J. Antosiewicz

Obstructive sleep apnea and type 2 diabetes

Type 2 diabetes and obstructive sleep apnea (OSA) are diseases with high prevalence and major public health impact. There is evidence that regular snoring and OSA are independently associated with alterations in glucose metabolism. Thus, OSA might be a risk factor for the development of type 2 diabetes. Possible causes might be intermittent hypoxia and sleep fragmentation, which are typical features of OSA. OSA might also be a reason of ineffective treatment of type 2 diabetes. There is further evidence that the treatment of OSA by continuous positive airway pressure (CPAP) therapy might correct metabolic abnormalities in glucose metabolism. It is assumed that this depends on therapy compliance to CPAP. On the other hand, there are also hints in the literature that type 2 diabetes per se might induce sleep apnea, especially in patients with autonomic neuropathy. Pathophysiological considerations open up new insights into that problem. Based on the current scientific data, clinicians have to be aware of the relations between the two diseases, both from the sleep medical and the diabetological point of view. The paper summarizes the most important issues concerning the different associations of OSA and type 2 diabetes.

Intranasal TRPV1 agonist capsaicin challenge and its effect on c-fos expression in the guinea pig brainstem.

Central neuronal interaction seems to play a role in pathogenesis of upper airway cough syndrome. In the guinea pig model we used the method c-fos expression to identify neurons involved in processing of nociceptive nasal stimuli and their contribution to enhancement of cough. 21 spontaneously breathing, urethane anaesthetized animals were used. The controls received intranasal saline, stimulation group received capsaicin (15 microl, 50 microM), and not-treated group was free of nasal challenge. After 2 h animals were deeply anaesthetized, exsanguinated and transcardially perfused with saline and paraformaldehyde. The brainstems were removed, post-fixed, and slices were processed immunohistochemically for c-fos. In capsaicin group the FLI was detected in the nTs 0.5 mm caudal, 1.5 mm lateral to the obex, the area postrema, LRN and VRG. Intensive FLI was identified in trigeminal nuclear complex. Mean number of FOS positive neurons per section was significantly higher in capsaicin group than that in no-treatment controls or saline controls at the level of obex (p<0.01). Neurons of nTs and VRG clearly activated after nasal provocation may participate in enhancement of cough.

Effect of Alkaloid-Free and Alkaloid-Rich preparations from Uncaria tomentosa bark on mitotic activity and chromosome morphology evaluated by Allium Test

ETHNOPHARMACOLOGICAL RELEVANCE Uncaria tomentosa (Willd.) DC. is the most popular Peruvian plant, used in folk medicine for different purposes. It contains thousands of active compounds with great content of alkaloids. AIM OF STUDY Two different fractions of Alkaloid-Rich and Alkaloid-Free were researched on chromosome morphology, mitotic activity and phases indexes. MATERIALS AND METHODS Cells of Allium Test (meristematic cells of root tips) were incubated up to 24h in different concentrations of Alkaloid-Free and Alkaloid-Rich fraction obtained from Uncaria tomentosa bark followed by 48 h of postincubation in water. The chromosome morphology was analyzed and the content of mitotic and phase indexes were done. Individual compounds, oxindole alkaloids, phenolic compounds and sugars were determined. RESULTS In Alkaloid-Rich and Alkaloid-Free fractions (different in chemical composition) we observed condensation and contraction of chromosomes (more in Alkaloid-Rich) with retardation and/or inhibition of mitoses and changed mitotic phases. Postincubation reversed results in the highest concentration which was lethal (in mostly Alkaloid-Rich fraction). CONCLUSIONS Our studies indicate that different action can depend on different groups of active compounds in a preparation either containing alkaloids or not. Other fraction analysis may be useful in the future.

Development and aging are oxygen-dependent and correlate with VEGF and NOS along life span.

During development and aging, vascular remodeling represents a critical adaptive response to modifications in oxygen supply to tissues. Hypoxia inducible factor (HIF) has a crucial role and is modulated by oxygen levels, with an age-dependent response in neonates, adult, and aged people. ROS are generated under hypoxic conditions and the accumulation of free radicals during life reduces the ability of tissues to their removal. In this immunohistochemical study we investigated the presence and localization of VEGF and iNOS in human carotid bodies (CB) sampled at autopsy from three children (mean age - 2 years), four adult young subjects (mean age - 44.3 years), and four old subjects (mean age - 67.3 years). VEGF immunoreactivity was significantly enhanced in CB tissues from the children (7.2 ± 1.2%) and aged subjects (4.7 ± 1.7%) compared with the young adults (1.4 ± 0.7%). On the other hand, iNOS immunoreactivity was enhanced in CB tissues from the children (0.4 ± 0.04%) and young adult subjects (0.3 ± 0.02%) compared with the old subjects (0.2 ± 0.02%). Prevention of oxygen desaturation, reducing all causes of hypoxemia from neonatal life to aging would decrease the incidence of diseases in the elderly population with lifespan extension.

Hypoxic Ventilatory Reactivity in Experimental Diabetes

Diabetes, apart from generalized neuropathy and microangiopathy, involves tissue hypoxia, which may drive chronic proinflammatory state. However, studies on the ventilatory control in diabetes are sparse and conflicting. In this study we examined the function and morphology of diabetic carotid bodies (CBs). Diabetes was evoked in Wistar rats with streptozotocin (70 mg/kg, i.p.). The acute hypoxic ventilatory responses (HVR) to 12 and 8 % O(2) were investigated in conscious untreated rats after 2 and 4 weeks in a plethysmographic chamber. CBs were dissected and subjected to morphologic investigations: (1) electron transmission microscopy for ultrastructure and (2) laser scanning confocal microscopy to visualize the microvascular bed in sections labeled with the lectin Griffonia simplicifolia-I (GSI), an endothelial cell marker, and fluorescein isothiocyanate (FITC). All findings were referenced to the normal healthy rats. We found that diabetes distinctly dampened the HVR. At the ultrastructural level, the diabetic CB displayed proliferation of connective tissue and neovascularization deranging the interglomal structure, and lengthening the O(2) diffusion path from capillaries to chemoreceptor cells. The chemoreceptor cells remained largely unchanged. The endothelial cell labeling confirmed the intensive angiopathy and the induction of microvessel growth. We conclude that diabetes hampers the chemical regulation of ventilation due to remodeling of CB parenchyma, which may facilitate chronic hypoxia and inflammation in the organ.

Iron Chelation and the Ventilatory Response to Hypoxia

Chelation of iron in in vitro carotid body emulates the effects of hypoxia. The role iron plays in in vivo ventilatory responses is unclear. In the current study we addressed this issue by examining the effects of chronic iron chelation on the hypoxic ventilatory response in 9 conscious Wistar rats. Acute responses to 14 and 9% O(2)in N(2) were recorded in the same rat before and then after 7 and 14 days of continuous iron chelation. Iron chelation was carried out with ciclopirox olamine (CPX) in a dose of 20 mg/kg daily, i.p. Ventilation was recorded with whole body plethysmography. We found that the peak hypoxic ventilation (V(E) achieved during 14 and 9% hypoxia was lower by 239.6+/-55.4(SE) and 269.6.2+/-69.2 ml min(-1)kg(-1), respectively, in the rats treated with CPX for 7 days. The decreases were not intensified by a longer duration of iron chelation. CPX failed to alter hypoxic sensitivity, assessed from the gain of peak V(E) with increasing strength of the hypoxic stimulus. In conclusion, we believe we have shown that iron is operational in shaping the hypoxic ventilatory response, but is not liable to be the underlying determinant of the hypoxic chemoreflex.

Antioxidation and the Hypoxic Ventilatory Response

Reactive oxygen species favor the reductive state of iron. Antioxidation, by depleting biologically active ferrous iron, could then have a stabilizing effect, akin to hypoxia, on HIF-1α; the process which controls the genetic responses to hypoxia. However, the influence of antioxidation on the hypoxic ventilatory responses (HVR) is unclear. In this study we set out to determine the influence of mangiferin, a natural polyphenolic compound present in mango trees, with strong antioxidant and iron chelating properties, on the HVR. The study was performed in awake Wistar rats. Acute HVR to 12% and 8% FiO(2) before and 40 min after mangiferin (300 mg/kg, i.p.) pretreatment were recorded plethysmographically. We found that mangiferin significantly dampened the HVR over its course. To distinguish between the scavenging and chelating mechanisms of mangiferin we reinvestigated its effects on the HVR in a separate group of rats after chronic antecedent iron chelation with ciclopirox olamine (20 mg/kg daily for 1 week). The dampening effect on the HVR of mangiferin was preserved in the pre-chelated rats, which points to the preponderance of the antioxidant over chelating properties of mangiferin in its ventilatory effects. Although the exact determinants of mangiferin action remain unclear, the study suggests a role for oxidative signaling in the peripheral chemosensory processing of the HVR. The study also implies the possible clinical use of the antioxidant mangiferin in the regulation of lung ventilation.

Reduced pulmonary function is age-dependent in the rat lung in normoxia

BackgroundOxygen transport is optimized at the cellular level, since oxygen serves as the terminal electron acceptor in mitochondrial oxidative phosphorylation and several enzymatic processes require molecular oxygen as substrate. During development and aging, redundant cells and exhausted cells are eliminated, respectively, whereas others can adapt to the stressful environment and survive.ObjectiveThe study investigated the molecular mechanisms activated in the lung during normal aging, through the expression of hypoxia inducible factor (HIF), vascular endothelial growth factor (VEGF), p53, p66Shc, putative cysteine protease (CPP32) and kinaseB-α phosphorylation (pIkB-α).Materials and methodsTwelve male Wistar rats divided into two age-groups, each consisting of 6 animals, 3 and 24 months old, were used. The rats were anesthetized with Nembutal (40 mg/kg, ip) and the lungs were excised from each rat and processed for TUNEL and Western blotting analyses.ResultsThe expressions of p53, p66Shc and CPP32 were significantly increased in the old normoxic rat lung specimens, when compared with the young ones. In parallel, expressions of VEGF and pIkBα were increased in old rather than young rats.ConclusionsAging leads to increased expressions of p53, p66Shc and CPP32, suggesting that apoptosis is in progress. At the same time, the lung tries to counteract apoptosis through the production of VEGF and pIkB-α to adapt itself to a stressful situation. The aging lung creates a life-support system in order to counteract the apoptotic process.