Attenuation of Skeletal Muscle and Renal Injury to the Lower Limb following Ischemia-Reperfusion Using mPTP Inhibitor NIM-811.

INTRODUCTION: Operation on the infrarenal aorta and large arteries of the lower extremities may cause rhabdomyolysis of the skeletal muscle, which in turn may induce remote kidney injury. NIM-811 (N-metyl-4-isoleucine-cyclosporine) is a mitochondria specific drug, which can prevent ischemic-reperfusion (IR) injury, by inhibiting mitochondrial permeability transition pores (mPTP). OBJECTIVES: Our aim was to reduce damages in the skeletal muscle and the kidney after IR of the lower limb with NIM-811. MATERIALS AND METHODS: Wistar rats underwent 180 minutes of bilateral lower limb ischemia and 240 minutes of reperfusion. Four animal groups were formed called Sham (receiving vehicle and sham surgery), NIM-Sham (receiving NIM-811 and sham surgery), IR (receiving vehicle and surgery), and NIM-IR (receiving NIM-811 and surgery). Serum, urine and histological samples were taken at the end of reperfusion. NADH-tetrazolium staining, muscle Wet/Dry (W/D) ratio calculations, laser Doppler-flowmetry (LDF) and mean arterial pressure (MAP) monitoring were performed. Renal peroxynitrite concentration, serum TNF-alpha and IL-6 levels were measured. RESULTS: Less significant histopathological changes were observable in the NIM-IR group as compared with the IR group. Serum K+ and necroenzyme levels were significantly lower in the NIM-IR group than in the IR group (LDH: p<0.001; CK: p<0.001; K+: p = 0.017). Muscle mitochondrial viability proved to be significantly higher (p = 0.001) and renal function parameters were significantly better (creatinine: p = 0.016; FENa: p<0.001) in the NIM-IR group in comparison to the IR group. Serum TNF-alpha and IL-6 levels were significantly lower (TNF-alpha: p = 0.003, IL-6: p = 0.040) as well as W/D ratio and peroxynitrite concentration were significantly lower (p = 0.014; p<0.001) in the NIM-IR group than in the IR group. CONCLUSION: NIM-811 could have the potential of reducing rhabdomyolysis and impairment of the kidney after lower limb IR injury

The impact of urbanization on French Canadian medical attitudes.

The interest in the problem of the French Canadian habitant who, upon entering industry, comes into conflict with a system of principles and practices so entirely different from his own, was derived from the experience gained through working in the Medical Department of Canadian Industries Limited and of its wartime subsidiary, Defence Industries Limited, where the writer was employed during the course of this study. [...

Acute Respiratory Failure, Ischemic Modifications on Electrocardiogram: Alternative Etiology&mdash;A Case of Morgagni Hernia

We discovered a rare pathology described in adulthood, followed by the development of a long asymptomatic evolution, which underlined the importance of multidisciplinary collaboration. We present the case of a 62-year-old female smoker patient, with a known previous medical history of chronic ischemic heart disease, hypertension, chronic obstructive pulmonary disease (COPD), gastric ulcer and gastritis. The patient was rushed to the emergency room (ER) with acute respiratory failure, chest discomfort, ankle and facial edema and a chest X-ray showing a right lower pulmonary lobe consolidation, with an alarming ischemic electrocardiogram (ECG) modification without increasing myocardial cytolysis indicators. This led our medical team to investigate a possible cardiovascular event that might have been in development. After immediate admission, thoracic computer tomography (CT) imaging was carried out, which found a Morgagni diaphragmatic hernia, containing adipose tissue and the hepatic flexure of the colon with approximate dimensions of 50/100 mm. We faced differential diagnostic problems. We knew the subject&rsquo;s existing cardiac and chronic respiratory tract pathologies from their previous medical history; therefore, multiple investigations and check-ups were carried out. A chest CT and surgery intervention were needed to resolve this case. Subsequently, the acute respiratory failure and alarming ischemic ECG modification disappeared

Parameters of muscle injury, muscle fiber viability and muscle wet content.

<p>(<b>A–B</b>)<b>:</b> Serum creatine-kinase (CK) and lactate-dehydrogenase (LDH) concentrations were significantly elevated in the IR group compared with the Sham and NIM-Sham groups. Significantly lower value was detectable in the NIM-IR group compared with the IR group, leading to the conclusion that there may be a lower extent of muscle necrosis (CK: # p<0.01 vs. Sham; † p<0.01 vs. NIM-Sham; § p<0.01 vs. IR; ‡ p<0.01 vs. Sham; & p<0.01 vs. NIM-Sham; LDH: # p<0.01 vs. Sham; † p<0.01 vs. NIM-Sham; § p<0.01 vs. IR; ‡ p<0.01 vs. Sham; & p<0.01 vs. NIM-Sham; U/l – Unit/liter). (<b>C</b>)<b>:</b> Muscle fiber viability was assessed by NADH-tetrazolium staining and was expressed as percentage of viability measured in untreated controls (%). In the IR group there was a significant decline in viability compared with the Sham and NIM-Sham groups. Significantly higher value was found in the NIM-IR group, compared with the IR group (# p<0.01 vs. Sham; † p<0.01 vs. NIM-Sham; § p<0.01 vs. IR; ‡ p<0.01 vs. Sham; & p<0.05 vs. NIM-Sham). (<b>D</b>)<b>:</b> Wet/Dry ratio is suitable to determine the amount of interstitial edema. The wet content of the skeletal muscle tissue was significantly lower in the NIM-IR group compared with the IR group (# p<0.01 vs. Sham; † p<0.01 vs. NIM-Sham; § p<0.05 vs. IR; ‡ p<0.05 vs. Sham; & p<0.05 vs. NIM-Sham).</p

Laboratory measurements, haemodynamics data and wet/dry ratios.

<p>LDH: lactate dehydrogenase; CK: creatine kinase; W/D: wet/dry ratio; LDF RA: Laser Doppler flowmeter, reperfusion area; TNF-α: tumor necrosis factor alpha; IL-6: interleukin 6; MAP: mean arterial pressure; BUN: blood urea nitrogen; FENa: fractional Na⁺ excretion.</p

Muscle and kidney histopathology (hematoxillin-eosin (HE) stain, light microscopy).

<p>(<b>A–B</b>)<b>:</b> An almost physiologically histological picture is observable in the Sham (A) and NIM-Sham (B) groups, with intact muscle fibers and normal wide interstitial spaces. (<b>C</b>)<b>:</b> In the IR group segmental necrosis (circle), disintegrated myofilaments and thicker interstitial spaces (arrow) are detectable. (<b>D</b>)<b>:</b> NIM-IR group shows intact muscle fibers (circle) with no expanded interstitial spaces (arrow), similar to the normal structure. (<b>E–F</b>)<b>:</b> Sham and NIM-Sham groups show the normal structure of kidney cortical tissue. Tubules have normal appearance. (<b>G</b>)<b>:</b> In the IR group massive injury can be detected with loss of cell integrity and intracellular vacuolization (arrows). (<b>H</b>)<b>:</b> In the NIM-IR group cell necrosis is less severe (arrow) and the tubular integrity remained intact (circle), an almost normal picture can be seen.</p

Systemic hemodinamycs and microcirculation of skeletal muscle of lower limb.

<p>(<b>A</b>)<b>:</b> Microcirculation of the lower limb skeletal muscle was monitored by laser Doppler flowmeter (LDF). Data are shown as percentage of baseline flow before ischemia (%). In the IR group a significant decline can be observed compared with the Sham and NIM-Sham groups after the onset of reperfusion. Microcirculation became stabilized at a significantly higher level in the NIM-IR group than in the IR group (# p<0.05 vs. Sham; † p<0.05 vs. NIM-Sham; § p<0.05 vs. IR). (<b>B</b>)<b>:</b> Mean arterial pressure (MAP) was registered during blood pressure monitoring. MAP of the Sham and NIM-Sham groups remained constant during the entire experimental period, whereas values of both the IR and NIM-IR groups decreased at the beginning of reperfusion. MAP of the NIM-IR group was significantly higher after the onset of reperfusion as compared with the IR group (# p<0.05 vs. Sham; † p<0.05 vs. NIM-Sham; § p<0.05 vs. IR).</p

Serum TNF-α and peroxynitrite concentration in the kidney.

<p>(<b>A</b>)<b>:</b> Serum TNF-α concentration was significantly elevated in the IR group, compared with the Sham and NIM-Sham groups. A significantly lower level was detected in the NIM-IR group compared with the IR group, leading to the conclusion that there may be a lower extent of systemic inflammation (# p<0.01 vs. Sham; † p<0.01 vs. NIM-Sham; § p<0.01 vs. IR; ‡ p>0.05 vs. Sham; & p>0.05 vs. NIM-Sham; pg/ml – pictogram/mililitre). (<b>B</b>)<b>:</b> A significantly elevated peroxynitrite concentration can be observed in homogenized kidney samples in the IR group, compared with the Sham and NIM-Sham groups. In the NIM-IR group, a significantly lower value was measured compared with the IR group (# p<0.01 vs. Sham; † p<0.05 vs. NIM-Sham; § p<0.01 vs. IR).</p