This study examined mechanisms by which immune cells participate in the development of hypertension and renal disease in Dahl salt-sensitive (SS) rats. Increasing dietary salt from 0.4% to 4.0% NaCl significantly increased renal infiltration of T lymphocytes from 8.8 +/- 1.2 x 10(5) to 14.4 +/- 2.0 x 10(5) cells/2 kidneys, increased arterial blood pressure from 131 +/- 2 to 165 +/- 6 mmHg, increased albumin excretion rate from 17 +/- 3 to 129 +/- 20 mg/day, and resulted in renal glomerular and tubular damage. Furthermore, renal tissue ANG II was not suppressed in the kidneys of SS rats fed 4.0% NaCl. Administration of the immunosuppressive agent mycophenolate mofetil (MMF; 20 mg.kg(-1).day(-1)) prevented the infiltration of T lymphocytes and attenuated Dahl SS hypertension and renal disease. In contrast to vehicle-treated rats, Dahl SS rats administered MMF demonstrated a suppression of renal tissue ANG II from 163 +/- 26 to 88 +/- 9 pg/g of tissue when fed high salt. Finally, it was demonstrated that the T lymphocytes isolated from the kidney possess renin and angiotensin-converting enzyme activity. These data indicate that infiltrating T cells are capable of participating in the production of ANG II and are associated with increased intrarenal ANG II, hypertension, and renal disease. The suppression of T-cell infiltration decreased intrarenal ANG II and prevented Dahl SS hypertension and kidney damage. As such, infiltrating cells are capable of participating in the established phase of Dahl SS hypertension.

Writing Committee for the REMAP-CAP Investigators IMPORTANCE The evidence for benefit of convalescent plasma for critically ill patients with COVID-19 is inconclusive.OBJECTIVE To determine whether convalescent plasma would improve outcomes for critically ill adults with COVID-19. DESIGN, SETTING, AND PARTICIPANTSThe ongoing Randomized, Embedded, Multifactorial, Adaptive Platform Trial for Community-Acquired Pneumonia (REMAP-CAP) enrolled and randomized 4763 adults with suspected or confirmed COVID-19 between March 9, 2020, and January 18, 2021, within at least 1 domain; 2011 critically ill adults were randomized to open-label interventions in the immunoglobulin domain at 129 sites in 4 countries. Follow-up ended on April 19, 2021. INTERVENTIONSThe immunoglobulin domain randomized participants to receive 2 units of high-titer, ABO-compatible convalescent plasma (total volume of 550 mL ± 150 mL) within 48 hours of randomization (n = 1084) or no convalescent plasma (n = 916). MAIN OUTCOMES AND MEASURESThe primary ordinal end point was organ support-free days (days alive and free of intensive care unit-based organ support) up to day 21 (range, −1 to 21 days; patients who died were assigned -1 day). The primary analysis was an adjusted bayesian cumulative logistic model. Superiority was defined as the posterior probability of an odds ratio (OR) greater than 1 (threshold for trial conclusion of superiority >99%). Futility was defined as the posterior probability of an OR less than 1.2 (threshold for trial conclusion of futility >95%). An OR greater than 1 represented improved survival, more organ support-free days, or both. The prespecified secondary outcomes included in-hospital survival; 28-day survival; 90-day survival; respiratory support-free days; cardiovascular support-free days; progression to invasive mechanical ventilation, extracorporeal mechanical oxygenation, or death; intensive care unit length of stay; hospital length of stay; World Health Organization ordinal scale score at day 14; venous thromboembolic events at 90 days; and serious adverse events. RESULTS Among the 2011 participants who were randomized (median age, 61 [IQR, 52 to 70] years and 645/1998 [32.3%] women), 1990 (99%) completed the trial. The convalescent plasma intervention was stopped after the prespecified criterion for futility was met. The median number of organ support-free days was 0 (IQR, -1 to 16) in the convalescent plasma group and 3 (IQR, -1 to 16) in the no convalescent plasma group. The in-hospital mortality rate was 37.3% (401/1075) for the convalescent plasma group and 38.4% (347/904) for the no convalescent plasma group and the median number of days alive and free of organ support was 14 (IQR, 3 to 18) and 14 (IQR, 7 to 18), respectively. The median-adjusted OR was 0.97 (95% credible interval, 0.83 to 1.15) and the posterior probability of futility (OR <1.2) was 99.4% for the convalescent plasma group compared with the no convalescent plasma group. The treatment effects were consistent across the primary outcome and the 11...

The present studies examined the role and mechanism of action of infiltrating T lymphocytes in the kidney during salt-sensitive hypertension. Infiltrating T lymphocytes in the Dahl salt-sensitive (SS) kidney significantly increased from 7.2 Ϯ 1.8 ϫ 10 5 cells/2 kidneys to 18.2 Ϯ 3.9 ϫ 10 5 cells/2 kidneys (n ϭ 6/group) when dietary NaCl was increased from 0.4 to 4.0%. Furthermore, the expression of immunoreactive p67 phox , gp91 phox , and p47 phox subunits of NADPH oxidase was increased in T cells isolated from the kidneys of rats fed 4.0% NaCl. The urinary excretion of thiobarbituric acid-reactive substances (TBARS; an index of oxidative stress) also increased from 367 Ϯ 49 to 688 Ϯ 92 nmol/day (n ϭ 8/group) when NaCl intake was increased in Dahl SS rats. Studies were then performed on rats treated with a daily injection of vehicle (5% dextrose) or tacrolimus (0.25 mg · kg Ϫ1 · day Ϫ1 ip), a calcineurin inhibitor that suppresses immune function, during the period of high-NaCl intake (n ϭ 5/group). In contrast to the immune cell infiltration, increased NADPH oxidase expression, and elevated urine TBARS excretion in vehicle-treated Dahl SS fed high salt, these parameters were unaltered as NaCl intake was increased in Dahl SS rats administered tacrolimus. Moreover, tacrolimus treatment blunted high-salt mean arterial blood pressure and albumin excretion rate (152 Ϯ 3 mmHg and 20 Ϯ 9 mg/day, respectively) compared with values in dextrose-treated Dahl SS rats (171 Ϯ 8 mmHg and 74 Ϯ 28 mg/day). These experiments indicate that blockade of infiltrating immune cells is associated with decreased oxidative stress, an attenuation of hypertension, and a reduction of renal damage in Dahl SS rats fed high salt. reactive oxygen species generation; chronic renal insufficiency OXIDATIVE STRESS, DEFINED as a persistent imbalance between the production of highly reactive molecular species (mainly oxygen and nitrogen) and antioxidant defenses, has been implicated in pathophysiological conditions that affect the cardiovascular system (12,28,35). Increased levels of oxidative stress have been described in experimental models of hypertension (2, 6, 20) and hypertensive patients (22,35).A number of studies in animal models of hypertension demonstrated elevations of blood pressure by stimulation of reactive oxygen species (ROS) generation (24,44,47). Moreover, treatment with a variety of antioxidants reduces blood pressure in several genetic and experimental models of hypertension (4,7,30,40,48). One of the most important biological mechanisms for the production of ROS results from the generation of superoxide (O 2 ·Ϫ ) from O 2 by the enzyme NADPH oxidase (14). Stimulation of NADPH oxidase appears to be the primary source of oxidants in systemic arterial vessels in renovascular hypertension (16), ANG II-induced hypertension (8, 34), DOCA-salt hypertension (42, 49), chronic renal insufficiency (47), and the spontaneously hypertensive rat (49). In humans, NADPH oxidase is the principal source of O 2 ·Ϫ in vascular smooth muscle cells (1...

Mattson DL, Lund H, Guo C, Rudemiller N, Geurts AM, Jacob H. Genetic mutation of recombination activating gene 1 in Dahl salt-sensitive rats attenuates hypertension and renal damage.