Incidence and outcome of contrast-associated acute kidney injury assessed with Risk, Injury, Failure, Loss, and End-stage kidney disease (RIFLE) criteria in critically ill patients of medical and surgical intensive care units: a retrospective study

The incidence and risk factors of proximal lower extremity deep vein thrombosis without pharmacologic prophylaxis in critically ill surgical Taiwanese patients: A prospective study

Background

Venous thromboembolism (VTE) in critically ill patients has been well-studied in Western countries. Many studies have developed risk assessments and established pharmacological protocols to prevent deep venous thrombosis (DVT). However, the DVT rate and need for pharmacologic VTE prophylaxis in critically ill Taiwanese patients are limited. This study aimed to prospectively determine the DVT incidence, risk factors, and outcomes in critically ill Taiwanese patients who do not receive pharmacologic VTE prophylaxis.

Methods

We conducted a prospective study in a surgical intensive care unit (SICU) of a tertiary academic medical center in Taiwan. Adult patients admitted to SICU from March 2021 to June 2022 received proximal lower extremities DVT surveillance with venous duplex ultrasound. No patient received pharmacologic VTE prophylaxis. The outcomes were the incidence and risk factors of DVT.

Results

Among 501 enrolled SICU patients, 21 patients (4.2%) were diagnosed with proximal lower extremities DVT. In a multivariate regression analysis, hypoalbuminemia (odd ratio (OR) = 6.061, 95% confidence interval (CI): 1.067-34.421), femoral central venous catheter (OR = 4.515, 95% CI: 1.547-13.174), ICU stays more than 10 days (OR = 4.017, 95% CI: 1.270-12.707), and swollen leg (OR = 3.427, 95% CI: 1.075-10.930) were independent risk factors for DVT. In addition, patients with proximal lower extremities DVT have more extended ventilator days (p = 0.045) and ICU stays (p = 0.044).

Conclusion

Our findings indicate critically ill Taiwanese patients have a higher incidence of DVT than results from prior retrospective studies in the Asian population. Physicians who care for this population should consider the specific risk factors for DVT and prescribe pharmacologic prophylaxis in high-risk groups.

Incomplete Recovery from the Radiocontrast-Induced Dysregulated Cell Cycle, Adhesion, and Fibrogenesis in Renal Tubular Cells after Radiocontrast (Iohexol) Removal

Contrast-induced nephropathy (CIN) is one of the most common causes of acute kidney injury (AKI). However, management is still limited, and the cellular response to radiocontrast removal for CIN remains unclear. This study aimed to explore the latent effects of iohexol in cultured renal tubular cells with or without the removal of iohexol by medium replacement. HK2 renal tubular cells were subcultured 24 h before use in CIN experiments. Three treatment groups were established: the control, a radiocontrast (iohexol)-only group at 75 mg I/mL (I-75), and iohexol exposure for 24 h with culture medium replacement (I-75/M). Cell cycle arrest, fibrogenic mediator assays, cell viability, cell function, and cell-cycle-related protein expression were compared between groups. Iohexol induced numerous changes in HK2 renal tubular cells, such as enlarged cell shape, cell cycle arrest, increased apoptosis, and polyploidy. Iohexol inhibited the expression of cyclins, CDKs, ZO-1, and E-cadherin but conversely enhanced the expression of p21 and fibrosis-related genes, including TGF-β1, CTGF, collagen I, collagen III, and HIF-1α within 60 hr after the exposure. Except for the recovery from cell cycle arrest and cell cycle gene expression, notably, the removal of iohexol by medium replacement could not fully recover the renal tubular cells from the formation of polyploid cells, the adhesion or spreading, or the expression of fibrosis-related genes. The present study demonstrates, for the first time, that iohexol exerts latent cytotoxic effects on cultured renal tubular cells after its removal, suggesting that these irreversible cell changes may cause the insufficiency of radiocontrast reduction in CIN, which is worth investigating further.

Additional benefit of induced pluripotent stem cell-derived mesenchymal stem cell therapy on sepsis syndrome-associated acute kidney injury in rat treated with antibiotic

BACKGROUND

This study tested whether human induced-pluripotent stem-cell-derived mesenchymal-stem-cells (iPS-MSCs) would offer an additional benefit to the rodent with acute kidney injury (AKI) (ischemia for 1 h followed by reperfusion for 120 h) associated sepsis syndrome (SS) (by cecal-ligation-puncture immediately after AKI-induction) undergoing ciprofloxacin therapy.

RESULTS

Male-adult SD rats (n = 80) were categorized into group 1 (sham-operated-control, n = 10), group 2 (AKI + SS, n = 24), group 3 (AKI + SS + ciprofloxacin/3 mg/kg, orally for 120 h, n = 12), group 4 (AKI + SS + iPS-MSCs/1.2 × 10⁶/intravenously administered by 3 h after AKI, n = 12), group 5 (AKI + SS + iPS-MSCs/1.2 × 10⁶/intravenously administered by 18 h after AKI, n = 12), group 6 (AKI + SS + iPS-MSCs/1.2 × 10⁶/intravenously administered by 3 h after AKI induction + ciprofloxacin, n = 10] and euthanized by 120 h. The result showed that the mortality was significantly higher in group 2 than in other groups (all p < 0.01). The creatinine level was highest in group 2, lowest in group 1, significantly lower in group 6 than in groups 3, 4 and 5, (all p < 0.0001), but it showed no difference among the latter 3 groups. Flow cytometric analysis showed that the circulatory inflammatory cells (Ly6G/CD11^b/c), early (AN-V+/PI-)/late (AN-V+/PI+) apoptosis, and circulatory/splenic immune cells (CD3+/CD4+, CD3+/CD8a+) were highest in group 2, lowest in group 1, significantly lower in group 6 than in groups 3/4/5 and significantly lower in group 4 than in groups 3/5 (all p < 0.0001), but they showed no difference between groups 3/5. Protein expressions of oxidative-stress (NOX-1/NOX2/oxidized protein), apoptotic (cleaved-caspase3/cleaved-PARP/mitochondrial-Bax), fibrotic (TGF-ß/Smad3), inflammatory (MMP-9/IL-6/TNF-α) and autophagic (Atg5/Beclin) biomarkers in kidney exhibited an identical pattern of circulatory inflammatory cells (all p < 0.0001).

CONCLUSION

Combined iPS-MSCs-ciprofloxacin therapy was superior to either one alone for protecting AKI complicated by SS.

Combined tacrolimus and melatonin effectively protected kidney against acute ischemia-reperfusion injury

Acute kidney injury (AKI) is commonly encountered and causes high mortality in hospitalized patients; however, effective therapies for AKI have still not been established. Accordingly, we performed a rodent model with acute renal ischemia-reperfusion (IR) and tested the hypothesis that combined tacrolimus and melatonin therapy could be superior to either one for protecting the kidney against IR injury. Adult-male SD rat (n = 30) were equally categorized into group 1 (receiving laparotomy only), group 2 (IR treated by 3.0 cc/normal-saline), group 3 [IR + tacrolimus/0.5 mg/kg by intravenous administration at 30 minutes and at days 1/2/3 after IR], group 4 (IR + melatonin/50 mg/kg by intra-peritoneal administration at 30 minutes and 25 mg/kg at days 1/2/3 after IR] and group 5 (IR + tacrolimus +melatonin). By day 3 after IR, the creatinine/BUN levels and ratio of urine protein to urine creatinine were highest in group 2, lowest in group 1 and significantly lower in group 5 than in groups 3/4 (all P < .0001), but they did not differ between the groups 3/4. The protein expressions of oxidative-stress (p47phox/NOX-1/NOX-2/NOX-4), upstream (TLR4/MAL/MyD88/TRAF6/ASK1/MKK4/MKK7/NF-κB) and downstream (IL-6/INF-γ/MMP-9/IL-1ß) inflammatory signaling, MAPK-family-signaling cascades(ERK1/2, JNK/p38/c-JUN), apoptotic/autophagic (p53/caspase 3/mitochondrial-Bax, ratio of LC3B-II/LC3B-I), and mitochondrial-damaged (cyclophilin D/cytochrome C/DRP1) biomarkers, and the expressions of inflammatory-immune cells (F4/80, CD14/CD3/CD8) as well as the kidney injured score exhibited an identical pattern of creatinine level (all P < .0001). In conclusion, combined tacrolimus and melatonin therapy was better than either single one on protecting the kidney functional and anatomical integrity against IR injury through suppressing inflammation and the generation of oxidative stress.

Iatrogenic Toxicities in the Intensive Care Unit

Drug-induced iatrogenic toxicities are common in critically ill patients and have been associated with increased morbidity and mortality. Early recognition and management of iatrogenic toxicities is essential; however, the diagnosis is usually complicated by the underlying critical illness, comorbidities, and administration of multiple medications. This article reviews several types of iatrogenic toxicities associated with medications that are commonly used in critically ill patients. The mechanism of the iatrogenic toxicities, clinical presentation, and diagnosis, as well as management are discussed.

Contrast-associated acute kidney injury: An update of risk factors, risk factor scores, and preventive measures

As lifespans lengthen, age-related diseases such as cardiovascular disease and diabetes are becoming more prevalent. Correspondingly, the use of contrast agents for medical imaging is also becoming more common, and there is increasing awareness of contrast-associated acute kidney injury (CA-AKI). There is no specific treatment for CA-AKI, and clinicians currently focus on prevention, interventions that alter its pathogenesis, and identification of risk factors. Although the incidence of CA-AKI is low in the general population, the risk of CA-AKI can reach 20% to 30% in patients with multiple risk factors. Many models have been applied in the clinic to assess the risk factors for CA-AKI, enable identification of high-risk groups, and improve clinical management. Hypotonic or isotonic contrast media are recommended to prevent CA-AKI in high-risk patients. Patients with risk factors should avoid using contrast media multiple times within a short period of time. All nephrotoxic drugs should be stopped at least 24 h before the administration of contrast media in high-risk populations, and adequate hydration is recommended for all patients. This review summarizes the pathophysiology of CA-AKI and the progress in diagnosis and differential diagnosis; updates the risk factors and risk factor scoring systems; reviews the latest advances related to prevention and treatment; discusses current problems in epidemiological studies; and highlights the importance of identifying high-risk subjects to control modifiable risk factors and use of a rating scale to estimate the risk and implement appropriate prevention strategies.

Clinical Usefulness of Contrast-Enhanced Computed Tomography in Patients with Non-Obstructive Acute Pyleonephritis

Objectives The aim of this study is to investigate the clinical utility of contrast-enhanced computed tomography (CE-CT) in patient with non-obstrcutive acute pyelonephritis (APN). Methods From 2007 to 2013, 537 APN patients who underwent a CE-CT scan within 24 hours after hospital admission were enrolled. We divided these patients into greater (50% or greater involvment, n = 143) and lesser (less than 50% involvement, n = 394) groups based on renal parenchymal involvement in CE-CT examination. We compared clinical characteristics between two groups and analyzed the clinical value of CE-CT scan as a reliable marker for predicting clinical severity and disease course in patient with non-obstructive APN. Results The mean estimated glomerular filtration rate was 70.6 ± 25.5 mL/min/1.73m2. Compared with patients in lesser group, the patients in greater group had lower serum albumin levels (3.5 ± 0.5 vs 3.8 ± 0.6, P &lt; 0.01) and longer hosptal stay (10.1 ± 4.7 vs 8.8 ± 4.5, P &lt; 0.05). In addition, acute kidney injury (AKI) (23.1% vs 11.4%, P &lt; 0.005) and bacteremia (36.4% vs 26.8%, P = 0.02) were frequently developed in greater group, respectively. The overall incidence of AKI was 14.8% based on RIFLE criteria. In a multivariate logistic regression analysis for predciting AKI, age, presence of diabetes mellitus and the presence of renal parenchymal involvement of greater than 50% in CE-CT were significant predictors of AKI. Conclusions The CE-CT scan could be useful to predict the clinical severity and course in non-obstructive APN patients with preserved renal function.

Pre-existing chronic kidney disease and acute kidney injury among critically ill patients

BACKGROUND

The impact of pre-existing chronic kidney disease (CKD) and acute kidney injury (AKI) on health outcomes in critically ill patients is unclear. Yet, CKD complicated by AKI in critically ill patients is common.

OBJECTIVES

To compare risk of death within one-month of admission in critically ill patients with and without pre-existing CKD who developed AKI.

METHODS

A multicenter retrospective comparative study using medical records review was conducted. Study participants consisted of 826 adult patients who received mechanical ventilation for at least 6 h in the critical care units from January 2012 to December 2017. Assessment of kidney function was established by serum creatinine. Severity and staging of AKI were defined using RIFLE criteria: Risk, Injury, Failure, Loss and End stage of renal disease. Chronic kidney disease was defined as eGFR > 60 ml/mg/1.73 m² on admission.

RESULTS

Pre-existing CKD was present in 55% of patients and 7% had AKI within 7 days of admission. The overall mortality rate among these patients was 87.3%. The mortality rate was highest in patients with CKD (70.1%) followed by that of patients without pre-existing CKD but with AKI (20.7%) and that of patients with pre-existing CKD (7.1%) and AKI. Risks associated with mortality were APACHE II score (1.03; 95% CI 1.02-1.05;(P<0.001) and AKI (1.68; 95% CI 1.12-2.5;P<0.01) in patients with pre-existing CKD. Only APACHI-II (1.03; 95% CI 1.0-1.1; p < 0.001) was predictive of death in patients without pre-existing CKD.

CONCLUSION

Pre-existing comorbid CKD increases risks of death among critically ill patients compared to patients without CKD and regardless of whether they develop AKI or not. Early identification of CKD and recognition of the risk for mortality among these patients may result in earlier intervention that could reduce mortality.

Adipose-derived mesenchymal stem cell exosomes: a novel pathway for tissues repair

The well-characterized curative effect of transplanted mesenchymal stem cells has been mainly attributed to their homing and subsequent differentiation for the repair and regeneration of damaged tissue. Adipose-derived mesenchymal stem cells (ADMSCs) are not only multipotent and plastic, but also abundant as they can be easily harvested with minimally invasive surgical techniques. This makes ADMSCs conducive for clinical applications. Recently, the secretory function of ADMSCs has been regarded as the primary mediator of MSC-based therapy. Exosomes are one kind of small cell extracellular membrane vesicles, which are primarily used to deliver cell-specific proteins, as well as nucleic acids secreted by various cell types. This review will introduce and characterize exosomes-derived ADMSCs (ADMSCs-Exo) and look at new therapies and prospective, including the limitations and outlook for therapeutic strategy. We will describe the latest research progress on myocardial repair, neuroprotection and neurotrophic effects, hepatic repair, renal repair, cutaneous repair, regeneration and other aspects using these cells.

Is the risk of contrast-induced nephropathy a real contraindication to perform intravenous contrast enhanced Computed Tomography for non-traumatic acute abdomen in Emergency Surgery Department?

BACKGROUND

Contrast enhanced Computed Tomography (CCT) is the most used imaging test to investigate acute abdominal clinical conditions, because of its high sensitivity and specificity. It is mandatory to make a correct and prompt diagnosis when life threatening abdominal diseases as mesenteric ischemia are suspected. Contrast medium administration was linked to acute renal failure, therefore radiologist often prefer to perform CCT without contrast in patients needing to undergo the exam with increased serum creatinine.  The aim of the review was to focus on the incidence of contrast induced nephropathy in patients presenting non-traumatic acute abdominal clinical conditions, who underwent CCT with intravenous contrast agent administration in emergency setting.

MATERIALS AND METHODS

The systematic review protocol was guided by the Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocol (PRISMA-P). Quality of the evidence will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology.

RESULTS

The strongest currently available evidence on the incidence of post-contrast acute kidney injury (AKI) following intravenous contrast agent administration consists in a meta-analysis of observational studies. Data extracted from meta-analyses demonstrate that, compared with non-contrast CT, CCT was not significantly associated with AKI. Moreover, the risk of AKI (RR=0.79; 95% confidence interval [CI]: 0.62, 1.02; P=.07), death (RR=0.95; 95% CI: 0.55, 1.67; P=.87), and dialysis (RR=0.88; 95% CI: 0.23, 3.43; P=.85) is similar, compared with the risk of AKI in the non-contrast medium group. Furthermore, intravenous low-osmolality iodinated contrast material is a nephrotoxic risk factor, but not in patients with a stable SCr level less than 1.5 mg/dL, therefore many factors other than contrast material could affect PC-AKI rates.

DISCUSSION AND CONCLUSIONS

The benefits of diagnostic information gained from contrast enhanced TC in assessing AA are fundamental in some clinical scenarios. The risk of contrast induced nephropathy (CIN) is negligible in patients with normal renal function but the incidence appears to rise to as high as 25% in patients with pre-existing renal impairment or in the presence of risk factors such as diabetes, advanced age, vascular disease and use of certain concurrent medications. The incidence of CIN/AKI after intravenous contrast administration is very low in general population. Radiologists and referring physicians should be familiar with the risk factors for renal disease, CIN and preventing measures.

Urinary Mitochondrial DNA Levels Identify Acute Kidney Injury in Surgical Critical Illness Patients

BACKGROUND

Recent studies showed that mitochondrial injury and mitochondrial DNA (mtDNA) damage are associated with the initiation and progression of acute kidney injury (AKI). However, practical limitations of existing assays of mitochondrial function have limited our ability to study the link between mitochondrial dysfunction and renal injury. Therefore, we evaluated urinary mtDNA (UmtDNA) as a biomarker of AKI in critical illness patients.

METHODS

DNA was isolated from urine samples in surgical intensive care unit (SICU) patients and quantified by quantitative polymerase chain reaction (PCR). Correlation analyses showed the relationships between the UmtDNA and several biomarkers of renal dysfunction. Moreover, we evaluated the predictive and diagnostic values of UmtDNA in newly developed AKI, renal replacement therapy (RRT), and hospital mortality using receiver operating characteristics curves.

RESULTS

MtDNA were expressed as PCR threshold cycle (Tc) number. Lower Tc indicated increased urinary mtDNA concentration. The baseline UmtDNA levels were elevated in SICU patients especially in AKI patients, compared with that in healthy controls. UmtDNA Tc number inversely correlated with serum creatine and urinary neutrophil gelatinase-associated lipocalin and directly with estimated glomerular filtration rate. Furthermore, baseline UmtDNA levels had high effectiveness in predicting development of AKI, initiation of RRT, and hospital mortality.

CONCLUSIONS

Elevated UmtDNA levels could identify newly developed AKI and predict RRT or hospital mortality in SICU patients. UmtDNA Tc number correlated with markers of renal injury and dysfunction, suggesting the involvement of mitochondrial injury in kidney damage among surgical critical illness patients.

Combination of adipose-derived mesenchymal stem cells (ADMSC) and ADMSC-derived exosomes for protecting kidney from acute ischemia-reperfusion injury

BACKGROUND

In this study, we tested the hypothesis that a combined adipose-derived mesenchymal stem cell (ADMSC) and ADMSC-derived exosome therapy protected rat kidney from acute ischemia-reperfusion (IR) injury (i.e., ligation of both renal arteries for 1h and reperfusion for 72h prior to euthanization).

METHODS AND RESULTS

Adult-male SD rats (n=40) were equally categorized into group 1 (sham control), group 2 (IR), group 3 [IR+exosome (100μg)], group 4 [IR+ADMSC (1.2×10(6) cells)], and group 5 (IR-exosome-ADMSC). All therapies were performed at 3h after IR procedure from venous administration. By 72h, the creatinine level and kidney injury score were the lowest in group 1 and the highest in group 2, significantly higher in group 3 than in groups 4 and 5, and significantly higher in group 4 than in group 5 (all P<0.0001). The protein expression of inflammatory (TNF-α/NF-κB/IL-1β/MIF/PAI-1/Cox-2), oxidative-stress (NOX-1/NOX-2/oxidized protein), apoptotic (Bax/caspase-3/PARP), and fibrotic (Smad3/TGF-β) biomarkers showed an identical pattern, whereas the anti-apoptotic (Smad1/5, BMP-2) and angiogenesis (CD31/vWF/angiopoietin) biomarkers and mitochondrial cytochrome-C showed an opposite pattern of creatinine level among the five groups (all P<0.001). The microscopic findings of glomerular-damage (WT-1), renal tubular-damage (KIM-1), DNA-damage (γ-H2AX), inflammation (MPO/MIF/CD68) exhibited an identical pattern, whereas the podocyte components (podocin/p-cadherin/synaptopodin) displayed a reversed pattern of creatinine level (all P<0.0001).

CONCLUSION

Combined exosome-ADMSC therapy was superior to either one for protecting kidney from acute IR injury.