Can postural changes in spirometry in children with Duchenne muscular dystrophy predict sleep hypoventilation?

AIM

To explore the relationship between postural changes in lung function and polysomnography (PSG) in children with Duchenne muscular dystrophy (DMD).

METHODS

In this prospective cross-sectional study, children with DMD performed spirometry in sitting and supine positions. A control group of age and gender matched healthy children also underwent postural lung function testing. PSG was performed within six months of spirometry.

RESULTS

Seventeen children with DMD, aged 12.3 ± 3 years performed sitting spirometry. 14 (84%) performed acceptable spirometry in the supine position. Mean FEV1sit and FVCsit were 77% (SD ± 22) and 74% (SD ± 20.4) respectively, with mean% ΔFVC(sit-sup) 9% (SD ± 11) (range 2% to 20%), and was significantly greater than healthy controls 4% (n = 30, SD ± 3, P < 0.001). PSG data on the 14 DMD children with acceptable supine spirometry showed total AHI 6.9 ± 5.9/hour (0.3 to 29), obstructive AHI 5.2 ± 4.0/hour (0.2 to 10), and REM AHI 14.1 ± -5.3/hour (0.1 to 34.7). ΔFVC(sit-sup) had poor correlation with hypoventilation on polysomnography.

CONCLUSION

Children with DMD and mild restrictive lung disease showed greater postural changes in spirometry than healthy controls but lower supine spirometry was not predictive of sleep hypoventilation.

Use of non-invasive ventilation in children with congenital tracheal stenosis

INTRODUCTION

Congenital tracheal stenosis (CTS) is a rare airway condition characterized by complete tracheal rings. Most patients undergo a slide tracheoplasty, which greatly reduces mortality but significant morbidity remains. The assessment of sleep disordered breathing (SDB) and use of non-invasive ventilation (NIV) in these children has not been described.

AIM

To describe the presence of SDB and use of NIV in children diagnosed with CTS over a 10-year period (2005-2015).

DESIGN

Retrospective case series at a tertiary children's hospital.

RESULTS

There were 16 patients identified with CTS with a median [range] age at diagnosis of 2.5 months (0-9 months). One child died in the immediate post-operative period following a slide tracheoplasty, leaving 15 survivors. There were no later deaths during follow-up while using NIV for up to 3 years after surgery. Slide tracheoplasty was undertaken in (12/15) with long-segment tracheal stenosis. 3/15 patients had a short-segment tracheal stenosis and were managed conservatively. The use of NIV occurred in 10/15 (66.67%) patients, all of whom had long-segment CTS. Pre-operative polysomnography (PSG) showed a median (±SD) obstructive apnoea/hypopnoea index (OAHI) of 14.6/hr (±6.2) which reduced to 7.2/hour (±4.2) on NIV prior to slide tracheoplasty. The median oxygen desaturation index (ODI) before NIV use was 15.3 (±19.4) episodes/hour, which reduced to 6.3 (±11) on NIV. The median period of NIV use was 5 [1-24 months] months.

CONCLUSION

Patients with CTS have obstructed sleep disordered breathing. Trials of NIV are well-tolerated and improve sleep disordered breathing.

Pepper and cinnamon improve cold induced cognitive impairment via increasing non-shivering thermogenesis; a study

Despite an understanding that a major effect of cold exposure is a fall in core body temperature which is responsible for the observed decrements in the performance, it is surprising that thermogenic supplements are seldom evaluated to verify if they can aid in improving the performance during cold exposure. Following evidence from our previous study indicating the ability of pepper and cinnamon to improve cold endurance, we investigated further here if the improved endurance had advantages in real time where they could positively affect cognitive performance (assessed by Novel object test) when exposed to cold in albino wistar rats. In order to delineate if the observed improvement if any, was due to their cognitive enhancing ability or thermogenic potential, distinctive room temperature (RT) and cold temperature (CT) groups were used. Cold exposure impaired cognitive performance which improved following treatment with both the spices. We noted an increased rate of cold adaptive thermogenesis in CT treated group as evidenced by an elevated norepinephrine, free fatty acid levels in blood, increased expression of UCP1 in brown adipose tissue, the net effect being a decreased fall in the core body temperature. Absence of any notable effect in these parameters in the RT treated group ascertained that at least in the current experimental set up the observed improvement in performance in CT treated group is due to the thermogenic potential of the spices alone. In conclusion, our results demonstrate that the cognitive impairment caused by exposure to cold can be effectively countered by agents with thermogenic potential.

Cold adaptive thermogenesis following consumption of certain pungent spice principles: A validation study

Identifying a means to activate or potentiate thermogenic mechanisms through ingestion of dietary compounds have important implications in cold endurance and survival. Although many reports discuss the thermogenic potential of spices, it is surprising that none of the studies verify whether consumption of spices can improve cold endurance. In this study, we have attempted to evaluate if ingestion of certain spices can activate heat-generating mechanisms in the body such that a fall in. core body temperature (CBT) can be delayed or prevented when faced with a cold challenge. Ten commonly used spices in the Indian cuisine were chosen and 70% ethanol extract of the spices were fed orally to male Wistar rats at a dose of 250mg/kg for a period of 7 days. A change in CBT during cold exposure was recorded before and after treatment. At the end of the experiment, plasma norepinephrine and serum free fatty acid levels were estimated. We observed that among the ten spices, treatment with cinnamon and pepper extracts showed significant improvement in comparison to the control group. Based on evidence in literature and the HPLC-MS analysis from our lab, we hypothesized that the effects of the pepper and cinnamon extracts might be due to their piperine and cinnamaldehyde content respectively. However, no improved endurance was observed when they were administered alone. Poor endurance following depletion of endogenous norepinephrine levels using reserpine indicated its involvement in mediating the heat generating processes. However, it is noteworthy that green tea and spice treated animals exhibited a fall in CBT which was lower than their initial fall. In conclusion, our findings provide experimental evidence that ingestion of spices, viz., pepper and cinnamon, might elicit thermogenic responses such that hypothermia can be delayed or prevented upon cold exposure.

To hydrolyze or not to hydrolyze: the dilemma of platelet-activating factor acetylhydrolase

Mounting ambiguity persists around the functional role of the plasma form of platelet-activating factor acetylhydrolase (PAF-AH). Because PAF-AH hydrolyzes PAF and related oxidized phospholipids, it is widely accepted as an anti-inflammatory enzyme. On the other hand, its actions can also generate lysophosphatidylcholine (lysoPC), a component of bioactive atherogenic oxidized LDL, thus allowing the enzyme to have proinflammatory capabilities. Presence of a canonical lysoPC receptor has been seriously questioned for a multitude of reasons. Animal models of inflammation show that elevating PAF-AH levels is beneficial and not deleterious and overexpression of PAF receptor (PAF-R) also augments inflammatory responses. Further, many Asian populations have a catalytically inert PAF-AH that appears to be a severity factor in a range of inflammatory disorders. Correlation found with elevated levels of PAF-AH and CVDs has led to the design of a specific PAF-AH inhibitor, darapladib. However, in a recently concluded phase III STABILITY clinical trial, use of darapladib did not yield promising results. Presence of structurally related multiple ligands for PAF-R with varied potency, existence of multi-molecular forms of PAF-AH, broad substrate specificity of the enzyme and continuous PAF production by the so called bi-cycle of PAF makes PAF more enigmatic. This review seeks to address the above concerns.