Heterologous immunization with BNT162b2 followed by mRNA-1273 in dialysis patients: seroconversion and presence of neutralizing antibodies

INTRODUCTION

The vital renal replacement therapy makes it impossible for dialysis patients to distance themselves socially. This results in a high risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and developing coronavuris disease 2019, with excess mortality due to disease burden and immunosuppression. We determined the efficacy of a 100-µg booster of mRNA-1273 (Moderna, Cambridge, MA, USA) 6 months after two doses of BNT162b2 (BioNTech/Pfizer, Mainz, Germany/New York, USA) in 194 SARS-CoV-2-naïve dialysis patients.

METHODS

Anti-SARS-CoV-2 spike antibodies were measured with the Elecsys Anti-SARS-CoV-2 S assay (Roche Diagnostics, Mannheim, Germany) 4 and 10-12 weeks after two doses of BNT162b2 as well as 4 weeks after the mRNA-1273 booster. The presence of neutralizing antibodies was measured by the SARS-CoV-2 Surrogate Virus Neutralization Test (GenScript Biotech, Piscataway, NJ, USA). Two different cut-offs for positivity were used, one according to the manufacturer's specifications and one correlating with positivity in a plaque reduction neutralization test (PRNT). Receiver operating characteristics analyses were performed to match the anti-SARS-CoV-2 spike antibody cut-offs with the cut-offs in the surrogate neutralization assay accordingly.

RESULTS

Any level of immunoreactivity determined by the anti-SARS-CoV-2 spike antibody assay was found in 87.3% (n = 144/165) and 90.6% (n = 164/181) of patients 4 and 10-12 weeks, respectively, after two doses of BNT162b2. This was reduced to 68.5% or 60.6% 4 weeks and 51.7% or 35.4% 10-12 weeks, respectively, when using the ROC cut-offs for neutralizing antibodies in the surrogate neutralization test (manufacturer's cut-off ≥103 U/mL and cut-off correlating with PRNT ≥196 U/mL). Four weeks after the mRNA-1273 booster, the concentration of anti-SARS-CoV-2 spike antibodies increased to 23 119.9 U/mL and to 97.3% for both cut-offs of neutralizing antibodies.

CONCLUSION

Two doses of BNT162b2 followed by one dose of mRNA-1273 within 6 months in patients receiving maintenance dialysis resulted in significant titres of SARS-CoV-2 spike antibodies. While two doses of mRNA vaccine achieved adequate humoral immunity in a minority, the third vaccination boosts the development of virus-neutralizing quantities of SARS-CoV-2 spike antibodies (against wild-type SARS-CoV-2) in almost all patients.

Renal Transplantation in HIV-positive Renal Transplant Recipients: Experience at the Mannheim University Hospital

Renal transplantation in HIV-positive patients with end-stage renal disease has in recent years become a successful treatment option. We report two patients who underwent renal transplantation using a combination of basiliximab, calcineurin inhibitors, mycophenolate mofetil (MMF), and steroids with a "non-interacting" antiretroviral combination therapy consisting of stavudine or abacavir, lamivudine, and nevirapine. We observed no acute rejection but a BK polyomavirus infection in both patients. In conclusion, a quadruple immunosuppression with an interleukin 2 receptor antagonist, a calcineurin inhibitor, MMF, and steroids appears to be advisable to prevent high rates of acute rejection, but if possible thereafter immunosuppression should be tapered rapidly (eg, MMF stop, prednisolone dose 5 mg/d). The selection of antiretroviral agents should avoid compounds that interact severely with the immunosuppression used.

Minoxidil for Treatment of Resistant Hypertension in Chronic Kidney Disease--A Retrospective Cohort Analysis

Resistant hypertension is still a challenge and reserve antihypertensive agents are often necessary to achieve blood pressure control. One reserve antihypertensive is minoxidil, a direct vasodilator that is known for its strong blood pressure-lowering effect, but contemporary studies are sparse. The authors retrospectively analyzed 54 inpatients with uncontrolled hypertension despite the combined use of current antihypertensive agents. To investigate the effect of minoxidil when added to other antihypertensive agents, blood pressure was evaluated at the time minoxidil treatment was initiated and at discharge. Minoxidil treatment was associated with a significant reduction in blood pressure from 162.4±15.1/83.2±12.7 mm Hg to 135.8±12.2/72.8±6.9 mm Hg (P<.0001). This effect was sustained across all analyzed subgroups. Although the well-known adverse events of minoxidil limit its widespread use, these data show that minoxidil as a reserve antihypertensive agent still has a niche indication in the particular subgroup of patients with treatment-resistant or uncontrolled hypertension.

Donor Desmopressin Treatment Does Not Affect Transplant Outcome in the Fischer to Lewis Rat Renal Transplant Model

OBJECTIVES

Retrospective studies suggest that donor desmopressin (DDAVP) treatment improves renal transplant outcome. The present study tests the hypothesis that desmopressin neutralizes the graft's endothelium from proinflammatory angiopoietin 2 containing Weibel-Palade bodies in the donor, resulting in reduced Weibel-Palade body release at the time of reperfusion in the recipient.

MATERIALS AND METHODS

Using rat models, we examined the influence of desmopressin treatment on the expression of vasopressin 2 receptors and adhesion molecules in brain-dead donors, with renal function examined in allogeneic recipients. The influence of desmopressin on the expression of adhesion molecules also was tested in vitro.

RESULTS

Vasopressin 2 receptors were restricted to collecting ducts and distal tubules and only scarcely found in the renal vasculature. Vasopressin 2 receptor expression was down-regulated in brain-dead rats by desmopressin. Renal expression of vascular cellular adhesion molecule 1 and intercellular adhesion molecule 1 were significantly reduced in these rats. In contrast, angiopoietin 2 did not influence the expression of adhesion molecules in in vitro cultured endothelial cells after tumor necrosis factor ? stimulation. Donor desmopressin treatment improved neither renal function nor histology in allogeneic renal transplant recipients.

CONCLUSIONS

Our data do not support the hypothesis that the clinically observed salutary effect of desmopressin is mediated by depletion of Weibel-Palade bodies in renal allografts.

A rare case of fever of unknown origin: inflammatory myofibroblastic tumor of the liver. Case report and review of the literature

We present the case of a rare cause of fever of unknown origin (FUO). FUO is challenging for patients as well as for physicians as there are more than 200 differential diagnoses of FUO (1,2). Pointing out a diagnosis often requires numerous noninvasive and invasive procedures that sometimes even fail to explain the fever. Our patient was admitted twice to our hospital due to remitting fever rising up to 40 degrees C without any subjective discomfort. At the first presentation no clinical focus could be identified. This included the examination of multiple blood and urine cultures, serology, autoimmune serology, transesophageal echocardiography, CT-scan of the lung and the abdomen, and bone scintigraphy. Elevated C-reactive protein (268 mg/l) decreased spontaneously and fever disappeared after 4 weeks. However, the patient was re-admitted 4 months later with identical symptoms. Multiple blood and urine cultures, serology, bone marrow examination, CT-scan of the lung and the abdomen, esophago-gastro-duodenoscopy and colonoscopy still showed no pathological findings. MRI-scan of the abdomen identified a liver tumor of 3.3 cm in diameter in segment 6 without typical signs of an adenoma, focal nodular hyperplasia or hepatocellular carcinoma. Biopsy of the suspect liver lesion revealed an inflammatory myofibroblastic tumor (inflammatory pseudotumor). After surgical resection of the tumor elevated inflammation markers as C-reactive protein normalized and fever disappeared. One year after surgery no more episodes of fever re-occurred. An inflammatory myofibroblastic tumor of the liver can be a rare cause of fever of unknown origin. MRI-scan can be an additional imaging tool to identify previously not recognized liver tumors.

Effects of N-acetylcysteine on renal hemodynamics in contrast media-induced nephropathy

BACKGROUND

N-acetylcysteine (NAC) has been proposed to prevent radiocontrast nephropathy in high-risk patients.

METHODS

The effect of single-dose and prolonged administration of NAC before application of either the ionic, high-osmolar radiocontrast agent diatrizoate sodium (DTZ) or the nonionic, low-osmolar radiocontrast agent iohexol (IOH) in a rat model combining uninephrectomy, salt depletion, and administration of indomethacin was explored. Arterial blood pressure and total, cortical, and medullary blood flow were continuously recorded in anesthetized Sprague-Dawley rats.

RESULTS

NAC had no effect on renal hemodynamics in control rats. Both DTZ and IOH induced biphasic changes in renal blood flow and cortical renal blood flux and persistently reduced medullary blood flux. Neither single-dose nor prolonged administration of NAC prevented the hemodynamic changes following administration of DTZ or IOH, respectively. Acute prophylactic administration of NAC prevented increased urinary ET excretion after injection of IOH and, to a smaller degree, of DTZ. Both an ionic, high-osmolar (DTZ) and a nonionic, low-osmolar (IOH) radiocontrast agent induce marked changes in renal hemodynamics in salt-depleted rats treated with indomethacin.

CONCLUSIONS

Renal perfusion is not affected by NAC application in a model of experimental contrast nephropathy in rats. Other effects of NAC might thus account for the presumed renoprotective properties.

Prevention of cold-preservation injury of cultured endothelial cells by catecholamines and related compounds

The present study was conducted to dissect the underlying mechanisms by which catecholamines protect cells against preservation injury. To this end, we firstly defined the cellular and molecular differences between protected and nonprotected cells and secondly defined the mediators that were involved in cold-induced damage. Cold storage of untreated human umbilical vein endothelial cells (HUVECs) resulted in profound cellular damage as assessed by lactate dehydrogenase (LDH) release and by morphological changes, e.g. cell size alterations and loss of cytoskeletal organization. Treatment of HUVECs with catecholamines before cold storage prevented cellular damage in a dose- and time-dependent fashion. Similar results were obtained with carvedilol or its hydroxylated derivative BM91.0228. Protection was not receptor-mediated and did not require de novo protein synthesis. The onset of protection occurred relatively quickly and the duration was long lasting. Addition of superoxide dismutase (SOD) to untreated HUVECs during cold preservation also was protective. Oxidation of catecholamines completely abrogated the protective effect of these compounds on cold-induced damage. Both at 4 degrees and 37 degrees C, catecholamines reduced the amount of reactive oxygen species (ROS) produced by HUVECs. In conclusion we have demonstrated that catecholamines protect cells against preservation injury either by scavenging of ROS or by inhibition of ROS production.

Endothelin Receptor Antagonists: A New Therapeutic Option for Improving the Outcome after Solid Organ Transplantation?

Initially described as the most potent vasoconstrictor peptide, endothelin (ET) has also been shown to possess extraordinary immunomodulatory and proinflammatory properties. Because of this broad spectrum of biological activities, a possible role of the ET-system in solid organ transplantation has soon become a focus of research. Several studies demonstrated a pathogenetic involvement of ET in ischemia/reperfusion injury of heart, liver, kidney, and lung grafts. ET accumulates during cold storage of organs and can be detected in the effluent preservation solution. In addition ET is very, likely to play a pivotal role in the development of chronic rejection, which represents the major cause of late allograft loss. Increased expression of components of the ET-system has been described in areas of neointimal proliferation, a hallmark of chronic graft rejection. Both selective ET-A as well as non-selective ET-A/B receptor antagonists improved histomorphological and functional sequelae of chronic rejection. However these data have largely been derived from experimental animal transplantation, and ET receptor blockers have only recently been introduced in clinical medicine. A significant number of investigational drugs are now being tested in humans, with a main focus on cardiovascular diseases, such as congestive heart failure and pulmonary hypertension. First results have markedly dampened the initial enthusiastic vision of ET receptor blockers being organoprotective super-weapons. Thus the clinical potential of ET antagonists in general, and especially in solid-organ transplantation, is still to be defined.

Oxidative stress in chronic renal allograft nephropathy in rats: effects of long-term treatment with carvedilol, BM 91.0228, or alpha-tocopherol

Oxidative stress is markedly increased after kidney transplantation and may participate in the development and/or progression of chronic renal allograft nephropathy. In the present study we sought to assess the nephroprotective potential of antioxidative treatment in renal allograft recipients. Experiments were performed in the Fisher-Lewis rat model of chronic renal allograft nephropathy, with isografted Lewis rats serving as controls. Allografted rats were orally treated with carvedilol, an antihypertensive drug with antioxidative properties (25 mg/kg/d), its purely antioxidative derivative BM 91.0228 (5 mg/kg/d), alpha-tocopherol (100 mg/kg/d), a combination of propranolol/doxazosine (10/5 mg/kg/d), or vehicle for 24 weeks. At the end of the study, oxidative status and influence of antioxidative treatment were assessed in transplanted animals. Chronic allograft nephropathy was characterized by a marked increase of markers for oxidative stress (increased plasma and kidney levels of malondialdehyde, reduced glutathione, and tocopherol levels in renal allografts). Treatment with carvedilol, BM 91.0228, and tocopherol significantly improved antioxidative status of allograft kidney recipients. In addition, carvedilol reduced elevated blood pressure in allografted rats. However none of the drugs had a beneficial influence on functional and morphologic renal changes. Our data thus demonstrate that long-term treatment with the antioxidants carvedilol, BM 91.0228, or alpha-tocopherol does not prevent development of chronic transplant nephropathy, despite an improvement of antioxidative status.

Influence of acute selective endothelin-receptor-A blockade on renal hemodynamics in a rat model of chronic allograft rejection

We have recently demonstrated up-regulation of renal endothelin (ET) synthesis in a rat model of chronic renal allograft rejection. Treatment with a selective ET-A receptor antagonist improved survival and reduced functional and morphological kidney damage. However, the underlying mechanisms have not yet been elucidated, as ET exhibits both hemodynamic and inflammatory properties. Therefore, in the present study we investigated acute hemodynamic effects of the selective ET-A receptor antagonist LU 302146 (LU) on chronic renal allograft rejection in rats. Experiments were performed in the Fisher-to-Lewis model of chronic renal allograft rejection. Lewis-to-Lewis isografts served as controls. After 2, 12, and 24 weeks, hemodynamic measurements were performed on anesthetized animals. Measurement of mean arterial pressure (MAP) was performed via a catheter in the femoral artery. Renal blood flow (RBF) was measured by an ultrasonic flow probe placed around the renal transplant artery. Medulla blood flow (MBF) and cortex blood flow (CBF) were determined with laser Doppler probes. Hemodynamic response upon intravenous bolus injection of LU (50 mg/kg) was investigated. The application of LU was followed by a decline in MAP that reached statistical significance only in isografts (ISOs) after 12 weeks and allografts (ALLOs) after 24 weeks. RBF slightly decreased in all groups; however, without reaching statistical significance. MBF showed a small increase in ALLO12 and ALLO24 whereas CBF slightly decreased in all groups. Acute ET-A receptor blockade does not induce important hemodynamic effects in kidneys undergoing chronic rejection. The lack of response to ET-A receptor blockade suggests that the beneficial effect of ET receptor antagonists in this model is likely to be due to improvement of renal morphology.

Influence of acute selective endothelin-receptor-A blockade on renal hemodynamics in a rat model of chronic allograft rejection

We have recently demonstrated up-regulation of renal endothelin (ET) synthesis in a rat model of chronic renal allograft rejection. Treatment with a selective ET-A receptor antagonist improved survival and reduced functional and morphological kidney damage. However, the underlying mechanisms have not yet been elucidated, as ET exhibits both hemodynamic and inflammatory properties. Therefore, in the present study we investigated acute hemodynamic effects of the selective ET-A receptor antagonist LU 302146 (LU) on chronic renal allograft rejection in rats. Experiments were performed in the Fisher-to-Lewis model of chronic renal allograft rejection. Lewis-to-Lewis isografts served as controls. After 2, 12, and 24 weeks, hemodynamic measurements were performed on anesthetized animals. Measurement of mean arterial pressure (MAP) was performed via a catheter in the femoral artery. Renal blood flow (RBF) was measured by an ultrasonic flow probe placed around the renal transplant artery. Medulla blood flow (MBF) and cortex blood flow (CBF) were determined with laser Doppler probes. Hemodynamic response upon intravenous bolus injection of LU (50 mg/kg) was investigated. The application of LU was followed by a decline in MAP that reached statistical significance only in isografts (ISOs) after 12 weeks and allografts (ALLOs) after 24 weeks. RBF slightly decreased in all groups; however, without reaching statistical significance. MBF showed a small increase in ALLO12 and ALLO24 whereas CBF slightly decreased in all groups. Acute ET-A receptor blockade does not induce important hemodynamic effects in kidneys undergoing chronic rejection. The lack of response to ET-A receptor blockade suggests that the beneficial effect of ET receptor antagonists in this model is likely to be due to improvement of renal morphology.

Utilization of N-acetyl-L-tyrosine and glycyl-L-tyrosine during long-term parenteral nutrition in the growing rat

Utilization of N-acetyl-L-tyrosine and glycyl-L-tyrosine as a source of tyrosine in infusion solutions was tested in rats receiving total parenteral nutrition for 4 wk. The four solutions tested were isonitrogenous and isocaloric. One of the solutions contained an adequate amount of L-phenylalanine; in the other three, two-thirds of the phenylalanine was replaced by a corresponding amount of either glycine, glycyl-L-tyrosine or N-acetyl-L-tyrosine. No differences in weight gain or N-balance could be detected as a result of administering either the solution with glycyl-L-tyrosine or with N-acetyl-L-tyrosine in place of the solution containing an adequate phenylalanine content. The solution in which two-thirds of the L-phenylalanine was replaced by glycine yielded only half of the weight gain and correspondingly reduced values for N-balance. Daily urinary excretion rates for N-acetyl-L-tyrosine and glycyl-L-tyrosine were 11% and 0.5%, respectively, of the infused amount. Plasma amino acid pattern was affected differently by the four solutions. The results indicate that both N-acetyl-L-tyrosine and glycyl-L-tyrosine are efficiently utilized by the rat during total parenteral nutrition.

[Effect of the composition of the diet on the excretion of 3-methylhistidine and creatinine in urine]

3-Methylhistidine in a defined amount of meat, consumed by 7 healthy persons is excreted quantitatively in the urine within 2 days. Simultaneously recorded creatinine excretion remained constant in 4 of the participants while in 3 cases a considerable increase was observed during the day of meat consumption. An increase in nitrogen excretion as a result of meat consumption was observed in 5 out of 7 persons.

[Experimental model for long-term trials of parenteral nutrition in the growing rat]

Young male Sprague-Dawley rats (weighing approximately 170 gs) are entirely maintained by parenteral nutrition over a period of 4 weeks. The nutrient solution - a mixture of amino acids, glucose, fat, electrolytes, vitamins, and trace elements in a composition optimal for rats - is infused by means of a roller pump through a catheter leading to the vena cava and having its outlet in the midscapular region. The animals are provided with a little harness and kept in metabolic cages. They are freely movable during the entire infusion period. The average weight gain with an energy supply of 350 kcal and 1 g N/kg/24 h was recorded to be 3.8g/day. Since the requirement of nitrogen and energy per unit of body weight decreases with growth, nitrogen balance becomes increasingly positive in the course of the experimental period. Cumulative nitrogen retention during 24 days was 4.23 g. Operation techniques, treatment of the animals and composition of the infusion solutions are described in detail.