Therapeutic treatment with phosphodiesterase-4 inhibitors alleviates kidney injury and renal fibrosis by increasing MMP-9 in a doxorubicin-induced nephrotoxicity mouse model

Nephrotic syndrome (NS) is associated with kidney dysfunction and is an important cause of morbidity and mortality in industrialized countries. Here, we evaluated the effects of the phosphodiesterase-4 (PDE-4) inhibitors rolipram and roflumilast on a doxorubicin-induced NS model. Early-stage rolipram treatment preserved glomerular filtration barrier function, as indicated by reduced serum protein and albumin loss and the prevention of hypercholesterolemia. These effects were associated with reduced glomerular and tubular lesions and abrogated renal cell apoptosis. In addition, rolipram treatment reduced inflammation, which was characterized by a decrease in macrophage accumulation and reduced levels of CCL2 and TNF in the kidneys. Rolipram also reduced renal fibrosis, which was associated with decreased α-smooth muscle actin (α-SMA) area and increased metalloproteinase 9 (MMP9) activity in renal tissue. Late-stage rolipram or roflumilast treatment preserved glomerular filtration barrier function, as characterized by reduced serum albumin loss, decreased proteinuria, and the prevention of hypercholesterolemia. Importantly, only roflumilast treatment was associated with a reduction in glomerular and tubular lesions at this time point. In addition, both rolipram and roflumilast reduced renal tissue fibrosis and MMP9 activity in renal tissue.

A Single Bout of Fatiguing Aerobic Exercise Induces Similar Pronounced Immunological Responses in Both Sexes

Introduction: Physical exercise can acutely and chronically modulate immunological responses. Women and men have different innate and adaptive immune responses, and in this sense, these two groups may also have different acute immunological responses induced by exercise. In addition, it is essential to understand further whether the effects of physical exercise on the immune system responses depend on sex because limited scientific evidence on this topic is available. This information may allow athletes and coaches to improve the training process, mainly to understand if the physiological impact of given training stimuli in women is similar to that in men.

Objective: The present study aimed to investigate the acute effects of continuous submaximal exercise until fatigue on physiological and immunological parameters in amateur female and male runners.

Methods: This study included 18 female and 15 male volunteers. Each participant visited the laboratory on four consecutive days. The first visit consisted of medical history taking and explaining the study design. On the second visit, the participants were subjected to an incremental test to determine their maximal rate of oxygen consumption (VO_2max) that was required to prescribe the intensity of the submaximal exercise protocol. On the third visit, the fatiguing exercise protocol was performed at 77%–80% of the VO_2max. During this submaximal exercise, the heart rate, rating of perceived exertion (RPE), and blood lactate were recorded. Blood samples were collected before, immediately after, and 1 h after the fatiguing protocol to analyze the plasma levels of cytokines and creatine kinase (CK) and to count leukocytes. Finally, on the fourth visit, the participants underwent physical evaluations to measure their body composition using dual-energy X-ray absorptiometry (DXA) imaging.

Results: The average ages of the female and male groups were 34.2 ± 3.7 and 30.5 ± 4.3 years old, respectively. The female group ran 57 ± 27 min, while the male group ran 52 ± 15 min before fatiguing. In the female group, when comparing before and after the submaximal exercise, marked increases were observed in the following variables: heart rate (from 68.5 to 180.4 bpm), RPE (from 3.6 to 8.2), lactate (from 2.1 to 4.49 mmol/L), and CK (from 89.5 to 126.3 U/L). In addition, the female group showed an increased number of total leukocytes (from 7222.3 to 11162.9 × 10⁶/μl), neutrophils (from 4,403 to 6,480 × 10⁶/μl), and lymphocytes (from 2,342 ± to 3,562 × 10⁶/μl) from pre- to post-submaximal exercise. In the male group, similar elevations in psychophysiological variables were observed, as evidenced by comparing the heart rate (from 52.8 to 184.1 bpm), RPE (from 0.0 to 8.9), lactate (from 2.7 to 7.2 mmol/L), and CK (from 106.2 to 165 U/L) before and after the submaximal exercise. The male group also showed an augmented number of total leukocytes (from 6,245 to 8,050 × 10⁶/μl), neutrophils (from 3,335 to 4,128 × 10⁶/), and lymphocytes (from 2,191 to 3,212 × 10⁶/μl) when comparing pre- and post-submaximal exercise. There were no differences in the changes between women and men for these parameters.

Conclusion: The aerobically fatiguing exercise protocol induced pronounced changes in the heart rate, plasma levels of lactate and CK, total leukocyte count, especially the number of neutrophils and lymphocytes, in both sexes. The fatiguing exercise protocol also changed the plasma levels of IL-6 and IL-10 in the female and male groups. Under the present conditions, the physiological changes induced by fatiguing submaximal exercise, including the immunological changes, were not influenced by sex. This study shows that the same aerobic physical exercise can alter immunological parameters in women and men, and this response is similar between sexes.

Biochanin A Regulates Key Steps of Inflammation Resolution in a Model of Antigen-Induced Arthritis via GPR30/PKA-Dependent Mechanism

Biochanin A (BCA) is a natural organic compound of the class of phytochemicals known as flavonoids and isoflavone subclass predominantly found in red clover (Trifolium pratense). It has anti-inflammatory activity and some pro-resolving actions, such as neutrophil apoptosis. However, the effect of BCA in the resolution of inflammation is still poorly understood. In this study, we investigated the effects of BCA on the neutrophilic inflammatory response and its resolution in a model of antigen-induced arthritis. Male wild-type BALB/c mice were treated with BCA at the peak of the inflammatory process (12 h). BCA decreased the accumulation of migrated neutrophils, and this effect was associated with reduction of myeloperoxidase activity, IL-1β and CXCL1 levels, and the histological score in periarticular tissues. Joint dysfunction, as seen by mechanical hypernociception, was improved by treatment with BCA. The resolution interval (Ri) was also quantified, defining profiles of acute inflammatory parameters that include the amplitude and duration of the inflammatory response monitored by the neutrophil infiltration. BCA treatment shortened Ri from ∼23 h observed in vehicle-treated mice to ∼5.5 h, associated with an increase in apoptotic events and efferocytosis, both key steps for the resolution of inflammation. These effects of BCA were prevented by H89, an inhibitor of protein kinase A (PKA) and G15, a selective G protein–coupled receptor 30 (GPR30) antagonist. In line with the in vivo data, BCA also increased the efferocytic ability of murine bone marrow–derived macrophages. Collectively, these data indicate for the first time that BCA resolves neutrophilic inflammation acting in key steps of the resolution of inflammation, requiring activation of GPR30 and via stimulation of cAMP-dependent signaling.

Effect of Physical Training on Exercise-Induced Inflammation and Performance in Mice

Acute exercise increases the amount of circulating inflammatory cells and cytokines to maintain physiological homeostasis. However, it remains unclear how physical training regulates exercise-induced inflammation and performance. Here, we demonstrate that acute high intensity exercise promotes an inflammatory profile characterized by increased blood IL-6 levels, neutrophil migratory capacity, and leukocyte recruitment to skeletal muscle vessels. Moreover, we found that physical training amplified leukocyte-endothelial cell interaction induced by acute exercise in skeletal muscle vessels and diminished exercise-induced inflammation in skeletal muscle tissue. Furthermore, we verified that disruption of the gp-91 subunit of NADPH-oxidase inhibited exercise-induced leukocyte recruitment on skeletal muscle after training with enhanced exercise time until fatigue. In conclusion, the training was related to physical improvement and immune adaptations. Moreover, reactive oxygen species (ROS) could be related to mechanisms to limit aerobic performance and its absence decreases the inflammatory response elicited by exercise after training.

Neutrophil activity in sepsis: a systematic review

The neutrophil is an important cell in host defense against infections, acting as the first line of microorganism control. However, this cell exhibits dysregulated activity in sepsis and may contribute to the pathogenesis of the disease. This systematic review aimed to highlight the major scientific findings regarding neutrophil activity in sepsis reported in clinical and experimental research published in the last 10 years. The search was conducted in the Virtual Health Library of PAHO-WHO (BVS) and PubMed databases, and articles published between January 2007 and May 2017 in Portuguese, English, and Spanish were eligible. Article selection was carried out independently by two reviewers (CB and IB). A total of 233 articles were found, of which 87 were identified on PubMed and 146 on BVS. Eighty-two articles were duplicates. Of the remaining 151 articles, 19 met the inclusion criteria after title, abstract, and full-text analysis. Overall, research in clinical samples and animal models of sepsis showed reduced capacity of neutrophils to migrate and delayed apoptosis, but there was no consensus on the phagocytic activity of neutrophils in sepsis. Molecules, such as pentraxin 3 (PTX3), have been analyzed as potential diagnostic markers in sepsis but the diversity of soluble molecules detected in blood samples of sepsis patients did not enable further understanding of the correlation of these circulating molecules with neutrophil activity during sepsis. Optimal understanding of the function of neutrophils in sepsis remains a challenge that, if overcome, would eventually allow targeted therapeutic interventions in patients affected by this severe syndrome.

Sensory Ganglia-Specific TNF Expression Is Associated With Persistent Nociception After Resolution of Inflammation

Joint pain is a distressing symptom of arthritis, and it is frequently persistent even after treatments which reduce local inflammation. Continuous production of algogenic factors activate/sensitize nociceptors in the joint structures and contribute to persistent pain, a challenging and difficult condition to treat. TNF is a crucial cytokine for the pathogenesis of several rheumatic diseases, and its inhibition is a mainstay of treatment to control joint symptoms, including pain. Here, we sought to investigate the inflammatory changes and the role of TNF in dorsal root ganglia (DRG) during persistent hypernociception after the resolution of acute joint inflammation. Using a model of antigen-induced arthritis, the peak of joint inflammation occurred 12–24 h after local antigen injection and was characterized by an intense influx of neutrophils, pro-inflammatory cytokine production, and joint damage. We found that inflammatory parameters in the joint returned to basal levels between 6 and 8 days after antigen-challenge, characterizing the resolving phase of joint inflammation. Mechanical hyperalgesia was persistent up to 14 days after joint insult. The persistent nociception was associated with the inflammatory status of DRG after cessation of acute joint inflammation. The late state of neuroinflammation in the ipsilateral side was evidenced by gene expression of TNF, TNFR2, IL-6, IL-1β, CXCL2, COX2, and iNOS in lumbar DRG (L3-L5) and leukocyte adhesion in the lumbar intumescent vessels between days 6 and 8. Moreover, there were signs of resident macrophage activation in DRG, as evidenced by an increase in Iba1-positive cells. Intrathecal or systemic injection of etanercept, an agent clinically utilized for TNF neutralization, at day 7 post arthritis induction, alleviated the persistent joint hyperalgesia by specific action in DRG. Our data suggest that neuroinflammation in DRG after the resolution of acute joint inflammation drives continuous neural sensitization resulting in persistent joint nociception in a TNF-dependent mechanism.