超声辐照微泡促骨髓间充质干细胞修复大鼠急性肾损伤的实验研究

目的探讨超声辐照靶向破坏微泡促骨髓间充质干细胞（MSCs）修复大鼠急性肾小管坏死的作用。 方法选择40只SD大鼠构建急性肾小管坏死模型。将制备成功的40只急性肾小管坏死大鼠随机分为4组：单纯模型组、1.0 W/cm²超声辐照+微泡组（1.0 US+MB组）、干细胞组（MSCs组）、1.0 W/cm²超声辐照+微泡+干细胞组（1.0 US+MB+MSCs组）,每组各10只。1.0 US+MB组、1.0 US+MB+MSCs组大鼠均以强度为1.0 W/cm²及频率为1 MHz的超声辐照肾脏组织,并尾静脉输入0.5 ml造影剂,密度约为1.0×10⁸个/ml,辐照5 s,停5 s,共1 min。在急性肾小管坏死模型建立后第1天及第3天分别辐照1次。1.0 US+MB+MSCs组大鼠最后一次超声辐照完毕后1 min内经股静脉注入MSCs1 ml（密度为2.0×10⁶个/ml）。同时MSCs组大鼠经股静脉注入MSCs1 ml（密度为2.0×10⁶个/ml）。单纯模型组不做任何处理。MSCs移植7 d后将各组大鼠处死并取材,采用Western印迹法测定各组大鼠肾组织肝细胞生长因子（HGF）及表皮生长因子（EGF）蛋白表达并进行定量分析,采用HE染色观察各组大鼠肾小管坏死情况并进行评分。采用单因素方差分析比较单纯模型组、1.0 US+MB组、MSCs组、1.0 US+MB+MSCs组大鼠HGF蛋白表达水平、EGF蛋白表达水平、肾小管上皮细胞坏死评分差异,进一步组间两两比较采用SNK-q检验。 结果Western印迹结果显示,HGF在各组相对分子质量为84 000处均有特异性条带,EGF在各组相对分子质量为6 000处均有特异性条带,其中1.0 US+MB+MSCs组的条带最为明显。单纯模型组、1.0 US+MB组、MSCs组、1.0 US+MB+MSCs组大鼠HGF蛋白表达水平分别为0.16±0.30、0.35±0.50、0.37±0.50、0.70±0.60,EGF蛋白表达水平分别为0.19±0.40、0.41±0.50、0.43±0.50、0.82±0.70,肾小管上皮细胞坏死评分分别为（4.1±0.8）、（3.6±0.6）、（1.8±0.4）、（1.0±0.3）分。1.0 US+MB+MSCs组大鼠HGF蛋白、EGF蛋白表达水平均高于单纯模型组、1.0 US+MB组及MSCs组大鼠,且差异均有统计学意义（HGF蛋白：q值分别为23.6、18.7、9.6;EGF蛋白：q值分别为21.8、17.1、9.3;均P<0.05);1.0 US+MB+MSCs组大鼠肾小管坏死评分低于单纯模型组、1.0 US+MB组及MSCs组大鼠,且差异均有统计学意义（q值分别为20.1、16.7、6.9,均P<0.05),提示1.0US+MB+MSCs组大鼠肾小管修复情况优于其他各组大鼠。 结论1.0 W/cm²超声辐照微泡促进MSCs归巢并修复急性肾小管坏死,可为急性肾小管坏死提供一种新型的干细胞移植治疗方法。     

Ultrasound-Mediated Microbubble Destruction Suppresses Melanoma Tumor Growth

Melanoma is one of the most aggressive types of cancer, and its incidence has increased rapidly in the past few decades. In this study, we investigated a novel treatment approach, the use of low-intensity ultrasound (2.3 W/cm² at 1?MHz)-mediated Optison microbubble (MB) destruction (UMMD) to treat melanoma in a flank tumor model. The effect of UMMD was first evaluated in the melanoma cell line B16 F10 (B16) in vitro and then in mice inoculated with B16 cells. MB⁺B16 cells were exposed to US in vitro, resulting in significant cell death proportional to duty cycle (R²?=?0.74): approximately 30%, 50%, 80% and 80% cell death at 10%, 30%, 50% and 100% DC respectively. Direct implantation of tumors with MBs, followed by sonication, resulted in retarded tumor growth and improved survival (p?=?0.0106). Immunohistochemical analyses confirmed the significant changes in expression of the cell proliferation marker Ki67 (p?=?0.037) and a microtubule-associated protein 2 (p?=?0.048) after US?+?MB treatment. These results suggest that UMMD could be used as a possible treatment approach in isolated melanoma and has the potential to translate to clinical trials.     

Ultrasound-Mediated Microbubble Cavitation Transiently Reverses Acute Hindlimb Tissue Ischemia through Augmentation of Microcirculation Perfusion via the eNOS/NO Pathway

Ultrasound-mediated microbubble cavitation improves perfusion in chronic limb and myocardial ischemia. The purpose of this study was to determine the effects of ultrasound-mediated microbubble cavitation in acute limb ischemia and investigate the mechanism of action. The animal with acute hindlimb ischemia was established using male Sprague-Dawley rats. The rats were randomly divided into three groups: intermittent high-mechanical-index ultrasound pulses combined with microbubbles (ultrasound [US] + MB group), US alone (US group) and MB alone (MB group). Both hindlimbs were treated for 10 min. Contrast ultrasound perfusion imaging of both hindlimbs was performed immediately and 5, 10, 15, 20 and 25 min after treatment. The role of the nitric oxide (NO) pathway in increasing blood flow in acutely ischemic tissue was evaluated by inhibiting endothelial nitric oxide synthase (eNOS) with N^ω-nitro-L-arginine methyl ester hydrochloride (L-NAME). In the US + MB group, microvascular blood volume and microvascular blood flow of the ischemic hindlimb were significantly increased after treatment (both p values <0.05), while the microvascular flux rate (β) increased, but not significantly (p > 0.05). The increases were observed immediately after treatment, and had dissipated by 25 min. Changes in the US and MB groups were minimal. Inhibitory studies indicated cavitation increased phospho-eNOS concentration in ischemic hindlimb muscle tissue, and the increase was significantly inhibited by L-NAME (p < 0.05). Ultrasound-mediated microbubble cavitation transiently increases local perfusion in acutely ischemic tissue, mainly by improving microcirculatory perfusion. The eNOS/NO signaling pathway appears to be an important mediator of the effect.     

超声微泡介导血管内皮生长因子基因转染大鼠阴茎组织

目的 探讨超声靶向破坏微泡介导血管内皮生长因子165(VEGF₁₆₅)转染于高脂模型大鼠阴茎海绵体组织的可行性。方法 以含4％胆固醇及1％胆酸饲料饲养36只2月龄雄性SD大鼠3个月,建立大鼠高脂模型,将其随机均分为高脂模型组(对照组)、VEGF₁₆₅组和1.0 W/cm²超声+微泡+VEGF₁₆₅组(US+MB＋VEGF₁₆₅组)。于基因转染后7天处死大鼠,采用荧光定量PCR检测VEGF₁₆₅基因表达水平,以Western Blot检测大鼠阴茎组织VEGF蛋白质的表达水平,用免疫组织化学法(IHC)检测大鼠阴茎组织内皮型一氧化氮合成酶(eNOS)蛋白质表达。结果 转基因7天后,US+MB＋VEGF₁₆₅组VEGF₁₆₅基因水平明显高于VEGF₁₆₅组及对照组(P均<0.05),其阴茎海绵体组织VEGF蛋白质表达较VEGF₁₆₅组及对照组增加(P均<0.05);IHC结果显示,US+MB＋VEGF₁₆₅组大鼠阴茎组织eNOS较其他组高表达(P均<0.05)。结论 超声靶向破坏微泡可介导VEGF₁₆₅基因在大鼠高脂模型阴茎海绵体组织的高效转移,为基因治疗高脂勃起功能障碍提供了实验依据。     

超声辐射微泡配合内皮祖细胞移植治疗糖尿病大鼠阴茎勃起功能障碍

目的探讨超声微泡配合内皮祖细胞(EPCs)移植至海绵体组织治疗大鼠糖尿病阴茎勃起功能障碍的可行性。方法体外培养、分离EPCs。将54只成功建立糖尿病勃起功能障碍模型的SD大鼠随机分为空白对照组、EPCs治疗组、1.0W/cm2超声+微泡+EPCs组(US+MB+EPCs治疗组)。EPCs移植7天后,以脱水吗啡(APO)诱导实验检测大鼠阴茎勃起次数和勃起率,组织学观察阴茎海绵体,计数毛细血管数目,计算血管密度,免疫组化检测EPCs移植大鼠阴茎海绵体的情况,Western blot检测VEGF蛋白的表达。结果 US+MB+EPCs治疗组勃起次数和勃起率、毛细血管密度、EPCs染色强度的阳性指数均高于其他两组(P均<0.05),且VEGF蛋白表达水平最高(P<0.05)。结论超声微泡联合EPCs移植可提高EPCs的转染率和靶向性,改善糖尿病大鼠的阴茎勃起功能。     

Microbubble-Mediated Cavitation Promotes Apoptosis and Suppresses Invasion in AsPC-1 Cells

The aim of this study was to identify the potential and mechanisms of microbubble-mediated cavitation in promoting apoptosis and suppressing invasion in cancer cells. AsPC-1 cells were used and divided into four groups: control group, microbubble-only (MB) group, ultrasound-only (US) group and ultrasound plus microbubble (US + MB) group. Pulse ultrasound was used at a frequency of 360 kHz and a SPPA (spatial peak, pulse average) intensity of 1.4 W/cm² for 1 min (duty rate = 50%). Then cells in the four groups were cultured for 24 h. Cell Counting Kit?8 (Biosharp, Hefei, Anhui, China) revealed decreased cell viability in the US + MB group. Western blot confirmed that there were increased cleaved caspase?3 and Bcl-2-associated X protein levels and decreased B?cell lymphoma?2 (Bcl-2) levels, as well as increased intracellular calcium ions and downregulated cleaved caspase-8, in the US + MB group. With respect to proliferation, cells in the US + MB group had lower expression of Ki67 and the weakened colony formation ability. The transwell invasion assay revealed that invasion ability could be decreased in AsPC-1 cells in the US + MB group. Further, it was found that cells in the US + MB group had lower levels of hypoxia-inducible factor-1α (HIF-1α) and vimentin and higher levels of E-cadherin compared with the other three groups. Finally, the US + MB cells had less invadopodium formation. In conclusion, these results suggest that microbubble-mediated cavitation promotes apoptosis and suppresses invasion in AsPC-1 cells.     

Inertial Cavitation Ultrasound with Microbubbles Improves Reperfusion Efficacy When Combined with Tissue Plasminogen Activator in an In Vitro Model of Microvascular Obstruction

We have previously reported that long-tone-burst, high-mechanical-index ultrasound (US) and microbubble (MB) therapy can restore perfusion in both in vitro and in vivo models of microvascular obstruction (MVO). Addition of MBs to US has been found to potentiate the efficacy of thrombolytics on large venous thrombi; however, the optimal US parameters for achieving microvascular reperfusion of MVO caused by microthrombi, when combined with tissue plasminogen activator (tPA), are unknown. We sought to elucidate the specific effects of US, with and without tPA, for effective reperfusion of MVO in an in vitro model using both venous and arterial microthrombi. Venous- and arterial-type microthrombi were infused onto a mesh with 40-μm pores to simulate MVO. Pulsed US (1 MHz) was delivered with inertial cavitation (IC) (1.0 MPa, 1000 cycles, 0.33 Hz) and stable cavitation (SC) US (0.23 MPa, 20% duty cycle, 0.33 Hz) regimes while MB suspension (2 × 10⁶ MBs/mL) was infused. The efficacy of sonoreperfusion with these parameters was tested with and without tPA. Sonoreperfusion efficacy was significantly greater for IC + tPA compared with tPA alone, IC, SC and SC + tPA, suggesting lytic synergism between tPA and US for both venous- and arterial-type microthrombi. In contrast to our previous in vitro studies using 1.5 MPa at 5000 US cycles without tPA, the IC regime employed herein used 90% less US energy. These findings suggest an IC regime can be used with tPA synergistically to achieve a high degree of fibrinolysis for both thrombus types.     

Estimating the Delivery Efficiency of Drug-Loaded Microbubbles in Cancer Cells with Ultrasound and Bioluminescence Imaging

The application of drug-loaded microbubbles (MBs) in combination with ultrasound (US), which results in an increase in capillary permeability at the site of US-sonication-induced MB destruction, may be an efficient method of localized drug delivery. This study investigated the mechanism underlying the US-mediated release of luciferin-loaded MBs through the blood vessels to targeted cells using an in vivo bioluminescence imaging (BLI) system. The luciferin-loaded MBs comprised an albumin shell with a diameter of 1234 ± 394 nm (mean ± SD) and contained 2.48 × 10⁹ bubbles/mL; within each MB, the concentration of encapsulated luciferin was 1.48 × 10⁻¹⁰ mg/bubble. The loading efficiency of luciferin in MBs was only about 19.8%, while maintaining both the bioluminescence and acoustic properties. In vitro and in vivo BLI experiments were performed to evaluate the US-mediated release of luciferin-loaded MBs. For in vitro results, the increase in light emission of luciferin-loaded albumin-shelled MBs after destruction via US sonication (6.24 ± 0.72 × 10⁷ photons/s) was significantly higher than that in the luciferin-loaded albumin-shelled MBs (3.11 ± 0.33 × 10⁷ photons/s) (p < 0.05). The efficiency of the US-mediated release of luciferin-loaded MBs in 4T1-luc2 tumor-bearing mice was also estimated. The signal intensity of the tumor with US destruction at 3 W/cm² for 30 s was significantly higher than without US destruction at 3 (p = 0.025), 5 (p = 0.013), 7 (p = 0.012) and 10 (p = 0.032) min after injecting luciferin-loaded albumin-shelled MBs. The delivery efficiency was, thus, improved with US-mediated release, allowing reduction of the total injection dose of luciferin.     

Ultrasound Irradiation Combined with Hepatocyte Growth Factor Accelerate the Hepatic Differentiation of Human Bone Marrow Mesenchymal Stem Cells

This study investigated the impact of ultrasound (US) irradiation on the hepatic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) induced by hepatocyte growth factor (HGF) and the possible mechanisms. We treated hBMSCs, using HGF with and without US irradiation. Cell viability and stem cell surface markers were analyzed. Hepatocyte-like cell markers and functional markers including α-fetoprotein (αFP/AFP), cytokeratin 18 (CK18), albumin (ALB) and glycogen content were analyzed at the time point of day 1, 3 and 5 after treatment. The involvement of Wnt/β-catenin signaling pathway was evaluated as well. The results showed that the US treatment at 1.0 W/cm² or 1.5 W/cm² for 30?s or 60?s conditions yielded favorable cell viability and engendered stem cell differentiation. At day 5, the expressions of AFP, CK18, ALB and the glycogen content were significantly elevated in the US-treated group at both messenger ribonucleic acid and protein levels (all p?<0.05), in comparison with HGF and control groups. Among all the US treated groups, the expression levels of specific hepatic markers in the (1.5 W/cm² for 60?s) group were the highest. Furthermore, Wnt1, β-Catenin, c-Myc and Cyclin D1 were significantly increased after US irradiation (all p?<0.05), and the enhancements of c-Myc and Cyclin D1 could be obviously impaired by the inhibitor ICG-001 (p?<0.05, p?<0.05), in accordance with decreased ALB and CK18 expression and glycogen content (all p?<0.05). In conclusion, US irradiation was able to promote the hBMSCs' differentiation mediated by HGF in vitro safely, easily and controllably. The activation of Wnt/β-catenin signaling pathway was involved in this process. US irradiation could serve as a potentially beneficial tool for the research and application of stem cell differentiation.     

Dependence of the Rate and Completeness of Fibrin Clot Destruction on the Acoustic Dose and Ultrasound Intensity

The kinetics of fibrin clot destruction under catheter-delivered 32- to 45-kHz ultrasound (US) has been studied at 36°C–38°C in isotonic saline solution. A pseudo-first-order rate constant increased linearly from 0.06/min to 0.57/min with increasing US intensity I₀ from 21.6 to 51.2 W/cm². At I₀ = 4.4 and 11.4 W/cm², the degree of clot destruction did not exceed 11%–15% regardless of the time of US exposure. Starting from I₀ = 21.6 W/cm², the maximum achievable level of clot destruction increased linearly with US intensity, reaching 68% at I₀ = 51.2 W/cm² after 3 min of US exposure. Thus, US intensity is a key parameter determining the maximum achievable level of clot destruction. However, an increase in US intensity above 30 W/cm² is limited by the intensified negative sonochemical effect on the enzymatic system of hemostasis caused by an increase in inertial cavitation. The best effect can be achieved with ultrasound of a sufficiently high intensity that ensures a large contribution of stable cavitation, generating microstreaming flows, and a minimum contribution of inertial cavitation, generating microjets and shock waves.     

超声靶向破坏微泡介导骨髓间充质干细胞移植促进大鼠血管新生

目的 探讨超声破坏微泡介导骨髓间充质干细胞(MSCs)移植在大鼠缺血骨骼肌中的作用. 方法 24只Wister大鼠离断右侧股动脉7 d后分为4组:①超声+微泡组(US+MB);②干细胞静脉移植组(MSCs-iv);③超声+微泡+干细胞静脉移植组(US+MB+MSCs-iv);④对照组.处理后第7 d取局部缺血骨骼肌行免疫组化检测. 结果 US+MB+MSCs-iv组缺血骨骼肌可见较多移植的MSCs,其新生血管数量较其他组明显增加. 结论 超声靶向破坏微泡有可能成为一种增强MSCs移植和促进血管新生的新方法 .     

Acute kidney injury in patients with malignant middle cerebral artery infarction undergoing hyperosmolar therapy with mannitol

PurposeTo assess the kidney safety profile of mannitol in patients with malignant middle cerebral artery (MCA) infarction.Material and methodsWe studied consecutive patients with malignant MCA infarction (01/2008–01/2018). Malignant MCA infarction was defined according to DESTINY criteria. We compared clinical endpoints including acute kidney injury (AKI; according to Kidney Disease: Improving Global Outcomes [KDIGO]) and dialysis between patients with and without mannitol. Multivariable model was built to explore predictor variables of AKI and in-hospital death.ResultsOverall, 219 patients with malignant MCA infarction were included. Mannitol was administered in 93/219 (42.5%) patients with an average dosage of 650 g (250-950 g). Patients treated with mannitol more frequently suffered from AKI (39.8% vs. 11.9%; p < 0.001) and required hemodialysis (7.5% vs. 0.8%; p = 0.01) than patients without mannitol. At discharge, more patients in the mannitol group had persistent AKI than control patients (23.7% vs. 6.4%, p < 0.001). In multivariable model, mannitol emerged as independent predictor of AKI (OR 5.02, 95%CI 2.36–10.69; p < 0.001).ConclusionsAcute kidney injury appears to be a frequent complication of hyperosmolar therapy with mannitol in patients with malignant MCA infarction. Given the lack of evidence supporting effectiveness of mannitol in these patients, its routine use should be carefully considered.     

The incidence and outcomes of patients with acute kidney injury in a multidisciplinary intensive care unit in Durban,South Africa

Background Acute kidney injury (AKI) in critically ill and resource-limited settings is under investigated. Objectives To describe the incidence, outcomes and healthcare burden of AKI in a multidisciplinary intensive care unit (ICU) in Durban, South Africa (SA). Methods All adult patients admitted to the ICU at King Edward VIII Hospital from January 2016 to June 2016, who did not have end-stage renal disease and survived for more than 6 hours after admission were evaluated for AKI using the kidney disease improving global outcomes (KDIGO) creatinine criteria. Potential risk factors for AKI and an association between AKI and outcomes including ICU mortality and length of stay were analysed. Results We screened 204 patients for inclusion into the study and 26 patients were excluded. About half of the patients (50.5%; n=90/178) who were included in the study were diagnosed with AKI at the time of admission and 16.3% (n= 29/178 developed AKI in the ICU. Among the patients who had AKI on admission, 50% (n=45/90) were classified as KDIGO stage1, 21.1% (n=19/90) as stage 2 and 28.8% (n=26/90) as stage 3. Less than one-third (24.7%; n=44/178) of the patients who developed AKI in the ICU were classified as KDIGO stage 1, 14% (n=25/178) were stage 2, and 28% (n=50/178) were stage 3. The mortality rate for patients with AKI on admission was 40.0% (n=36/90) compared with 39.8% (n=35/88) for those without AKI on admission (p=0.975). The mortality rate for all patients with AKI was 46.2% (n=55/119) compared with 27.1% (n=16/59) in patients who did not develop AKI (p=0.014). Conclusion AKI is common in critically ill patients presenting to a tertiary ICU in Durban, SA. AKI is associated with increased mortality and length of stay in the ICU. Strategies to prevent the development or worsening of AKI must be emphasised. These include prevention or at least early treatment of sepsis, adequate fluid resuscitation, aggressive haemodynamic optimisation and avoidance of nephrotoxins. This is especially important in settings where there is limited access to renal replacement therapy (RRT). Contributions of the study This is one of the first studies to describe the incidence and outcomes of AKI in a general critical care population in a resource-limited setting. The study highlights that AKI is very common in critically ill patients in a resource-limited setting, and is associated with increased mortality and resource utilisation. It also highlights the importance of sepsis as a risk factor for AKI.     

Microbubble-Facilitated Ultrasound Catheter Ablation Causes Microvascular Damage and Fibrosis

High-intensity ultrasound (US) ablation produces deeper myocardial lesions than radiofrequency ablation. The presence of intravascular microbubble (MB) contrast agents enhances pulsed-wave US ablation via cavitation-related histotripsy, potentially facilitating ablation in persistently perfused/conducting myocardium. US ablation catheters were developed and tested in the presence of MBs using ex vivo and in vivo models. High-frame-rate videomicroscopy and US imaging of gel phantom models confirmed MB destruction by inertial cavitation. MB-facilitated US ablation in an ex vivo perfused myocardium model generated shallow (2 mm) lesions and, in an in vivo murine hindlimb model, reduced perfusion by 42% with perivascular hemorrhage and inflammation, but no myonecrosis.     

Risk factors and outcomes of acute kidney injury after intracoronary stent implantation

BACKGROUND:

Acute kidney injury following percutaneous coronary intervention (PCI) is associated with a worse outcome. However, the risk factors and outcomes of acute kidney injury (AKI) in patients after intracoronary stent implantation are still unknown.

METHODS:

A retrospective case control study was done in 325 patients who underwent intracoronary stent implantation from January 2010 to March 2011 at the Drum Tower Hospital of Nanjing University School of Medicine. Those were excluded from the study if they had incomplete clinical data. The patients were divided into a normal group and a AKI group according to the standard of post-operation day 7 to identify AKI. The parameters of the patients included: 1) pre-operative ones: age, gender, hypertension, diabetes mellitus, cerebrovascular disease, left ventricular insufficiency, peripheral angiopathy, creatinine, urea nitrogen, estimated glomerular filtration rate (eGFR), hyperuricemia, proteinuria, emergency operation, hydration, medications (ACEI/ARBs, statins); 2) intraoperative ones: dose of contrast media, operative time, hypotension; and 3) postoperative one: hypotension. The parameters were analyzed with univariate analysis and multivariate logistical regression analysis.

RESULTS:

Of the 325 patients, 51(15.7%) developed AKI. Hospital day and in-hospital mortality were increased significantly in the AKI-group. Univariate analysis showed that age, pre-operative parameters (left ventricular insufficiency, peripheral angiopathy, creatinine, urea nitrogen, estimated glomerular filtration rate, hyperuricemia, proteinuria, hydration), emergency operation, intraoperative parameters (operative time, hypotension) and postoperative hypotension were significantly different. However, multivariate logistic regression analysis revealed that increased age (OR=0.253, 95%CI=0.088–0.727), pre-operative proteinuria (OR=5.351, 95%CI=2.128–13.459), pre-operative left ventricular insufficiency (OR=8.704, 95%CI=3.170–23.898), eGFR≤60 ml/min/1.73 m² (OR=6.677, 95%CI=1.167–38.193), prolonged operative time, intraoperative hypotension (OR=25.245, 95%CI=1.001–1.034) were independent risk factors of AKI.

CONCLUSIONS:

AKI is a common complication and associated with ominous outcome following intracoronary stent implantation. Increased age, pre-operative proteinuria, pre-operative left ventricular insufficiency, pre-operative low estimated glomerular filtration rate, prolonged operative time, intraoperative hypotension were the significant risk factors of AKI.KEY WORDS: Intracoronary stent implantation, Acute kidney injury, Risk factor, Outcome     

A randomized,double-blind clinical trial comparing the effects of continuous and pulsed ultrasound in patients with chronic rhinosinusitis

The objective of the present study was to compare the effects of continuous ultrasound (CUS) with pulsed ultrasound (PUS) in patients with chronic rhinosinusitis (CRS). In this prospective, randomized, double-blind, parallel group study, 40 patients (10 losses) with CRS participated. Patients received either continuous or pulsed (1:9) 1 MHz ultrasound (US) using a US head of 1?cm² at 1 W/cm² and 0.5 W/cm² for the maxillary and frontal sinuses, respectively. Treatment was performed in 10 sessions, 3 days per week, with US given every other day. The primary outcome measure was percent improvement in the Sinusitis Symptom Score. Measurements were taken before and after 10 treatment sessions. The patients were followed up monthly for 2 months. After treatment, both groups improved significantly on the Sinusitis Symptoms Score. Patients who received PUS had significantly decreased total symptom scores compared with patients receiving CUS (mean change 9.8 vs. 5.6, p?=?0.049). The percent improvement in the Sinusitis Symptom Score between the PUS group (65.2 SD 23.1) and the CUS group (43.9 SD 40.7) was not statistically significant (p?=?0.09). The effect size for each treatment was large; PUS: d?=?3.92 and CUS: d?=?1.93. Symptom improvement in both groups was similar at the 2-month follow-up. These results support the use of therapeutic US for CRS. This pilot study gives only marginal evidence to favor PUS over CUS.     

Acute kidney injury after cardiac arrest

Aim

Cardiac arrest (CA) in humans causes warm renal ischemia-reperfusion injury, similar to animal models of ischemic acute kidney injury (AKI). We aimed to investigate the incidence and risk associations of AKI after CA, with or without post-resuscitation cardiogenic shock (PRCS).

Methods

We examined the renal outcomes of adult patients admitted to the intensive care unit (ICU), who survived for more than 48 h following successful resuscitation after CA.

Results

Of 105 patients (median age 65 years; 69% male), 58 (55.2%) had PRCS and were on vasoactive drugs beyond 24 h; and 9 (8.6%) (all of whom had PRCS) received renal replacement therapy. Only 3 (6.4%) of 47 patients without PRCS had RIFLE-‘I’/‘F’ AKI, compared to 30 (51.7%) of 58 patients with PRCS (p < 0.001). Median peak serum creatinine in the non-PRCS group was 102 μmol/L (interquartile range 85–115), compared to 155 μmol/L (interquartile range 112–267) (p < 0.001) in the PRCS group. On multivariate analysis, cumulative noradrenaline dose during the first 24 h in ICU, PRCS, and pre-CA renin–angiotensin–aldosterone-system blockade were independently associated with RIFLE-‘I’/‘F’ AKI; while higher serum lactate 12 h after CA, baseline creatinine, and PRCS were independently associated with greater rise in creatinine from pre-CA levels. Estimated time without spontaneous circulation, total adrenaline dose and initial cardiac rhythm during CA, had no independent associations with renal outcomes.

Conclusions

In the absence of PRCS, CA in isolation is uncommonly associated with significant AKI. The human kidney may be more resistant to warm ischemia-reperfusion injury than previously thought.     

Validation of the KDIGO acute kidney injury criteria in a pediatric critical care population

Purpose

Acute kidney injury (AKI) occurs commonly in critically ill children and has been associated with increased mortality of up to 50 %. The Kidney Disease: Improving Global Outcomes (KDIGO) AKI working group has proposed a standardized definition of AKI. Utilizing routinely available clinical data, we evaluated the KDIGO AKI criteria and the relationship of AKI with relevant outcomes in a single center tertiary pediatric intensive care (PICU) and cardiac intensive care unit (CICU) population.

Methods

The University of Michigan Pediatric Critical Care Database was probed for all discharges from the pediatric intensive care and cardiac intensive care units between July 2011 and October 2013 (N = 4,645). The KDIGO serum creatinine (SCr)-based criteria staged AKI with the modification that a minimum SCr of greater than 0.5 mg/dL was required to be classified as AKI. Exclusion: end-stage renal disease, new renal transplant, missing PRISM III data, or no measured Cr during intensive care unit (ICU) admission (N = 1,636).

Results

AKI occurred in 737 (24.5 %, stage 1 = 193, stage 2 = 189, and stage 3 = 355) of 3,009 discharges (PICU N = 1,870, CICU N = 1,139) that included 2,415 patients. In multivariate analysis AKI was associated with increased ICU length of stay (LOS) in hours (stage I β = 42.2, p = 0.024, II β = 74.1, p = 0.003, III β = 215.8, p < 0.001). Multivariate analysis showed that AKI was associated with increased odds of ICU mortality (OR 3.4, 95 % CI 2.0–6.0) and increased length of mechanical ventilation among those requiring mechanical ventilation (β = 2.3 days, p < 0.001).

Conclusions

Using the KDIGO criteria to define AKI, we observed a high prevalence of AKI among critically ill children. Worsening stages of AKI were associated with increased ICU LOS, and AKI was independently associated with prolonged mechanical ventilation and increased mortality. The KDIGO criteria describe clinically relevant AKI in a broad pediatric critical care population.     

Ultrasound-Mediated Microbubble Destruction Increases Renal Interstitial Capillary Permeability in Early Diabetic Nephropathy Rats

Diabetic nephropathy (DN) is defined as persistent proteinuria corresponding to a urinary albumin excretion rate >300 μg/mg in the absence of other non-diabetic renal diseases. The aim of this study was to determine if ultrasound (US)-mediated microbubble (MB) destruction could increase renal interstitial capillary permeability in early DN rats. Diabetes was induced with streptozotocin. DN rats presented with mild micro-albuminuria 30 d after onset of diabetes. DN rats (N = 120) were divided into four groups that received Evans blue (EB) followed by: (i) no treatment (control group); (ii) continuous ultrasonic irradiation for 5 min (frequency = 7.00 MHz, mechanical index = 0.9, peak rarefactional pressure = 2.38 MPa: US group); (iii) microbubble injection (0.05 mL/kg: MB group); and (iv) both ultrasound and microbubble injection (US + MB group). Another 8 DN rats were subjected to ultrasound and microbubbles and then injected with EB after 24 h (recovery group). EB content, EB extravasation and E-selectin mRNA and protein expression significantly increased, and interstitial capillary walls became discontinuous in the US + MB group. Neither hemorrhage nor necrosis was observed on renal histology. Urine samples were collected 24 h post-treatment. There was no hematuria, and the urinary albumin excretion rate did not increase after ultrasound-microbubble interaction detected by urinalysis. EB content returned to the control group level after 24 h, as assessed for the recovery group. In conclusion, ultrasound-mediated microbubble destruction locally increased renal interstitial capillary permeability in DN rats, and should be considered a therapy for enhancing drug and gene delivery to the kidney in the future.