Hydrocellular foam dressing increases the leptin level in wound fluid

Hydrocellular foam dressing (HCF) absorbs excessive wound fluid, which contains various cytokines and growth factors, and ensures a moist environment to promote wound healing. However, the molecular mechanisms underlying the wound fluid component changes induced by HCF are poorly understood. In the present study, we examined the effect of HCF on wound healing and the associated regulatory mechanisms in relation to variations in cytokine levels in the wound fluid. We created full‐thickness wounds on the dorsolateral skin of rats and collected the resulting wound fluid samples. HCF was immersed in a plate containing the wound fluids. HCF was then removed and the excess wound fluid remaining in the plate was examined by cytokine array and enzyme‐linked immunosorbent assay. We also used a rat model and human dermal fibroblast cultures to examine the effect of wound fluid component changes during the wound healing process. Upon treatment with HCF, leptin levels were upregulated in the wound fluid. Fibroblast proliferation was enhanced and the effect was suppressed in the presence of leptin antagonist. In our in vivo model, HCF increased wound contraction compared with film dressings and this positive effect of HCF was suppressed by addition of leptin antagonist. Our results suggest that dermal fibroblast proliferation is upregulated by HCF due to increased leptin level at the wound surface, and these effects promote wound healing. We believe that the present study contributes to furthering the understanding of the mechanisms underlying the effects of HCF‐induced wound healing.     

Clinical usage of serum ferritin to assess liver fibrosis in patients with non‐alcoholic fatty liver disease: Proceed with caution

Serum ferritin was recently reported to have low diagnostic accuracy for the detection of advanced fibrosis in patients with non‐alcoholic fatty liver disease (NAFLD). To corroborate these findings, we investigated the diagnostic accuracy of serum ferritin levels for detecting liver fibrosis in NAFLD patients utilizing a large Japanese cohort database. A total 1201 biopsy‐proven NAFLD patients, seen between 2001 and 2013, were enrolled into the Japan Study Group of NAFLD. Analysis was performed on data from this cohort comparing between serum ferritin levels and hepatic histology. Serum ferritin increased with increasing histological grade of steatosis, lobular inflammation and ballooning. Multivariate analyses revealed that sex differences, steatotic grade and fibrotic stage were independently associated with serum ferritin levels (P < 0.0001, <0.0001, 0.0248, respectively). However, statistical analyses performed using serum ferritin levels demonstrated that the area under the receiver–operator curve for detecting fibrosis was not adequate for rigorous prediction. Several factors including sex differences, steatosis and fibrosis were found to correlate with serum ferritin levels. Therefore, serum ferritin may have low diagnostic accuracy for specifically detecting liver fibrosis in NAFLD patients due to the involvement of multiple hepatocellular processes.     

Loss of Miro1-directed mitochondrial movement results in a novel murine model for neuron disease

Defective mitochondrial distribution in neurons is proposed to cause ATP depletion and calcium-buffering deficiencies that compromise cell function. However, it is unclear whether aberrant mitochondrial motility and distribution alone are sufficient to cause neurological disease. Calcium-binding mitochondrial Rho (Miro) GTPases attach mitochondria to motor proteins for anterograde and retrograde transport in neurons. Using two new KO mouse models, we demonstrate that Miro1 is essential for development of cranial motor nuclei required for respiratory control and maintenance of upper motor neurons required for ambulation. Neuron-specific loss of Miro1 causes depletion of mitochondria from corticospinal tract axons and progressive neurological deficits mirroring human upper motor neuron disease. Although Miro1-deficient neurons exhibit defects in retrograde axonal mitochondrial transport, mitochondrial respiratory function continues. Moreover, Miro1 is not essential for calcium-mediated inhibition of mitochondrial movement or mitochondrial calcium buffering. Our findings indicate that defects in mitochondrial motility and distribution are sufficient to cause neurological disease.Motor neuron diseases (MNDs), including ALS and spastic paraplegia (SP), are characterized by the progressive, length-dependent degeneration of motor neurons, leading to muscle atrophy, paralysis, and, in some cases, premature death. There are both inherited and sporadic forms of MNDs, which can affect upper motor neurons, lower motor neurons, or both. Although the molecular and cellular causes of most MNDs are unknown, many are associated with defects in axonal transport of cellular components required for neuron function and maintenance (1–6).A subset of MNDs is associated with impaired mitochondrial respiration and mitochondrial distribution. This observation has led to the hypothesis that neurodegeneration results from defects in mitochondrial motility and distribution, which, in turn, cause subcellular ATP depletion and interfere with mitochondrial calcium ([Ca²⁺]_m) buffering at sites of high synaptic activity (reviewed in ref. 7). It is not known, however, whether mitochondrial motility defects are a primary cause or a secondary consequence of MND progression. In addition, it has been difficult to isolate the primary effect of mitochondrial motility defects in MNDs because most mutations that impair mitochondrial motility in neurons also affect transport of other organelles and vesicles (1, 8–11).In mammals, the movement of neuronal mitochondria between the cell body and the synapse is controlled by adaptors called trafficking kinesin proteins (Trak1 and Trak2) and molecular motors (kinesin heavy chain and dynein), which transport the organelle in the anterograde or retrograde direction along axonal microtubule tracks (7, 12–24). Mitochondrial Rho (Miro) GTPase proteins are critical for transport because they are the only known surface receptors that attach mitochondria to these adaptors and motors (12–15, 18, 25, 26). Miro proteins are tail-anchored in the outer mitochondrial membrane with two GTPase domains and two predicted calcium-binding embryonic fibroblast (EF) hand motifs facing the cytoplasm (12, 13, 25, 27, 28). A recent Miro structure revealed two additional EF hands that were not predicted from the primary sequence (29). Studies in cultured cells suggest that Miro proteins also function as calcium sensors (via their EF hands) to regulate kinesin-mediated mitochondrial “stopping” in axons (15, 16, 26). Miro-mediated movement appears to be inhibited when cytoplasmic calcium is elevated in active synapses, effectively recruiting mitochondria to regions where calcium buffering and energy are needed. Despite this progress, the physiological relevance of these findings has not yet been tested in a mammalian animal model. In addition, mammals ubiquitously express two Miro orthologs, Miro1 and Miro2, which are 60% identical (12, 13). However, the individual roles of Miro1 and Miro2 in neuronal development, maintenance, and survival have no been evaluated.We describe two new mouse models that establish the importance of Miro1-mediated mitochondrial motility and distribution in mammalian neuronal function and maintenance. We show that Miro1 is essential for development/maintenance of specific cranial neurons, function of postmitotic motor neurons, and retrograde mitochondrial motility in axons. Loss of Miro1-directed retrograde mitochondrial transport is sufficient to cause MND phenotypes in mice without abrogating mitochondrial respiratory function. Furthermore, Miro1 is not essential for calcium-mediated inhibition of mitochondrial movement or [Ca²⁺]_m buffering. These findings have an impact on current models for Miro1 function and introduce a specific and rapidly progressing mouse model for MND.     

Circadian clock signals in the adrenal cortex

Circadian secretion of steroid hormones by the adrenal cortex is required to maintain whole body homeostasis and to adequately respond to or anticipate environmental changes. The richly vascularized zona glomerulosa (ZG) cells in the pericapsular region regulate osmotic balance of body fluid by secreting mineralocorticoids responding to circulating bioactive substances, and more medially located zona fasciculata (ZF) cells regulate energy supply and consumption by secreting glucocorticoids under neuronal and hormonal regulation. The circadian clock regulates both steroidogenic pathways: the clock within the ZG regulates mineralocorticoid production via controlling rate-limiting synthetic enzymes, and the ZF secretes glucocorticoid hormones into the systemic circulation under the control of central clock in the suprachiasmatic nucleus. A functional biological clock at the systemic and cellular levels is therefore necessary for steroid synthesis and secretion.     

The observational study of delayed wound healing after tooth extraction in patients receiving oral bisphosphonate therapy

IntroductionIn this study, we investigated whether such a discontinuation of oral bisphosphonate (BP) for 3 months might influence the incidence of BP-related osteonecrosis of the jaw (BRONJ) and wound healing after tooth extraction in patients receiving oral BP therapy.Material and methodsThere were a total of 434 teeth in 201 patients (18 males and 183 females). The patients were divided into two groups depending on whether or not they underwent a 3-month discontinuation of BP therapy (BP? and BP+) before tooth extraction. In this observational study investigated delayed wound healing after tooth extraction in patients receiving oral BP therapy.ResultsIn all cases of the BP? group, there were no BRONJ although there was delayed wound healing in two cases. However, in one case of the BP+ group, oral BP was continued because it was deemed high risk to discontinue treatment by the patient's physician. In this case, an intraoral fistula was still present with bone exposure at 120 weeks after extraction (BRONJ stage 1).ConclusionThis study supports the idea of a drug holiday and encourages further clinical research on this topic of tooth extraction in patients receiving oral BP therapy.     

Comparison of PPIs and H2-receptor antagonists plus prokinetics for dysmotility-like dyspepsia

AIM: To compare efficacy of proton pump inhibitors (PPIs) with H₂-receptor antagonists (H₂RAs) plus prokinetics (Proks) for dysmotility-like symptoms in functional dyspepsia (FD).METHODS: Subjects were randomized to receive open-label treatment with either rabeprazole 10 mg od (n = 57) or famotidine 10 mg bid plus mosapride 5 mg tid (n = 57) for 4 wk. The primary efficacy endpoint was change (%) from baseline in total dysmotility-like dyspepsia symptom score. The secondary efficacy endpoint was patient satisfaction with treatment.RESULTS: The improvement in dysmotility-like dyspepsia symptom score on day 28 was significantly greater in the rabeprazole group (22.5% ± 29.2% of baseline) than the famotidine + mosapride group (53.2% ± 58.6% of baseline, P < 0.0001). The superior benefit of rabeprazole treatment after 28 d was consistent regardless of Helicobacter pylori status. Significantly more subjects in the rabeprazole group were satisfied or very satisfied with treatment on day 28 than in the famotidine + mosapride group (87.7% vs 59.6%, P = 0.0012). Rabeprazole therapy was the only significant predictor of treatment response (P < 0.0001), defined as a total symptom score improvement ≥ 50%.CONCLUSION: PPI monotherapy improves dysmotility-like symptoms significantly better than H₂RAs plus Proks, and should be the treatment of first choice for Japanese FD.     

Motor vehicle accidents: How should cirrhotic patients be managed?

Motor vehicle accidents (MVAs) are serious social issues worldwide and driver illness is an important cause of MVAs. Minimal hepatic encephalopathy (MHE) is a complex cognitive dysfunction with attention deficit, which frequently occurs in cirrhotic patients independent of severity of liver disease. Although MHE is known as a risk factor for MVAs, the impact of diagnosis and treatment of MHE on MVA-related societal costs is largely unknown. Recently, Bajaj et al demonstrated valuable findings that the diagnosis of MHE by rapid screening using the inhibitory control test (ICT), and subsequent treatment with lactulose could substantially reduce the societal costs by preventing MVAs. Besides the ICT and lactulose, there are various diagnostic tools and therapeutic strategies for MHE. In this commentary, we discussed a current issue of diagnostic tools for MHE, including neuropsychological tests. We also discussed the advantages of the other therapeutic strategies for MHE, such as intake of a regular breakfast and coffee, and supplementation with zinc and branched chain amino acids, on the MVA-related societal costs.