Role of the C1858T polymorphism of protein tyrosine phosphatase non-receptor type 22 (PTPN22) in children and adolescents with type 1 diabetes.

In recent years, increasing interest has been devoted to the susceptibility gene polymorphisms in type 1 diabetes (T1D) as well as in other autoimmune diseases. Among these, a nucleotide polymorphism of the gene encoding for the protein tyrosine phosphatase non-receptor type 22 (PTPN22) has been associated with T1D in several studies. The aim of this study is to define the frequency of the C1858T polymorphism in the PTPN22 gene in a cohort of 113 Caucasian patients (58 males and 55 females) with T1D, and to assess a possible correlation with a group of clinically relevant variables: age at onset, gender, diabetes-related autoantibodies, residual ß-cell function and daily insulin requirement (IR) 6 months after diagnosis. Using a PCR-RFLP approach, we evidenced a 17.7% frequency of the PTPN22 C1858T polymorphism in diabetic patients, higher than the frequency showed in the general population. A statistically significant correlation between this polymorphism and higher levels of C-peptide at diagnosis and lower IR at 6 months from diagnosis was observed (P=0.001 and P=0.04). Moreover, 1858T variant carriers were more frequently positive for glutamic acid decarboxylase (GAD) autoantibodies at diagnosis than wild-type subjects (P=0.19). On the other hand, no significant difference regarding age at onset, gender distribution, insulinoma-associated 2 molecule (IA2) and islet cell antibodies (ICA) positivity was found. These findings, if adequately confirmed in the future and extended to larger samples, may characterize a subset of T1D patients with a defined genetic pattern, who may be eligible for trials aimed to preserve residual ß-cell function in the coming years.

Influence of Sensory Stimulation on Exhaled Volatile Organic Compounds.

The real-time exhaled volatile organic compounds (VOCs) have been suggested as a new biomarker to detect and monitor physiological processes in the respiratory system. The VOCs profile in exhaled breath reflects the biochemical alterations related to metabolic changes, organ failure, and neuronal activity, which are, at least in part, transmitted via the lungs to the alveolar exhaled breath. Breath analysis has been applied to investigate cancer, lung failure, and neurodegenerative diseases. There are by far no studies on the real-time monitoring of VOCs in sensory stimulation in healthy subjects. Therefore, in this study we investigated the breath parameters and exhaled VOCs in humans during sensory stimulation: smell, hearing, sight, and touch. Responses sensory stimulations were recorded in 12 volunteers using an iAQ-2000 sensor. We found significant effects of sensory stimulation. In particular, olfactory stimulation was the most effective stimulus that elicited the greatest VOCs variations in the exhaled breath. Since the olfactory pathway is distinctly driven by the hypothalamic and limbic circuitry, while other senses project first to the thalamic area and then re-project to other brain areas, the findings suggest the importance of olfaction and chemoreception in the regulation lung gas exchange. VOCs variations during sensory activation may become putative indicators of neural activity.

Swelling of Erectile Nasal Tissue Induced by Human Sexual Pheromone.

Most chemically mediated sexual communication in humans remains uncharacterized. Yet the study of sexual communication is decisive for understanding sexual behavior and evolutive mechanisms in our species. Here we provide the evidence to consider 4,16-androstadien-3-one (AND) as a man's sexual pheromone. Our experiment provides support for the physiological effect of AND on nasal airway resistance (Rna) in women, as assessed by anterior rhinomanometry. We found that AND administration increased the area of turbinate during the ovulatory phase, resulting in an increase of Rna. Thus, we discovered that minute amounts of AND, acting through neuroendocrine brain control, regulate Rna and consequently affect the sexual physiology and behavior. Fascinatingly, this finding provides the evidence of the preservation of chemosexual communication in humans, which it has been largely neglected due to its unconscious perception and concealed nature. Therefore, chemical communication is a plesiomorphic evolutive phenomenon in humans.

Sperm forward motility is negatively affected by short-term exposure to altitude hypoxia.

Human exposure to altitude is a model to study the role of oxygen in different areas of physiology and pathophysiology. The aim of this study was to evaluate whether a short exposure to hypoxia (5 days) combined with exercise, at altitude ranging from 900 m above sea level to 5895 m above sea level (Kilimanjaro Expedition) can modify seminal and reproductive hormonal parameter levels in human beings. During the ascent, blood oxygen saturation at 3.848 m above sea level was found to be decreased when compared to sea level (P < 0.02). The sperm forward motility at sea level after the expedition showed a significant reduction ​​(P < 0.02). There were no changes in other seminal parameters among those compared. Determination of the hormonal plasma concentrations showed that baseline values of follicle-stimulating hormone, total testosterone, prolactin and oestradiol were unchanged at sea level after the hypoxic experience, with respect to baseline values at sea level. On the other hand, luteinising hormone levels after altitudes trekking significantly increased compared to levels before the expedition (P < 0.05). Because of the short-term exposure, we can assume that the reduced forward motility described here may result from the effects of the acute altitude hypoxia on spermatozoa during the epididymal transit where they mature acquiring their motility.

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.

Adaptation of olfactory threshold at high altitude.

The aim of this study was to investigate the effects of the extreme environment of high altitude hypoxia on olfactory threshold. The study was conducted before, during, and after a scientific expedition to Mera Peak (5,800 m). The n-butanol test was used for the assessment of the magnitude of the olfactory threshold. The finding was that the olfactory threshold dramatically increased at high altitude. We conclude that there is a physiological adaptation of olfaction due to altitude-hypoxia.

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.

Proteomic analysis of the carotid body: a preliminary study.

We present a proteomic analysis of the rat carotid body (CB) preparation by comparison between normoxia and hypoxia. Proteomic investigation would be helpful to identify the stress-induced protein during hypoxia and to know what O(2) species are being sensed by CB cells. Adult Wistar rats were used, one group was kept in room air (21% O(2)) as control, and the other was kept in a Plexiglas chamber for 12 days in chronic hypoxia (10-11% inspired oxygen). A total protein extract for each lysated tissue was separated using a broad pH range no-linear IPG strip (3-10) and the second dimension was performed on a 9-16% polyacrylamide gel. Exposure to hypoxia for 12 days produced significant changes in protein expression, providing an initial insight into the mechanism underlying differences in susceptibility to hypoxia. Further investigation is needed to have an overview of the specific set of proteins present in the CB and the functions of such proteins in signal transduction and adaptation during hypoxia.

Cytoglobin and neuroglobin in the human brainstem and carotid body.

The aim of the present study was to evaluate the presence of Neuroglobin (Ngb) and Cytoglobin (Cygb) in the solitary tract nucleus (STN) and in the carotid body of human subjects. Transverse serial sections of formalin-fixed, paraffin-embedded brainstems, taken from six subjects, were investigated. Ngb and Cygb are expressed in both the structures. Differences in expression of Ngb and Cygb among dorsal and ventral area of the STN may be related to their different functions and different metabolic demands. Because the STN plays an important role in the processing of cardiovascular and respiratory reflex inputs, Ngb and Cygb may play an integrative central modulatory action for the two systems.

Physiological analysis of 8-ISO-PGF2 alpha: a homeostatic agent in superficial bladder cancer.

Recent studies underscore the importance of oxygen supply in bladder cancer. Tumour growth stimulates the production of vasoactive factors to increase oxygen delivery to tissues by vasodilatation. Any vasoconstrictor mediator could impair this vasodilatation reducing the oxygen supply. 8-Iso-PGF2 alpha is a potent vasoconstrictor agent. The aim of this work is to determine 8-Iso-PGF2 alpha release in healthy bladder mucosa and in superficial bladder cancer in order to investigate a pathophysiological vasoconstrictor answer of the superficial bladder cancer. The study was conducted on a sample of 12 patients; for every subject studied 8-Iso-PGF2 alpha release was assayed in healthy bladder mucosa and in superficial bladder tumour. 8-Iso-PGF2 alpha release was significantly reduced (p less than 0.001) in superficial bladder cancer compared with healthy bladder mucosa. The inhibition of the production of a powerful vasoconstrictor such as 8-Iso-PGF2 alpha in the vascular homeostatic mechanism of bladder cancer can represent a response of the tumor tending to contrast an antagonist effect of vasodilatation and the necessary to support the oxygen supply.

Interaction of arachidonic acid with electrogenic properties of mouse chemosensory neurons.

Chemosensory neurons respond to stimulation induced by gasses, volatile and non-volatile compounds. Neuronal excitation mediated via second messengers involves typically: cGMP, cAMP, or IP⊂3. Transduction pathways based on cyclic nucleotide have three-phosphate nucleotide as substrate, while IP⊂3 has a membrane lipid substrate. These derivatives of cholesterol are signaling molecules with modulator-like effects on many proteins, including membrane ion channels. In the present study, spontaneous and induced activities were recorded in a whole-cell configuration, in current and voltage clamp modes, in isolated chemosensory neurons obtained from the mouse. Chemosensory neurons responded with an inward depolarizing current to application of arachidonic acid, which suggests a role for it in putative mechanisms of signal transduction.

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

BACKGROUND: Oxygen 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. OBJECTIVE: The 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, p66⊃Shc, putative cysteine protease (CPP32) and kinaseB-α phosphorylation (pIkB-α). MATERIAL AND METHODS: Twelve 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. RESULTS: The expressions of p53, p66⊃Shc 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. CONCLUSIONS: Aging leads to increased expressions of p53, p66⊃Shc 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.

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.

Protein kinase Calpha early activates splicing factor SC-35 during post-natal rat heart development.

Rat myocardial fiber development and formation is a complex event which begins in the early stages of fetal life and continues until the end of the first month of life. In fact, a progressive morphological structure arrangement is observed until the 22nd day of life. These modifications are based on biochemical events which are switched on at plasma membrane level and then transduced into the nucleus. Since the presence of Protein Kinase C (PKC) inside the nucleus could allow the enzyme to phosphorylate also proteins located on chromatin, on nuclear matrix and speckles, in this study attention was paid to the role played by phospho-Protein Kinase C-alpha (p-PKCalpha) in regulating the activation of SC-35 splicing factor which leads to the occurrence of morphological modifications during post-natal rat heart development. Besides the parallel increase of the expression of both proteins up to 4/8 days of life, firstly p-PKCalpha and SC-35 co-localize at nuclear level at day 1 after birth, thus suggesting a main role of p-PKCalpha in modulating the early transcription of components related to post-natal rat heart development.

Does hypoxia cause sarcopenia? Prevention of hypoxia could reduce sarcopenia.

Sarcopenia is the physiological age-related reduction of muscle mass and strength. Considering that life span is correlated with metabolic rate and mitochondria are the site of oxygen consumption, muscle mitochondria volume densities were determined by morphometric analysis. We found a tight correlation between aging and hypoxia with decrease in muscle total mitochondria volume. Therefore, hypoxia and aging seem to share some common pathways, allowing hypoxic models to be used for the study of the aging processes. Additional research will be required to fully elucidate the correlations among aging, sarcopenia and hypoxia, but these findings provide a starting point for such investigations.

Carotid body sensory discharge and glomus cell HIF-1 alpha are regulated by a common oxygen sensor.

The carotid body responds to both acute and more prolonged periods of lowered oxygen pressure. In the acute response, the decrease in oxygen pressure is coupled to increased afferent neural activity while the latter involves, at least in part, increase in the hypoxia inducible transcription factor HIF-1 alpha. In this paper, we summarize evidence that both the acute changes in neural activity and the longer term adaptive changes linked to HIF-1 alpha induction share the same oxygen sensor, mitochondrial cytochrome c oxidase.

Neuroglobin in aging carotid bodies.

Neuroglobin (Ngb) is a member of the vertebrate globin family expressed particularly in the brain and in the retina. Ngb is concentrated in the mitochondria-containing areas of neurons, and its distribution is correlated with oxygen consumption rates. Previously we have shown that Ngb is expressed in carotid body (CB) tissues. Considering that hypoxia and aging may be linked through a series of adaptive and protective mechanisms (e.g. reduction in mitochondrial numbers), we investigate the role of Ngb during aging and hypoxia. Two groups of six rats (age-matched 3 and 24 months old) were kept in room air as a control groups, the others two groups were kept in a Plexiglas chamber for 12 days in chronic hypoxia (10-12% inspired oxygen). The presence of Ngb in the CB tissue was detected by immunohistochemistry using a polyclonal antibody. Ngb immunoreactivity was significantly higher in CB tissues from young rats exposed to chronic intermittent hypoxia, whereas CB tissues from old rats did not show any significant increase in Ngb levels after hypoxia. Similar to hemoglobin, Ngb may act as a respiratory protein by reversibly binding gaseous ligands NO and O(2) and could act as a NO scavenger and participate in detoxification of Reactive Oxygen Species (ROS) generated under hypoxic conditions.

Physiological carotid body denervation during aging.

Aging is characterized by a lower homeostatic capacity and the carotid body (CB) plays an important role during aging. Here, we sought to elucidate whether the aging effects on the oxygen-sensitive mechanisms in CB cells occur through a reduction of the contact surfaces in the synaptic junctions. The hypothesis was that the CB would undergo a "physiological denervation" in old age. Two groups of male Wistar rats, young (2-3 months old) and senescent (22 months old) were used. CBs were rapidly dissected and the specimens were subjected to a routine transmission electron microscopic procedure. Expressions of HIF-1 proportional, variant, VEGF and NOS-1 were evaluated by immunohistochemical analysis. Our results show that in the old CB, HIF-1 proportional, variant, VEGF and NOS-1 expressions decrease. The cell volume, the number of mitochondria and that of dense-cored vesicles were reduced, and the nucleus shrank. There also was an accumulation of lipofuscin and a proliferation of extracellular matrix. Most importantly, there were fewer synaptic connections between chemoreceptor cells. The total number of synapses observed in all electronograms decreased from 125 in the young to 28 in the old CB. These results suggest the aging CB undergoes a "physiological denervation" leading to a reduction in homeostatic capacity. The age-related reduction of synaptic junctions may be a self-protective mechanism through which cells buffer themselves against reactive oxygen species accumulation during aging.

Long-term regulation of carotid body function: acclimatization and adaptation--invited article.

Physiological responses to hypoxia either continuous (CH) or intermittent (IH) depend on the O(2)-sensing ability of the peripheral arterial chemoreceptors, especially the carotid bodies, and the ensuing reflexes play important roles in maintaining homeostasis. The purpose of this article is to summarize the effects of CH and IH on carotid body function and the underlying mechanisms. CH increases baseline carotid body activity and sensitizes the response to acute hypoxia. These effects are associated with hyperplasia of glomus cells and neovascularization. Enhanced hypoxic sensitivity is due to alterations in ion current densities as well as changes in neurotransmitter dynamics and recruitment of additional neuromodulators (endothelin-1, ET-1) in glomus cells. Morphological alterations are in part due to up-regulation of growth factors (e.g. VEGF). Hypoxia-inducible factor-1 (HIF-1), a transcriptional activator might underlie the remodeling of carotid body structure and function by CH. Chronic IH, on the other hand, is associated with recurrent apneas in adults and premature infants. Two major effects of chronic IH on the adult carotid body are sensitization of the hypoxic sensory response and long-lasting increase in baseline activity i.e., sensory long-term facilitation (LTF) which involve reactive oxygen species (ROS) and HIF-1. In neonates, chronic IH leads to sensitization of the hypoxic response but does not induce sensory LTF. Chronic IH-induced sensitization of the carotid body response to hypoxia increases the likelihood of unstable breathing perpetuating in more number of apneas, whereas sensory LTF may contribute to increased sympathetic tone and systemic hypertension associated with recurrent apneas.

Pampiniform plexus and oxidative stress during chronic hypoxia and hyperoxia.

The aim of the present study is to investigate oxidative stress produced by experimental hypoxia and hyperoxia in young and old pampiniform plexus rats, in order to evaluate the oxidative role of oxygen. Oxidative stress causing molecular and cellular dysfunction increases in hypertension and can therefore be considered a state of oxidative stress. This consideration makes us reflect on the responsibility of oxidative stress in the veins of the pampiniform plexus, notoriously under high hydrostatic pressure. After experimental hypoxia and hyperoxia we studied the 8-iso-PGF2alpha release (a specific index of cellular oxidative stress) in young and old left pampiniform plexus rats. The basal 8-iso-PGF2alpha release showed a statistically significant difference P=0.0067 between young and old rats PP. After hypoxia and hyperoxia, the release was higher in young rats as compared to normoxia, respectively P=0.0001 and P=0.0002. After hypoxia the release was not modified in old rats P=0.544 while after hyperoxia the release was increased in old rats as compared to control P less than 0.0001. The results show how chronic hypoxia and hyperoxia represent two important causes of oxidative stress and lipid peroxidation in pampiniform plexus rats. In young rats an increase of oxidative stress suggests that pampiniform plexus is sensitive to variations of oxygen supply. In old rats the pampiniform plexus is liable to a reduction of oxygen-sensing mechanisms and it is possible that the missing oxidative answer to the hypoxia in old rats is attributable in all likelihood to adaptation to a hypoxic condition typical of aging.