MO1050: Covid-19 Vaccination Improved Psychological Distress (Anxiety and Depression Scores) in Chronic Kidney Disease Patients: A Prospective Study

BACKGROUND AND AIMS

To our knowledge, the psychological impact of coronavirus disease (COVID-19) vaccination has not yet been evaluated for the general population nor for chronic kidney disease (CKD) patients.

The purpose of the study is to analyse the impact of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on anxiety and depression scores in patients with different modalities of CKD.

METHOD

A total of 117 renal patients (50 haemodialysis patients, 13 peritoneal dialysis patients, 32 kidney transplants and 22 advanced CKD patients at pre-dialysis care) were evaluated for depression, anxiety, health-related quality of life (HRQOL) and perceived fears and resources with standardized (The Hospital Anxiety and Depression Scale; HADS) and self-reported questionnaires. The measure points were before vaccination and 15 days after vaccination.

RESULTS

The main finding of the study is that there is a decrease in the global mean of normal scores for anxiety and depression symptoms in CKD patients, post-vaccination. We did not find statistically significant differences in depression or anxiety scores, nor HRQOL differences between the treatment groups. The three main fears reported by the participants at baseline were those of adverse effects, not getting the vaccine and lack of information.

CONCLUSION

These findings highlight the potential interest of assessing psychological variables related to the impact of vaccination against SARS-CoV-2. New studies will be required to assess the impact of comprehensive vaccine coverage and its psychological impact.

MO877: Dynamics of SARS-COV-2-Spike-Reactive Antibody and T-Cell Responses in Chronic Kidney Disease Patients Within 3 Months After Covid-19 Full Vaccination

BACKGROUND AND AIMS

Little is known regarding the dynamics of antibody and T-cell responses in chronic kidney disease (CKD) following COVID-19 vaccination.

METHOD

Prospective observational cohort study including 144 participants on haemodialysis (HD) (n = 52), peritoneal dialysis (PD) (n = 14), kidney transplantation (KT) (n = 30) or advanced chronic kidney disease not on dialysis (ACKD), and healthy controls (n = 18). Anti-Spike(S) antibody and T-cell responses were assessed at 15 days (15D) and 3 months (3M) after vaccination.

RESULTS

Anti-S antibodies at 15D and 3M were detectable in 95% (48/50)/98% (49/50) of HD patients, 93% (13/14)/100% of PD patients, 67% (17/26)/75% (21/28) of KT patients and 96% (25/26)/100% (24/24) of ACKD patients. Rates for healthy controls were 81% (13/16)/100% (17/17). Antibody levels decreased at 3M in HD (P = 0.04), PD (P = 0.008) and ACKD patients (P = 0.0009). In KT, patients levels increased (P = 0.04) between 15D and 3M,  although they were low at both time points.

Detectable T-cell responses notably increased at 3M in HD patients (P < 0.022). In PD, patients response increased by 15D (13/14; 93%) and 3M (9/9; 100%), while they were present in KT patients at 41% (12/27), 84% (22/26) and 96% (25/26) at baseline. Detectable T-cell responses in ACKD patients reached 80% (20/25) and 89% (17/19) at 15D and 3M,  respectively. whereas in healthy controls it was 67% and 89% at 15D and 3M.

CONCLUSION

 Most HD, PD and ACKD patients develop SARS-CoV-2-S antibody responses comparable to that of healthy controls, in contrast to KT recipients. Antibody waning at 3M was faster in HD, PD, ACKD patients. No differences in SARS-CoV-2 T-cell immunity responses were noticed across study groups.

Calcium-dependent inhibition of L, N, and P/Q Ca2+ channels in chromaffin cells: role of mitochondria

The hypothesis that the buffering of Ca(2+) by mitochondria could affect the Ca(2+)-dependent inhibition of voltage-activated Ca(2+) channels, (I(Ca)), was tested in voltage-clamped bovine adrenal chromaffin cells. The protonophore carbonyl cyanide m-chlorophenyl-hydrazone (CCCP), the blocker of the Ca(2+) uniporter ruthenium red (RR), and a combination of oligomycin plus rotenone were used to interfere with mitochondrial Ca(2+) buffering. In cells dialyzed with an EGTA-free solution, peak I(Ca) generated by 20 msec pulses to 0 or +10 mV, applied at 15 sec intervals, from a holding potential of -80 mV, decayed rapidly after superfusion of cells with 2 microm CCCP (tau = 16.7 +/- 3 sec; n = 8). In cells dialyzed with 14 mm EGTA, CCCP did not provoke I(Ca) loss. Cell dialysis with 4 microm ruthenium red or cell superfusion with oligomycin (3 microm) plus rotenone (4 microm) also accelerated the decay of I(Ca). After treatment with CCCP, decay of N- and P/Q-type Ca(2+) channel currents occurred faster than that of L-type Ca(2+) channel currents. These data are compatible with the idea that the elevation of the bulk cytosolic Ca(2+) concentration, [Ca(2+)](c), causes the inhibition of L- and N- as well as P/Q-type Ca(2+) channels expressed by bovine chromaffin cells. This [Ca(2+)](c) signal appears to be tightly regulated by rapid Ca(2+) uptake into mitochondria. Thus, it is plausible that mitochondria might efficiently regulate the activity of L, N, and P/Q Ca(2+) channels under physiological stimulation conditions of the cell.

Synergism between toxin-gamma from Brazilian scorpion Tityus serrulatus and veratridine in chromaffin cells

Toxin-gamma (Tgamma) from the Brazilian scorpion Tityus serrulatus venom caused a concentration- and time-dependent increase in the release of norepinephrine and epinephrine from bovine adrenal medullary chromaffin cells. Tgamma was approximately 200-fold more potent than veratridine judged from EC50 values, although the maximal secretory efficacy of veratridine was 10-fold greater than that of Tgamma (1.2 vs. 12 microg/ml of catecholamine release). The combination of both toxins produced a synergistic effect that was particularly drastic at 5 mM extracellular Ca2+ concentration ([Ca2+]o), when 30 microM veratridine plus 0.45 microM Tgamma were used. Tgamma (0.45 microM) doubled the basal uptake of 45Ca2+, whereas veratridine (100 microM) tripled it. Again, a drastic synergism in enhancing Ca2+ entry was seen when Tgamma and veratridine were combined; this was particularly pronounced at 5 mM [Ca2+]o. Veratridine induced oscillations of cytosolic Ca2+ concentration ([Ca2+]i) in single fura 2-loaded cells without elevation of basal levels. In contrast, Tgamma elevated basal [Ca2+]i levels, causing only small oscillations. When added together, Tgamma and veratridine elevated the basal levels of [Ca2+]i without causing large oscillations. Tgamma shifted the current-voltage (I-V) curve for Na+ channel current to the left. The combination of Tgamma with veratridine increased the shift of the I-V curve to the left, resulting in a greater recruitment of Na+ channels at more hyperpolarizing potentials. This led to enhanced and more rapid accumulation of Na+ in the cell, causing cell depolarization, the opening of voltage-dependent Ca2+ channels, and Ca2+ entry and secretion.

Permeation and inactivation by calcium and manganese of bovine adrenal chromaffin cell calcium channels

Stimulation of fura-2-loaded bovine chromaffin cells with the nicotinic agonist 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP; 10 microM) or depolarization with high [K+] (50 mM) accelerated the entry of both Ca2+ and Mn2+, used here as a Ca2+ surrogate for Ca2+ channels. Removal of extracellular Na+ prevented the effects of DMPP but did not modify the effects of K+, indicating that Na+ is necessary for coupling of Ca2+ entry to the nicotinic receptor activation and that the ionophore associated with it is functionally impermeable to divalent cations. DMPP- as well as K(+)-evoked Ca2+ and Mn2+ influx were blocked completely by Ni2+ but only partially by dihydropyridines, suggesting that, in addition to L-type Ca2+ channels, other Ca2+ entry pathways may be present. Inactivation of Ca2+ channels, followed by comparing the rates of Mn2+ uptake at different time periods after the addition of DMPP or high K+, did not happen in the absence of extracellular Ca2+. When 1 mM Ca2+ was present, a delayed inhibition (half time, 10-20 s) was observed, suggesting that it is not due to the entry of Ca2+ itself but to the increase of the cytoplasmic Ca2+ concentration ([Ca2+]i) that takes a few seconds to develop. The influx of Ca2+, estimated from the increase of [Ca2+]i, was also impaired in a time-dependent fashion by previous entry of Mn2+. Inactivation of Ca2+ entry was achieved at estimated mean intracellular Mn2+ concentrations as low as 10(-9) M.

A two-dimensional electrophoresis study of phosphorylation and dephosphorylation of chromaffin cell proteins in response to a secretory stimulus

Phosphorylated proteins of bovine chromaffin cells, radioactively labeled with [32P]orthophosphate, have been analyzed by two-dimensional polyacrylamide gel electrophoresis and autoradiography. Complex two-dimensional electrophoretograms were studied with the aid of computer-assisted image analysis (CAIA). A database map of 32P-labeled proteins was constructed; approximately 500 polypeptides have been detected, numbered, and characterized according to the intensity of labeling, molecular weight, and isoelectric point. The database was constructed from cells kept in resting conditions or stimulated with 59 mM K+ in 2.5 mM Ca2+ or in 0 Ca2+ solution. These manipulations caused statistically significant changes in the degree of phosphorylation of 20 proteins; they were classified as Ca2+-dependent substrates for the phosphorylation or dephosphorylation processes. These changes were also shown in cells stimulated in the presence of the Ca2+ channel activator Bay K 8644. New proteins that show as much as a fivefold increase in their phosphorylation state during cell stimulation have been located with this methodology, as well as many others that had not previously been detected with conventional methods. These experiments provide the first CAIA database of chromaffin cell phosphoproteins; the map constructed with these data will allow the location of specific phosphoproteins and serve as a reference for future ongoing studies. The database will continue to grow to identify more proteins and to facilitate the comparison of complex patterns obtained in different laboratories for normal and transformed pheochromocytoma PC12 cells.

Dihydropyridine chirality at the chromaffin cell calcium channel

The racemic mixture of the dihydropyridine PN200-110 (Sandoz) inhibits K+-evoked catecholamine release from cat adrenal glands with an IC50 of 4.1 nM; IC50's for (+)- and (-)-PN200-110 were 0.84 and 45.8 nM, respectively. While the (+)-enantiomer of the dihydropyridine Sandoz 202-791 potentiated secretion (EC50 = 100 nM), the (-)-enantiomer behaved as a potent inhibitor (IC50 = 10 nM). Since K+-evoked 45Ca-uptake was also potently inhibited by (+)-PN200-110, it seems that the chromaffin cell dihydropyridine receptor is associated to the voltage-dependent Ca-channel and that it exhibits an exquisite stereoselectivity.