Reduced respiratory muscle strength and endurance in type 2 diabetes mellitus

Exendin-4 blockade of T1R2/T1R3 activation improves Pseudomonas aeruginosa-related pneumonia in an animal model of chemically induced diabetes

OBJECTIVE

Poorly controlled diabetes frequently exacerbates lung infection, thereby complicating treatment strategies. Recent studies have shown that exendin-4 exhibits not only hypoglycemic but also anti-inflammatory properties. This study aimed to explore the role of exendin-4 in lung infection with diabetes, as well as its association with NOD1/NF-κB and the T1R2/T1R3 sweet taste receptor.

METHODS

16HBE human bronchial epithelial cells cultured with 20 mM glucose were stimulated with lipopolysaccharide (LPS) isolated from Pseudomonas aeruginosa (PA). Furthermore, Sprague‒Dawley rats were fed a high-fat diet, followed by intraperitoneal injection of streptozotocin and intratracheal instillation of PA. The levels of TNF-α, IL-1β and IL-6 were evaluated using ELISAs and RT‒qPCR. The expression of T1R2, T1R3, NOD1 and NF-κB p65 was assayed using western blotting and immunofluorescence staining. Pathological changes in the lungs of the rats were observed using hematoxylin and eosin (H&E) staining.

RESULTS

At the same dose of LPS, the 20 mM glucose group produced more proinflammatory cytokines (TNF-α, IL-1β and IL-6) and had higher levels of T1R2, T1R3, NOD1 and NF-κB p65 than the normal control group (with 5.6 mM glucose). However, preintervention with exendin-4 significantly reduced the levels of the aforementioned proinflammatory cytokines and signaling molecules. Similarly, diabetic rats infected with PA exhibited increased levels of proinflammatory cytokines in their lungs and increased expression of T1R2, T1R3, NOD1 and NF-κB p65, and these effects were reversed by exendin-4.

CONCLUSIONS

Diabetic hyperglycemia can exacerbate inflammation during lung infection, promote the increase in NOD1/NF-κB, and promote T1R2/T1R3. Exendin-4 can ameliorate PA-related pneumonia with diabetes and overexpression of NOD1/NF-κB. Additionally, exendin-4 suppresses T1R2/T1R3, potentially through its hypoglycemic effect or through a direct mechanism. The correlation between heightened expression of T1R2/T1R3 and an intensified inflammatory response in lung infection with diabetes requires further investigation.

Exploring the impact of type II diabetes mellitus on voice quality

PURPOSE

This cross-sectional study aimed to investigate the potential of voice analysis as a prescreening tool for type II diabetes mellitus (T2DM) by examining the differences in voice recordings between non-diabetic and T2DM participants.

METHODS

60 participants diagnosed as non-diabetic (n = 30) or T2DM (n = 30) were recruited on the basis of specific inclusion and exclusion criteria in Iran between February 2020 and September 2023. Participants were matched according to their year of birth and then placed into six age categories. Using the WhatsApp application, participants recorded the translated versions of speech elicitation tasks. Seven acoustic features [fundamental frequency, jitter, shimmer, harmonic-to-noise ratio (HNR), cepstral peak prominence (CPP), voice onset time (VOT), and formant (F1-F2)] were extracted from each recording and analyzed using Praat software. Data was analyzed with Kolmogorov-Smirnov, two-way ANOVA, post hoc Tukey, binary logistic regression, and student t tests.

RESULTS

The comparison between groups showed significant differences in fundamental frequency, jitter, shimmer, CPP, and HNR (p < 0.05), while there were no significant differences in formant and VOT (p > 0.05). Binary logistic regression showed that shimmer was the most significant predictor of the disease group. There was also a significant difference between diabetes status and age, in the case of CPP.

CONCLUSIONS

Participants with type II diabetes exhibited significant vocal variations compared to non-diabetic controls.

A 'one stone, two birds' approach with mesenchymal stem cells for acute respiratory distress syndrome and Type II diabetes mellitus

This review explores the intricate relationship between acute respiratory distress syndrome (ARDS) and Type II diabetes mellitus (T2DM). It covers ARDS epidemiology, etiology and pathophysiology, along with current treatment trends and challenges. The lipopolysaccharides (LPS) role in ARDS and its association between non-communicable diseases and COVID-19 are discussed. The review highlights the therapeutic potential of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) for ARDS and T2DM, emphasizing their immunomodulatory effects. This review also underlines how T2DM exacerbates ARDS pathophysiology and discusses the potential of hUC-MSCs in modulating immune responses. In conclusion, the review highlights the multidisciplinary approach to managing ARDS and T2DM, focusing on inflammation, oxidative stress and potential therapy of hUC-MSCs in the future.

Respiratory Muscle Strength and Aerobic Performance Among Chronic Obstructive Pulmonary Disease (COPD) Patients: A Correlational Study

Background Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition, yielding various respiratory symptoms and categorized under several descriptors: early, mild, young, pre-COPD, and preserved ratio impaired spirometry. COPD is synonymous with symptoms such as dyspnea and cough, in addition to others like exercise intolerance, which result from respiratory muscle weakness. Therefore, the emergence of respiratory strength assessment tools for such patients is not surprising. However, evidence is limited regarding the impact of respiratory muscle strength on the physical performance of COPD patients. Therefore, this study employs the MicroRPM device (Medikart HealthCare Systems Pvt. Ltd., Delhi, India) to measure maximum inspiratory and expiratory pressure utilizing mouth pressure. Methodology We recruited a total of 40 patients for the study. All patients received a thorough assessment for hemodynamic stability and were categorized according to the Global Initiative for Chronic Obstructive Lung Disease criteria of COPD. The patients then underwent a training session for the MicroRPM device. We took each patient's inspiratory and expiratory pressure measurements, then determined their six-minute walk distance and modified the Borg scale rating. Results We observed no significant correlation between maximum inspiratory pressure (Pimax) and six-minute walk distance (r=-0.023, p=0.890) or modified Borg scale (r=-0.044, p=0.788); additionally, the correlation between maximum expiratory pressure (Pemax) and modified Borg scale was not significant (r=-0.192, p=0.235). However, the correlation between Pemax and six-minute walk distance was both negative and significant (r=-0.384, p=0.014). Conclusion Based on our results, respiratory muscle strength can influence the aerobic performance of COPD patients.

Association of Multiple Cardiovascular Risk Factors with Musculoskeletal Function in Acute Coronary Syndrome Ward Inpatients

This study explored the association of multiple risk factors with musculoskeletal function in adults hospitalized for acute coronary syndrome. Sixty-nine inpatients (55 ± 6 years; 67% male) admitted to the cardiology ward within <12 h were assessed regarding stress, smoking, alcoholism, hypertension, diabetes mellitus, and obesity. The musculoskeletal function was assessed by predicted values of handgrip strength of the dominant hand (HGS-D%) and maximal inspiratory and expiratory pressures (MIP% and MEP%, respectively). After adjustment by age and sex, drinking habits showed the strongest linear association with the total number of cardiovascular disease risk factors [standardized ß, p-value] (ß = 0.110, p < 0.001), followed by smoking load (ß = 0.028, p = 0.009). Associations were also observed for HGS-D% with mean blood pressure (ß = 0.019 [0.001; 0.037], p = 0.048); MIP% with mean blood pressure (ß = 0.025 [0.006; 0.043], p = 0.013); and MEP% with drinking habits (ß = 0.009 [0.002; 0.016], p = 0.013) and body mass index (ß = 0.008 [0.000; 0.015], p = 0.035). Peripheral and respiratory muscle strength must be interpreted in the context of its association with cardiovascular disease risk factors in adults hospitalized for acute coronary syndrome.

Disparities in Comorbidities in Lung Cancer: Findings From the Behavioral Risk Factor Surveillance System

BACKGROUND

In persons with lung cancer, sex and race are independent predictors of comorbidities and are associated survival. It is unclear how comorbidity profiles differ across sex and race.

OBJECTIVE

The objective was to examine comorbidity differences between men and women and Blacks and Whites.

METHODS

Data from the 2014, 2016, 2017, and 2018 Behavioral Risk Factor Surveillance System were analyzed using descriptive statistics, χ2 test of independence, and multiple logistic regression. Variables included sociodemographics and comorbidities.

RESULTS

Among individuals with lung cancer (N = 594), men were more likely to experience a heart attack (odds ratio [OR], 3.59; 95% confidence interval [CI], 1.62-7.96) and diabetes (OR, 2.83; 95% CI, 1.57-5.10) and less likely to experience depressive disorder (OR, 0.360; 95% CI, 0203-0.637). Black men (OR, 28.57; 95% CI, 9.22-88.55) and women (OR, 2.48; 95% CI, 1.02-6.05) were more likely to have a history of stroke.

CONCLUSION

Findings show that there may be differences in patterns of comorbidities among individuals with lung cancer. As we continue to move toward individualized medicine in cancer care, future work in this area should examine social determinants of health and how they may influence the patterns of comorbidities.

IMPLICATION FOR NURSES

Although nurses may be aware that certain groups have an increased risk for certain comorbid conditions, this study highlights what groups with lung cancer may be more likely to have certain comorbidities. Nurses can assess individuals for comorbidities and provide education on how to manage comorbidities during cancer treatment.

Muscle Microcirculatory Responses to Incremental Exercises Are Correlated with Peak Oxygen Uptake in Individuals With and Without Type 2 Diabetes Mellitus

Background: The role of impaired oxygen extraction on peak oxygen uptake (V̇O_2peak) has been extensively studied using noninvasive and indirect methods in both diabetic patients and healthy participants. Methods: A total of 22 participants with type 2 diabetes mellitus [T2DM; median (range) age: 60 (47-70) years] and 22 controls [58 (52-69) years] with no history of diabetes were recruited (reference no. 201812135RINB). Subjects performed an exhaustive incremental exercise and were evaluated using a gas analyzer and near-infrared spectroscopy (NIRS) to determine V̇O_2peak and changes in muscle oxygenation (SmO₂) in the vastus lateralis, respectively. Measurements were taken at rest, warm-up, a period during exercise when SmO₂ reached a minimum saturation plateau, and recovery. The microcirculatory responses of the vastus lateralis muscle during incremental exercise in patients with T2DM were compared with those in control individuals, and the correlation between changes in SmO₂ and V̇O_2peak was estimated. Results: The diabetic group demonstrated lower V̇O_2peak, peak workload, peak heart rate, peak minute ventilation (all P < 0.05), and lower SmO₂ during the rest, warm-up, and recovery phases (all P < 0.05) compared with the control group. A correlation was observed between the change in SmO₂ between the warm-up and plateau value and the V̇O_2peak (r = 0.608, P = 0.006). Conclusions: The results obtained in this study using NIRS support the feasibility of directly measuring changes in muscle SmO₂ magnitudes to estimate the contributions of peripheral active muscle to systemic O₂ uptake (V̇O₂) during incremental exercise.

Scoping review of the relationship between diabetes and voice quality

AIMS

The objective of this scoping review is to synthesize all of the known information about the relationship between diabetes mellitus and voice quality and to explore its potential applications for new technology.

METHODS

We conducted a scoping literature review of articles published between March 2000 and September 2021 using the following databases: PubMed, Web of Science, Scopus, and Embase. Additionally, we did a manual search of Google Scholar. The search strategy abides by the PRISMA-ScR guidelines. Studies pertaining to the relationship between diabetes and the voice were categorized separately for further evaluation.

RESULTS

Out of the 2732 originally identified articles, nine were ultimately included in this scoping review. The chosen articles address both diabetes and its impact on a variety of vocal parameters.

CONCLUSIONS

There is currently very little research investigating the relationship between diabetes, neuropathy, and phonatory symptoms. Additionally, existing publications contain some contradictory findings. Further research that incorporates imaging technology is needed to clarify the physiological explanations for the differences observed between healthy individuals and those with diabetes mellitus. Such information can be used to develop noninvasive technology for diabetes diagnosis and monitoring.

Altered Expiratory Flow Dynamics at Peak Exercise in Adult Men With Well-Controlled Type 1 Diabetes

Type 1 diabetes may, in time, cause lung dysfunction including airflow limitation. We hypothesized that ventilatory flow morphology during a cardiopulmonary exercise test (CPET) would be altered in adult men with well-controlled type 1 diabetes. Thirteen men with type 1 diabetes [glycated hemoglobin A1c 59 (9) mmol/mol or 7.5 (0.8)%, duration of diabetes 12 (9) years, and age 33.9 (6.6) years] without diagnosed diabetes-related complications and 13 healthy male controls [age 37.2 (8.6) years] underwent CPET on a cycle ergometer (40 W increments every 3 min until volitional fatigue). We used a principal component analysis based method to quantify ventilatory flow dynamics throughout the CPET protocol. Last minute of each increment, peak exercise, and recovery were examined using linear mixed models, which accounted for relative peak oxygen uptake and minute ventilation. The type 1 diabetes participants had lower expiratory peak flow (P = 0.008) and attenuated slope from expiration onset to expiratory peak flow (P = 0.012) at peak exercise when compared with the healthy controls. Instead, during submaximal exercise and recovery, the type 1 diabetes participants possessed similar ventilatory flow dynamics to that of the healthy controls. In conclusion, men with relatively well-controlled type 1 diabetes and without clinical evidence of diabetes-related complications exhibited attenuated expiratory flow at peak exercise independently of peak oxygen uptake and minute ventilation. This study demonstrates that acute exercise reveals alterations in ventilatory function in men with type 1 diabetes but not until peak exercise.

Interaction of polycyclic aromatic hydrocarbon exposure and high-fasting plasma glucose on lung function decline in coke oven workers: a cross-lagged panel analysis

Individuals with abnormal fasting plasma glucose (FPG) may be more susceptible to lung diseases associated with environmental pollutants. A cross-sectional survey of 629 workers in 2017 and a panel study of 304 workers from 2014 to 2019 were performed in China. The results showed that elevated total hydroxylated polycyclic aromatic hydrocarbon (ΣOH-PAH) concentration was associated with lower the percentage of predicted forced vital capacity (FVC%) among high-FPG workers (β for the cross-sectional analysis: -1.78%, 95%CI: -2.92%, -0.64%; β for the panel study: -1.10%, 95%CI: -2.19%, -0.02%). The absolute value of the cross-lagged path coefficient from FPG to FVC% (β₂ = -0.096) was significantly greater than that from FVC% to FPG (β₁ = 0.037). Our results suggest that FPG abnormalities may precede the lung function decline induced by PAH exposure and that high-FPG and high ΣOH-PAH levels have an interactive effect on lung function decline.

Effect of Glycated Hemoglobin (HbA1c) and Duration of Disease on Lung Functions in Type 2 Diabetic Patients

Diabetes mellitus is a highly challenging global health care problem. This study aimed to assess the effect of glycated hemoglobin (HbA1c) and duration of diabetes on lung function in type 2 diabetic patients and assess whether duration or high HbA1c is more noxious to damage the lung functions. A total of 202 participants, 101 patients with type 2 diabetes mellitus (T2DM), and 101 age-, gender-, height-, and weight-matched controlled subjects were recruited. The HbA1c was measured through a clover analyzer, and lung function test parameters were recorded by spirometry. The results revealed a significant inverse correlation between HbA1c and Vital Capacity (VC) (r = -0.221, p = 0.026), Forced Vital Capacity (FVC) (r = -0.261, p = 0.008), Forced Expiratory Volume in First Second (FEV1) (r = -0.272, p = 0.006), Forced Expiratory Flow 25% (FEF-25%) (r = -0.196, p = 0.050), Forced Expiratory Flow 50% (FEF-50%) (r = -0.223, p = 0.025), and Forced Expiratory Flow 75% (FEF-75%) (r = -0.169, p = 0.016). Moreover, FEV1 (p = 0.029), FEV1/FVC% (p = 0.006), FEF-50% (p = 0.001), and FEF-75% (p = 0.003) were significantly lower in the diabetic group with duration of disease 5-10 and >10 years compared to the control group. The overall results concluded that high HbA1c or uncontrolled diabetes mellitus has a more damaging effect on lung function impairment compared to the duration of diabetes mellitus. Physicians must regularly monitor the HbA1c level while treating diabetic patients, as good glycemic control is essential to minimize the complications of DM, including lung function impairment in patients with T2DM.

Effect of inspiratory muscle training on respiratory muscle strength and functional capacity in patients with type 2 diabetes mellitus: A randomized clinical trial

BACKGROUND

Type 2 diabetes mellitus (T2DM) is usually associated with respiratory manifestations including inspiratory muscle weakness which affects exercise capacity. The present study aimed to determine the effect of inspiratory muscle training (IMT) on inspiratory muscle strength and exercise capacity in patients with Type 2 diabetes mellitus (T2DM).

METHODS

This was a randomized controlled trial in patients with type 2 diabetes mellitus with no previous cardiopulmonary or neuromuscular diseases. Patients had no back pain. Patients were randomized into interventional or placebo groups. Sniff nasal inspiratory pressure (SNIP), maximum inspiratory pressure (MIP), and six-minute walking test (6MWT) were measured at baseline and 8 weeks post incremental inspiratory muscle training.

RESULTS

At baseline, interventional and placebo groups were similar in age, body mass index, sex inspiratory muscle strength, and exercise capacity. After 8 weeks of incremental inspiratory muscle training at 40% of MIP, the interventional group had a significant increase in the SNIP (mean difference: 18.5 ± 5.30 cm H2O vs 2.8 ± 4.8 cm H2O) and MIP (mean difference: 19.4 ± 4.3 Vs 5.4 ± 3.6 cm H2O) compared to the placebo group, respectively. The interventional group showed improvement in the 6MWT (mean difference: 70 ± 29 m vs 34 ± 24 m) compared to the placebo group, P < .05.

CONCLUSION

Incremental inspiratory muscle training increased the diaphragm strength in patients with T2DM and improved exercise capacity.

Impact of the severity of restrictive spirometric pattern on nutrition, physical activity, and quality of life: results from a nationally representative database

The general disease burden associated with the restrictive spirometric pattern (RSP) is substantial. However, the impact of RSP by its severity on general health problems and quality of life has not been well elucidated. This study aimed to analyse nutrition, physical activity, and quality of life in subjects who participated in the Korea National Health and Nutrition Examination Survey 2007–2016 according to severity of RSP. Participants were classified as subjects with normal spirometry, those with mild-to-moderate RSP, and those with severe RSP. Poor quality of life was defined as 25th percentile value on the EuroQoL five dimensions (Eq5D) questionnaire index, i.e., 0.90. This study included 23,615 subjects composed of 20,742 with normal spirometry, 2758 with mild-to-moderate RSP, and 115 with severe RSP. The subjects with severe RSP were more likely to have attained lower education levels, had a lower total caloric intake, had less physical activity, had experienced a higher prevalence of comorbidities, and poorer quality of life than those with normal spirometry (P < 0.001 for all). In multivariable analysis, subjects with a mild-to-moderate RSP and severe RSP were more likely to show decreased total calories (coefficient for change in calorie = − 56.6 kcal and − 286.7 kcal, respectively) than those with normal spirometry; subjects with mild-to-moderate RSP and those with severe RSP were 1.26 times and 1.96 times more likely, respectively, to have a poorer quality of life than those with normal spirometry. Additionally, subjects with mild-to-moderate RSP and those with severe RSP were 0.84 times and 0.36 times less likely, respectively, to have high-intensity physical activity than those with normal spirometry in univariable analysis. The trends of a poorer quality of life and physical activity were only significant in the male subgroups. In conclusion, our study revealed that the severity of general health problems and quality of life reductions are correlated with the severity of RSP, especially in males.

Type II diabetes accentuates diaphragm blood flow increases during submaximal exercise in the rat

We investigated the effect of type 2 diabetes mellitus (T2DM) on respiratory muscle blood flow (BF) during exercise. Using the Goto-Kakizaki (GK) rat model of T2DM, we hypothesized that diaphragm, intercostal and transverse abdominis BFs (radiolabeled microspheres) would be higher in male GK rats (n = 10) compared to healthy male Wistar controls (CON; n = 8) during submaximal exercise (20 m/min, 10 % grade). Blood glucose was significantly higher in GK (246 ± 29 mg/dL) compared to CON (103 ± 4 mg/dL; P < 0.01). Respiratory muscle BFs were not different at rest (P> 0.50). From rest to submaximal exercise, respiratory muscle BFs increased in both groups to all muscles (P < 0.01). During submaximal exercise GK rats had higher diaphragm BFs (GK: 189 ± 13; CON: 138 ± 14 mL/min/100 g, P < 0.01), and vascular conductance (GK: 1.4 ± 0.1; CON: 1.0 ± 0.1 mL/min/mmHg/100 g; P < 0.01) compared to CON. There were no differences in intercostal or transverse abdominis BF or VC during exercise (P> 0.15). These findings suggest that submaximal exercise requires a higher diaphragm BF and VC in T2DM compared to healthy counterparts.

Protective effect of exogenous hydrogen sulfide on diaphragm muscle fibrosis in streptozotocin-induced diabetic rats

IMPACT STATEMENT

Diabetes mellitus is a group of chronic metabolic disorders, which causes serious damage to a variety of organs, such as the retina, heart, and skeletal muscle. The diaphragm is an important skeletal muscle involved in respiration in mammals. Fibrosis of the diaphragm muscle affects its contractility, which in turn impairs respiratory function. Accumulating evidence suggests that exogenous hydrogen sulfide (H₂S) exhibits anti-fibrotic activity in diabetes mellitus, but whether and how H₂S exerts this anti-fibrotic effect in the diabetic diaphragm remains unclear. The current work for the first time reveals that exogenous H₂S attenuates hyperglycemia-induced fibrosis of the diaphragm muscle and strengthens diaphragmatic biomechanical properties in diabetes mellitus, and the mechanism may involve the alleviation of collagen deposition by suppression of the nucleotide-binding oligomerization domain-like receptor protein (NLRP) 3 inflammasome-mediated inflammatory reaction. Therefore, H₂S supplementation could be used as an efficient targeted therapy against the NLRP3 inflammasome in the diabetic diaphragm.

Respiratory Inflammation and Short-Term Ambient Air Pollution Exposures in Adult Beijing Residents with and without Prediabetes: A Panel Study

BACKGROUND

Accumulating evidence suggests that individuals with glucose metabolism disorders are susceptible to mortality associated with fine particles. However, the mechanisms remain largely unknown.

OBJECTIVES

We examined whether particle-associated respiratory inflammation differed between individuals with prediabetes and healthy control participants.

METHODS

Based on a panel study [A prospective Study COmparing the cardiometabolic and respiratory effects of air Pollution Exposure on healthy and prediabetic individuals (SCOPE)] conducted in Beijing between August 2013 and February 2015, fractional exhaled nitric oxide (FeNO) was measured from 112 participants at two to seven visits to indicate respiratory inflammation. Particulate pollutants-including particulate matter with an aerodynamic diameter of ≤2.5μm (PM2.5), black carbon (BC), ultrafine particles (UFPs), and accumulated-mode particles-were monitored continuously at a single central monitoring site. Linear mixed-effects models were used to estimate associations between ln-FeNO with pollutant concentrations at individual 1-h lags (up to 24 h) and with average concentrations at 8 and 24 h before the clinical visit. We evaluated glucose metabolism disorders as a potential modifier by comparing associations between participants with high vs. low average fasting blood glucose (FBG) and homeostasis model assessment insulin resistance (HOMA-IR) levels.

RESULTS

FeNO was positively associated with all pollutants, with the strongest associations for an interquartile range increase in 1-h lagged exposures (ranging from 21.3% for PM2.5 to 74.7% for BC). Associations differed significantly according to average HOMA-IR values when lagged 6-18 h for PM2.5, 15-19 h for BC, and 6-15 h for UFPs, with positive associations among those with HOMA-IR≥1.6 while associations were closer to the null or inverse among those with HOMA-IR<1.6. Associations between PM2.5 and FeNO were consistently higher among individuals with average FBG≥6.1 mmol/L vs. low FBG, with significant differences for multiple hourly lags.

DISCUSSION

Glucose metabolism disorders may aggravate respiratory inflammation following exposure to ambient particulate matter. https://doi.org/10.1289/EHP4906.

Atrophy of Diaphragm and Pectoral Muscles in Critically Ill Patients

WHAT WE ALREADY KNOW ABOUT THIS TOPIC

Muscle atrophy is common in the critically ill, and diaphragm atrophy occurs during mechanical ventilation. It is not known whether wasting of diaphragm and nondiaphragm muscle is related.

WHAT THIS ARTICLE TELLS US THAT IS NEW

Ultrasound was used for serial assessment of diaphragm and pectoral muscle in 97 critically ill patients. Diaphragm and pectoral atrophy occurred in 48% and 29%, respectively, and was associated with septic shock (diaphragm) and steroid use (pectoral); atrophy of the two muscle types appears unrelated.

BACKGROUND

Muscle atrophy occurs early during critical illnesses. Although diffuse, this atrophy may specifically affect the diaphragm under artificial inactivity accompanying invasive mechanical ventilation. The primary objective of this study was to highlight diaphragm atrophy during the first 5 days of critical illness. Monitoring of pectoral thickness (a nonpostural muscle with mainly phasic function) served as a control.

METHODS

Diaphragm and pectoral thicknesses were measured by ultrasound within the first 24 h of admission in 97 critically ill patients, including 62 on mechanical ventilation. Thirty-five patients were reexamined at day 5.

RESULTS

Baseline median (interquartile) values of diaphragm and pectoral thicknesses at day 1 were 2.4 (2.0, 2.9) and 5.9 (4.7, 7.2) mm, respectively (n = 97). Higher values of diaphragm thickness at baseline were positively associated with male sex, chronic obstructive pulmonary disease, and diabetes. Diaphragm and pectoral atrophies (defined as a decrease of 10% or more between day 1 and day 5) were detected in 48% (17 of 35) and 29% (10 of 34) respectively, and were uncorrelated with each other. Diaphragm atrophy was significantly more frequent in patients with septic shock and in those with mechanical ventilation, as compared with their respective counterparts (71% [10 of 14] vs. 33% [7 of 21], P = 0.027 and 71% [17 of 28] vs. 0% [0 of 7], P = 0.004, respectively), whereas pectoral atrophy was more common in patients treated with steroids as compared with their counterparts (58% [7 of 12] vs. 14% [3 of 22], P = 0.006). A statistically significant association between diaphragm atrophy and outcome was not found. Pectoral atrophy seemed associated with less successful weaning from mechanical ventilation at day 14 (12% [1 of 8] vs. 58% [11 of 19], P = 0.043).

CONCLUSIONS

Ultrasound enables identification of specific early diaphragm atrophy that affects the majority of mechanically ventilated patients and septic shock patients. Diaphragm atrophy and pectoral muscle atrophy seem to be two unrelated processes.

Circadian Clock and Sirtuins in Diabetic Lung: A Mechanistic Perspective

Diabetes-induced tissue injuries in target organs such as the kidney, heart, eye, liver, skin, and nervous system contribute significantly to the morbidity and mortality of diabetes. However, whether the lung should be considered a diabetic target organ has been discussed for decades. Accumulating evidence shows that both pulmonary histological changes and functional abnormalities have been observed in diabetic patients, suggesting that the lung is a diabetic target organ. Mechanisms underlying diabetic lung are unclear, however, oxidative stress, systemic inflammation, and premature aging convincingly contribute to them. Circadian system and Sirtuins have been well-documented to play important roles in above mechanisms. Circadian rhythms are intrinsic mammalian biological oscillations with a period of near 24 h driven by the circadian clock system. This system plays an important role in the regulation of energy metabolism, oxidative stress, inflammation, cellular proliferation and senescence, thus impacting metabolism-related diseases, chronic airway diseases and cancers. Sirtuins, a family of adenine dinucleotide (NAD⁺)-dependent histone deacetylases, have been demonstrated to regulate a series of physiological processes and affect diseases such as obesity, insulin resistance, type 2 diabetes (T2DM), heart disease, cancer, and aging. In this review, we summarize recent advances in the understanding of the roles of the circadian clock and Sirtuins in regulating cellular processes and highlight the potential interactions of the circadian clock and Sirtuins in the context of diabetic lung.

Type 2 Diabetes Mellitus, Glycated Hemoglobin Levels, and Cardiopulmonary Exercise Capacity in Patients With Ischemic Heart Disease

PURPOSE

Diabetes mellitus (DM) is associated with long-term cardiovascular complications, including ischemic heart disease (IHD). Nonetheless, DM may directly impair myocardial and lung structure and function. The aim of this study was to assess the impact of type 2 DM (T2DM) and glycemic control on cardiopulmonary exercise capacity in patients with IHD.

METHODS

The study involved a cross-sectional analysis of 91 consecutive patients (57 ± 10 yr, 90% men) who underwent a cardiopulmonary exercise test at the beginning of an exercise-based standard phase-II cardiac rehabilitation program, 2 to 3 mo after an acute coronary syndrome. Association of T2DM with cardiopulmonary exercise test parameters was assessed using multiple linear regression analysis controlling for prespecified potential confounders.

RESULTS

There were 26 (29%) diabetic subjects among IHD patients included in the study. After adjustment, T2DM was an independent predictor of a reduced peak oxygen uptake ((Equation is included in full-text article.)O2peak) (P = .005), a reduced pulse O2 trajectory (P = .001), a steeper minute ventilation to carbon dioxide output (VE/(Equation is included in full-text article.)CO2) slope (P = .046), and an increased dead space-to-tidal volume ratio (VD/VT) at peak exercise (P = .049). Glycated hemoglobin (HbA1c) levels were significantly associated with a reduced forced expiratory volume in the first second of expiration (FEV1) (P = .013), VE (P = .001), and VT (P = .007). (Equation is included in full-text article.)O2peak (P trend < .001), (Equation is included in full-text article.)O2 at anaerobic threshold (P trend < .001), and pulse O2 trajectory (P trend < .001) decreased among HbA1c tertiles.

CONCLUSIONS

Patients with IHD and a previous diagnosis of T2DM had a reduced aerobic capacity and a ventilation- perfusion mismatch compared with nondiabetic patients. Poor glycemic control in men further deteriorates aerobic capacity probably due to ventilatory inefficiency.

Diabetic lung, an underrated complication from restrictive functional pattern to pulmonary hypertension

In patients with type 1 and type 2 diabetes mellitus (DM), respiratory function abnormalities have been reported with regard to lung volumes, pulmonary diffusing capacity, control of ventilation, bronchomotor tone, and neuroadrenergic bronchial innervation. Indeed, the decrease in lung volumes and the impairment of diffusing capacity might have important clinical implications. Furthermore, there is an increasing evidence of a link between DM and pulmonary hypertension (PH) related to an involvement of the pulmonary vascular structures. These findings support the view of the lung as target organ in DM. In this paper, we briefly describe the main derangements of the respiratory system in DM and the inherent mechanisms.

Diabetic lung disease: fact or fiction?

Diabetes mellitus is a chronic, progressive, incompletely understood metabolic disorder whose prevalence has been increasing steadily worldwide. Even though little attention has been paid to lung disorders in the context of diabetes, its prevalence has recently been challenged by newer studies of disease development. In this review, we summarize and discuss the role of diabetes mellitus involved in the progression of pulmonary diseases, with the main focus on pulmonary fibrosis, which represents a chronic and progressive disease with high mortality and limited therapeutic options.

The association between glycemic control and lung function impairment in individuals with diabetes: the Saku study

Aim

Though diabetes is a risk factor for lung function impairment, whether the glycemic control level affects lung function in individuals with diabetes remains unclear. The present study aimed to assess the association between glycemic control level and restrictive or obstructive lung function impairment in individuals with diabetes.

Methods

This cross-sectional study included 1028 individuals with diabetes, aged 40-69 years, who underwent a medical checkup between April 2008 and March 2014. Hemoglobin A1c (HbA1c) was categorized as  < 6.9%, 7.0-7.9%, and  ≥ 8.0%. Restrictive and obstructive lung function impairment was defined by a forced vital capacity (FVC) < 80% predicted and a forced expiratory volume in 1 s to FVC ratio < 0.70.

Results

Of the participants, 8.7% and 6.3% were classified as having restrictive and obstructive lung function impairment, respectively. The multivariable-adjusted odds ratios and 95% confidence intervals for restrictive lung function impairment were 1.43 (0.84-2.42) in individuals with HbA1c 7.0-7.9%, and 2.42 (1.38-4.26) in individuals with HbA1c ≥ 8.0%, compared with those who had HbA1c < 6.9% (p for trend = 0.002). In contrast, glycemic control level was not associated with obstructive lung function impairment (p for trend = 0.749).

Conclusions

Poor glycemic control was associated with restrictive lung function impairment in individuals with diabetes. Good glycemic control would be important to minimize restrictive lung function impairment in individuals with diabetes.

Impairment of respiratory muscle strength in Berardinelli-Seip congenital lipodystrophy subjects

BACKGROUND

Berardinelli-Seip Congenital Generalized Lipodystrophy (BSCL) is an ultra-rare metabolic disease characterized by hypertriglyceridemia, hyperinsulinemia, hyperglycemia, hypoleptinemia, and diabetes mellitus. Although cardiovascular disturbances have been observed in BSCL patients, there are no studies regarding the Respiratory Muscle Strength (RMS) in this type of lipodystrophy. This study aimed to evaluate RMS in BSCL subjects compared with healthy subjects.

METHODS

Eleven individuals with BSCL and 11 healthy subjects matched for age and gender were included in this study. The Maximum Inspiratory Pressure (MIP), Maximum Expiratory Pressure (MEP), and Peripheral Muscle Strength (PMS) were measured for three consecutive years. BSCL subjects were compared to healthy individuals for MIP, MEP, and PMS. Correlations between PMS and MIP were also analyzed. The genetic diagnosis was performed, and sociodemographic and anthropometric data were also collected.

RESULTS

BSCL subjects showed significantly lower values for MIP and MEP (p <  0.0001 and p = 0.0002, respectively) in comparison to healthy subjects, but no changes in handgrip strength (p = 0.15). Additionally, we did not observe changes in MIP, MEP, and PMS two years after the first analysis, showing maintenance of respiratory dysfunction in BSCL subjects (p = 0.05; p = 0.45; p = 0.99). PMS and MIP were not correlated in these subjects (r = 0.56; p = 0.18).

CONCLUSION

BSCL subjects showed lower respiratory muscle strength when compared with healthy subjects; however, PMS was not altered. These findings were maintained at similar levels during the two years of evaluation. Our data reveal the first association of BSCL with the development of respiratory muscle weakness.

The effects of type 2 diabetes mellitus and its complications on physical and pulmonary functions: A case-control study

AIMS

This study was planned to determine the effects of type 2 diabetes mellitus (DM) and its complications on physical and pulmonary functions. Methods: A total of 110 individuals aged 40-65 years were included in the study, 58 with type 2 DM (study group) and 52 without DM (control group). Physical activity level, functional capacity, pulmonary function, and comorbidity levels were compared between the groups. Results: The mean age of the individuals was 52.42 ± 5.88 years. Six-minute walk test distance was 507.2 ± 51.70 m in the study group and 532.23 ± 50.32 m in the control group (p < 0.05, Cohen's d = 0.49). The pulmonary function test results of the study and control groups were determined as forced vital capacity (FVC) (%): 99.17 ± 14.13 and 104.65 ± 16.01 (p > 0.05), forced expiratory volume in one second (FEV1) (%): 96.78 ± 14.43 and 99.73 ± 15.80 (p > 0.05), and FEV1/FVC ratio: 81.97 ± 4.62 and 80.16 ± 5.27 (p > 0.05), respectively. The Charlson Comorbidity Index scores of the study and control groups were 1.83 ± 0.82 and 0.12 ± 0.32 (p < 0.05). Conclusions: Type 2 DM was associated with lower functional capacity and higher rates of comorbid diseases. Therefore, potential causes of these parameters should be considered in the rehabilitation of type 2 diabetic patients.

A prospective study of the impact of diabetes mellitus on restrictive and obstructive lung function impairment: The Saku study

BACKGROUND

To assess the impact of diabetes on restrictive and obstructive lung function impairment.

METHODS

This 5-year prospective study included 7524 participants aged 40-69years without lung function impairment at baseline who underwent a comprehensive medical check-up between April 2008 and March 2009 at Saku Central Hospital. Diabetes was defined by fasting plasma glucose ≥7.0mmol/l (126mg/dl), HbA1c≥6.5% (48mmol/mol), or a history of diabetes, as determined by interviews conducted by the physicians. Restrictive and obstructive lung function impairment were defined as forced vital capacity (FVC) <80% predicted and forced expiratory volume in 1s (FEV₁) to FVC ratio (FEV₁/FVC) <0.70, respectively. Participants were screened until they developed restrictive or obstructive lung function impairment or until March 2014.

RESULTS

During the follow-up period, 171 and 639 individuals developed restrictive and obstructive lung function impairment, respectively. Individuals with diabetes had a 1.6-fold higher risk of restrictive lung function impairment than those without diabetes after adjusting for sex, age, height, abdominal obesity, smoking status, exercise habits, systolic blood pressure, HDL-cholesterol, log-transformed high-sensitivity C-reactive protein, and baseline lung function [multivariable-adjusted HR and 95% CI; 1.57 (1.04-2.36)]. In contrast, individuals with diabetes did not have a significantly higher risk of obstructive lung function impairment [multivariable-adjusted HR and 95% CI; 0.93 (0.72-1.21)].

CONCLUSION

Diabetes was associated with restrictive lung function impairment but not obstructive lung function impairment.

Muscle grip strength is associated to reduced pulmonary capacity in patients with diabetes

AIM

This study investigates the role of muscle strength as a predictive factor for reduced pulmonary function in diabetes.

METHODS

Data from the NHANES 2011-2012 were analyzed. Lung function was assessed with spirometry (FEV1, FVC). Diabetes was assessed with an oral glucose tolerance test (OGTT), glycated hemoglobin (HbA1c), or fasting plasma glucose (FPG). Muscle strength was measured by a grip test using a handgrip dynamometer.

RESULTS

A total of 3521 people were suitable to be included for analysis in this study. Lung function was reduced in diabetes-after adjustment for covariates, the impact of diabetes on FVC was estimated as -331mL (SE 48) for known diabetes and -282mL (SE 41) for undiagnosed diabetes (P<0.001). Grip strength was also reduced in diabetes. After adjustment for covariates, the impact of diabetes was estimated as -5.9kg (SE 0.8) for known diabetes (P<0.001). An association between lung capacity and grip strength in people with known diabetes was observed (R=0.7, P<0.001). The adjusted impact on FVC from grip strength was estimated as 13.1mL (SE 3.4) per kg (P<0.001).

CONCLUSIONS

Muscle strength appears to be reduced in people with known diabetes, and this seems to affect the respiratory muscles as an independent factor.

The Influence of Clinically Diagnosed Neuropathy on Respiratory Muscle Strength in Type 2 Diabetes Mellitus

OBJECTIVES

This cross-sectional study investigated the influence of clinically diagnosed neuropathy (cdNP) on respiratory muscle strength in patients with type 2 diabetes mellitus (T2DM).

METHODS

110 T2DM patients and 35 nondiabetic healthy controls (≥60 years) were allocated to one of three groups depending on the presence of cdNP: T2DM without cdNP (D-; n = 28), T2DM with cdNP (D+; n = 82), and controls without cdNP (C; n = 35). Clinical neurological diagnostic examination consisted of Vibration Perception Threshold and Diabetic Neuropathy Symptom score. Respiratory muscle strength was registered by maximal Inspiratory and Expiratory Pressures (PI_max and PE_max), and respiratory function by Peak Expiratory Flow (PEF). Isometric Handgrip Strength and Short Physical Performance Battery were used to evaluate peripheral skeletal muscle strength and physical performance. Univariate analysis of covariance was used with age, level of physical activity, and body mass index as covariates.

RESULTS

PI_max, PE_max, and PEF were higher in C compared to D- and D+. Exploring more in detail, PI_max, PE_max, and PEF were significantly lower in D+ compared to C. PE_max and PEF were also significantly lower in D- versus C. Measures of peripheral muscle strength and physical performance showed less associations with cdNP and T2DM.

CONCLUSIONS

The presence of cdNP affects respiratory muscle strength in T2DM patients compared to healthy controls. Both cdNP and diabetes in themselves showed a distinctive impact on respiratory muscle strength and function; however, an accumulating effect could not be ascertained in this study. As commonly used measures of peripheral muscle strength and physical performance seemed to be less affected at the given time, the integration of PI_max, PE_max, and PEF measurements in the assessment of respiratory muscle weakness could be of added value in the (early) screening for neuropathy in patients with T2DM.

Pulmonary Function and Sleep Breathing: Two New Targets for Type 2 Diabetes Care

Population-based studies showing the negative impact of type 2 diabetes (T2D) on lung function are overviewed. Among the well-recognized pathophysiological mechanisms, the metabolic pathways related to insulin resistance (IR), low-grade chronic inflammation, leptin resistance, microvascular damage, and autonomic neuropathy are emphasized. Histopathological changes are exposed, and findings reported from experimental models are clearly differentiated from those described in humans. The accelerated decline in pulmonary function that appears in patients with cystic fibrosis (CF) with related abnormalities of glucose tolerance and diabetes is considered as an example to further investigate the relationship between T2D and the lung. Furthermore, a possible causal link between antihyperglycemic therapies and pulmonary function is examined. T2D similarly affects breathing during sleep, becoming an independent risk factor for higher rates of sleep apnea, leading to nocturnal hypoxemia and daytime sleepiness. Therefore, the impact of T2D on sleep breathing and its influence on sleep architecture is analyzed. Finally, the effect of improving some pathophysiological mechanisms, primarily IR and inflammation, as well as the optimization of blood glucose control on sleep breathing is evaluated. In summary, the lung should be considered by those providing care for people with diabetes and raise the central issue of whether the normalization of glucose levels can improve pulmonary function and ameliorate sleep-disordered breathing. Therefore, patients with T2D should be considered a vulnerable group for pulmonary dysfunction. However, further research aimed at elucidating how to screen for the lung impairment in the population with diabetes in a cost-effective manner is needed.

Hand Grip Strength And Peak Expiratory Flow Among Individuals With Diabetes: Findings From the China Health and Retirement Longitudinal Study Baseline Survey

The manifestation of muscle dysfunction associated with diabetes is commonly observed in skeletal muscles. The negative effect of hyperglycemia on muscle function is systemic and it may extend to abdominal muscles. Hence, the purpose of this study was to determine whether hand grip strength (HGS), an indicator of peripheral muscle strength, correlates with peak expiratory flow (PEF), which reflects the strength of abdominal muscles, among middle-aged and older Chinese individuals with diabetes. After controlling for all variables except for physical activity, 10 L/min increase in PEF was associated with 0.2 kg increase in HGS (β = .02, p < .0001). In the model additionally controlling for physical activity, the effect size of PEF on HGS did not change (β = .02, p < .0001). Our results suggest that among individuals with diabetes, PEF is positively related to HGS. The relationship may suggest a decline in PEF and a weakness of abdominal muscles.

Potential Biochemical Mechanisms of Lung Injury in Diabetes

Accumulating evidence has shown that the lung is one of the target organs for microangiopathy in patients with either type 1 or type 2 diabetes mellitus (DM). Diabetes is associated with physiological and structural abnormalities in the diabetic lung concurrent with attenuated lung function. Despite intensive investigations in recent years, the pathogenic mechanisms of diabetic lung injury remain largely elusive. In this review, we summarize currently postulated mechanisms of diabetic lung injury. We mainly focus on the pathogenesis of diabetic lung injury that implicates key pathways, including oxidative stress, non-enzymatic protein glycosylation, polyol pathway, NF-κB pathway, and protein kinase c pathway. We also highlight that while numerous studies have mainly focused on tissue or cell damage in the lung, studies focusing on mitochondrial dysfunction in the diabetic lung have remained sketchy. Hence, further understanding of mitochondrial mechanisms of diabetic lung injury should provide invaluable insights into future therapeutic approaches for diabetic lung injury.

Muscle fatigability in type 2 diabetes

BACKGROUND

Patients with type 2 diabetes (T2D) may be subject to premature muscle fatigue. However, the effect of diabetes on muscle fatigability has not yet been thoroughly examined. The purpose of this study was to investigate the effect of T2D on muscle fatigability at the upper and lower body.

METHODS

Thirty-three T2D patients (18 men and 15 women; mean age, 59.3 ± 5.3 years) and 34 matched healthy control participants (17 men and 17 women; mean age, 60.1 ± 6.1 years) were recruited. Clinical characteristics of diabetic patients were assessed by considering a wide range of vascular and neurological parameters in order to exclude the presence of micro- and macro-vascular complications. Gender-specific muscle function was evaluated measuring the maximal voluntary isometric contraction (MVIC), and the endurance time at 50% of the MVIC at the shoulder and at the knee extensor muscles.

RESULTS

Muscle strength in the upper body was similar among groups, whereas in the lower body, it was significantly reduced in T2D men (-16%) and women (-22%) compared with the controls. Additionally, the endurance time in both upper and lower body was significantly lower in T2D men (-18% and -29%) and women (-19% and -25%, respectively) than controls.

CONCLUSIONS

Besides the reduction in strength, muscle dysfunction in T2D is characterized by a higher fatigability that affects both upper and lower body muscles. This effect is independent to the presence of diabetic complications and may represent a more sensitive marker of muscular dysfunction than muscle strength. Copyright © 2016 John Wiley & Sons, Ltd.

Spirometric prediction equations and the relationship between metabolic syndrome and spirometric parameters from an island in Fujian, China

BACKGROUND

We investigated risk factors for decreased lung function among Chinese island residents (≥30 years) to determine the relationship between metabolic syndrome (MS) and decreased lung function.

METHODS

From October 17, 2011 to November 1, 2011, 2607 residents aged ≥30 years who lived on the Huangqi Peninsula of Fujian were enlisted by random cluster sampling. They completed a questionnaire designed according to the Burden of Obstructive Lung Disease (BOLD) questionnaire, and underwent physical examination, blood test, and lung function evaluation. We constructed spirometric prediction equations for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), determined the lower limits of normal for FVC, FEV1 and FEV1/FVC, and examined the relationship between lung function and MS.

RESULTS

Prediction equations for normal island residents were as follows: FVC (L) = -0.023 × age (years) + 0.042 × height (cm) + 0.641 × weight (kg) - 3.607 (males); FVC (L) = -0.017 × age (years) + 0.030 × height (cm) + 0.009 × weight (kg) - 1.741 (females); FEV1 (L) = -0.023 × age (years) + 0.040 × height (cm) + 0.010 × weight (kg) - 2.999 (males); FEV1 (L) = -0.017 × age (years) + 0.026 × height (cm) + 0.007 × weight (kg) -1.135 (females). The odds ratio for MS for increased risk of decreased FVC was 4.623 (95%CI =3.626-5.894, P<0.001), and for increased risk of decreased FEV1 was 3.043 (95%CI =2.447-3.785, P<0.001).

CONCLUSIONS

MS is a risk factor for decreased lung function in island residents ≥30 years old.

Type 2 diabetes affects sleep quality by disrupting the respiratory function

BACKGROUND

The effects of diabetes on the respiratory system were investigated with arterial blood gas, sleep quality index and respiratory functions tests.

METHODS

Fifty-three patients with type II diabetes and 41 healthy cases were included. Their biochemical data, demographic characteristics, anthropometric measurements and echocardiographic findings were collected from polyclinic records. Respiratory function tests were performed for all subjects and Pittsburgh Sleep Quality Index questionnaire was conducted. Aforementioned data were compared between these two groups.

RESULTS

The age, body weight and body mass index were similar but oxygen pressure, oxygen saturation, forced vital capacity (FVC; %), and sleep quality were decreased in patients with diabetes. Sleep quality was correlated with the presence of diabetes and hypertension, duration of diabetes, fasting and postprandial blood glucose levels, homeostasis model of assessment-insulin resistance, Glycosylated hemoglobin levels, and FVC. Half of the diabetic patients exhibited respiratory failure during sleep. Especially diabetic patients with autonomic neuropathy, experienced a more severe and prolonged decrease in oxygen saturation.

CONCLUSIONS

Blood gas, respiratory functions and sleep quality, which need to be evaluated as a whole, were affected in patients with diabetes. Assessment of sleep and its quality requires special attention in patients with diabetes.

High-mobility group box 1 enhances the inflammatory process in diabetic lung

Diabetes mellitus generates metabolic changes associated with inflammatory events that may eventually affect all body tissues. Both high-mobility group box 1 (HMGB1) and β-catenin are active players in inflammation. The study aimed to determine whether HMGB1 modulates the β-catenin activity in supporting inflammation, using an experimental type 1 diabetes mouse model. The protein and gene expression of HMGB1 were significantly increased (2-fold) in the diabetic lung compared to control and were positively correlated with the HMGB1 levels detected in serum. Co-immunoprecipitation of HMGB1 with RAGE co-exists with activation of PI3K/AKT1 and NF-kB signaling pathways. At the same time β-catenin was increased in nuclear fraction (3.5 fold) while it was down-regulated in diabetic plasma membrane (2-fold). There was no difference of β-catenin gene expression between the control and diabetic mice. β-Catenin phosphorylation at Ser552 was higher in diabetic nuclear fraction, suggesting that AKT1 activation promotes β-catenin nuclear translocation. In addition, c-Jun directly binds β-catenin indicating the transcriptional activity of β-catenin in diabetes, sustained by significantly COX2 increase by 6-fold in the cytosolic extract of diabetic lung compared to control. Taken together, the data support the new concept that HMGB1 maintains the inflammation through RAGE/AKT1/β-catenin pathway in the diabetic lung.

Inspiratory muscle training in patients with diabetic autonomic neuropathy: a randomized clinical trial

AIMS AND METHODS

We evaluated the effects of an 8-week inspiratory muscle training (IMT, n = 5) or placebo IMT (P-IMT, n = 5) on maximal respiratory pressures, pulmonary function, functional capacity, and cardiac autonomic control in patients with type 2 diabetes and diabetic autonomic neuropathy (DAN).

RESULTS AND CONCLUSIONS

The IMT group had a greater increase in maximum inspiratory pressure as compared to P-IMT (p < 0.05). The IMT improved inspiratory muscle strength in patients with DAN.

Decline of the lung function and quality of glycemic control in type 2 diabetes mellitus

OBJECTIVE

The aim of this study was to verify to which extent in type 2 diabetes mellitus respiratory function and respiratory muscle efficiency decline over time in relation to the quality of glycemic control (GC).

METHODS

Forty-five non-smoker diabetic patients without pulmonary diseases performed a complete respiratory function assessment at baseline and after a follow-up of 4.9±0.6 years. The respiratory muscle efficiency was assessed by maximal inspiratory pressure (MIP) and maximum voluntary ventilation (MVV). Patients with an average yearly value of glycosylated hemoglobin≥7.5% at least in two years during follow-up were considered to have a poor GC.

RESULTS

Residual volume and pulmonary diffusing capacity significantly declined over time in the whole sample of patients (p=0.049 and 0.025, respectively), but without difference between patients with poor (n. 12) and good (n. 33) GC. MIP declined in patients with poor GC (from 83.75±32.42 to 71.16±30.43% pred), and increased in those with good GC (from 76.22±26.00 to 82.42±30.34% pred), but the difference between groups was not significant (p=0.091). Finally, MVV significantly declined in patients with poor GC (from 70.60±25.49 to 68.10±18.82% pred) and increased in those with good GC (from 66.40±20.39 to 84.00±23.09% pred) with a significant difference between the two groups (p=0.003).

CONCLUSION

These results show that, in type 2 diabetic patients, respiratory muscle efficiency, but not lung volumes and diffusing capacity, might suffer from a poor GC over time.

Fixed airflow obstruction among nonsmokers with asthma:a case-comparison study

BACKGROUND

Airflow obstruction in asthma is usually reversible, but fixed obstruction develops in some individuals. Little is known about risk factors for development of fixed airflow obstruction in nonsmokers with asthma.

METHODS

This case-comparison study recruited nonsmokers aged over 45 years with physician-diagnosed asthma from specialist outpatient clinics and primary care. Two age-matched groups were recruited on the basis of spirometry: anobstructed group (post-bronchodilator FEV(1) ≤ 70% predicted, FEV1/FVC ratio < lower limit of normal) and a control group with normal lung function. Subjects completed a questionnaire and interview, and underwent spirometry, venesection, exhaled nitric oxide (ENO) measurement, allergen skinprick testing, and formal lung function testing.

RESULTS

Thirty-four obstructed subjects and 40 controls participated in the study. Obstructed subjects exhibited greater evidence of systemic inflammation, abnormal glucose homeostasis, and central obesity than controls. Obstructed subjects reported longer duration of asthma, and childhood respiratory infection was commoner in that group. Metabolic syndrome prevalence was similar between groups, but several features of insulin resistance were associated with reduced FEV(1). Cough and sputum were common among controls.

CONCLUSIONS

Risk of fixed airflow obstruction may correlate with lifetime asthma duration. Individuals with coexisting asthma and fixed airflow obstruction have heightened systemic inflammation. A variety of chronic respiratory symptoms are common among "healthy" nonsmokers with asthma.

Lung function changes in older people with metabolic syndrome and diabetes

AIM

Restrictive lung dysfunction (RLD; defined as reduced forced vital capacity [FVC] in the presence of normal forced expiratory volume in 1 s [FEV1]/FVC ratio) is highly prevalent in the elderly, and is associated with diabetes, metabolic syndrome (MetS) and abdominal obesity. The aim of this study was to assess the relative contribution of diabetes, MetS and abdominal obesity in characterizing RLD in the elderly.

METHODS

This was cross-sectional analysis of 192 consecutive, community-dwelling persons (mean age 70.8 ± 8 years). The participants were grouped according to the number of MetS components (i.e. 0, 1, 2, 3 or 4) and the presence of diabetes. According to the Adult Treatment Panel-III criteria, participants with three or four components were considered to be affected by MetS. Independent correlates of RLD and obstructive lung dysfunction (OLD; FEV1/FVC < 0.70) were assessed by logistic regression models.

RESULTS

The mean age of the sample population was 70.8 years. FVC expressed as percent of the predicted value declined for an increasing number of MetS components (P < 0.0001), but diabetes did not account for further ventilatory decline. Consistently, MetS (OR 3.03, 95% CI 1.16-7.89) and abdominal obesity (OR 4.89, 95% CI 1.17-20.3), but not diabetes, were independently associated with RLD. OLD did not worsen for an increasing number of MetS components and was only related to age (OR 1.07, 95% CI 1.01-1.13) and smoking (OR 1.04, 95% CI 1.01-1.06).

CONCLUSIONS

MetS and abdominal obesity, two conditions of prediabetes, but not diabetes itself, are closely associated with RLD. These conditions might be implicated in the pathogenesis of the RLD, which is frequently observed in diabetic patients.

Chronic obstructive pulmonary disease and glucose metabolism: a bitter sweet symphony

Chronic obstructive pulmonary disease, metabolic syndrome and diabetes mellitus are common and underdiagnosed medical conditions. It was predicted that chronic obstructive pulmonary disease will be the third leading cause of death worldwide by 2020. The healthcare burden of this disease is even greater if we consider the significant impact of chronic obstructive pulmonary disease on the cardiovascular morbidity and mortality. Chronic obstructive pulmonary disease may be considered as a novel risk factor for new onset type 2 diabetes mellitus via multiple pathophysiological alterations such as: inflammation and oxidative stress, insulin resistance, weight gain and alterations in metabolism of adipokines. On the other hand, diabetes may act as an independent factor, negatively affecting pulmonary structure and function. Diabetes is associated with an increased risk of pulmonary infections, disease exacerbations and worsened COPD outcomes. On the top of that, coexistent OSA may increase the risk for type 2 DM in some individuals. The current scientific data necessitate a greater outlook on chronic obstructive pulmonary disease and chronic obstructive pulmonary disease may be viewed as a risk factor for the new onset type 2 diabetes mellitus. Conversely, both types of diabetes mellitus should be viewed as strong contributing factors for the development of obstructive lung disease. Such approach can potentially improve the outcomes and medical control for both conditions, and, thus, decrease the healthcare burden of these major medical problems.

The diabetic lung--a new target organ?

Several abnormalities of the respiratory function have been reported in patients with type 1 and type 2 diabetes. These abnormalities concern lung volume, pulmonary diffusing capacity, control of ventilation, bronchomotor tone, and neuroadrenergic bronchial innervation. Many hypotheses have emerged, and characteristic histological changes have been described in the "diabetic lung", which could explain this abnormal respiratory function. Given the specific abnormalities in diabetic patients, the lung could thus be considered as a target organ in diabetes. Although the practical implications of these functional changes are mild, the presence of an associated acute or chronic pulmonary and/or cardiac disease could determine severe respiratory derangements in diabetic patients. Another clinical consequence of the pulmonary involvement in diabetes is the accelerated decline in respiratory function. The rate of decline in respiratory function in diabetics has been found to be two-to-three times faster than in normal non-smoking subjects, as reported in longitudinal studies. This finding, together with the presence of anatomical and biological changes similar to those described in the aging lung, indicates that the "diabetic lung" could even be considered a model of accelerated aging. This review describes and analyses the current insight into the relationship of diabetes and lung disease, and suggests intensifying research into the lung as a possible target organ in diabetes.