Optimization of Seleno-chitosan-phytic acid nanocomplex for efficient removal of patulin from apple juice

A novel and effective adsorbent known as Seleno-chitosan-phytic acid nanocomplex (Se-CS-PA) has been developed specifically for efficiently removing patulin (PAT) from a simulated juice solution. The synthesis of Se-CS-PA nanocomplex was confirmed through Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and energy dispersive X-Ray (EDX) analyses. Response surface methodology (RSM) was employed using central composite design (CCD) to examine the impact of four independent variables (PA concentration, amount of nano-complex, duration of interaction between PAT and nano-complex, and initial concentration of PAT) on the removal of PAT. PA concentration of 0.1 % with 2.1 g Se-CS-PA nanocomplex according to RSM polynomial equation and apple juice with 25 μg.L-1 PAT yielded a remarkable adsorption rate of 94.23 % and 87.52 % respectively after 7 h. The process of PAT adsorption was explained using the pseudo-first-order model (R2 = 0.8858) for the kinetic model and the Freundlich isotherm (R2 = 0.9988) for the isotherm model.

Patterns of cortical oxygenation may predict the response to stenting in subjects with renal artery stenosis: A radiomics-based model

BACKGROUND

Percutaneous-transluminal renal angioplasty (PTRA) and stenting aim to halt the progression of kidney disease in patients with renal artery stenosis (RAS), but its outcome is often suboptimal. We hypothesized that a model incorporating markers of renal function and oxygenation extracted using radiomics analysis of blood oxygenation-level dependent (BOLD)-MRI images may predict renal response to PTRA in swine RAS.

MATERIALS AND METHODS

Twenty domestic pigs with RAS were scanned with CT and BOLD MRI before and 4 weeks after PTRA. Stenotic (STK) and contralateral (CLK) kidney volume, blood flow (RBF), and glomerular filtration rate (GFR) were determined, and BOLD-MRI R2 * maps were generated before and after administration of furosemide, a tubular reabsorption inhibitor. Radiomics features were extracted from pre-PTRA BOLD maps and Robust features were determined by Intraclass correlation coefficients (ICC). Prognostic models were developed to predict post-PTRA renal function based on the baseline functional and BOLD-radiomics features, using Lasso-regression for training, and testing with resampling.

RESULTS

Twenty-six radiomics features passed the robustness test. STK oxygenation distribution pattern did not respond to furosemide, whereas in the CLK radiomics features sensitive to oxygenation heterogeneity declined. Radiomics-based model predictions of post-PTRA GFR (r = 0.58, p = 0.007) and RBF (r = 0.68; p = 0.001) correlated with actual measurements with sensitivity and specificity of 92% and 67%, respectively. Models were unsuccessful in predicting post-PTRA systemic measures of renal function.

CONCLUSIONS

Several radiomics features are sensitive to cortical oxygenation patterns and permit estimation of post-PTRA renal function, thereby distinguishing subjects likely to respond to PTRA and stenting.

Gelling and rheological properties of a polysaccharide extracted from Ocimum album L. seed

In this study, a new polysaccharide was isolated from Ocimum album L. seed (OA), and its physicochemical and rheological properties were investigated. Ocimum album polysaccharide (OAP) was an acidic heteropolysaccharide with a molecular weight of 1935 kDa, and it was composed of five types of sugars: mannose (32.95 %), glucose (27.57 %), galactose (19.29 %), rhamnose, (15.96 %) and galacturonic acid (4.23 %). According to the results obtained from Huggins and Kraemer equations, the intrinsic viscosity was 6.9 dL/g in distilled water. The OAP solutions at a concentration between 0.1 and 1.5 %, showed shear-thinning behavior, and the Herschel-Bulkley and Cross models exhibited a high ability to describe the flow behavior of OAP solutions. The apparent viscosity of 1 % OAP solution was decreased in the presence of different concentrations of NaCl (0.1, 0.3, and 0.5 M), at different pHs (3-11), and in temperatures between 5 and 100 °C. Also, the pseudoplastic behavior was observed in all samples. In OAP solutions (0.1-1.5 %), the up and down curves in the shear stress-shear rate diagram did not coincide, which indicated time-dependent (thixotropic) behavior. Although, the thixotropic properties of 1 % OAP solution were weakened with adding NaCl (0.1-0.5 M) and at different pH (3-11). The results obtained from the dynamic oscillatory test showed that the OAP solutions at concentrations higher than 0.1 % had a gel-like behavior, and the viscoelastic moduli (G' and G″) were weakened in the presence of salt and with a change in pH. Also, in the temperature sweep test, the 1 % solution showed the behavior of thermally irreversible gels.

Diverse Tsunamigenesis Triggered by the Hunga Tonga-Hunga Ha'apai Eruption

On the evening of 15 January 2022, the Hunga Tonga-Hunga Ha’apai volcano¹ unleashed a violent underwater eruption, blanketing the surrounding land masses in ash and debris^2,3. The eruption generated tsunamis observed around the world. An event of this type last occurred in 1883 during the eruption of Krakatau⁴, and thus we have the first observations of a tsunami from a large emergent volcanic eruption captured with modern instrumentation. Here we show that the explosive eruption generated waves through multiple mechanisms, including: (1) air–sea coupling with the initial and powerful shock wave radiating out from the explosion in the immediate vicinity of the eruption; (2) collapse of the water cavity created by the underwater explosion; and (3) air–sea coupling with the air-pressure pulse that circled the Earth several times, leading to a global tsunami. In the near field, tsunami impacts are strongly controlled by the water-cavity source whereas the far-field tsunami, which was unusually persistent, can be largely described by the air-pressure pulse mechanism. Catastrophic damage in some harbours in the far field was averted by just tens of centimetres, implying that a modest sea level rise combined with a future, similar event would lead to a step-function increase in impacts on infrastructure. Piecing together the complexity of this event has broad implications for coastal hazards in similar geophysical settings, suggesting a currently neglected source of global tsunamis.

January 2022 saw the first observations of a tsunami resulting from a large emergent volcanic eruption (Hunga Tonga) captured using modern instrumentation, with broad implications for hazard management in similar geophysical settings.

Phase I/II trial of palbociclib, pembrolizumab and letrozole in patients with hormone receptor-positive metastatic breast cancer

BACKGROUND

CDK4/6 inhibitors modulate immune response in breast cancer. This phase I/II trial was designed to test the safety and efficacy of palbociclib, pembrolizumab and letrozole in women with hormone receptor positive (HR⁺) human epidermal growth factor receptor 2 negative (HER2^-) metastatic breast cancer (MBC).

PATIENTS AND METHODS

Women with stage IV HR⁺ HER2^- MBC were enrolled and treated with palbociclib, pembrolizumab and letrozole. Primary end-points were safety, tolerability and efficacy.

RESULTS

Between November 2016 and July 2020, 23 patients were enrolled with 20 evaluable for response, including 4 patients in cohort 1 and 16 patients in cohort 2. Cohort 1 median age was 48 years (33-70) and cohort 2 median age was 55 (37-75). Cohort 1 closed early due to limited accrual. Grade III-IV adverse events were neutropenia (83%), leucopaenia (65%), thrombocytopenia (17%) and elevated liver enzymes (17%). In cohort 1, 50% achieved a partial response (PR) and 50% had stable disease (SD). In cohort 2, 31% achieved complete response (CR), 25% had PR and 31% had SD by Response Evaluation Criteria in Solid Tumours version 1.1. Median progression-free survival was 25.2 months (95% confidence interval [CI] 5.3, not reached) and median overall survival was 36.9 months (95% CI 36.9, not reached) in cohort 2 with a median follow-up of 24.8 months (95% CI 17.1, not reached). A correlative immune biomarker analysis was published separately.

CONCLUSION

The combination of palbociclib, pembrolizumab and letrozole is well tolerated, and a complete response rate of 31% was identified in HR⁺ MBC patients who received this combination as front-line therapy. Confirmatory trials are required to better understand the immune-priming effects of CDK4/6 inhibitors.

P–125 Evaluation of N-acetylcysteine (NAC) effect on in vitro culture of immature mouse testis following vitrification

Study question

Can the Culture of cryopreserved immature mouse testicular tissue in the presence of NAC improves the developmental process and prevent apoptosis induction during the culture?

Summary answer

An appropriate dosage of NAC in the culture medium of immature mouse testicular tissue was associated with increased cell survival and spermatogonia stem cell regeneration.

What is known already

Spermatogonial stem cells (SSCs) are the most advanced type of stem cells in the testes of prepubertal boys which are the main targets of oncological treatments. Therefore, the only possible alternative to maintain fertility in prepubertal boys is to preserve SSCs before their depletion by cryopreserving the testicular tissue. Despite the possibility of obtaining viable spermatozoa using cryopreserved testicular tissue cultivated in vitro,cryopreservation methods and damages caused by the culture procedure would be obstacles for maintaining the testicular tissueand it seems that optimizing the culture condition is vital.

Study design, size, duration

Testis tissues were harvested from 6-days-old immature NMRI male mice (n = 100) after cervical dislocation and vitrified. After 3 days testicular biopsies were warmed and distributed into control, culture Ӏ (not supplemented with NAC) and culture ӀӀ (supplemented with NAC) groups. To determine the appropriate NAC concentration 8 different dosages of NAC were evaluated in terms of cell survival and the best dose, a culture medium containing 125mmol/L NAC was selected to continue the study.

Participants/materials, setting, methods

Vitrified-warmed fragments (2mm3) obtaining from immature NMRI mice were cultured in vitro for 7 days on agar gel. The effects of culture conditions were assessed by Morphological evaluation of seminiferous tubules (using Hematoxylin-eosin staining). Cell viability, protein expression (caspase–3), and gene expression (Bax, Bcl2, Caspase–3, plzf) were evaluated by flow cytometry, immunofluorescence staining, and real time polymerase chain reaction respectively. Additionally, Malondialdehyde (MDA) concentration in the culture medium was measured by MAD Assay Kit.

Main results and the role of chance

Significant (p < 0.01) increase in cell viability was observed in the culture ӀӀ group after 7 days of culture compared to the culture Ӏ. Bax/Bcl2 ratio was significantly (p < 0.01) lower in the culture ӀӀ group compared to the control and culture Ӏ group. The expression of caspase–3 showed a significant (p < 0.001) increase in the culture ӀӀ group while immunofluorescence analysis showed low expression of it in all groups. These results were consistent with the high level of Bcl2expression that inhibited Caspase–3 expression and consequently the inhibition of apoptosis, and on the other hand, the presence of NAC showed that plzf expressions significantly (p < 0.001) increased in culture ӀӀ group compared to the control and culture Ӏ group. Although the presence of NAC did not inhibit all the deleterious effects of culture medium on tissue morphology, NAC was able to maintain better integrity of tissue and seminiferous tubules within central regions compared to the group without NAC. The decrease in MDA level in the presence of NAC (culture ӀӀ) was also a good indicator to confirm the desired results obtained from the presence of NAC in the culture medium.

Limitations, reasons for caution

Although the findings of the study were satisfactory in mice tissue after 1 week of culture, it is essential to replicate the experiments using human tissue and evaluate the quality and reproductive potential of surviving spermatogonia after long-term storage to become clinically applicable.

Wider implications of the findings: This study highlights the necessity for further experiments to improve the testicular tissue culture conditions for better spermatogonial survival and differentiation to sperm, as the prepubertal fertility restoration methods are promising to be implemented in the clinic in the near future.

Trial registration number

Not applicable

O-218 The effect of mTOR activation on human primordial follicle activation during in-situ culture

Study question

What is the effect of mTOR pathway activation on human primordial follicles in-situ activation and subsequent development following tissue cryopreservation?

Summary answer

Temporary treatment of cryopreserved human ovarian tissue with mTOR activators cause the initiation of primordial follicle development and influence steroidogenesis.

What is known already

In-vitro activation of primordial follicles to produce mature oocytes provides an alternative technique for fertility preservation. The employment of different stimulators of PI3K pathway has been successfully used to activate resting follicles during culture or prior to grafting in patients with premature ovarian insufficiency. The addition of phosphatidic acid (PA) and propranolol (PP), as mTOR stimulators, in the culture medium has promoted primordial follicle activation morphologically in mouse and human ovaries. Molecular and functional evaluations of primordial follicle activation after treatment with the mentioned stimulators has not been conducted.

Study design, size, duration

Ovarian tissues which were donated from 6 transsexual patients (23-35 years old), were dissected and cryopreserved with slow-freezing technique. After thawing, they were cut into 1x1x1 mm fragments and incubated with different stimulators in three groups: 1) Control (without stimulators), 2) PA (200µM), and 3) PA+PP (200µM & 50µM respectively). In groups two and three, ovarian fragments were cultured for 24 hours in presence of stimulators and then cultured for additional 6 days without stimulators.

Participants/materials, setting, methods

The cultured ovarian fragments were directly processed for Hematoxylin and Eosin staining and Western blot analysis. The proportion of morphologically normal and degenerated primordial and growing follicles and 17β-estradiol (E2) level in the culture medium were compared after 1 and 7 days of culture to assess follicular development and function. Western blot analysis for phosphorylated and non-phosphorylated status of FOXO3a and RSP6 proteins expression were compared after 24 hours of incubation.

Main results and the role of chance

The proportion of primordial and growing follicles were not significantly different in the experimental groups after 24 hours of incubation with either of the stimulators. Western blot analyses indicated a significant reduction of FOXO3a in the PA+PP group compared to the control group. The phosphorylation level of RPS6 protein did not significantly change in either of the groups. The proportion of transitional follicles were significantly higher in the PA group compared to other groups after 7 days of culture. The E2 secretion level was significantly higher at the last day of culture compared to day 1 for all groups. At the end of the culture period, E2 levels was significantly higher in both PA and PA+PP groups compared to the control group.

Limitations, reasons for caution

Due to ovarian fragmentation before culture, the HIPPO pathway downstream molecules should have also been evaluated by western blot, which was not contributed in this study.

Wider implications of the findings

The results demonstrate the beneficial effect of mTOR signaling to accelerate early primordial follicle recruitment in cryopreserved-thawed human ovarian fragments.

Trial registration number

not applicable

Gums from Indigenous Plants of Iran: A Review on Physicochemical, Rheological and Functional Properties

Background:

Recently, public interests have increased to study novel and vernacular polysaccharides due to their various uses, especially in food formulations as well as pharmaceuticals and herbal medicines. Plant-based gums are commercially produced from a large number of plants that include complex polysaccharides.

Scope and Approach:

he present study has summarized physicochemical, rheological and functional properties of tragacanth, basil seed and balangu gums from indigenous plants of Iran.

Conclusion:

The results of this review study demonstrate that the highlighted gums are commonly used as dietary fibers, thickening agents, emulsifiers, stabilizers and drug delivery agents. The general appearance of gums varies from dark-brown to whitish in color. At various concentrations, pH and ionic strengths, aqueous dispersions show great variations in their rheological behavior. In conclusion, industrial applications of these gums are possible as a result of their strong thickening properties. Additionally, significant surface activity and emulsification capacity enable their application in the food, pharmaceutical and/or cosmetic industries.

The Effect of Vitamin C Supplementation on Cardiac Enzymes After Coronary Artery Bypass Graft: A Double-blind Randomized Control Trial

Background:

Coronary artery bypass graft (CABG) is associated with oxidative stress and tissue damage. Vitamin C, as an antioxidant agent, has an important role in attenuating the oxidative stress damage and might have cardio-protective effects after CABG. We aimed to evaluate the probable roles of vitamin C supplementation in cardiac biomarkers after CABG.

Methods::

In this randomized control trial, 122 patients undergoing CABG were randomly assigned to the intervention (n=54) and control group (n=68) and received vitamin C (2 g intravenously) or placebo, respectively. The surgical methods of the patients in the two groups were identical. The primary efficacy endpoint of this trial is the difference in the levels of CK-MB, Troponin and Total Antioxidant Capacity (TAC) were measured at study entry and 24 hrs after surgery between the two groups.

Results::

The two groups were not significantly different in terms of basic variables. Within-group comparison showed significant rises in the level of troponin (P < 0.001) and CK-MB (P < 0.001) over time. However, between-group comparison showed no significant difference between the two groups in terms of CK-MB (P=0.826) and troponin (P=0.821). As a whole, the correlation between cardiac enzymes and surgical characteristic was not seen.

Conclusion::

The results showed that pretreatment with vitamin C could not reduce cardiac marker following CABG. After the intervention, TAC did not differ between and within the intervention and the control groups. Pretreatment with vitamin C as an antioxidant agent could not reduce ischemicreperfusion resulting in CABG.

The emulsifying and foaming properties of Amuniacum gum (Dorema ammoniacum) in comparison with gum Arabic

In this study, the emulsifying and foaming properties of a novel exudate gum from Dorema ammoniacum (AMG) were assessed in comparison with the well-known gum Arabic from Acacia tree (GAC). The sunflower oil-based emulsion (10% v/v) containing various concentrations (5%-15% w/v) of AMG and GAC was prepared. At all concentrations, AMG showed higher surface and interface activity than GAC. Increasing in AMG and GAC concentrations caused to increase and decrease in Z average, respectively. Overall, the GAC-stabilized emulsion showed lower Z average and PDI value than the AMG-stabilized emulsion during storage time. The sample containing AMG showed higher emulsion capacity and lower emulsion stability in comparison with the one containing GAC at all concentrations. The storage stability decreased and increased with increasing in AMG and GAC concentrations, respectively. After two-week storage, the emulsions containing 10 and 15% AMG showed higher phase separation than those containing GAC; however, this was opposite about sample containing 5% AMG. At thermal, centrifuge, and freezing conditions, the emulsion containing 5% AMG indicated significantly higher stability than GAC samples; however, at higher concentration, opposite effect could be observed. The foaming capacity of the samples containing AMG increased from 81% to 93% by increasing gum concentration from 5% to 15%. The solutions containing AMG showed higher foam capacity than control samples (without gum) and those containing GAC at all concentrations. Increasing in AMG and GAC concentrations slightly improved foam stability, and the highest value (92%) belonged to 15% AMG solution.

Identification of Mislabeling Some Meat Products Sold on the Iran Market Using PCR-RFLP

Background:

Mislabeling of meat products due to their high market values is a food fraud, which can result in economic deception. Currently, a little information on mislabeling is available in Iran. Therefore, the aim of this study was to carry out a market survey on a variety of meat products sold in Iran to investigate mislabeling.

Methods:

A total of 31 meat product samples were purchased from local retailers including supermarkets and local butchers. These samples included salami (n = 6), hamburger (n = 15) and minced meat (n = 10). Labels claimed that the products only contained beef. DNA was extracted from samples and tested using PCR-RFLP for the presence of chicken traces.

Results:

Of the 31 meat products, 23 included mislabeling, which substituted low-cost chicken for costly beef. Results showed that six of six salami (100%), nine of 15 hamburger (60%) and eight of ten minced meat (80%) contained chicken meat not listed in ingredient labels.

Conclusion:

Overall, results from the current study greatly warn consumers on potential economic deception occurring in meat products in Iran. This study helps meat industries to address potentially fraudulent activities and improve sanitary techniques during meat processes.

Formulation of Stable Frying Oil for Food Industry by Using Various Edible Oils and Antioxidants

Background:

Frying oils are important nutrition due to their significant changes during the frying process. These changes can cause serious health problems in consumers.

Methods:

The aims of this 3-stage study were to investigate chemical changes of Total Polar Compounds (TPC), Peroxide Value (PV), Free Fatty Acid (FFA), Anisidine Value (AV) and TOTOX Value (TV) during heating of four improved frying oil formulations including super palm olein, sunflower, rapeseed and corn oil and to assess their frying quality, blends and subsequent changes using various antioxidant compounds, including ter-butyl Hydroquinone (TBHQ) and its mixture with Ascorbyl Palmitate (ASCP).

Results:

Results showed that the best formulation at the end of frying time was FO5 including 1:1 super palm olein and corn oil containing 120 ppm of TBHQ, 120 ppm of ASCP and 0.01% of Citric Acid (CA). This formulation showed the minimum TPC, PV, TV and FFA, compared to those other formulations.

Conclusion:

Furthermore, AP was demonstrated to include synergistic effects on TBHQ in preventing thermal deterioration of the frying oils.

Heavy Metal Contamination of Milk and Milk Products Consumed in Tabriz

Background:

In this study, lead (Pb), cadmium (Cd), copper (Cu), Iron (Fe) and arsenic (As) contents in milk and different dairy product samples from in Iran (Tabriz) were measured.

Methods:

Samples of 10 brands of pasteurized milk, yoghurt, traditional and industrial kashk were selected and quantitative analysis for heavy metals were performed by a Varian AA240fs atomic absorption spectrometer with a Graphite Furnace (GTA 120).

Results:

The obtained ranges of mean heavy metals are given in the following: in milk 6.066-10.83, 2.343-6.070, 141.73-241.23, 2764.3-3151.3, 3.246-7.536ppb, in yoghurt 5.543-19.341, 3.143-8.830, 276.17-423.53, 2412.4-4115.7, 6.650-10.84, in industrial kashk 2.163-19.621, 1.541-13.45, 115.87- 565.40, 2588.4-5014.3, 4.346-20.351ppb, and in traditional kashk 7.972-32.723, 5.233-9.966, 416.42- 923.62, 4491.4-6402.3, 7.661-28.413 ppb, respectively.

Conclusion:

All the samples were below the internationally recognized permissible limits and did not pose any health risk to the consumption of milk and dairy products in Tabriz.

The Metabolic Syndrome Does Not Affect Development of Collateral Circulation in the Poststenotic Swine Kidney

BACKGROUND

The collateral circulation is important in maintenance of blood supply to the ischemic kidney distal to renal artery stenosis (RAS). Obesity metabolic syndrome (MetS) preserves renal blood flow (RBF) in the stenotic kidney, but whether this is related to an increase of collateral vessel growth is unknown. We hypothesized that MetS increased collateral circulation around the renal artery.

METHODS

Twenty-one domestic pigs were randomly divided into unilateral RAS fed an atherogenic (high-fat/high-fructose, MetS-RAS) or standard diet, or controls (n = 7 each). RBF, glomerular filtration rate (GFR), and the peristenotic collateral circulation were assessed after 10 weeks using multidetector computed tomography (CT) and the intrarenal microcirculation by micro-CT. Vascular endothelial growth factor (VEGF) expression was studied in the renal artery wall, kidney, and perirenal fat. Renal fibrosis and stiffness were examined by trichrome and magnetic resonance elastography.

RESULTS

Compared with controls, RBF and GFR were decreased in RAS, but not in MetS-RAS. MetS-RAS formed peristenotic collaterals to the same extent as RAS pigs but induced greater intrarenal microvascular loss, fibrosis, stiffness, and inflammation. MetS-RAS also attenuated VEGF expression in the renal tissue compared with RAS, despite increased expression in the perirenal fat.

CONCLUSIONS

MetS does not interfere with collateral vessel formation in the stenotic kidney, possibly because decreased renal arterial VEGF expression offsets its upregulation in perirenal fat, arguing against a major contribution of the collateral circulation to preserve renal function in MetS-RAS. Furthermore, preserved renal function does not protect the poststenotic kidney from parenchymal injury.

Comparison of the effects of stellate ganglion block and paroxetine on hot flashes and sleep disturbance in breast cancer survivors

Background

The incidence of menopausal symptoms, including hot flashes and sleep disturbance, caused by drug treatment is a common problem in breast cancer survivors. Considering the limitations of hormone therapy in such patients, several studies have been conducted to find alternative methods. The aim of this study was to investigate and compare the effectiveness of stellate ganglion block (SGB) with that of paroxetine, which was approved by the US Food and Drug Administration (FDA) as a medicine for the treatment of hot flashes and ensuing sleep disturbance.

Patients and methods

A total of 40 patients survived from breast cancer and complaining of these symptoms were equally assigned to two groups of 20 each. In the study group, SGB was performed successfully under sonography guidance using 10 mL of 0.5% bupivacaine, and in the control group (paroxetine), the daily administration of 7.5 mg of paroxetine was conducted for 6 weeks. The frequency and severity of hot flash attacks and sleep quality of patients were evaluated prior to the intervention and after 2, 4 and 6 weeks. The incidence of adverse events during treatment or follow-up was recorded.

Results

A significant decrease in hot flash score and sleep disturbance index (SDI) was observed in both groups. Comparison of the results showed no noticeable difference between the two groups. Two participants in the control group had discontinued medication due to gastrointestinal symptoms, and only one case of mild headache was reported in the study group.

Conclusion

SGB is as much effective as paroxetine in controlling hot flashes and sleep disturbances in breast cancer survivors and is associated with few complications.

Impact of motion and partial volume effects correction on PET myocardial perfusion imaging using simultaneous PET-MR

PET is an established modality for myocardial perfusion imaging (MPI) which enables quantification of absolute myocardial blood flow (MBF) using dynamic imaging and kinetic modeling. However, heart motion and partial volume effects (PVE) significantly limit the spatial resolution and quantitative accuracy of PET MPI. Simultaneous PET-MR offers a solution to the motion problem in PET by enabling MR-based motion correction of PET data. The aim of this study was to develop a motion and PVE correction methodology for PET MPI using simultaneous PET-MR, and to assess its impact on both static and dynamic PET MPI using 18F-Flurpiridaz, a novel 18F-labeled perfusion tracer. Two dynamic 18F-Flurpiridaz MPI scans were performed on healthy pigs using a PET-MR scanner. Cardiac motion was tracked using a dedicated tagged-MRI (tMR) sequence. Motion fields were estimated using non-rigid registration of tMR images and used to calculate motion-dependent attenuation maps. Motion correction of PET data was achieved by incorporating tMR-based motion fields and motion-dependent attenuation coefficients into image reconstruction. Dynamic and static PET datasets were created for each scan. Each dataset was reconstructed as (i) Ungated, (ii) Gated (end-diastolic phase), and (iii) Motion-Corrected (MoCo), each without and with point spread function (PSF) modeling for PVE correction. Myocardium-to-blood concentration ratios (MBR) and apparent wall thickness were calculated to assess image quality for static MPI. For dynamic MPI, segment- and voxel-wise MBF values were estimated by non-linear fitting of a 2-tissue compartment model to tissue time-activity-curves. MoCo and Gating respectively decreased mean apparent wall thickness by 15.1% and 14.4% and increased MBR by 20.3% and 13.6% compared to Ungated images (P  <  0.01). Combined motion and PSF correction (MoCo-PSF) yielded 30.9% (15.7%) lower wall thickness and 82.2% (20.5%) higher MBR compared to Ungated data reconstructed without (with) PSF modeling (P  <  0.01). For dynamic PET, mean MBF across all segments were comparable for MoCo (0.72  ±  0.21 ml/min/ml) and Gating (0.69  ±  0.18 ml/min/ml). Ungated data yielded significantly lower mean MBF (0.59  ±  0.16 ml/min/ml). Mean MBF for MoCo-PSF was 0.80  ±  0.22 ml/min/ml, which was 37.9% (25.0%) higher than that obtained from Ungated data without (with) PSF correction (P  <  0.01). The developed methodology holds promise to improve the image quality and sensitivity of PET MPI studies performed using PET-MR.

Noninvasive Assessment of Renal Fibrosis with Magnetization Transfer MR Imaging: Validation and Evaluation in Murine Renal Artery Stenosis

Purpose To test the utility of magnetization transfer imaging in detecting and monitoring the progression of renal fibrosis in mice with unilateral renal artery stenosis. Materials and Methods This prospective study was approved by the Institutional Animal Care and Use Committee. Renal artery stenosis surgery (n = 10) or sham surgery (n = 5) was performed, and the stenotic and contralateral kidneys were studied longitudinally in vivo at baseline and 2, 4, and 6 weeks after surgery. After a 16.4-T magnetic resonance imaging examination, magnetization transfer ratio was measured as an index of fibrosis (guided by parameters selected in preliminary phantom studies). In addition, renal volume, perfusion, blood flow, and oxygenation were assessed. Fibrosis was subsequently measured ex vivo by means of histologic analysis and hydroxyproline assay. The Wilcoxon rank sum or signed rank test was used for statistical comparisons between or within groups, and Pearson and Spearman rank correlation was used to compare fibrosis measured in vivo and ex vivo. Results In the stenotic kidney, the median magnetization transfer ratio showed progressive increases from baseline to 6 weeks after surgery (increases of 13.7% [P = .0006] and 21.3% [P = .0005] in cortex and medulla, respectively), which were accompanied by a progressive loss in renal volume, perfusion, blood flow, and oxygenation. The 6-week magnetization transfer ratio map showed good correlation with fibrosis measured ex vivo (Pearson r = 0.9038 and Spearman ρ = 0.8107 [P = .0002 vs trichrome staining]; r = 0.9540 and ρ = 0.8821 [P < .0001 vs Sirius red staining]; and r = 0.8429 and ρ = 0.7607 [P = .001 vs hydroxyproline assay]). Conclusion Magnetization transfer imaging was used successfully to measure and longitudinally monitor the progression of renal fibrosis in mice with unilateral renal artery stenosis. ^© RSNA, 2016 Online supplemental material is available for this article.

Low-Energy Shockwave Therapy Improves Ischemic Kidney Microcirculation

Microvascular rarefaction distal to renal artery stenosis is linked to renal dysfunction and poor outcomes. Low-energy shockwave therapy stimulates angiogenesis, but the effect on the kidney microvasculature is unknown. We hypothesized that low-energy shockwave therapy would restore the microcirculation and alleviate renal dysfunction in renovascular disease. Normal pigs and pigs subjected to 3 weeks of renal artery stenosis were treated with six sessions of low-energy shockwave (biweekly for 3 consecutive weeks) or left untreated. We assessed BP, urinary protein, stenotic renal blood flow, GFR, microvascular structure, and oxygenation in vivo 4 weeks after completion of treatment, and then, we assessed expression of angiogenic factors and mechanotransducers (focal adhesion kinase and β1-integrin) ex vivo A 3-week low-energy shockwave regimen attenuated renovascular hypertension, normalized stenotic kidney microvascular density and oxygenation, stabilized function, and alleviated fibrosis in pigs subjected to renal artery stenosis. These effects associated with elevated renal expression of angiogenic factors and mechanotransducers, particularly in proximal tubular cells. In additional pigs with prolonged (6 weeks) renal artery stenosis, shockwave therapy also decreased BP and improved GFR, microvascular density, and oxygenation in the stenotic kidney. This shockwave regimen did not cause detectable kidney injury in normal pigs. In conclusion, low-energy shockwave therapy improves stenotic kidney function, likely in part by mechanotransduction-mediated expression of angiogenic factors in proximal tubular cells, and it may ameliorate renovascular hypertension. Low-energy shockwave therapy may serve as a novel noninvasive intervention in the management of renovascular disease.

Restoration of Mitochondrial Cardiolipin Attenuates Cardiac Damage in Swine Renovascular Hypertension

Background

Renovascular hypertension (RVH) impairs cardiac structure and left ventricular (LV) function, but whether mitochondrial injury is implicated in RVH‐induced myocardial damage and dysfunction has not been defined. We hypothesized that cardiac remodeling in swine RVH is partly attributable to cardiac mitochondrial injury.

Methods and Results

After 12 weeks of hypercholesterolemic (HC)‐RVH or control (n=14 each), pigs were treated for another 4 weeks with vehicle or with the mitochondrial‐targeted peptide (MTP), Bendavia (0.1 mg/kg subcutaneously, 5 days/week), which stabilizes mitochondrial inner‐membrane cardiolipin (n=7 each). Cardiac function was subsequently assessed by multidetector‐computed tomography and oxygenation by blood‐oxygen‐level–dependent magnetic resonance imaging. Cardiolipin content, mitochondrial biogenesis, as well as sarcoplasmic‐reticulum calcium cycling, myocardial tissue injury, and coronary endothelial function were assessed ex vivo. Additionally, mitochondrial cardiolipin content, oxidative stress, and bioenergetics were assessed in rat cardiomyocytes incubated with tert‐butyl hydroperoxide (tBHP) untreated or treated with MTP. Chronic mitoprotection in vivo restored cardiolipin content and mitochondrial biogenesis. Thapsigargin‐sensitive sarcoplasmic reticulum Ca²⁺‐ATPase activity that declined in HC‐RVH normalized in MTP‐treated pigs. Mitoprotection also improved LV relaxation (E/A ratio) and ameliorated cardiac hypertrophy, without affecting blood pressure or systolic function. Myocardial remodeling and coronary endothelial function improved only in MTP‐treated pigs. In tBHP‐treated cardiomyocytes, mitochondrial targeting attenuated a fall in cardiolipin content and bioenergetics.

Conclusions

Chronic mitoprotection blunted myocardial hypertrophy, improved LV relaxation, and attenuated myocardial cellular and microvascular remodeling, despite sustained HC‐RVH, suggesting that mitochondrial injury partly contributes to hypertensive cardiomyopathy.

Early atherosclerosis aggravates renal microvascular loss and fibrosis in swine renal artery stenosis

Renal function in patients with atherosclerosis and renal artery stenosis (ARAS) deteriorates more frequently than in nonatherosclerotic RAS. We hypothesized that ARAS aggravates stenotic-kidney micro vascular loss compared to RAS. Domestic pigs were randomized to normal, RAS, and ARAS (RAS fed a high-cholesterol diet) groups (n = 7 each). Ten weeks later stenotic-kidney oxygenation, renal blood flow, and glomerular filtration rate (GFR) were evaluated in vivo, and micro vascular density by micro-computed tomography. Blood pressure in both RAS and ARAS was elevated; and stenotic-kidney renal blood flow and GFR similarly decreased. RAS decreased the density of small-size cortical microvessels (<200 μm), whereas ARAS extended the decrease to medium-sized microvessels (200-300 μm). Cortical hypoxia and interstitial fibrosis increased in both RAS and ARAS but correlated inversely with micro vascular density only in RAS. Atherosclerosis aggravates loss of stenotic-kidney microvessels, yet additional determinants likely contribute to cortical hypoxia and fibrosis in swine ARAS.

Cardiac metabolic alterations in hypertensive obese pigs

Obesity and hypertension are major risk factors for cardiovascular diseases, and their growing coexistence accounts for an increase in adverse cardiac events, but the mechanisms are yet to be determined. We hypothesized that obesity exacerbates mitochondrial dysregulation imposed by hypertension and augments left ventricular dysfunction. Obesity-prone Ossabaw pigs were randomized to lean (standard diet) and obese (high-fat diet), without (Lean-sham and Obese-sham) or with renovascular hypertension (Lean-hypertension and Obese-hypertension), induced after 12 weeks of diet (n=7 each). Cardiac function, myocardial perfusion and oxygenation, and microvascular remodeling were assessed 4 weeks later. Mitochondrial biogenesis signals and structural proteins, respiratory chain complex activities, and mitochondrial self-degradation were examined, as was fibrosis. Obesity alone exerted no apparent effect on mitochondrial dynamics, but aggravated in hypertensive hearts the reduction of mitochondrial proteins, deoxyribonucleic acid content, and respiratory chain complex IV subunits activity, and amplified mitochondrial self-degradation. Synergistic interaction of obesity with hypertension also exacerbated myocardial fibrosis and left ventricular diastolic dysfunction. Mitochondrial content, respiratory chain complex IV subunits activity, and mitophagy were correlated with myocardial fibrosis. These findings suggest that obesity aggravates in renovascular hypertension cardiac mitochondrial aberrations. Mitochondrial function may regulate the progression of cardiac injury and functional deterioration in hypertension concomitant with obesity.

Utilizing magnetization transfer imaging to investigate tissue remodeling in a murine model of autosomal dominant polycystic kidney disease

Purpose

Noninvasive imaging techniques that quantify renal tissue composition are needed to more accurately ascertain prognosis and monitor disease progression in polycystic kidney disease (PKD). Given the success of magnetization transfer (MT) imaging to characterize various tissue remodeling pathologies, it was tested on a murine model of autosomal dominant PKD.

Methods

C57Bl/6 Pkd1 R3277C mice at 9, 12, and 15 months were imaged with a 16.4T MR imaging system. Images were acquired without and with RF saturation in order to calculate MT ratio (MTR) maps. Following imaging, the mice were euthanized and kidney sections were analyzed for cystic and fibrotic indices, which were compared with statistical parameters of the MTR maps.

Results

The MTR‐derived mean, median, 25th percentile, skewness, and kurtosis were all closely related to indices of renal pathology, including kidney weight/body weight, cystic index, and percent of remaining parenchyma. The correlation between MTR and histology‐derived cystic and fibrotic changes was R² = 0.84 and R² = 0.70, respectively.

Conclusion

MT imaging provides a new, noninvasive means of measuring tissue remodeling PKD changes and may be better suited for characterizing renal impairment compared with conventional MR techniques. Magn Reson Med 75:1466–1473, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.

A low-cost mesocosm for the study of behaviour and reproductive potential in Afrotropical mosquito (Diptera: Culicidae) vectors of malaria

A large-scale mesocosm was constructed and tested for its effectiveness for use in experiments on behaviour, reproduction and adult survivorship in the Afrotropical malaria vector Anopheles gambiae s.s. Giles (Diptera: Culicidae) in temperate climates. The large space (82.69 m(3) ) allowed for semi-natural experiments that increased demand on a mosquito's energetic reserves in an environment of widely distributed resources. A one-piece prefabricated enclosure, made with white netting and vinyl, prevented the ingress of predators and the egress of mosquitoes. Daylight and white materials prompted the mosquitoes to seclude themselves in restricted daytime resting sites and allowed the easy collection of dead bodies so that daily mortality could be assessed accurately using a method that accounts for the loss of a proportion of bodies. Here, daily, age-dependent mortality rates of males and females were estimated using Bayesian Markov chain Monte Carlo simulation. In overnight experiments, mosquitoes successfully located plants and took sugar meals. A 3-week survival trial with a single cohort demonstrated successful mating, blood feeding, oviposition and long life. The relatively low cost of the mesocosm and the performance of the mosquitoes in it make it a viable option for any behavioural or ecological study of tropical mosquitoes in which space and seasonal cold are constraining factors.

Trauma in pregnancy and its consequences in Kermanshah, Iran from 2007 to 2010

OBJECTIVE

Nowadays, with decreased mortality of pregnant women by obstetrical causes, trauma has become a leading cause of morbidity and mortality in pregnant women. This study was carried out to determine the frequency of trauma in pregnancy and related causes and selected consequences in pregnant women of Kermanshah, Iran from 2007 to 2010.

METHODS

In this descriptive-analytical study, all pregnant women who suffered trauma and were admitted to Imam Reza, Taleghani, and Motazedi hospitals located in Kermanshah from 2007-2010 were studied. Sampling was done by census method and medical records of all eligible patients were studied. Data analysis was done by the SPSS software for Windows 9ver. 16.0).

RESULTS

There were 102 cases of trauma in pregnancy registered in this time period. Mean age of the cases was 26 years. Most cases (43%) were in their third trimester of pregnancy upon admission. Most trauma cases were of blunt traumas (68%). In 68 cases (66.67%), trauma resulted in maternal injury (independent of pregnancy) and 13 cases (12.75%) resulted in obstetrical or fetal injuries. Maternal injuries showed significant difference (P= 0.02) in different years. Motor vehicle accidents with a frequency of 47% were the most common cause of trauma.

CONCLUSION

Trauma in pregnancy can be a leading cause of injury and fatality in mother and fetus. The most common type of injury was motor vehicle accidents. Therefore, any strategy that can decrease the rate of motor vehicle accident in a community can decrease mortalities of women (even pregnant or non-pregnant).

Intrarenal Delivery of Mesenchymal Stem Cells and Endothelial Progenitor Cells Attenuates Hypertensive Cardiomyopathy in Experimental Renovascular Hypertension

Renovascular hypertension (RVH) leads to left ventricular (LV) hypertrophy and diastolic dysfunction, associated with increased cardiovascular mortality. Intrarenal delivery of endothelial progenitor cells (EPCs) and mesenchymal stem cells (MSCs) improves kidney function in porcine RVH, and the potent anti-inflammatory properties of MSCs may serve to blunt inflammatory mediators in the cardiorenal axis. However, their relative efficacy in attenuating cardiac injury and dysfunction remains unknown. This study tested the hypothesis that the cardioprotective effect of EPCs and MSCs delivered into the stenotic kidney in experimental RVH are comparable. Pigs (n = 7 per group) were studied after 10 weeks of RVH or control untreated or treated with a single intrarenal infusion of autologous EPCs or MSCs 4 weeks earlier. Cardiac and renal function (fast CT) and stenotic kidney release of inflammatory mediators (ELISA) were assessed in vivo, and myocardial inflammation, remodeling, and fibrosis ex vivo. After 10 weeks of RVH, blood pressure was not altered in cell-treated groups, yet stenotic kidney glomerular filtration rate (GFR), blunted in RVH, improved in RVH + EPC, and normalized in RVH + MSCs. Stenotic kidney release of monocyte chemoattractant protein (MCP)-1 and its myocardial expression were elevated in RVH + EPC, but normalized only in RVH + MSC pigs. RVH-induced LV hypertrophy was normalized in both EPC- and MSC-treated pigs, while diastolic function (E/A ratio) was restored to normal levels exclusively in RVH + MSCs. RVH-induced myocardial fibrosis and collagen deposition decreased in RVH + EPCs but further decreased in RVH + MSC-treated pigs. Intrarenal delivery of EPCs or MSCs attenuates RVH-induced myocardial injury, yet MSCs restore diastolic function more effectively than EPCs, possibly by greater improvement in renal function or reduction of MCP-1 release from the stenotic kidney. These observations suggest a therapeutic potential for EPCs and MSCs in preserving the myocardium in chronic experimental RVH.

Renal Vein Levels of MicroRNA-26a Are Lower in the Poststenotic Kidney

MicroRNA-26a (miR-26a) is a post-transcriptional regulator that inhibits cellular differentiation and apoptosis. Renal vascular disease (RVD) induces ischemic injury characterized by tubular cell apoptosis and interstitial fibrosis. We hypothesized that miR-26a levels are reduced in the poststenotic kidney and that kidney repair achieved by adipose tissue-derived mesenchymal stem cells (ad-MSCs) is associated with restored miR-26a levels. Renal function and renal miR-26a levels were assessed in pigs with RVD not treated (n=7) or 4 weeks after intrarenal infusion of ad-MSC (2.5×10(5) cells/kg; n=6), patients with RVD (n=12) or essential hypertension (n=12), and healthy volunteers (n=12). In addition, the direct effect of miR-26a on apoptosis was evaluated in a renal tubular cell culture. Compared with healthy control kidneys, swine and human poststenotic kidneys had 45.5±4.3% and 90.0±3.5% lower levels of miR-26a, respectively, which in pigs, localized to the proximal tubules. In pigs, ad-MSC delivery restored tubular miR-26a expression, attenuated tubular apoptosis and interstitial fibrosis, and improved renal function and tubular oxygen-dependent function. In vitro, miR-26a inhibition induced proximal tubular cell apoptosis and upregulated proapoptotic protein expression, which were both rescued by ad-MSC. In conclusion, decreased tubular miR-26a expression in the poststenotic kidney may be responsible for tubular cell apoptosis and renal dysfunction but can be restored using ad-MSC. Therefore, miR-26a might be a novel therapeutic target in renovascular disease.

Mitochondrial targeted peptides attenuate residual myocardial damage after reversal of experimental renovascular hypertension

BACKGROUND

Renovascular hypertension (RVHT) increases cardiovascular morbidity and mortality. Renal revascularization with percutaneous transluminal renal angioplasty and stenting (PTRS) may reverse RVHT but may not fully regress cardiac remodeling and damage, possibly due to persistent myocardial insults. Bendavia is a mitochondrial targeted peptide that reduces ischemic cardiomyopathy by improving mitochondrial function. However, its potential for attenuating residual myocardial damage after reversal of RVHT has not been explored. We hypothesized that treatment with Bendavia as an adjunct to PTRS would improve cardiac function and oxygenation, and decrease myocardial injury in swine RVHT.

METHODS AND RESULTS

After 6 weeks of RVHT (unilateral renal artery stenosis) or control, pigs underwent PTRS (or sham), with adjunct continuous infusion of Bendavia (0.05  mg/kg intravenously, 30  min before to 3.5  h after PTRS) or vehicle (n = 7 each). Four weeks later, systolic and diastolic function were assessed by multidetector computed tomography, myocardial oxygenation by blood oxygen level-dependent MRI, and myocardial morphology, apoptosis, mitochondrial biogenesis, and fibrosis evaluated ex vivo. PTRS restored blood pressure in both groups, yet E/A ratio remained decreased. Myocardial oxygenation and mitochondrial biogenesis improved, and myocardial inflammation, oxidative stress, and fibrosis normalized in association with improvement in diastolic function in RVHT + PTRS + Bendavia animals.

CONCLUSION

Adjunct Bendavia during PTRS in swine RVHT improved diastolic function and oxygenation and reversed myocardial tissue damage. This approach may allow a novel strategy for preservation of cardiac function and structure in RVHT.

Mitochondrial protection restores renal function in swine atherosclerotic renovascular disease

AIMS

The mechanisms responsible for renal injury in atherosclerotic renovascular disease (ARVD) are incompletely understood, and few therapeutic options are available to reverse it. We hypothesized that chronic renal damage involves mitochondrial injury, and that mitochondrial protection would reduce renal fibrosis and dysfunction in ARVD pigs.

METHODS AND RESULTS

Domestic pigs were studied after 10 weeks of ARVD or sham, treated for the last 4 weeks with daily subcutaneous injections (5 days/week) of vehicle or Bendavia (0.1 mg/kg), a tetrapeptide that preserves cardiolipin content in the mitochondrial inner membrane. Single-kidney haemodynamics and function were studied using fast-computer tomography, oxygenation using blood oxygen level-dependent magnetic resonance imaging, microvascular architecture, oxidative stress, and fibrosis ex vivo. Cardiolipin content was assessed using mass spectrometry and staining. Renal endothelial function was studied in vivo and ex vivo. In addition, swine renal artery endothelial cells incubated with tert-butyl hydroperoxide were also treated with Bendavia. Stenotic-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) decreased in ARVD + Vehicle compared with normal (318.8 ± 61.0 vs. 553.8 ± 82.8 mL/min and 48.0 ± 4.0 vs. 84.0 ± 3.8 mL/min, respectively) associated with loss of cardiolipin, intra-renal microvascular rarefaction, and hypoxia. Bendavia restored cardiolipin content in ARVD and improved vascular density, oxygenation, RBF (535.1 ± 24.9 mL/min), and GFR (86.6 ± 11.2 mL/min). Oxidative stress and fibrosis were ameliorated, and renovascular endothelial function normalized both in vivo and in vitro.

CONCLUSION

Preservation of mitochondrial cardiolipin attenuated swine stenotic-kidney microvascular loss and injury, and improved renal oxygenation, haemodynamics, and function. These observations implicate mitochondrial damage in renal deterioration in chronic experimental ARVD, and position the mitochondria as a central therapeutic target.

Obesity-metabolic derangement exacerbates cardiomyocyte loss distal to moderate coronary artery stenosis in pigs without affecting global cardiac function

Obesity associated with metabolic derangements (ObM) worsens the prognosis of patients with coronary artery stenosis (CAS), but the underlying cardiac pathophysiologic mechanisms remain elusive. We tested the hypothesis that ObM exacerbates cardiomyocyte loss distal to moderate CAS. Obesity-prone pigs were randomized to four groups (n = 6 each): lean-sham, ObM-sham, lean-CAS, and ObM-CAS. Lean and ObM pigs were maintained on a 12-wk standard or atherogenic diet, respectively, and left circumflex CAS was then induced by placing local-irritant coils. Cardiac structure, function, and myocardial oxygenation were assessed 4 wk later by computed-tomography and blood oxygenation level dependent (BOLD) MRI, the microcirculation with micro-computed-tomography, and injury mechanisms by immunoblotting and histology. ObM pigs showed obesity, dyslipidemia, and insulin resistance. The degree of CAS (range, 50-70%) was similar in lean and ObM pigs, and resting myocardial perfusion and global cardiac function remained unchanged. Increased angiogenesis distal to the moderate CAS observed in lean was attenuated in ObM pigs, which also showed microvascular dysfunction and increased inflammation (M1-macrophages, TNF-α expression), oxidative stress (gp91), hypoxia (BOLD-MRI), and fibrosis (Sirius-red and trichrome). Furthermore, lean-CAS showed increased myocardial autophagy, which was blunted in ObM pigs (downregulated expression of unc-51-like kinase-1 and autophagy-related gene-12; P < 0.05 vs. lean CAS) and associated with marked apoptosis. The interaction diet xstenosis synergistically inhibited angiogenic, autophagic, and fibrogenic activities. ObM exacerbates structural and functional myocardial injury distal to moderate CAS with preserved myocardial perfusion, possibly due to impaired cardiomyocyte turnover.

Renal relevant radiology: renal functional magnetic resonance imaging

Because of its noninvasive nature and provision of quantitative measures of a wide variety of physiologic parameters, functional magnetic resonance imaging (MRI) shows great potential for research and clinical applications. Over the past decade, application of functional MRI extended beyond detection of cerebral activity, and techniques for abdominal functional MRI evolved. Assessment of renal perfusion, glomerular filtration, interstitial diffusion, and parenchymal oxygenation turned this modality into an essential research and potentially diagnostic tool. Variations in many renal physiologic markers can be detected using functional MRI before morphologic changes become evident in anatomic magnetic resonance images. Moreover, the framework of functional MRI opened a window of opportunity to develop novel pathophysiologic markers. This article reviews applications of some well validated functional MRI techniques, including perfusion, diffusion-weighted imaging, and blood oxygen level-dependent MRI, as well as some emerging new techniques such as magnetic resonance elastography, which might evolve into clinically useful tools.

Evolution of cardiac and renal impairment detected by high-field cardiovascular magnetic resonance in mice with renal artery stenosis

BACKGROUND

Renal artery stenosis (RAS) promotes hypertension and cardiac dysfunction. The 2-kidney, 1-clip mouse model in many ways resembles RAS in humans and is amenable for genetic manipulation, but difficult to evaluate noninvasively. We hypothesized that cardiovascular magnetic resonance (CMR) is capable of detecting progressive cardiac and renal dysfunction in mice with RAS and monitoring the progression of the disease longitudinally.

METHODS

RAS was induced at baseline in eighteen mice by constricting the renal artery. Nine additional animals served as normal controls. CMR scans (16.4 T) were performed in all mice one week before and 2 and 4 weeks after baseline. Renal volumes and hemodynamics were assessed using 3D fast imaging with steady-state precession and arterial spin labelling, and cardiac function using CMR cine. Renal hypoxia was investigated using blood oxygen-level dependent (BOLD) MR.

RESULTS

Two weeks after surgery, mean arterial pressure was elevated in RAS mice. The stenotic kidney (STK) showed atrophy, while the contra-lateral kidney (CLK) showed hypertrophy. Renal blood flow (RBF) and cortical oxygenation level declined in the STK but remained unchanged in CLK. Moreover, cardiac end-diastolic and stroke volumes decreased and myocardial mass increased. At 4 weeks, STK RBF remained declined and the STK cortex and medulla showed development of hypoxia. Additionally, BOLD detected a mild hypoxia in CLK cortex. Cardiac end-diastolic and stroke volumes remained reduced and left ventricular hypertrophy worsened. Left ventricular filling velocities (E/A) indicated progression of cardiac dysfunction towards restrictive filling.

CONCLUSIONS

CMR detected longitudinal progression of cardiac and renal dysfunction in 2K, 1C mice. These observations support the use of high-field CMR to obtain useful information regarding chronic cardiac and renal dysfunction in small animals.

Effect of cysteine and glutamine added to extender on post-thaw sperm functional parameters of buffalo bull

Amino acids seem to be crucial components for semen freezing extender due to antioxidant properties. Therefore, this study aimed to assess motility parameters, membrane integrity, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and DNA damage to detect the optimum concentrations of cysteine and glutamine for buffalo semen cryopreservation. Twenty ejaculates of four buffalo bulls were diluted in tris-egg yolk extender and divided into seven equal groups consisting of cysteine (5, 7.5 and 10 mmol), glutamine (10, 15 and 20 mmol) and no additive. Supplementation of 5 and 7.5 mmol cysteine and 15 mmol glutamine in cryopreservation extender significantly increased post-thaw motility and plasma membrane integrity of spermatozoa with significant reduction in intracellular ROS when compared with control groups (P < 0.05). Cysteine at 7.5 mmol concentration elevated progressive motility and MMP, compared with control (P < 0.05). No significant differences were observed for motion patterns and DNA damage of frozen-thawed buffalo spermatozoa in extender containing amino acids. The findings of this study showed that supplementation of 7.5 mmol cysteine and 15 mmol glutamine in semen cryopreservation extender has more potential to decrease intracellular ROS, and subsequently elevate motility and membrane integrity of buffalo frozen-thawed spermatozoa.

Stent revascularization restores cortical blood flow and reverses tissue hypoxia in atherosclerotic renal artery stenosis but fails to reverse inflammatory pathways or glomerular filtration rate

BACKGROUND

Atherosclerotic renal artery stenosis (ARAS) is known to reduce renal blood flow, glomerular filtration rate (GFR) and amplify kidney hypoxia, but the relationships between these factors and tubulointerstitial injury in the poststenotic kidney are poorly understood. The purpose of this study was to examine the effect of renal revascularization in ARAS on renal tissue hypoxia and renal injury.

METHODS AND RESULTS

Inpatient studies were performed in patients with ARAS (n=17; >60% occlusion) before and 3 months after stent revascularization, or in patients with essential hypertension (n=32), during fixed Na(+) intake and angiotensin converting enzyme/angiotensin receptors blockers Rx. Single kidney cortical, medullary perfusion, and renal blood flow were measured using multidetector computed tomography, and GFR by iothalamate clearance. Tissue deoxyhemoglobin levels (R(2)*) were measured by blood oxygen level-dependent MRI at 3T, as was fractional kidney hypoxia (percentage of axial area with R(2)*>30/s). In addition, we measured renal vein levels of neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α. Pre-stent single kidney renal blood flow, perfusion, and GFR were reduced in the poststenotic kidney. Renal vein neutrophil gelatinase-associated lipocalin, tumor necrosis factor-α, monocyte chemoattractant protein-1, and fractional hypoxia were higher in untreated ARAS than in essential hypertension. After stent revascularization, fractional hypoxia fell (P<0.002) with increased cortical perfusion and blood flow, whereas GFR and neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α remained unchanged.

CONCLUSIONS

These data demonstrate that despite reversal of renal hypoxia and partial restoration of renal blood flow after revascularization, inflammatory cytokines and injury biomarkers remained elevated and GFR failed to recover in ARAS. Restoration of vessel patency alone failed to reverse tubulointerstitial damage and partly explains the limited clinical benefit of renal stenting. These results identify potential therapeutic targets for recovery of kidney function in renovascular disease.

Mesenchymal stem cells improve medullary inflammation and fibrosis after revascularization of swine atherosclerotic renal artery stenosis

Atherosclerotic renal artery stenosis (ARAS) raises blood pressure and can reduce kidney function. Revascularization of the stenotic renal artery alone does not restore renal medullary structure and function. This study tested the hypothesis that addition of mesenchymal stem cells (MSC) to percutaneous transluminal renal angioplasty (PTRA) can restore stenotic-kidney medullary tubular transport function and attenuate its remodeling. Twenty-seven swine were divided into three ARAS (high-cholesterol diet and renal artery stenosis) and a normal control group. Six weeks after ARAS induction, two groups were treated with PTRA alone or PTRA supplemented with adipose-tissue-derived MSC (10×10⁶ cells intra-renal). Multi-detector computed tomography and blood-oxygenation-level-dependent (BOLD) MRI studies were performed 4 weeks later to assess kidney hemodynamics and function, and tissue collected a few days later for histology and micro-CT imaging. PTRA effectively decreased blood pressure, yet medullary vascular density remained low. Addition of MSC improved medullary vascularization in ARAS+PTRA+MSC and increased angiogenic signaling, including protein expression of vascular endothelial growth-factor, its receptor (FLK-1), and hypoxia-inducible factor-1α. ARAS+PTRA+MSC also showed attenuated inflammation, although oxidative-stress remained elevated. BOLD-MRI indicated that MSC normalized oxygen-dependent tubular response to furosemide (-4.3±0.9, −0.1±0.4, −1.6±0.9 and −3.6±1.0 s⁻¹ in Normal, ARAS, ARAS+PTRA and ARAS+PTRA+MSC, respectively, p<0.05), which correlated with a decrease in medullary tubular injury score (R² = 0.33, p = 0.02). Therefore, adjunctive MSC delivery in addition to PTRA reduces inflammation, fibrogenesis and vascular remodeling, and restores oxygen-dependent tubular function in the stenotic-kidney medulla, although additional interventions might be required to reduce oxidative-stress. This study supports development of cell-based strategies for renal protection in ARAS.

Human renovascular disease: estimating fractional tissue hypoxia to analyze blood oxygen level-dependent MR

PURPOSE

To test the hypothesis that fractional kidney hypoxia, measured by using blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging, correlates with renal blood flow (RBF), tissue perfusion, and glomerular filtration rate (GFR) in patients with atherosclerotic renal artery stenosis (RAS) better than regionally selected region of interest-based methods.

MATERIALS AND METHODS

The study was approved by the institutional review board according to a HIPAA-compliant protocol, with written informed consent. BOLD MR imaging was performed in 40 patients with atherosclerotic RAS (age range, 51-83 years; 22 men, 18 women) and 32 patients with essential hypertension (EH) (age range, 26-85 years; 19 men, 13 women) during sodium intake and renin-angiotensin blockade. Fractional kidney hypoxia (percentage of entire axial image section with R2* above 30 sec(-1)) and conventional regional estimates of cortical and medullary R2* levels were measured. Stenotic and nonstenotic contralateral kidneys were compared for volume, tissue perfusion, and blood flow measured with multidetector computed tomography. Statistical analysis was performed (paired and nonpaired t tests, linear regression analysis).

RESULTS

Stenotic RBF was reduced compared with RBF of contralateral kidneys (225.2 mL/min vs 348 mL/min, P = .0003). Medullary perfusion in atherosclerotic RAS patients was lower than in EH patients (1.07 mL/min per milliliter of tissue vs 1.3 mL/min per milliliter of tissue, P = .009). While observer-selected cortical R2* (18.9 sec(-1) [stenosis] vs 18.5 sec(-1) [EH], P = .07) did not differ, fractional kidney hypoxia was higher in stenotic kidneys compared with kidneys with EH (17.4% vs 9.6%, P < .0001) and contralateral kidneys (7.2%, P < .0001). Fractional hypoxia correlated inversely with blood flow (r = -0.34), perfusion (r = -0.3), and GFR (r = -0.32).

CONCLUSION

Fractional tissue hypoxia rather than cortical or medullary R2* values used to assess renal BOLD MR imaging demonstrated a direct relationship to chronically reduced blood flow and GFR.

Obesity-metabolic derangement preserves hemodynamics but promotes intrarenal adiposity and macrophage infiltration in swine renovascular disease

Obesity-metabolic disorders (ObM) often accompany renal artery stenosis (RAS). We hypothesized that the coexistence of ObM and RAS magnifies inflammation and microvascular remodeling in the stenotic kidney (STK) and aggravates renal scarring. Twenty-eight obesity-prone Ossabaw pigs were studied after 16 wk of a high-fat/high-fructose diet or standard chow including ObM-sham, ObM-RAS, Lean-RAS, or Lean-sham (normal control) groups. Single-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were assessed by multidetector computed tomography (CT), renal oxygenation and tubular transport capability by blood-oxygen-level-dependent MRI, and microcirculation by micro-CT for vessel density, and Western blotting for protein expressions of angiogenic factors (VEGF/FLK-1). Renal vein and inferior vena cava levels of inflammatory cytokines were measured to evaluate systemic and kidney inflammation. Macrophage (MØ) infiltration and subpopulations, fat deposition in the kidney, and inflammation in perirenal and abdominal fat were also examined. GFR and RBF were decreased in Lean-STK but relatively preserved in ObM-STK. However, ObM-STK showed impaired tubular transport function, suppressed microcirculation, and stimulated glomerulosclerosis. ObM diet interacted with RAS to blunt angiogenesis in the STK, facilitated the release of inflammatory cytokines, and led to greater oxidative stress than Lean-STK. The ObM diet also induced fat deposition in the kidney and infiltration of proinflammatory M1-MØ, as also in perirenal and abdominal fat. Coexistence of ObM and RAS amplifies renal inflammation, aggravates microvascular remodeling, and accelerates glomerulosclerosis. Increased adiposity and MØ-accentuated inflammation induced by an ObM diet may contribute to structural injury in the post-STK kidney.

Angiotensin receptor blockade has protective effects on the poststenotic porcine kidney

Angiotensin converting enzyme inhibitors (ACEI)/ angiotensin-II receptor blockers (ARBs) may induce an acute decrease of glomerular filtration rate (GFR) in the stenotic kidney in renal artery stenosis, but most patients tolerate these drugs well. We hypothesized that ACEI/ARBs stabilize stenotic kidney function during prolonged treatment by conferring protective effects. We tested this in control domestic pigs and pigs with renal artery stenosis untreated or treated with valsartan, or triple therapy (7 pigs in each group) for 4 weeks starting 6 weeks after stenosis induction. Renal function, oxygenation, tubular function, and microcirculation were assessed by multi-detector computed tomography (CT), blood-oxygen-level-dependent magnetic-resonance imaging, and micro-CT. Valsartan and triple therapy decreased blood pressure similarly, however, valsartan did not change the GFR of the stenotic kidney compared to renal artery stenosis and was similar to triple therapy. Both valsartan and triple therapy stimulated microvascular density, and improved tubular function. Valsartan also caused a greater increase of angiogenic factors and a decrease in oxidative stress, which were related to higher cortical perfusion and tubular response than triple therapy. Thus, valsartan did not decrease stenotic kidney GFR, but improved cortical perfusion and microcirculation. These beneficial effects may partly offset the hemodynamic GFR reduction in renal artery stenosis and preserve kidney function.

Endothelial outgrowth cells shift macrophage phenotype and improve kidney viability in swine renal artery stenosis

OBJECTIVE

Endothelial outgrowth cells (EOC) decrease inflammation and improve endothelial repair. Inflammation aggravates kidney injury in renal artery stenosis (RAS), and may account for its persistence upon revascularization. We hypothesized that EOC would decrease inflammatory (M1) macrophages and improve renal recovery in RAS.

APPROACH AND RESULTS

Pigs with 10 weeks of RAS were studied 4 weeks after percutaneous transluminal renal angioplasty (PTRA+stenting) or sham, with or without adjunct intrarenal delivery of autologous EOC (10×10(6)), and compared with similarly treated normal controls (n=7 each). Single-kidney function, microvascular and tissue remodeling, inflammation, oxidative stress, and fibrosis were evaluated. Four weeks after PTRA, EOC were engrafted in injected RAS-kidneys. Stenotic-kidney glomerular filtration rate was restored in RAS+EOC, RAS+PTRA, and RAS+PTRA+EOC pigs, whereas stenotic-kidney blood flow and angiogenesis were improved and fibrosis attenuated only in EOC-treated pigs. Furthermore, EOC increased cell proliferation and decreased the ratio of M1 (inflammatory)/M2 (reparative) macrophages, as well as circulating levels and stenotic-kidney release of inflammatory cytokines. Cultured-EOC released microvesicles in vitro and induced phenotypic switch (M1-to-M2) in cultured monocytes, which was inhibited by vascular endothelial growth factor blockade. Finally, a single intrarenal injection of rh-vascular endothelial growth factor (0.05 μg/kg) in 7 additional RAS pigs also restored M1/M2 ratio 4 weeks later.

CONCLUSIONS

Intrarenal infusion of EOC after PTRA induced a vascular endothelial growth factor-mediated attenuation in macrophages inflammatory phenotype, preserved microvascular architecture and function, and decreased inflammation and fibrosis in the stenotic kidney, suggesting a novel mechanism and therapeutic potential for adjunctive EOC delivery in experimental RAS to improve PTRA outcomes.

Changes in glomerular filtration rate after renal revascularization correlate with microvascular hemodynamics and inflammation in Swine renal artery stenosis

BACKGROUND

The selection of patients with renal artery stenosis (RAS) likely to improve glomerular filtration rate (GFR) after percutaneous transluminal renal angioplasty is difficult. We examined basal hemodynamic and inflammatory factors linked to improved stenotic kidney (STK) function after percutaneous transluminal renal angioplasty in swine RAS.

METHODS AND RESULTS

Fifteen pigs after 6 weeks of hemodynamically significant RAS were studied before and 4 weeks after technically successful percutaneous transluminal renal angioplasty+stenting. STK and contralateral kidney hemodynamics and function were evaluated by multidetector computed-tomography before and after acetylcholine challenge. Single-kidney deoxyhemoglobin (R2*, reciprocal to blood relaxation) and energy-dependent tubular function were assessed using blood-oxygen-level-dependent magnetic resonance imaging before and after furosemide. Baseline renal vein and inferior vena cava levels of inflammatory markers were measured and their gradient and net release calculated. Baseline parameters were compared with normal (n=7) and sham-RAS (n=7) pigs and correlated with the change in STK-GFR after revascularization (ΔGFR). Four weeks after percutaneous transluminal, renal angioplasty blood pressure was normalized in all animals, but STK-GFR improved in 10 of 15 (ΔGFR =+22.0±8.5 mL/min). ΔGFR correlated inversely with basal STK-GFR, renal release of inflammatory markers, and medullary R2* response to furosemide, but directly with GFR response to acetylcholine. Basal contralateral kidney GFR correlated directly with ΔGFR.

CONCLUSIONS

Low basal STK-GFR with preserved response to acetylcholine may predict benefit from revascularization in RAS, whereas renal inflammation and robust STK-R2* responses to furosemide (possibly reflecting avid tubular oxygen consumption) are associated with less favorable outcomes. These tools may be useful for identification of patients likely to improve renal function after revascularization.

Abstract 54: Tissue Oxygenation Using Fractional Hypoxia Correlates Inversely With Blood Flow in Human Renovascular Disease (RVD) and Essential Hypertension (EH)

Determinants of Intra-renal oxygenation in human RVD are poorly understood. Blood oxygen level-dependent (BOLD) MRI measures deoxyhemoglobin (R2*) to determine cortical and medullary R2* which have focal variations and gradients. We hypothesized that tissue fractional hypoxia (% of axial kidney area with R2*>30s -1 ) would correlate better with tissue perfusion, renal blood flow (RBF), and O2 consumption than using regions of interest (ROI).

METHODS: Inpatient studies were performed in EH (n=68 kidneys), and high-grade RVD (n=18 kidneys, 71±5.5% occlusion) before and 3 months after stents. All were treated with ACE/ARB Rx and thiazides during 150 mEq/d Na+ intake. BOLD MR images were obtained at 3T before and after furosemide (20mg IV), and axial images analyzed to estimate R2* levels above 30s -1 (fractional hypoxia) over the entire kidney section. Maximal R2* levels using regions of interest (ROIs) also were determined. Single-kidney cortical and medullary RBF (ml/min) perfusion (ml/min/cc) were determined by MDCT.

Results: RBF was lower in kidneys with untreated RVD than EH (285.6±141 vs. 399±159 ml/min p<0.05), as was cortical perfusion (2.58±.63 vs. 3.50±1.05, p<.05 ). Cortical and medullary R2* did not differ, but fractional hypoxia was greater in RVD as compared to EH (18.3±12 vs. 11.5±8.5%, p<.05). Fractional hypoxia was inversely correlated with blood flow (R=-.29, p<.01) and perfusion (R=-.26, p<.01). R2* fell after furosemide (p<0.01) indicating a role for O2 consumption in determining tissue hypoxia. RBF and cortical perfusion increased after stenting (285±141 vs. 318±178 ml/min and 2.58±0.6 vs. 2.9±0.7ml/min/cc, p<0.05) respectively. Fractional hypoxia, but not cortical or medullary R2* based on ROI-methods, decreased in patients 3 months after renal revascularization (18.3 ±12 vs. 10.52%, p<0.05)

Conclusions: These data demonstrate for the first time that fractional hypoxia in the kidney is directly related to chronically reduced blood flow and cortical perfusion in human RVD, whereas selective ROI-based measures identified only minor changes in peak R2* gradients between cortex and medulla. The reversibility of fractional hypoxia after stenting supports the use of this new method to identify critical renovascular lesions.