MO1003: Role of Tacrolimus Trough Levels on Intra-Abdominal Pressure After Kidney Transplantation

BACKGROUND AND AIMS

Increased intra-abdominal pressure (IAP) is common after kidney transplantation (KT). However, the role of potential transplant-specific predictors of this complication, such as tacrolimus-associated endothelial dysfunction, remains unclear. We aimed to describe the relationship between tacrolimus trough levels and IAP in a sample of incident KT patients.

METHOD

Single-centre prospective cohort of deceased-donor KTs. Anesthesia, surgical technique and immunosuppression induction therapy were the same in all cases. IAP monitoring was performed according to WSACS guidelines using the urinary bladder technique (UnoMeter Abdo-Pressure kit). IAP values were registered every 8h during the first 72 h after surgery or until reoperation. Mean IAP values during the first 7 2h (72 h-IAP) were used in this analysis. The first measured tacrolimus trough levels after transplantation were included as a potential predictor of IAP. Patients without recorded tacrolimus trough levels during the first 7 days after surgery were excluded. The study was approved by the local ethics committee.

RESULTS

A total of 192 patients were enrolled in the study. Table 1A summarizes relevant patient and haemodynamic variables. Subjects with more severe intra-abdominal hypertension were more commonly males, with longer dialysis vintage, higher BMI and suffered diabetes more frequently. Multivariate linear regression analysis was used to examine potential predictors of 72 h-IAP, including male sex, months on dialysis, body mass index (BMI) (Table 1B), 72 h-fluid balance and tacrolimus trough levels. Recipient age, months on dialysis, BMI and tacrolimus trough levels were independent predictors of 72 h-IAP.

CONCLUSION

Tacrolimus-associated endothelial dysfunction may play a role in the increase of IAP after transplantation. In contrast, accumulated fluid balance, one of the strongest predictors of IAP in the ICU setting, failed to predict IAP values in our sample. These results offer new insight both into the pathophysiology of increased IAP and into the complex mechanisms of tacrolimus-associated nephrotoxicity in the early post-transplant period.

MO335: Reaching SCR 4.0 mg/dL, the Magical Number for KDIGO-2012 AKI Stage 3. Is it Adequate for Stratifying Severity of Acute on Chronic Kidney Disease?

BACKGROUND AND AIMS

Reaching a SCr ≥ 4 is one criterion of classification for stage 3 in the KDIGO-2012 AKI guidelines. No previous study has challenged this arbitrary cut point by comparing its performance on how patients with pure AKI (pAKI) versus acute on chronic kidney disease (AoCKD) reach that ‘magical number’, and how it affects the prognosis.

METHOD

Retrospective study of patients with AKI, classified according to the KDIGO-2012 guidelines. We analysed a sub-group of patients that reached a maximum SCr ≥ 4 and divided them in pAKI (basal eGFR ≥ 60) and AoCKD (≥15–≤59). We evaluated epidemiological and clinical variables, and compared the clinical outcomes needed for HD, in-hospital mortality and HD dependence at discharge. As 21 (6%) of AoCKD individuals already had a basal SCr ≥ 4.0, they were excluded in the analysis.

RESULTS

A total of 492 individuals met the inclusion criteria: 341 (69%) in the AoCKD group. Individuals in this group were older and had a higher Charlson's index. Table 1A summarizes the comparison of clinical characteristics, all patients in the pAKI group reached a four SCr with a rate of SCr increments ≥ 3×. We found no statistically significant difference in in-hospital mortality and the need for HD. The AoCKD group was more dependent on HD at discharge (Table 1B). Figure 1 shows the rate of SCr increments by which individuals reached > 4.0 mg/dL.

CONCLUSION

We found that individuals in the AoCKD group differ in their basal characteristics from the pAKI group and need lesser increments in SCr to reach the magical number of 4.0 mg/dL to be classified in stage 3. May be, one size does not fit all, and individuals with prior CKD may benefit from a lower rate of SCr increase to stratify AKI severity. We consider that a pitfall in this staging criterion consists in the small portion of patients in the AoCKD group that have a basal SCr ≥ 4.0, with a skew to AKI-KDIGO stage 3.

MO442: COVID-19 Disease Severity and Risk of 12-Month CKD Progression

BACKGROUND AND AIMS

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been in our daily practice for almost 2 years now. Since the beginning of the pandemic, we have aimed to study its most immediate effects on patients to find the best line of treatment or, at least, mitigate its worst outcomes. Nevertheless, we also know some long-term health consequences such as fatigue, sleep difficulties, headache, among others, but its long-term kidney effects are not entirely clear yet. The aim of this study was to describe if coronavirus disease's (COVID-19) severity increases the risk of chronic kidney disease (CKD) progression after a previous hospitalization and observe if there are any additional risk factors that could help us predict this outcome.

METHOD

In this study, a sample of consecutive patients who required admission due to COVID-19 during the first wave of the pandemic (from March to May of 2020) was recruited. Patients were followed for 12 months since initial admission. The composite outcome of the study included either death or CKD progression. CKD progression was defined as incremental progression to a higher KDIGO CKD stage compared to baseline pre COVID-19 renal function [(in mL/min/1.73 m2): estimated glomerular filtration rate (eGFR) ≥60; stage 3a: 45–59; stage 3b: 30–44; stage 4: 15–29; stage 5: <15], or dialysis initiation. Cardiovascular disease was defined as a history of myocardial infarction, stroke, or peripheral vascular disease. Chronic lung diseases included asthma, chronic obstructive pulmonary disease and chronic bronchitis.

RESULTS

The sample was composed of 93 patients, of which 14 (15.1%) died during follow-up. Of those alive 12 months after initial admission, 17 (21.5%) suffered CKD progression. No patient required renal replacement therapy. Patients that suffered the composite outcome presented a higher prevalence of cancer, tended to be slightly older and suffered from additional comorbidities more frequently (Table). In multivariate logistic regression analysis, previous history of CKD [odds ratio (OR): 1.066 (0.433–2.624); P = 0.889], severe or critical COVID-19 on admission [OR: 0.657 (0.24–1.8); P =0.414] or ICU admission [OR: 0.986 (0.082–11.898); P = 0.991] failed to predict the composite outcome.

CONCLUSION

Our main hypothesis was that COVID-19 sequelae should be due to an exaggerated activation of the immune system against the virus. Thus, patients that suffered severe COVID-19 should be expected to develop more long-term health consequences of the infection when compared with those with milder disease. However, we failed to prove any link between COVID-19 severity and long-term CKD progression. History of CKD or ICU admission was also unable to predict the composite outcome.

Previous studies have described a relationship between COVID-19 severity and adverse renal outcomes, a relationship that we failed to observe. These discrepancies could be due to the small sample size of our study and the different definition of CKD progression applied. In addition, age could act as a potential modifier of CKD progression after admission due to COVID. More studies are required to further clarify the mechanisms and long-term renal consequences of COVID-19 and define potential lines of treatment.

MO334: Incidence of AKI Among Hospitalized COVID-19 Patients During the First and Sixth Waves of the Pandemic

BACKGROUND AND AIMS

During the last 2 years, we have witnessed several waves of the COVID-19 pandemic characterized by massive infections among the general population, sudden increases in the number of hospitalizations and variable rates of complications and mortality among patients.

Acute kidney injury (AKI) has been described as a common and serious complication of COVID-19. However, multiple factors that are involved in the development of this complication have been modified throughout these months, including the appearance of new variants of the virus, the modification of treatment protocols or the advancement of vaccination among the general population.

In this study, we aimed to compare the rates of AKI among patients who required admission due to COVID-19 in the first and current (sixth) waves of the pandemic.

METHOD

Consecutive patients that required admission due to COVID-19 in a tertiary referral hospital during the first (March to May 2020) and current (December 2021) waves of the pandemic were enrolled in the study. Patient characteristics, rates of AKI incidence, 28-day mortality and in-hospital length of stay were compared between groups. Viral infection was confirmed by real-time RT-qPCR in all cases. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines using peak serum creatinine and acute dialysis criteria. Multivariate logistic regression was performed to define potential predictors of AKI.

RESULTS

Table 1 summarizes demographic and clinical characteristics among enrolled patients. Compared with the current wave, patients admitted during the first wave were older, had higher baseline serum creatinine and lower baseline eGFR. During the first wave, patients presented higher peak serum creatinine values and a higher incidence of in-hospital AKI. Age, male sex, hypertension, diabetes, CKD and pandemic wave were included in multivariate logistic regression analysis as potential predictors of AKI. Only past history of hypertension [OR 2.867; 95% confidence interval (95% CI) 1.279–6.424; P-value: .011] and CKD (OR 2.418; 95% CI 1.237–4.73; P-value: .01) independently predicted AKI in the sample.

CONCLUSION

Despite multiple changes that have occurred throughout the pandemic, including new treatment protocols, the appearance of new variants of the virus with different clinical profiles or the extensive application of vaccines, these changes have not translated into a significant decrease in the risk of AKI among patients admitted due to COVID-19, which appears to still be conditioned mainly by comorbidities of each patient, including past history of CKD.

MO120STONE COMPOSITION AND CARDIOVASCULAR DISEASE IN PATIENTS WIITH NEPHROLITHIASIS

Background and Aims

Kidney stone disease is widely prevalent in the general population and has been associated with multiple comorbidities including hypertension, diabetes, chronic kidney disease and cardiovascular disease. We aimed to describe the possible link between stone composition and cardiovascular disease and its differential effect among women and men.

Method

Retrospective review of patients with known stone composition seen in a nephrolithiasis unit in the last five years. Anthropometric and clinical data were gathered from the hospital records. Stone composition was defined as such if ≥50% of the stone was made from a single component. Cardiovascular disease included coronary artery disease, stroke and peripheral vascular disease. Unadjusted and adjusted logistic regression analysis were applied to describe the potential relationship between stone composition and cardiovascular disease.

Results

337 patients were included in the study sample. Median age was 57 (IQR 47-67), 61.1% males. 58.2% suffered from recurrent stone disease and 28.5% from family history of stone formation. 32.9% of patients had hypertension, 22,4% diabetes and 13,1% chronic kidney disease. The most common kidney stone component was calcium oxalate (38.6%) followed by calcium phosphate (21.3%), uric acid (14.2%), struvite (8%) and brushite (0.9%). Only uric acid as main stone component was associated with cardiovascular disease among men but not women in our sample in univariate analysis. That relationship was lost in adjusted logistic regression analysis.

Conclusion

Calcium oxalate and phosphate were the most common components of kidney stones. No relationship was found between stone composition and cardiovascular disease in the study sample.

Validation of a survival benefit estimator tool in a cohort of European kidney transplant recipients

Pre-transplant prognostic scores help to optimize donor/recipient allocation and to minimize organ discard rates. Since most of these scores come from the US, direct application in non-US populations is not advisable. The Survival Benefit Estimator (SBE), built upon the Estimated Post-Transplant Survival (EPTS) and the Kidney Donor Profile Index (KDPI), has not been externally validated. We aimed to examine SBE in a cohort of Spanish kidney transplant recipients. We designed a retrospective cohort-based study of deceased-donor kidney transplants carried out in two different Spanish hospitals. Unadjusted and adjusted Cox models were applied for patient survival. Predictive models were compared using Harrell’s C statistics. SBE, EPTS and KDPI were independently associated with patient survival (p ≤ 0.01 in all models). Model discrimination measured with Harrell’s C statistics ranged from 0.57 (KDPI) to 0.69 (SBE) and 0.71 (EPTS). After adjustment, SBE presented similar calibration and discrimination power to that of EPTS. SBE tended to underestimate actual survival, mainly among high EPTS recipients/high KDPI donors. SBE performed acceptably well at discriminating post-transplant survival in a cohort of Spanish deceased-donor kidney transplant recipients, although its use as the main allocation guide, especially for high KDPI donors or high EPTS recipients requires further testing.

What binds us? Inter-brain neural synchronization and its implications for theories of human consciousness

The association between neural oscillations and functional integration is widely recognized in the study of human cognition. Large-scale synchronization of neural activity has also been proposed as the neural basis of consciousness. Intriguingly, a growing number of studies in social cognitive neuroscience reveal that phase synchronization similarly appears across brains during meaningful social interaction. Moreover, this inter-brain synchronization has been associated with subjective reports of social connectedness, engagement, and cooperativeness, as well as experiences of social cohesion and ‘self-other merging’. These findings challenge the standard view of human consciousness as essentially first-person singular and private. We therefore revisit the recent controversy over the possibility of extended consciousness and argue that evidence of inter-brain synchronization in the fastest frequency bands overcomes the hitherto most convincing sceptical position. If this proposal is on the right track, our understanding of human consciousness would be profoundly transformed, and we propose a method to test this proposal experimentally.

Role of the Furosemide Stress Test in Renal Injury Prognosis

Risk stratification and accurate patient prognosis are pending issues in the management of patients with kidney disease. The furosemide stress test (FST) has been proposed as a low-cost, fast, safe, and easy-to-perform test to assess tubular integrity, especially when compared to novel plasma and urinary biomarkers. However, the findings regarding its clinical use published so far provide insufficient evidence to recommend the generalized application of the test in daily clinical routine. Dosage, timing, and clinical outcomes of the FST proposed thus far have been significantly different, which further accentuates the need for standardization in the application of the test in order to facilitate the comparison of results between series. This review will summarize published research regarding the usefulness of the FST in different settings, providing the reader some insights about the possible implications of FST in clinical decision-making in patients with kidney disease and the challenges that research will have to address in the near future before widely applying the FST.

First Report of Monilinia fructicola Causing Brown Rot on Stored Japanese Plum Fruit in Chile

In autumn 2013, fruit of Japanese plum (Prunus salicina) cvs. Angelino and Black Kat developed an unusual brown and soft rot after 2 months in cold storage (0°C) on nearly 1% of the fruit. Fruit showed small, circular, light brown spots that eventually destroyed the entire fruit. Small sporodochia appeared on the fruit surface. Fruit was harvested from orchards located near San Francisco de Mostazal (33°59' S, 70°41' W), Chile. Small pieces of diseased tissue were selected from margins of lesions of surface disinfected (96% ethanol) fruit (n = 7) and placed on acidified potato dextrose agar (PDA) plates for 5 days at 20°C. Light brown colonies with even margins and concentric rings of spores were obtained. The conidia of five isolates were one-celled, hyaline, lemon-shaped, (min. 10.7) 14.9 ± 1.5 (max. 18.6) × (min. 8.1) 9.4 ± 0.8 (max. 10.8) μm (n = 30), and borne in branched monilioid chains. This fungus was identified as Monilinia fructicola (G. Winter) Honey (1). Identification was confirmed by amplifying and sequencing the ribosomal ITS1-5.8S-ITS2 region using ITS1 and ITS4 primers (3). BLAST analysis of Chilean plum isolates (GenBank Accession Nos. KF148610 and KF148611) were 99 to 100% identical to isolates of M. fructicola originating from the United States (DQ314727 and HQ846966, respectively) and 100% identical to the first Chilean isolate (JN001480) found in nectarines originating from California at the supermarkets in Santiago in June 2009. Koch's postulates were fulfilled by reproducing brown rot symptoms on mature wounded Japanese plums cv. Angelino (n = 8) inoculated with 10 μl of a conidial suspension (10⁵ conidia/ml) or with a mycelium plug (5-mm diameter). After 2 days in humid chambers (>80% relative humidity) at 25°C, all inoculated fruit developed brown rot symptoms with necrotic lesion means of 15.8 and 21.5 mm in diameter in fruit inoculated with conidia and mycelium, respectively. Non-inoculated control fruit remained healthy. Re-isolations were performed on PDA and the presence of M. fructicola was morphologically confirmed in 100% of the symptomatic fruits. To our knowledge, this is the first report demonstrating the presence of M. fructicola causing brown rot in stored Japanese plums in Chile after its first interception in 2009 in Chile, suggesting that this pathogen has been established in the field. Currently, M. fructicola is a quarantine organism under official control, restricted to Prunus orchards between Santiago and Nancagua in central Chile (2). References: (1) EPPO. EPPO Bull. 39:337, 2009. (2) Servicio Agrícola y Ganadero, SAG, Ministerio de Agricultura, Gobierno de Chile. www.sag.cl , accessed 15 November 2013. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, NY, 1990.

First Report of Nothofagus macrocarpa Dieback Caused by Phytophthora citrophthora and P. nicotianae in Chile

The genus Nothofagus, family Nothofagaceae, comprises 36 species of trees that are native to the Southern Hemisphere. N. macrocarpa (DC.) F.M. Vásquez & R.A. Rodríguez (Roble de Santiago) is an important deciduous tree, endemic to central Chile (32 to 35°S), and found above 800 m altitude. There is an increasing interest in N. macrocarpa as an ornamental. However, a general dieback (40 to 50% prevalence) was observed at a commercial nursery in Santiago in 2009, limiting its multiplication. Symptoms are wilting, partial defoliation, reddish brown cankers on the crowns, and root necrosis. The purpose of this work was to study the etiology of the dieback in nurseries. Phytophthora was isolated from the roots and cankers of symptomatic plants (n = 3) and soil samples (using apples and avocados as baits) on amended corn meal agar (3) at 20°C for 5 days in the dark. Morphologically, P. citrophthora (Smith & Smith) Leonian, and P. nicotianae Breda de Haan were identified (2). On V8 juice agar (V8) (1), P. citrophthora formed petaloid colonies, grew between 5 and 30°C (optimum of 25°C), and produced deciduous, mono- or bipapillated sporangia of (28.1) 45.0 to 64.1 × (18.8) 32.0 to 39.2 μm. On V8, P. nicotianae produced cottony colonies, grew between 10 and 30°C (optimum of 25°C), and produced spherical, intercalary chlamydospores (mean diameter of 19.6 μm) and persistent, papillate, spherical to ovoid, ellipsoid, obpyriform sporangia of (33.2) 47.5 to 67.6 × (24.1) 30.0 to 48.9 μm. Isolates of P. citrophthora were sexually sterile, but P. nicotianae formed oogonia with amphigenous antheridia in dual cultures with P. cinnamomi (A2 compatibility type). BLAST analysis of the internal transcribed spacer (ITS) region of rDNA of isolates identified as P. citrophthora (IMI 399056 and IMI 399054, GenBank Accession Nos. JF699756 and JF699755) and P. nicotianae (IMI 399055, Accession No. JF699757), amplified by PCR using ITS universal primers (4), revealed 100% similarity with reference isolates of P. citrophthora (Accession Nos. GU259324.1 and GU259317.1) and P. nicotianae (Accession No. GU983635.1). P. citrophthora (n = 2) and P. nicotianae (n = 1) were pathogenic when wounded detached twigs (n = 5) of N. macrocarpa and N. obliqua were inoculated with 20 μl of a mycelial suspension (10⁶ CFU/ml) of either Phytophthora spp. Twigs were placed in a moist chamber at 20°C for 12 days prior to determine the length of the necrotic lesions that developed. An equal number of noninoculated twigs were left as control. Reisolation of P. citrophthora and P. nicotianae from inoculated material was 100%. The length of the necrotic lesions (13 to 80 mm) from inoculated N. macrocarpa and N. obliqua was significantly greater (P < 0.05) compared with the controls. Regardless of Phytophthora isolates, necrotic lesions (53.9 ± 15.8 mm) in infected N. macrocarpa were significantly longer than in N. obliqua (28.6 ± 13.1 mm) (P < 0.0001). To our knowledge, this is the first report of P. citrophthora and P. nicotianae associated with dieback on N. macrocarpa in Chile. Therefore, there is a potential risk of Phytophthora dieback in N. macrocarpa in nature. References: (1) J. Ampuero et al. Plant Dis. 92:1529, 2008. (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (3) B. A. Latorre and R. Muñoz. Plant Dis. 77:715, 1993. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

First Report of Pestalotiopsis clavispora and Pestalotiopsis spp. Causing Postharvest Stem End Rot of Avocado in Chile

Avocado (Persea americana) production in Chile has increased to more than 33,500 ha. Chilean avocadoes are sent to markets 15 to 45 days away by overseas transport to the United States, Europe, and Asia. Although apparently healthy avocadoes were harvested in 2009, a 10 to 14% incidence of stem end rot appeared after 15 days of cold storage. Symptoms appeared as small, irregular, brown lesions on the peel at the stem end. Lesions enlarged rapidly, became sunken and soft, eventually comprising the entire fruit as ripening progressed. A white mycelium often developed around the stem cavity. A dark brown necrosis of the pulp was observed that comprised a big part of the pulp as the fruits matured. Isolations were performed from 'Hass' avocadoes that developed stem end rot after fruits were kept in humid chambers for 15 days at 5°C plus 6 days at 20°C (n = 50) to simulate a transport period from Chile to U.S. markets or from diseased fruits (n = 50) kept for 15 days at 20°C. Fruits were surface disinfected for 60 s in 75% ethanol, and small pieces of tissue were excised from the margins of the pulp lesions and then plated onto potato dextrose agar (PDA) plus 1 ml/liter of Igepal CO-630 (Sigma-Aldrich, Atlanta, GA) (MPDA). Fungal colonies that developed on PDA were white and cottony, turning slightly yellow after 15 days. Black acervuli appeared after 15 days at 20°C. Conidia (n = 40) were fusiform, (22.2) 27.0 to 30.4 × (6.3) 7.0 to 9.8 μm with a length/width ratio of 3.4 ± 0.4. All isolates had five-celled conidia. Apical and basal cells were colorless, while the three median cells were dark brown. Conidia had one basal appendage (9.3 ± 3.3 μm) and two to four long apical appendages (34.5 ± 6.9 μm). On the basis of colony and conidia morphology, most of these isolates were initially identified as Pestalotiopsis clavispora (G.F. Atk) Steyaert, but other nonidentified species of Pestalotiopsis were also found (3). Identification was confirmed by amplifying and sequencing the internal transcribed spacer (ITS) region of rDNA using ITS1/ITS4 primers of P. clavispora isolate PALUC-12 (Accession No. HQ659767). A BLAST search of the NCBI database showed that isolate PALUC-12 had 100% homology with P. clavispora (No. EU342214.1). Pathogenicity tests were conducted on surface-disinfected (75% ethanol, 30 s) fruits by placing agar pieces (3 mm in diameter) from 7-day-old cultures and a 20-μl drop of 10⁶ conidia/ml on wounded and unwounded stem cavities and equatorial area of five avocado fruits of 'Hass', per isolate tested, at the commercial maturity stage. Inoculated fruits were placed in moist chambers at 25°C for 10 days. Necrotic lesions resembling symptoms that occurred in storage fruits were observed on wounded fruits. No symptoms were observed on unwounded fruits inoculated in the equatorial zone. However, unwounded fruits inoculated in the stem cavity developed a slight necrosis probably because of undetectable wounds made at harvest. Koch's postulates were confirmed after the reisolation of P. clavispora and Pestalotiopsis spp. from diseased fruits. P. versicolor has been reported in South Africa (1), but to our knowledge, this is the first report of P. clavispora causing stem end rot of avocado. P. clavispora has been reported on blueberry in Chile (2). References: (1) J. M. Darvas and J. M. Kotzé. Phytophylactica 19:83, 1987. (2) J. G. Espinoza et al. Plant Dis. 92:1407, 2008. (3) E. F. Guba. Monograph of Pestalotia and Monochaetia. Harvard University Press, Cambridge, MA, 1961.