Dual anti-viral treatment for persistent COVID-19 in immunocompromised hemato-oncological patients is associated with a favorable prognosis and minor side effects.

In hemato-oncological patients, COVID-19 can present as a persistent infection with ongoing symptoms and viral replication over a prolonged period of time. Data are scarce on the preferred treatment options for these patients. We describe our experience with a five-day course of dual anti-viral treatment with remdesivir and nirmatrelvir/ritonavir for hemato-oncological immunocompromised patients with persistent COVID-19. Fifteen patients with a history of lymphoma, CLL, and MM were included. Eight were male, median age was 74. All patients had an immediate clinical and virological response. In 73 % of patients, PCR for SARS-CoV-2 became negative at the end of treatment and the rest had an increase in PCR cycle threshold (CT) values, with a median increase of 6 cycles. After a follow-up of three months, 60 % of patients remained in full clinical and virological remission. None required invasive mechanical ventilation or died. The side effects we observed, neutropenia, lactatemia and elevated transaminases, were mild and almost all transient in nature. We conclude that dual anti-viral treatment appears to be a valid treatment option for persistent COVID-19.

Rate of Correction and All-Cause Mortality in Patients With Severe Hypernatremia.

Importance: Hypernatremia is common among hospitalized patients and is associated with high mortality rates. Current guidelines suggest avoiding fast correction rates but are not supported by robust data. Objective: To investigate whether there is an association between hypernatremia correction rate and patient survival. Design, Setting, and Participants: This retrospective cohort study examined data from all patients admitted to the Tel Aviv Medical Center between 2007 and 2021 who were diagnosed with severe hypernatremia (serum sodium ≥155 mmol/L) at admission or during hospitalization. Statistical analysis was performed from April 2022 to August 2023. Exposure: Patients were grouped as having fast correction rates (>0.5 mmol/L/h) and slow correction rates (≤0.5 mmol/L/h) in accordance with current guidelines. Main Outcomes and Measures: All-cause 30-day mortality. Results: A total of 4265 patients were included in this cohort, of which 2621 (61.5%) were men and 343 (8.0%) had fast correction rates; the median (IQR) age at diagnosis was 78 (64-87) years. Slow correction was associated with higher 30-day mortality compared with fast correction (50.7% [1990 of 3922] vs 31.8% [109 of 343]; P < .001). These results remained significant after adjusting for demographics (age, gender), Charlson comorbidity index, initial sodium, potassium, and creatinine levels, hospitalization in an ICU, and severe hyperglycemia (adjusted odds ratio [aOR], 2.02 [95% CI, 1.55-2.62]), regardless of whether hypernatremia was hospital acquired (aOR, 2.19 [95% CI, 1.57-3.05]) or documented on admission (aOR, 1.64 [95% CI, 1.06-2.55]). There was a strong negative correlation between absolute sodium correction during the first 24 hours following the initial documentation of severe hypernatremia and 30-day mortality (Pearson correlation coefficient, -0.80 [95% CI, -0.93 to -0.50]; P < .001). Median (IQR) hospitalization length was shorter for fast correction vs slow correction rates (5.0 [2.1-14.9] days vs 7.2 [3.5-16.1] days; P < .001). Prevalence of neurological complications was comparable for both groups, and none were attributed to fast correction rates of hypernatremia. Conclusions and Relevance: This cohort study of patients with severe hypernatremia found that rapid correction of hypernatremia was associated with shorter hospitalizations and significantly lower patient mortality without any signs of neurologic complications. These results suggest that physicians should consider the totality of evidence when considering the optimal rates of correction for patients with severe hypernatremia.

Cardiologic Manifestations in Omicron-Type Versus Wild-Type COVID-19: A Systematic Echocardiographic Study.

Background Information about the cardiac manifestations of the Omicron variant of COVID-19 is limited. We performed a systematic prospective echocardiographic evaluation of consecutive patients hospitalized with the Omicron variant of COVID-19 infection and compared them with similarly recruited patients were propensity matched with the wild-type variant. Methods and Results A total of 162 consecutive patients hospitalized with Omicron COVID-19 underwent complete echocardiographic evaluation within 24 hours of admission and were compared with propensity-matched patients with the wild-type variant (148 pairs). Echocardiography included left ventricular (LV) systolic and diastolic, right ventricular (RV), strain, and hemodynamic assessment. Echocardiographic parameters during acute infection were compared with historic exams in 62 patients with the Omicron variant and 19 patients with the wild-type variant who had a previous exam within 1 year. Of the patients, 85 (53%) had a normal echocardiogram. The most common cardiac pathology was RV dilatation and dysfunction (33%), followed by elevated LV filling pressure (E/e' ≥14, 29%) and LV systolic dysfunction (ejection fraction <50%, 10%). Compared with the matched wild-type cohort, patients with Omicron had smaller RV end-systolic areas (9.3±4 versus 12.3±4 cm2; P=0.0003), improved RV function (RV fractional-area change, 53.2%±10% versus 39.7%±13% [P<0.0001]; RV S', 12.0±3 versus 10.7±3 cm/s [P=0.001]), and higher stroke volume index (35.6 versus 32.5 mL/m2; P=0.004), all possibly related to lower mean pulmonary pressure (34.6±12 versus 41.1±14 mm Hg; P=0.0001) and the pulmonary vascular resistance index (P=0.0003). LV systolic or diastolic parameters were mostly similar to the wild-type variant-matched cohort apart from larger LV size. However, in patients who had a previous echocardiographic exam, these LV abnormalities were recorded before acute Omicron infection, but not in the wild-type cohort. Numerous echocardiographic parameters were associated with higher in-hospital mortality (LV ejection fraction, stroke volume index, E/e', RV S'). Conclusions In patients with Omicron, RV function is impaired to a lower extent compared with the wild-type variant, possibly related to the attenuated pulmonary parenchymal and/or vascular disease. LV systolic and diastolic abnormalities are as common as in the wild-type variant but were usually recorded before acute infection and probably reflect background cardiac morbidity. Numerous LV and RV abnormalities are associated with adverse outcome in patients with Omicron.

Pericardial Involvement in Patients Hospitalized With COVID-19: Prevalence, Associates, and Clinical Implications.

Background The scope of pericardial involvement in COVID-19 infection is unknown. We aimed to evaluate the prevalence, associates, and clinical impact of pericardial involvement in hospitalized patients with COVID-19. Methods and Results Consecutive patients with COVID-19 underwent clinical and echocardiographic examination, irrespective of clinical indication, within 48 hours as part of a prospective predefined protocol. Protocol included clinical symptoms and signs suggestive of pericarditis, calculation of modified early warning score, ECG and echocardiographic assessment for pericardial effusion, left and right ventricular systolic and diastolic function, and hemodynamics. We identified predictors of mortality and assessed the adjunctive value of pericardial effusion on top of clinical and echocardiographic parameters. The study included 530 patients. Pericardial effusion was found in 75 (14%), but only 17 patients (3.2%) fulfilled the criteria for acute pericarditis. Pericardial effusion was independently associated with modified early warning score, brain natriuretic peptide, and right ventricular function. It was associated with excess mortality (hazard ratio [HR], 2.44; P=0.0005) in nonadjusted analysis. In multivariate analysis adjusted for modified early warning score and echocardiographic and hemodynamic parameters, it was marginally associated with mortality (HR, 1.86; P=0.06) and improvement in the model fit (P=0.07). Combined assessment for pericardial effusion with modified early warning score, left ventricular ejection fraction, and tricuspid annular plane systolic excursion was an independent predictor of outcome (HR, 1.86; P=0.02) and improved model fit (P=0.02). Conclusions In hospitalized patients with COVID-19, pericardial effusion is prevalent, but rarely attributable to acute pericarditis. It is associated with myocardial dysfunction and mortality. A limited echocardiographic examination, including left ventricular ejection fraction, tricuspid annular plane systolic excursion, and assessment for pericardial effusion, can contribute to outcome prediction.

Forced Diuresis with Matched Isotonic Intravenous Hydration Prevents Renal Contrast Media Accumulation.

The accumulation of contrast media in the kidneys might lead to contrast-induced acute kidney injury. In this prospective, controlled observational study, we aimed to evaluate whether forced diuresis with matched isotonic intravenous hydration prevents the accumulation of contrast media in the kidneys of patients undergoing cardiac interventional procedures. We compared the intensity of contrast media accumulation as observed in nephrograms following these procedures, with and without peri-procedural controlled renal flushing. The study group consisted of 25 patients with impaired renal function treated with the RenalGuard system. The two control groups included 25 patients with normal kidney function and 8 patients with impaired renal function undergoing similar procedures with routine pre-procedural hydration, but without controlled renal flushing. Renal contrast media accumulation at the end of each procedure was scored by blinded cardiologists. The renal contrast accumulation score (CAS) in the study group was significantly lower, with a median score of 0 (IQR (0-0)) compared with 1.5 (IQR (1-2)) in the normal renal function control group and 1 (IQR (0.38-1.62)) in the impaired renal function control group (p < 0.001 and 0.003, respectively). In a multivariate analysis of CAS, RenalGuard treatment was independently associated with lower CAS compared to both control groups. In conclusion, RenalGuard use prevents renal contrast accumulation in patients with impaired renal function undergoing cardiac procedures with intra-arterial contrast media injection.

Clinically Significant High-Grade AV Block as a Reversible Cause for Acute Kidney Injury in Hospitalized Patients-A Propensity Score Matched Cohort.

Background. High-grade AV block (HGAVB) is a life-threatening condition. Acute kidney injury (AKI) which is usually caused by renal hypo-perfusion is associated with adverse outcomes. We aimed to investigate the association between AKI and HGAVB. Methods. This is a retrospective cohort comparing the incidence of AKI among patients with HGAVB requiring pacemaker implantation compared with propensity score matched controls. Primary outcome was the incidence of AKI at admission. Secondary outcomes were change in creatinine levels, AKI during stay, recovery from AKI, mortality and major adverse kidney events (MAKE). Results. In total, 80 HGAVB patients were compared to 400 controls. HGAVB patients had a higher proportion of admission AKI compared to controls (36.2% versus 21.1%, RR = 1.71 [1.21-2.41], p = 0.004). Creatinine changes from baseline to admission and to maximum during hospitalization, were also higher in HGAVB (p = 0.042 and p = 0.033). Recovery from AKI was more frequent among HGAVB patients (55.2% vs. 25.9%, RR = 2.13 [1.31-3.47], p = 0.004) with hospitalization time, MAKE and crude mortality similar (p > 0.158). Conclusions. AKI occurs in about one third of patients admitted with HGAVB, more frequent compared to controls. Patients with AKI accompanying HGAVB were likelier to recover from AKI. Further studies to explore this relationship could aid in clinical decision making for HGAVB patients.

COVID-19, a tale of two peaks: patients' characteristics, treatments, and clinical outcomes.

Coronavirus 2019 disease (COVID-19) continues to challenge healthcare systems globally as many countries are currently experiencing an increase in the morbidity and mortality. Compare baseline characteristics, clinical presentation, treatments, and clinical outcomes of patients admitted during the second peak to those admitted during the first peak. Retrospective analysis of 258 COVID-19 patients consecutively admitted to the Tel Aviv Medical Center, of which, 131 during the first peak (March 21-May 30, 2020) and 127 during the second peak (May 31-July 16, 2020). First and second peak patients did not differ in baseline characteristics and clinical presentation at admission. Treatment with dexamethasone, full-dose anticoagulation, tocilizumab, remdesivir, and convalescent plasma transfusion were significantly more frequent during the second peak, as well as regimens combining 3-4 COVID-19-directed drugs. Compared to the first peak, 30-day mortality and invasive mechanical ventilation rates as well as adjusted risk were significantly lower during the second peak (10.2%, vs 19.8% vs p = 0.028, adjusted HR 0.39, 95% CI 0.19-0.79, p = 0.009 and 8.8% vs 19.3%, p = 0.002, adjusted HR 0.29, 95% CI 0.13-0.64, p = 0.002; respectively). Rates of 30-day mortality and invasive mechanical ventilation, as well as adjusted risks, were lower in the second peak of the COVID-19 pandemic among hospitalized patients. The change in treatment strategy and the experienced gained during the first peak may have contributed to the improved outcomes.

The Predictive Role of Combined Cardiac and Lung Ultrasound in Coronavirus Disease 2019.

BACKGROUND: The aim of this study was to evaluate sonographic features that may aid in risk stratification and to propose a focused cardiac and lung ultrasound (LUS) algorithm in patients with coronavirus disease 2019. METHODS: Two hundred consecutive hospitalized patients with coronavirus disease 2019 underwent comprehensive clinical and echocardiographic examination, as well as LUS, irrespective of clinical indication, within 24 hours of admission as part of a prospective predefined protocol. Assessment included calculation of the modified early warning score (MEWS), left ventricular systolic and diastolic function, hemodynamic and right ventricular assessment, and a calculated LUS score. Outcome analysis was performed to identify echocardiographic and LUS predictors of mortality or the composite event of mortality or need for invasive mechanical ventilation and to assess their adjunctive value on top of clinical parameters and MEWS. RESULTS: A simplified echocardiographic risk score composed of left ventricular ejection fraction < 50% combined with tricuspid annular plane systolic excursion < 18 mm was associated with mortality (P = .0002) and with the composite event (P = .0001). Stepwise analyses evaluating echocardiographic and LUS parameters on top of existing clinical risk scores showed that addition of tricuspid annular plane systolic excursion and stroke volume index improved prediction of mortality when added to clinical variables but not when added to MEWS. Once echocardiography was added, and patients were recategorized as high risk only if having both high-risk MEWS and high-risk cardiac features, specificity increased from 63% to 87%, positive predictive value from 28% to 48%, and accuracy from 66% to 85%. Although LUS was not associated with incremental risk prediction for mortality above clinical and echocardiographic criteria, it improved prediction of need for invasive mechanical ventilation. CONCLUSIONS: In hospitalized patients with coronavirus disease 2019, a very limited echocardiographic examination is sufficient for outcome prediction. The addition of echocardiography in patients with high-risk MEWS decreases the rate of falsely identifying patients as high risk to die and may improve resource allocation in case of high patient load.

Effect of pacemaker implantation after transcatheter aortic valve replacement on long- and mid-term mortality.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has become quite common. Atrioventricular conduction defects remain a frequent complication resulting with permanent pacemaker (PPM) implantation. Past studies showed conflicting results regarding PPM effect on mortality. OBJECTIVE: The purpose of this study was to assess the influence of PPM implantation on mid- and long-term mortality in a large cohort of patients who underwent TAVR. METHODS: Patients undergoing TAVR between 2009 and 2019 were categorized into groups: no PPM implanted (no-PPM), PPM implanted before the procedure (pre-PPM), and PPM implanted postprocedure (post-PPM). All-cause mortality up to 6 years was compared. Subanalyses were performed according to pacing burden. Proportion of patients who had decreased left ventricular ejection fraction within 1 year of the procedure after TAVR was also recorded. RESULTS: A total of 1489 patients were followed. Unadjusted mortality was similar for patients regardless of PPM status within 12 months (P > .187), yet within 72 months, mortality was similar for the post-PPM (P = .257) and higher for pre-PPM (hazard ratio 1.53; P = .002) groups. Analysis adjusted by clinical characteristics did not show any independent long- or mid-term survival effects of PPM (P > .563). Analysis according to pacing burden showed no significant mortality difference (P > .8). Analysis of post-PPM patients with "high" or "near constant" (>40%) pacing burden vs no-PPM patients showed similar mortality for both mid- and long-term mortality (P = .055 and P = .513). Left ventricular ejection fraction decrease within 1 year was more common in both PPM groups, with a higher proportion with higher pacing burden (P < .001). CONCLUSION: This cohort of consecutive patients undergoing TAVR showed that postprocedure PPM was not associated with increased long-term mortality. This conclusion was not altered by ventricular pacing burden.

Natural cannabinoids suppress the cytokine storm in sepsis-like in vitro model.

Natural cannabinoids may have beneficial effects on various tissues and functions including a positive influence on the immune system and the inflammatory process. The purpose of this study was to investigate the effects of natural cannabinoids on the production of pro-inflammatory cytokines by lipopolysaccharide (LPS)-stimulated whole human blood cells. Levels of the pro-inflammatory cytokines interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were measured before and after exposure of LPS-stimulated whole blood to different concentrations of Cannabidiol (CBD) or a combination of CBD and Tetrahydrocannabinol (THC) extract. LPS stimulated the production of the pro-inflammatory cytokines. Exposure to both CBD and CBD/THC extracts significantly suppressed cytokine production in a dose-dependent manner. Exposure to cannabinoid concentrations of 50 µg/ml or 100 µg/ml resulted in a near-complete inhibition of cytokine production. This study demonstrates that natural cannabinoids significantly suppress pro-inflammatory cytokine production in LPS-stimulated whole blood in a dose-dependent manner. The use of human whole blood, rather than isolated specific cells or tissues, may closely mimic an in vivo sepsis environment. These findings highlight the role that natural cannabinoids may play in suppressing inflammation and call for additional studies of their use as possible novel therapeutic agents for acute and chronic inflammation.

Correction to: Lung ultrasound predicts clinical course and outcomes in COVID-19 patients.

The original article can be found online.

Lung ultrasound predicts clinical course and outcomes in COVID-19 patients.

PURPOSE: Information regarding the use of lung ultrasound (LUS) in patients with Coronavirus disease 2019 (COVID-19) is quickly accumulating, but its use for risk stratification and outcome prediction has yet to be described. We performed the first systematic and comprehensive LUS evaluation of consecutive patients hospitalized with COVID-19 infection, in order to describe LUS findings and their association with clinical course and outcome. METHODS: Between 21/03/2020 and 04/05/2020, 120 consecutive patients admitted to the Tel Aviv Medical Center due to COVID-19, underwent complete LUS within 24 h of admission. A second exam was performed in case of clinical deterioration. LUS score of 0 (best)-36 (worst) was assigned to each patient. LUS findings were compared with clinical data. RESULTS: The median baseline total LUS score was 15, IQR [7-20]. Baseline LUS score was 0-18 in 80 (67%) patients, and 19-36 in 40 (33%) patients. The majority had patchy pleural thickening (n = 100; 83%), or patchy subpleural consolidations (n = 93; 78%) in at least one zone. The prevalence of pleural thickening, subpleural consolidations and the total LUS score were all correlated with severity of illness on admission. Clinical deterioration was associated with increased follow-up LUS scores (p = 0.0009), mostly due to loss of aeration in anterior lung segments. The optimal cutoff point for LUS score was 18 (sensitivity = 62%, specificity = 74%). Both mortality and need for invasive mechanical ventilation were increased with baseline LUS score > 18 compared to baseline LUS score 0-18. Unadjusted hazard ratio of death for LUS score was 1.08 per point [1.02-1.16], p = 0.008; Unadjusted hazard ratio of the composite endpoint (death or need for invasive mechanical ventilation) for LUS score was 1.12 per point [1.05-1.2], p = 0.0008. CONCLUSION: Hospitalized patients with COVID-19, at all clinical grades, present with pathological LUS findings. Baseline LUS score strongly correlates with the eventual need for invasive mechanical ventilation and is a strong predictor of mortality. Routine use of LUS may guide patients' management strategies, as well as resource allocation in case of surge capacity.

Infected Thrombus on a TAVI Aortic Valve.

After a series of tests, an 86-year-old patient was shown to have an infected thrombus on a TAVI valve and was referred to urgent surgery. The valve with the infected thrombus was removed and a biological prosthetic valve was implanted in its place.

Hospitalization as an opportunity to correct errors in anticoagulant treatment in patients with atrial fibrillation.

AIMS: To assess whether hospitalization may assist in correcting errors in anticoagulant therapy among patients with atrial fibrillation (AF). METHODS: Our cohort included patients admitted to our institution with a history of AF between 2016 and 2018. We categorized patient's treatment upon admission and discharge as lacking (no treatment despite indication), inadequate (according to individual characteristics) or adequate. We assessed adequacy of treatment upon discharge and determined factors associated with correcting admission errors. RESULTS: Of 4427 patients admitted with a history of AF, the categorization to lacking, inadequate and adequate treatment was 1746 (39.4%), 1237 (27.9%) and 1444 (32.6%) patients, respectively. Of those with inadequate treatment, the most common types of errors were direct oral anticoagulant (DOAC) underdosing (n = 578; 46.7%), vitamin-K antagonists when DOAC was indicated (n = 258; 20.9%), DOAC despite contraindication to DOAC (n = 166; 13.4%) and DOAC overdosing (n = 124; 10%). Upon discharge 688 (18.6%, out of n = 3694) corrections but also 316 (8.6%) new mistakes were found. On multivariate logistic regression, the factors associated with correction of an error on admission were hospitalization due to AF (odds ratio [OR] 2.94 [2.39-3.61]), hospitalization in the neurologic or geriatric wards (OR 2.79 [2.04-3.80]), female sex (OR 1.34 [1.10-1.63]) and a history of stroke (OR 1.47 [1.17-1.86]), while the presence of a contraindication to DOAC decreased the chance of correction (OR 0.10 [0.06-0.18]). CONCLUSION: Hospitalization for any reason may contribute to correction of errors in AC treatment in patients with AF. Unfortunately, a significant portion of patients remains inadequately treated by both outpatient and inpatient providers.

Dimethyl sulfoxide attenuates nitric oxide generation via modulation of cationic amino acid transporter-1 in human umbilical vein endothelial cells.

Dimethyl sulfoxide (DMSO) is a solvent that is commonly used in medicine. Conflicting data exist as to its effects on endothelial function. Endothelial cell dysfunction (ECD) is characterized by decreased endothelial nitric oxide synthase (eNOS) activity. Cationic amino acid transporter-1 (CAT-1), the specific arginine transporter for eNOS, has been shown to modulate eNOS activity. We hypothesize that DMSO inhibits eNOS activity through modulation of its selective arginine supplier CAT-1. We studied the effect of DMSO on arginine transport, NO2/NO3 generation as an index of NO production, as well as CAT-1 and Protein Kinase C alpha (PKC-α) (CAT-1 inhibitor) protein expression in human umbilical vein endothelial cell cultures (HUVECs). DMSO 2.5% and 3.5% (v/v) significantly attenuated arginine transport, a phenomenon which was prevented by co-incubation with l-arginine (1 mM). The aforementioned findings were accompanied by a decrease in NO2/NO3 generation. DMSO significantly increased the abundance of phosphorylated CAT-1 (the inactive form) and phosphorylated PKC-α protein, an effect that was attenuated by l-arginine. GO 6976 (PKC-α antagonist) prevented the decrease in arginine transport caused by DMSO. DMSO also induced profound transient morphological changes in HUVECs' structure but these were not related to its effect on arginine transport. In conclusion, DMSO inhibits NO generation by endothelial cells through modulation of CAT-1 activity.

Estradiol augments while progesterone inhibits arginine transport in human endothelial cells through modulation of cationic amino acid transporter-1.

Decreased generation of nitric oxide (NO) by endothelial NO synthase (eNOS) characterizes endothelial dysfunction (ECD). Delivery of arginine to eNOS by cationic amino acid transporter-1 (CAT-1) was shown to modulate eNOS activity. We found in female rats, but not in males, that CAT-1 activity is preserved with age and in chronic renal failure, two experimental models of ECD. In contrast, during pregnancy CAT-1 is inhibited. We hypothesize that female sex hormones regulate arginine transport. Arginine uptake in human umbilical vein endothelial cells (HUVEC) was determined following incubation with either 17ß-estradiol (E2) or progesterone. Exposure to E2 (50 and 100 nM) for 30 min resulted in a significant increase in arginine transport and reduction in phosphorylated CAT-1 (the inactive form) protein content. This was coupled with a decrease in phosphorylated MAPK/extracellular signal-regulated kinase (ERK) 1/2. Progesterone (1 and 100 pM for 30 min) attenuated arginine uptake and increased phosphorylated CAT-1, phosphorylated protein kinase Cα (PKCα), and phosphorylated ERK1/2 protein content. GO-6976 (PKCα inhibitor) prevented the progesterone-induced decrease in arginine transport. Coincubation with both progesterone and estrogen for 30 min resulted in attenuated arginine transport. While estradiol increases arginine transport and CAT-1 activity through modulation of constitutive signaling transduction pathways involving ERK, progesterone inhibits arginine transport and CAT-1 via both PKCα and ERK1/2 phosphorylation, an effect that predominates over estradiol.

Attenuated glomerular arginine transport prevents hyperfiltration and induces HIF-1α in the pregnant uremic rat.

Pregnancy worsens renal function in females with chronic renal failure (CRF) through an unknown mechanism. Reduced nitric oxide (NO) generation induces renal injury. Arginine transport by cationic amino acid transporter-1 (CAT-1), which governs endothelial NO generation, is reduced in both renal failure and pregnancy. We hypothesize that attenuated maternal glomerular arginine transport promotes renal damage in CRF pregnant rats. In uremic rats, pregnancy induced a significant decrease in glomerular arginine transport and cGMP generation (a measure of NO production) compared with CRF or pregnancy alone and these effects were prevented by l-arginine. While CAT-1 abundance was unchanged in all experimental groups, protein kinase C (PKC)-α, phosphorylated PKC-α (CAT-1 inhibitor), and phosphorylated CAT-1 were significantly augmented in CRF, pregnant, and pregnant CRF animals; phenomena that were prevented by coadministrating l-arginine. α-Tocopherol (PKC inhibitor) significantly increased arginine transport in both pregnant and CRF pregnant rats, effects that were attenuated by ex vivo incubation of glomeruli with PMA (a PKC stimulant). Renal histology revealed no differences between all experimental groups. Inulin and p-aminohippurate clearances failed to augment and renal cortical expression of hypoxia inducible factor-1α (HIF-1α) significantly increased in CRF pregnant rat, findings that were prevented by arginine. These studies suggest that in CRF rats, pregnancy induces a profound decrease in glomerular arginine transport, through posttranslational regulation of CAT-1 by PKC-α, resulting in attenuated NO generation. These events provoke renal damage manifested by upregulation of renal HIF-1α and loss of the ability to increase glomerular filtration rate during gestation.