharmacological Hsp90 inhibitor novobiocin (NB), we investigated the role of Hsp90 and the heat shock response in LPS-induced delayed renal preconditioning.

Methods

Male C57BL/6 mice were treated with preconditioning (P: 2 mg/kg, ip.) and subsequent lethal (L: 10 mg/kg, ip.) doses of LPS alone or in combination with NB (100 mg/kg, ip.). Controls received saline (C) or NB.

Results

Preconditioning LPS conferred protection from a subsequent lethal LPS treatment. Importantly, the protective effect of LPS preconditioning was completely abolished by a concomitant treatment with NB. LPS induced a marked heat shock protein increase as demonstrated by Western blots of Hsp70 and Hsp90. NB alone also stimulated Hsp70 and Hsp90 mRNA but not protein expression. However, Hsp70 and Hsp90 protein induction in LPS-treated mice was abolished by a concomitant NB treatment, demonstrating a NB-induced impairment of the heat shock response to LPS preconditioning.

Conclusion

LPS-induced heat shock protein induction and tolerance to a subsequent lethal LPS treatment was prevented by the Hsp90 inhibitor, novobiocin. Our findings demonstrate a critical role of Hsp90 in LPS signaling, and a potential involvement of the heat shock response in LPS-induced preconditioning.

Activation of the miR-17 family and miR-21 during murine kidney ischemia-reperfusion injury

BACKGROUND

Ischemia-reperfusion (I/R) is the main cause of acute kidney injury (AKI) in patients. We investigated renal microRNA (miRNA) expression profiles and the time course of changes in selected miRNA expressions after renal I/R to characterize the miRNA network activated during development and recovery from AKI.

METHODS AND RESULTS

One day after lethal (30 minutes) and sublethal (20 minutes) renal ischemia, AKI was verified by renal histology (tubular necrosis, regeneration), blood urea nitrogen (BUN) level, renal mRNA expression, and plasma concentration of neutrophil gelatinase-associated lipocalin (NGAL) in C57BL/6J mice. On the first day after 30-minute, lethal I/R miR-21, miR-17-5p, and miR-106a were elevated out of the 21 miRNAs successfully profiled on the Luminex multiplex assay. After 20-minute, sublethal I/R, renal miR-17-5p and miR-106a expressions were elevated on the first and second days of reperfusion, while miR-21 expression increased later and lasted longer. Renal miR-17-5p and miR-21 expressions correlated with each other. Renal function returned to normal on the fourth day after sublethal I/R.

CONCLUSIONS

Our results demonstrate that besides miR-21, miR-17-5p, and miR-106a are additionally activated during the maintenance and recovery phases of renal I/R injury. Furthermore, a correlation between renal miR-17-5p and miR-21 expressions warrants further investigation of how they may influence each other and the outcome of renal ischemia-reperfusion injury.

Chlorine dioxide is a size-selective antimicrobial agent

Background / Aims

ClO₂, the so-called “ideal biocide”, could also be applied as an antiseptic if it was understood why the solution killing microbes rapidly does not cause any harm to humans or to animals. Our aim was to find the source of that selectivity by studying its reaction-diffusion mechanism both theoretically and experimentally.

Methods

ClO₂ permeation measurements through protein membranes were performed and the time delay of ClO₂ transport due to reaction and diffusion was determined. To calculate ClO₂ penetration depths and estimate bacterial killing times, approximate solutions of the reaction-diffusion equation were derived. In these calculations evaporation rates of ClO₂ were also measured and taken into account.

Results

The rate law of the reaction-diffusion model predicts that the killing time is proportional to the square of the characteristic size (e.g. diameter) of a body, thus, small ones will be killed extremely fast. For example, the killing time for a bacterium is on the order of milliseconds in a 300 ppm ClO₂ solution. Thus, a few minutes of contact time (limited by the volatility of ClO₂) is quite enough to kill all bacteria, but short enough to keep ClO₂ penetration into the living tissues of a greater organism safely below 0.1 mm, minimizing cytotoxic effects when applying it as an antiseptic. Additional properties of ClO₂, advantageous for an antiseptic, are also discussed. Most importantly, that bacteria are not able to develop resistance against ClO₂ as it reacts with biological thiols which play a vital role in all living organisms.

Conclusion

Selectivity of ClO₂ between humans and bacteria is based not on their different biochemistry, but on their different size. We hope initiating clinical applications of this promising local antiseptic.

[Investigation of the venodilatory effect of vascular endothelial growth factor (VEGF) in rat gingiva]

VEGF induces proliferation of endothelial cells, stimulates angiogenesis, and increases vascular permeability in many organs. Nevertheless, we have only limited information about its role on gingival hemodynamics, especially in venules. Therefor the aim of this study was to assess the acute circulatory effects of VEGF on rat gingival venules by means of the following protocol. Wister rats (n=63) were devided into five study groups after anesthesia; each animal received 10 microl of experimental solution dripped onto the lower interincisal gingiva. The groups included: 1) saline control (after the experiment, gingiva was excised for VEGF receptor 2 [VEGFR2] immunohistochemistry); 2) VEGF (0.1, 1, 10, or 50 microg/ml); 3) VEGF2 receptor antagonist 5-((7-benzyloxyquinazolin-4-yl)amino)-4-fluoro-2-methyl-phenol-hydrochloride (ZM323881; 20 microg/ml); 4) ZM323881 (20 microg/ml) followed by VEGF application (50 microg/ml after 15 minutes); and 5) VEGF (10 microg/ml), these rats were premedicated with nitric oxide (NO) synthase blocker (NG-nitro-L-arginine-methyl-ester [L-NAME]; 1 mg/ml in drinking water) for 1 week before the experiment. Changes in gingival superficial venule diameter were measured by vital microscopy prior to and 1, 5, 15, 30, and 60 minutes after the administration of the experimental solutions. According to our findings, VEGF dose-dependently increased the venular diameter compared to saline. ZM323881 alone did not cause any alteration. Premedication with ZM323881 or L-NAME decreased the dilatory effects of VEGF. Occassionally moderate VEGFR2 immunohistochemical labeling was observed in the wall components of the venules. Concluding our results we can say, that there is no remarkable VEGF production under physiologic circumstances in rat gingiva, but VEGF is able to increase gingival blood flow through the activation of VEGF2 receptors and consequent NO release.

Characterization and role of SCAI during renal fibrosis and epithelial-to-mesenchymal transition

During progressive tubulointerstitial fibrosis, renal tubular epithelial cells transform into α-smooth muscle actin (SMA)-expressing myofibroblasts via epithelial-to-mesenchymal transition (EMT). SMA expression is regulated by transforming growth factor (TGF)-β1 and cell contact disruption, through signaling events targeting the serum response factor-myocardin-related transcription factor (MRTF) complex. MRTFs are important regulators of fibrosis, tumor cell invasion, and metastasis. Consistent with the role of MRTFs in tumor progression, suppressor of cancer cell invasion (SCAI) was recently identified as a negative regulator of MRTF. Herein, we studied the role of SCAI in a fibrotic EMT model established on LLC-PK1 cells. SCAI overexpression prevented SMA promoter activation induced by TGF-β1. When co-expressed, it inhibited the stimulatory effects of MRTF-A, MRTF-B or the constitutive active forms of RhoA, Rac1, or Cdc42 on the SMA promoter. SCAI interfered with TGF-β1-induced SMA, connective tissue growth factor, and calponin protein expression; it rescued TGF-β1-induced E-cadherin down-regulation. IHC studies on human kidneys showed that SCAI expression is reduced during fibrosis. Kidneys of diabetic rats and mice with unilateral ureteral obstruction depicted significant loss of SCAI expression. In parallel with the decrease of SCAI protein expression, diabetic rat and mouse kidneys with unilateral ureteral obstruction showed SMA expression, as evidenced by using Western blot analysis. Finally, TGF-β1 treatment of LLC-PK1 cells attenuated SCAI protein expression. These data suggest that SCAI is a novel transcriptional cofactor that regulates EMT and renal fibrosis.

A porcine model of complement-mediated infusion reactions to drug carrier nanosystems and other medicines

Intravenous administration of low (milligram) doses of nanoparticulate materials in pigs can lead to acute cardiopulmonary, hemodynamic, hematological, biochemical and dermatological changes within minutes, mimicking the human infusion (or anaphylactoid) reactions to many state-of-the-art (nano)medicines and biologicals. Because of the causal role of complement (C) activation, the phenomenon was called C activation-related pseudoallergy (CARPA). This review summarizes the available information on porcine CARPA caused by different liposomes and polymers. It provides methodical details of the model and addresses the quantitation, sensitivity, specificity, reproducibility and variability of symptoms caused by different reactogenic drugs. We describe a unique feature of the model: the rise of tachyphylaxis (self-induced tolerance) as a function of structural properties of reactogenic agents. For drugs that cause tachyphylactic CARPA, such as liposomal doxorubicin (Doxil), the review recapitulates a recently reported method of desensitization, which may prevent this, as well as many similar hypersensitivity reactions. In explaining the underlying mechanism of tachyphylactic CARPA, a new theory on "double hit" is outlined, wherein the pulmonary intravascular macrophages (PIM cells) of pigs give aggravated response to simultaneous stimulation of their anaphylatoxin and other surface receptors (e.g., toll-like, PAMP, DAMP or mannose) that recognize vesicle surface molecular patterns. The porcine CARPA model might provide unique advantages in studying the mechanism of severe hypersensitivity reactions in man to i.v. drugs, as well as in identifying drugs and drug carriers that may cause such reactions.