Articles: chronic.
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Am. J. Respir. Crit. Care Med. · Dec 2013
Classical Transient Receptor Potential Channel 1 in Hypoxia-induced Pulmonary Hypertension.
Pulmonary hypertension (PH) is a life-threatening disease, characterized by pulmonary vascular remodeling. Abnormal smooth muscle cell proliferation is a primary hallmark of chronic hypoxia-induced PH. Essential for cell growth are alterations in the intracellular Ca(2+) homeostasis. Classical transient receptor potential (TRPC) proteins have been suggested to contribute to PH development, as TRPC1 and TRPC6 are predominantly expressed in precapillary pulmonary arterial smooth muscle cells (PASMC). Studies in a TRPC6-deficient mouse model revealed an essential function of TRPC6 in acute but not in chronic hypoxia. ⋯ Our results indicate an important role of TRPC1 in pulmonary vascular remodeling underlying the development of hypoxia-induced PH.
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Asthma is a common chronic disease characterized by variable respiratory distress with underlying airway inflammation and airflow obstruction. The incidence of asthma has risen inexorably over the past 50 years, suggesting that environmental factors are important in its etiology. All inhaled environmental stimuli interact with the lung at the respiratory epithelium, and it is a testament to the effectiveness of the airway innate defenses that the majority of inhaled substances are cleared without the need to elicit an inflammatory response. ⋯ The potential of a susceptible epithelium and the underlying mesenchyme to create a microenvironment that enables deviation of immune and inflammatory responses to external stimuli may be crucial in the development and progression of asthma. In this review, we consider three important groups of environmental stimuli on the epithelium in asthma: oxidants, such as environmental pollution and acetaminophen; viruses, including rhinovirus; and agents that cause barrier disruption, such as house dust mite allergens. The pathology associated with each stimulus is considered, and potential future treatments arising from research on their effects are presented.
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Chronic muscle pain affects 20-50% of the population, is more common in women than men, and is associated with increased pain during physical activity and exercise. Muscle fatigue is common in people with chronic muscle pain, occurs in response to exercise, and is associated with release of fatigue metabolites. Fatigue metabolites can sensitize muscle nociceptors, which could enhance pain with exercise. ⋯ Finally, muscle insult with or without muscle fatigue results in minimal inflammatory changes in the muscle itself, and sex differences are not related to estradiol (ovariectomy) or changes in brainstem activity (pNR1). Thus, the current model mimics muscle fatigue-induced enhancement of pain observed in chronic muscle pain conditions in the human population. Interactions between fatigue and muscle insult may underlie the development of chronic widespread pain with an associated female predominance observed in human subjects.
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Randomized Controlled Trial
The effect of epidural methylprednisolone acetate injection on the hypothalamic-pituitary-adrenal axis.
To evaluate the effect of an epidural corticosteroid injection of 80 mg and 40 mg of methylprednisolone acetate on the hypothalamic-pituitary-adrenal axis and on back pain. ⋯ Epidural corticosteroid injection of methylprednisolone acetate in both groups was associated with very high rates of secondary adrenal insufficiency, but significantly more so in Group 1 at week one. This suppression was transient, with recovery of the gland in most patients noted over the ensuing weeks. An epidural corticosteroid injection of 80 mg had higher rates of favorable clinical response than a 40 mg injection, but significantly more so at week 4 only. This favorable response waned over a few weeks in both groups.