Iron supplementation effectively suppresses gastrocnemius muscle lesions to improve exercise capacity in chronic heart failure rats with anemia.

OBJECTIVE: For patients with chronic heart failure (CHF), exertional fatigue is one of the most common and debilitating symptoms. However, the poor relationship between heart dysfunction and exercise capacity has been ascribed to peripheral abnormalities. Several previous studies confirmed that iron supplementation could significantly improve the exercise capacity of patients with CHF, although they did not analyze effects in the musculoskeletal system. The aim of this study was to investigate the effect of iron treatment on gastrocnemius muscles of CHF rats with anemia. METHODS: Male Sprague-Dawley rats were subjected to coronary ligation to induce heart failure. At the same time, blood (1-1.5 mL) was withdrawn from the retro-orbital plexus once every week to induce anemia. After 6 wk of this process, iron dextran was administered to the CHF rats with anemia (CHFa rats) at the dose of 8, 16, 32, or 64 mg/kg every 2 d for 2 wk. RESULTS: Iron dextran (8 mg/kg every 2 d) effectively improved hemodynamic parameters (P < 0.05) compared with CHFa rats. Similarly, this dose of iron dextran significantly reduced the ratio of heart weight to body weight (P < 0.01), whereas it significantly increased the distance run (m) to exhaustion (P < 0.01). Iron dextran effectively inhibited sarcoplasmic vacuolation and muscle atrophy of gastrocnemius muscles in CHFa rats, as evaluated by pathologic examinations. Other iron treatments, however, were found to be ineffective on the same parameters, so particular focus was placed on the iron dextran (8 mg/kg every 2 d) group in subsequent analyses. Consistently, phospho-p38 in gastrocnemius muscles of CHFa rats was markedly suppressed by iron dextran. Additionally, iron dextran significantly decreased c-fos and c-jun and up-regulated cellular FLICE-inhibitory protein expression levels.

Heat treatment eliminates 'Candidatus Liberibacter asiaticus' from infected citrus trees under controlled conditions.

Huanglongbing (HLB) is one of the most destructive diseases of citrus worldwide. The three known causal agents of HLB are species of α-proteobacteria: 'Candidatus Liberibacter asiaticus', 'Ca. L. africanus', and 'Ca. L. americanus'. Previous studies have found distinct variations in temperature sensitivity and tolerance among these species. Here, we describe the use of controlled heat treatments to cure HLB caused by 'Ca. L. asiaticus', the most prevalent and heat-tolerant species. Using temperature-controlled growth chambers, we evaluated the time duration and temperature required to suppress or eliminate the 'Ca. L. asiaticus' bacterium in citrus, using various temperature treatments for time periods ranging from 2 days to 4 months. Results of quantitative polymerase chain reaction (qPCR) after treatment illustrate significant decreases in the 'Ca. L. asiaticus' bacterial titer, combined with healthy vigorous growth by all surviving trees. Repeated qPCR testing confirmed that previously infected, heat-treated plants showed no detectable levels of 'Ca. L. asiaticus', while untreated control plants remained highly infected. Continuous thermal exposure to 40 to 42°C for a minimum of 48 h was sufficient to significantly reduce titer or eliminate 'Ca. L. asiaticus' bacteria entirely in HLB-affected citrus seedlings. This method may be useful for the control of 'Ca. Liberibacter'-infected plants in nursery and greenhouse settings.