COVID-19 in lung transplant recipients: an overview of the Swedish national experience.

Although it is known that solid organ transplant recipients fare worse after COVID-19 infection, data on the impact of COVID-19 on clinical outcomes and allograft function in lung transplant (LTx) recipients are limited and based mainly on reports with short follow-up. In this nationwide study, all LTx recipients with COVID-19 diagnosed from 1 February 2020 to 30 April 2021 were included. The patients were followed until 1 August 2021 or death. We analysed demographics, clinical features, therapeutic management and outcomes, including lung function. Forty-seven patients were identified: median age was 59 (10-78) years, 53.1% were male, and median follow-up was 194 (23-509) days. COVID-19 was asymptomatic or mild at presentation in 48.9%. Nine patients (19.1%) were vaccinated pre-COVID infection. Two patients (4.3%) died within 28 days of testing positive, and the overall survival rate was 85.1%. The patients with asymptomatic or mild symptoms had a higher median % expected forced expiratory volume during the first second than the patients with worse symptoms (P = 0.004). LTx recipients develop the entire spectrum of COVID-19, and in addition to previously acknowledged risk factors, lower pre-COVID lung function was associated with more severe disease presentation.

Intestinal Preservation Injury: A Comparison Between Rat, Porcine and Human Intestines.

Advanced preservation injury (PI) after intestinal transplantation has deleterious short- and long-term effects and constitutes a major research topic. Logistics and costs favor rodent studies, whereas clinical translation mandates studies in larger animals or using human material. Despite diverging reports, no direct comparison between the development of intestinal PI in rats, pigs, and humans is available. We compared the development of PI in rat, porcine, and human intestines. Intestinal procurement and cold storage (CS) using histidine-tryptophan-ketoglutarate solution was performed in rats, pigs, and humans. Tissue samples were obtained after 8, 14, and 24 h of CS), and PI was assessed morphologically and at the molecular level (cleaved caspase-3, zonula occludens, claudin-3 and 4, tricellulin, occludin, cytokeratin-8) using immunohistochemistry and Western blot. Intestinal PI developed slower in pigs compared to rats and humans. Tissue injury and apoptosis were significantly higher in rats. Tight junction proteins showed quantitative and qualitative changes differing between species. Significant interspecies differences exist between rats, pigs, and humans regarding intestinal PI progression at tissue and molecular levels. These differences should be taken into account both with regards to study design and the interpretation of findings when relating them to the clinical setting.

COVID-19 Outcomes and Vaccinations in Swedish Solid Organ Transplant Recipients 2020-2021: A Nationwide Multi-Register Comparative Cohort Study.

Increased COVID-19-related morbidity and mortality have been reported in solid organ transplant recipients (SOTRs). Most studies are underpowered for rigorous matching. We report infections, hospitalization, ICU care, mortality from COVID-19, and pertinent vaccination data in Swedish SOTRs 2020-2021. We conducted a nationwide cohort study, encompassing all Swedish residents. SOTRs were identified with ICD-10 codes and immunosuppressant prescriptions. Comparison cohorts were weighted based on a propensity score built from potential confounders (age, sex, comorbidities, socioeconomic factors, and geography), which achieved a good balance between SOTRs and non-SOTR groups. We included 10,372,033 individuals, including 9073 SOTRs. Of the SARS-CoV-2 infected, 47.3% of SOTRs and 19% of weighted comparator individuals were hospitalized. ICU care was given to 8% of infected SOTRs and 2% of weighted comparators. The case fatality rate was 7.7% in SOTRs, 6.2% in the weighted comparison cohort, and 1.3% in the unweighted comparison cohort. SOTRs had an increased risk of contracting COVID-19 (HR = 1.15 p < 0.001), being hospitalized (HR = 2.89 p < 0.001), receiving ICU care (HR = 4.59 p < 0.001), and dying (HR = 1.42 p < 0.001). SOTRs had much higher morbidity and mortality than the general population during 2020-2021. Also compared with weighted comparators, SOTRs had an increased risk of contracting COVID-19, being hospitalized, receiving ICU care, and dying. In Sweden, SOTRs were vaccinated earlier than weighted comparators. Lung transplant recipients had the worst outcomes. Excess mortality among SOTRs was concentrated in the second half of 2021.

Novel Ex-Vivo Thrombolytic Reconditioning of Kidneys Retrieved 4 to 5 Hours After Circulatory Death.

BACKGROUND: Due to organ shortage, many patients do not receive donor organs. The present novel thrombolytic technique utilizes organs from donors with uncontrolled donation after circulatory deaths (uDCD), with up to 4-5 h warm ischemia, without advanced cardiopulmonary resuscitation (aCPR) or extracorporeal circulation (EC) after death. METHODS: The study group of pigs (n = 21) underwent simulated circulatory death. After 2 h, an ice slush was inserted into the abdomen. Kidneys were retrieved 4.5 h after death. Lys-plasminogen, antithrombin-III (ATIII), and alteplase (tPA) were injected through the renal arteries on the back table. Subsequent ex vivo perfusion at 15 °C was continued for 3 h, followed by 3 h with red blood cells (RBCs) at 32 °C. Perfusion outcome and histology were compared between uDCD kidneys, receiving no thrombolytic treatment (n = 8), and live donor kidneys (n = 7). The study kidneys were then transplanted into pigs as autologous grafts with a single functioning autologous kidney as the only renal support. uDCD control pigs (n = 8), receiving no ex vivo perfusion, served as controls. RESULTS: Vascular resistance decreased to <200 mmHg/mL/min ( P < 0.0023) and arterial flow increased to >100 mL/100 g/min ( P < 0.00019) compared to controls. In total 13/21 study pigs survived for >10 days, while all uDCD control pigs died. Histology was preserved after reconditioning, and the creatinine level after 10 days was next to normal. CONCLUSIONS: Kidneys from extended uDCD, not receiving aCPR/EC, can be salvaged using thrombolytic treatment to remove fibrin thrombi while preserving histology and enabling transplantation with a clinically acceptable early function.

Initial Report From a Swedish High-volume Transplant Center After the First Wave of the COVID-19 Pandemic.

BACKGROUND: Solid organ transplant (SOT) recipients may be more vulnerable to coronavirus disease 2019 (COVID-19). Data on the clinical course of COVID-19 in immunosuppressed patients are limited, and the optimal management strategy for these patients is yet unclear. METHODS: We present 53 SOT recipients (31 kidney transplant recipients, 8 liver transplant recipients, 5 heart transplant recipients, 5 lung transplant recipients, 3 liver-kidney transplant recipients, and 1 kidney-after-heart transplant recipient), transplanted at a Swedish high-volume transplant center and each diagnosed with COVID-19 between February 21, 2020 and June 22, 2020. Demographic, clinical, and treatment data were extracted from the electronic patient files. RESULTS: Patients reported fever (61%), cough (43%), diarrhea (31%), and upper respiratory symptoms (29%). The median age was 56 years, and 57% were male. According to severity, 55% had mild, 13% had moderate, 19% had severe, and 13% had critical disease. Thirty-seven patients (70%) were hospitalized, with 8 requiring intensive care. Thirteen of the 37 patients were initially managed as outpatients but later hospitalized. One patient received hydroxychloroquine, and no patients received antivirals. Antimetabolites and calcineurin inhibitors were held or reduced in two-thirds. Twenty-seven of 37 hospitalized patients (73%) received low-molecular-weight heparin. Five (13.5%) hospitalized patients died. Overall survival for the entire cohort was 90.5%. No rejection episodes were noted. CONCLUSIONS: Hospitalization, lowering of immunosuppression, and prophylactic anticoagulation were the most common therapeutic interventions for SOT recipients with COVID-19. A significant proportion of patients could be managed on an outpatient basis, while keeping a low threshold for admission. Mild and moderate disease forms seem to have a good outcome.

The Impact of Age and Luminal Preservation on the Development of Intestinal Preservation Injury in Rats.

BACKGROUND: Organs from older donors are believed to withstand ischemia worse than those from younger donors. The effect of age on the development of intestinal preservation injury (IPI) is unclear. METHODS: We compared the development of IPI in intestines from young (3 mo), adult (14 mo), and old (20 mo) rat donors and assessed if luminal preservation (LP) is effective in delaying IPI. Small intestines were perfused with, and stored in, preservation solution (Custodiol) with or without LP solution (polyethylene glycol 3350). IPI was studied using histology (Chiu score, Alcian blue staining), Western blot, and electrophysiological assessment (Ussing chamber) at 4, 8, and 14 hours. RESULTS: Intestines of old rats did not show major histological alterations, whereas their aortas and kidneys revealed typical age-related changes (arteriosclerosis and glomerulosclerosis). Intestines from old rats fared similarly to their younger counterparts at all time points regarding preservation injury and goblet cells count. Intestines undergoing LP showed fewer histological signs of damage and higher goblet cells count when compared with samples without LP, regardless of donor age. Ussing chamber experiments indicated a time-dependent deterioration of all parameters studied, which was delayed by the use of LP. CONCLUSIONS: Older intestines did not convincingly demonstrate a faster IPI compared with intestines from adult and young donors. The small differences between the age groups were nullified by the use of LP. LP significantly delayed the IPI in all age groups and may allow for longer preservation periods without an increased risk of mucosal damage.

Covid-19 in kidney transplant recipients: a systematic review of the case series available three months into the pandemic.

BACKGROUND: Coronavirus disease 2019 (COVID-19) ranges from a mild illness to acute respiratory distress syndrome (ARDS), multiorgan dysfunction, and death. Transplant recipients are vulnerable due to comorbidities and immunosuppressants that render them susceptible to infections. The information on COVID-19 in kidney transplant recipients remains limited to small case series. METHODS: A systematic literature search was conducted, and 12 case series totalling 204 kidney transplant recipients with COVID-19 were identified. Data were extracted, pooled and analysed. RESULTS: Most patients (74%) were men. The most frequent symptoms were fever (76%), cough (64%) and dyspnoea (43%). At admission, over 70% of the patients had abnormal radiological findings. Leukocyte counts were in the lower normal range. C-reactive protein, ferritin, and D-dimer were consistently increased. Treatments included lowering immunosuppression, hydroxychloroquine, antivirals, tocilizumab and intravenous immunoglobulins. Thirty-one percent of the patients were admitted to intensive care units (ICUs), and 16% required intubation. The overall mortality was 21.2%. Patients who died were significantly older than those who survived (61 ± 12 vs. 51 ± 15, p < .01). Logistic regression revealed that the odds for death increased by 4.3% for each additional year of age (odds ratio [OR] 1.043, 95% confidence interval [CI] 1.005-1.083, p value = .0265). CONCLUSIONS: No substantial conclusions could be drawn on the efficacy of any particular treatment. More rigorous patient stratification is needed when analysing and reporting data to facilitate future meta-analyses.