Pioglitazone treatment improves nitrosative stress in type 2 diabetes

Cutaneous vasodilator and vasoconstrictor mechanisms in temperature regulation

In this review, we focus on significant developments in our understanding of the mechanisms that control the cutaneous vasculature in humans, with emphasis on the literature of the last half-century. To provide a background for subsequent sections, we review methods of measurement and techniques of importance in elucidating control mechanisms for studying skin blood flow. In addition, the anatomy of the skin relevant to its thermoregulatory function is outlined. The mechanisms by which sympathetic nerves mediate cutaneous active vasodilation during whole body heating and cutaneous vasoconstriction during whole body cooling are reviewed, including discussions of mechanisms involving cotransmission, NO, and other effectors. Current concepts for the mechanisms that effect local cutaneous vascular responses to local skin warming and cooling are examined, including the roles of temperature sensitive afferent neurons as well as NO and other mediators. Factors that can modulate control mechanisms of the cutaneous vasculature, such as gender, aging, and clinical conditions, are discussed, as are nonthermoregulatory reflex modifiers of thermoregulatory cutaneous vascular responses.

Neurovascular function and sudorimetry in health and disease

In this review of thermoregulatory function in health and disease, we review the basic mechanisms controlling skin blood flow of the hairy and glabrous skin and illustrate the major differences in blood flow to glabrous skin, which is, in essence, sympathetically mediated, while hairy skin is dependent upon neuropeptidergic signals, nitric oxide, and prostaglandin, among others. Laser Doppler methods of quantification of blood flow--in response to iontophoresis of acetylcholine or heat--and nociceptor-mediated blood flow have relatively uniformly demonstrated an impaired capacity to increase blood flow to the skin in diabetes and in its forerunners, prediabetes and the metabolic syndrome. This reduced capacity is likely to be a significant contributor to the development of foot ulcerations and amputations in diabetes, and means of increasing blood flow are clearly needed. Understanding the pathogenic mechanisms is likely to provide a means of identifying a valuable therapeutic target. Thermoregulatory control of sweating is intimately linked to the autonomic nervous system via sympathetic C fibers, and sweat glands are richly endowed with a neuropeptidergic innervation. Sweating disturbances are prevalent in diabetes and its precursors, and quantification of sweating may be useful as an index of diagnosis of somatic and, probably, autonomic dysfunction. Moreover, quantifying this disturbance in sweating by various methods may be useful in identifying the risk of progression from prediabetes to diabetes, as well as responses to therapeutic intervention. We now have the technological power to take advantage of this physiological arrangement to better understand, monitor, and treat disorders of small nerve fibers and the somatic and autonomic nervous system (ANS). Newer methods of sudomotor function testing are rapid, noninvasive, not technically demanding, and accessible to the outpatient clinic. Whether the potential applications are screening for diabetes, following poorly controlled diabetes subjects during alteration of their treatment regimen, or simply monitoring somatic and autonomic function throughout the course of treatment, sudorimetry can be an invaluable tool for today's clinicians.

To accomplish preliminary Qigong simulation state by acupuncture

OBJECTIVE

The purpose of the study was to find out how to enter the preliminary Qigong simulation state in a short period of time.

METHODS

This is a non-randomized, human experiment with healthy participants. A multi-channel digital physiological data recorder was used to detect whether the participants had entered the Qigong state. Participants were assisted to enter the Qigong state (relaxation, tranquility and naturalness) by being given the sore (sour) feeling produced by acupuncturing Hegu (LI4), and suggestions (repeating words "relax" and "heat" from the hypogastrium).

RESULTS

About 72.2% of the participants who had no Qigong experience were found entering the preliminary Qigong simulation state. Most of the physiological parameters measured after the participants entering the Qigong state showed significant changes compared with the baseline data.

CONCLUSION

This study revealed that acupuncture-made sore feeling is able to induce the participants to quickly enter the preliminary Qigong simulation state; hence this can be seen as no longer a limited phenomenon, but can be commonly applied to everybody.

Advancing therapy in type 2 diabetes mellitus with early, comprehensive progression from oral agents to insulin therapy

BACKGROUND

Early and intensive glycemic control is necessary to prevent or minimize the development of microvascular and macrovascular complications in individuals with type 2 diabetes mellitus. However, many patients are unable to attain glycemic control, partly due to protracted treatment with oral antidiabetic drugs (OADs) despite inadequate control and barriers to initiating insulin therapy. Patients at different stages of disease may benefit from the early introduction of intensive glycemic control.

OBJECTIVE

This article discusses some of the potential barriers to achieving and maintaining optimal glycemic levels in patients whose blood glucose is sub-optimally controlled with OADs and reviews the benefits of early introduction of intensive glycemic control in patients at various stages of disease, with an emphasis on insulin therapy.

METHODS

Relevant English-language articles published from 1996 to 2006 were identified through searches of the National Center for Biotechnology PubMed database. Search terms included insulin, insulin therapy, type 2 diabetes, insulin analogs, early insulinization, and diabetes prevention, among others. Studies were assessed regarding designs, primary and secondary efficacy parameters, glycosylated hemoglobin (HbAM(lc)), fasting plasma glucose, incidence of hypoglycemia, and other safety assessments. Inclusion criteria were multicenter, randomized, open-label, parallel-group trials, as well as retrospective observational studies, conducted in Europe or the United States. Additional analyses and guideline-based recommendations are included.

RESULTS

The landmark results of the United Kingdom Prospective Diabetes Study, which found that an intensive strategy in 3867 newly diagnosed patients with type 2 diabetes was associated with stricter glycemic control than was conventional care (HbA(lc) over 10 years, 7.0% vs 7.9%; P < 0.001), as well as a 25% reduction in the risk for microvascular complications (P = 0.01). Early initiation of insulin therapy concomitantly with OADs appeared well tolerated in the populations studied, was effective in recently diagnosed patients, and may also confer anti-inflammatory and antiatherogenic effects. Characteristics associated with newer formulations of insulin (eg, basal insulin analogues as well as rapid-acting insulin analogues, the insulin pump, or inhaled insulin) may help overcome barriers associated with initiating insulin therapy.

CONCLUSIONS

Based on the literature, early and persistent intensification of antidiabetic therapy is an approach that most likely will achieve optimal glycemic control in patients with type 2 diabetes and help prevent associated complications. Greater clinical experience with newer therapeutic approaches, including incretin mimetics and dipeptidyl peptidase-IV inhibitors, will provide insight into their place in the spectrum of diabetes treatments.

Reactive nitrogen species: molecular mechanisms and potential significance in health and disease

Reactive nitrogen species (RNS) are various nitric oxide-derived compounds, including nitroxyl anion, nitrosonium cation, higher oxides of nitrogen, S-nitrosothiols, and dinitrosyl iron complexes. RNS have been recognized as playing a crucial role in the physiologic regulation of many, if not all, living cells, such as smooth muscle cells, cardiomyocytes, platelets, and nervous and juxtaglomerular cells. They possess pleiotropic properties on cellular targets after both posttranslational modifications and interactions with reactive oxygen species. Elevated levels of RNS have been implicated in cell injury and death by inducing nitrosative stress. The aim of this comprehensive review is to address the mechanisms of formation and removal of RNS, highlighting their potential cellular targets: lipids, DNA, and proteins. The specific importance of RNS and their paradoxic effects, depending on their local concentration under physiologic conditions, is underscored. An increasing number of compounds that modulate RNS processing or targets are being identified. Such compounds are now undergoing preclinical and clinical evaluations in the treatment of pathologies associated with RNS-induced cellular damage. Future research should help to elucidate the involvement of RNS in the therapeutic effect of drugs used to treat neurodegenerative, cardiovascular, metabolic, and inflammatory diseases and cancer.

Exercise status affects skin perfusion via prostaglandin, nitric oxide, and EDHF pathways in diabetes

Participation in regular exercise training improves dorsal skin perfusion, while type 2 diabetes mellitus (T2 DM) often limits it via reductions in the action or release of vasodilatory compounds. This study was undertaken to investigate the relative contributions of prostaglandins (PG), nitric oxide (NO), and endothelial-derived hyperpolarizing factor (EDHF) in dorsal foot skin perfusion in individuals with and without T2 DM and a sedentary lifestyle. Participants included 24 individuals with T2 DM and 28 nondiabetic controls whose exercise status was determined via questionnaire. Their dorsal foot skin perfusion was measured at rest using laser Doppler assessment during localized heating to 44 degrees C with oral aspirin (ASA, 325 mg) treatment. In addition, they received an infusion via a subcutaneous microdialysis probe of either saline (left foot) or L-NAME, a NOS-inhibitor (right foot). Compared to normative data without ASA, heat-stimulated perfusion in regular exercisers (n=22) was significantly more suppressed by ASA and by ASA/L-NAME than in sedentary individuals (n=30). Chronic exercisers exhibit a greater reliance on PG and lesser involvement of EDHF with unchanged NO compared to sedentary individuals, who rely more on EDHF and less on PG release. One possible exception may be diabetic, sedentary individuals, who may rely somewhat more on NO than EDHF. These results suggest that regular exercise may exhibit the greatest effect on the normal functioning of these vasodilatory pathways, although diabetes and a sedentary state together may somewhat alter their relative importance.

Nitrosylated proteins in monocytes as a new marker of oxidative-nitrosative stress in diabetic subjects with macroangiopathy

BACKGROUND

Peroxynitrite plays an important role in the pathogenesis of diabetic complications. Nitrosylated protein expression in peripheral blood monocytes reflects intracellular peroxynitrite injury, and thus could be a marker of higher diagnostic and prognostic value than plasma nitrotyrosine level. The purpose of this pilot study was to assess if peripheral blood monocytes of diabetic subjects accumulate nitrosylated proteins, and if nitrosylated protein expression correlates with blood glucose control, variables of lipid profile, C-reactive protein concentration (a marker of inflammation), and differs in patients with and without diabetic macrovascular and microvascular complications.

METHODS

Nitrosylated protein expression in peripheral blood monocytes (Western blot analysis) was assessed in 31 subjects with diabetes mellitus (29 Type 2, 2 Type 1; 20 males, 11 females; mean age 66 years). The presence of microangiopathy was defined by retinopathy, albumin excretion, and/or neuropathy, and macroangiopathy by carotid plaques, a history of myocardial infarction, and/or stroke.

RESULTS

Diabetic subjects accumulated significant amounts of nitrosylated proteins in peripheral blood monocytes. Nitrosylated protein expression positively correlated with body weight, blood glucose, HbA (1)C, and plasma C-reactive protein concentrations in the whole cohort as well as in subjects with diabetic macroangiopathy.

CONCLUSIONS

Monocyte nitrosylated protein expression is a new biomarker of metabolic control and inflammation in diabetic subjects with macroangiopathy. A more detailed assessment of diabetic microvascular complications in a larger group of patients is needed to determine if this variable can be employed as a biomarker of the presence, severity, and progression of diabetic neuropathy, retinopathy, and nephropathy.

Nitric oxide selective electrodes

Since nitric oxide (NO) was identified as the endothelial-derived relaxing factor in the late 1980s, many approaches have attempted to provide an adequate means for measuring physiological levels of NO. Although several techniques have been successful in achieving this aim, the electrochemical method has proved the only technique that can reliably measure physiological levels of NO in vitro, in vivo, and in real time. We describe here the development of electrochemical sensors for NO, including the fabrication of sensors, the detection principle, calibration, detection limits, selectivity, and response time. Furthermore, we look at the many experimental applications where NO selective electrodes have been successfully used.