Optoacoustic detection of tissue glycation

Oxidative-based diseases including diabetes, chronic renal failure, cardiovascular diseases and neurological disorders are accompanied by accumulation of advanced glycation endproducts (AGE). Therefore, AGE-associated changes in tissue optical properties could yield a viable pathological indicator for disease diagnostics and monitoring. We investigated whether skin glycation could be detected based on absorption changes associated with AGE accumulation using spectral optoacoustic measurements and interrogated the optimal spectral band for skin glycation determination. Glycated and non-glycated skin was optoacoustically measured at multiple wavelengths in the visible region. The detected signals were spectrally processed and compared to measurements of skin auto-fluorescence and to second harmonic generation multiphoton microscopy images. Optoacoustic measurements are shown to be capable of detecting skin glycolysis based on AGE detection. A linear dependence was observed between optoacoustic intensity and the progression of skin glycation. The findings where corroborated by autofluorescence observations. Detection sensitivity is enhanced by observing normalised tissue spectra. This result points to a ratiometric method for skin glycation detection, specifically at 540 nm and 620 nm. We demonstrate that optoacoustic spectroscopy could be employed to detect AGE accumulation, and possibly can be employed as a non-invasive quick method for monitoring tissue glycation.OCIS codes: (110.5125) Photoacoustics, (170.5810) Scanning microscopy, (170.6510) Spectroscopy, tissue diagnostics, (180.4315) Nonlinear microscopy     

Guanylyl cyclase is an ATP sensor coupling nitric oxide signaling to cell metabolism

Defending cellular integrity against disturbances in intracellular concentrations of ATP ([ATP](i)) is predicated on coordinating the selection of substrates and their flux through metabolic pathways (metabolic signaling), ATP transfer from sites of production to utilization (energetic signaling), and the regulation of processes consuming energy (cell signaling). Whereas NO and its receptor, soluble guanylyl cyclase (sGC), are emerging as key mediators coordinating ATP supply and demand, mechanisms coupling this pathway with metabolic and energetic signaling remain undefined. Here, we demonstrate that sGC is a nucleotide sensor whose responsiveness to NO is regulated by [ATP](i). Indeed, ATP inhibits purified sGC with a K(i) predicting >60% inhibition of NO signaling in cells maintaining physiological [nucleotide](i). ATP inhibits sGC by interacting with a regulatory site that prefers ATP > GTP. Moreover, alterations in [ATP](i), by permeabilization and nucleotide clamping or inhibition of mitochondrial ATP synthase, regulate NO signaling by sGC. Thus, [ATP](i) serves as a "gain control" for NO signaling by sGC. At homeostatic [ATP](i), NO activation of sGC is repressed, whereas insults that reduce [ATP](i,) derepress sGC and amplify responses to NO. Hence, sGC forms a key synapse integrating metabolic, energetic, and cell signaling, wherein ATP is the transmitter, allosteric inhibition the coupling mechanism, and regulated accumulation of cGMP the response.     

Chlorophyll derivatives can be an efficient weapon in the fight against dengue

Dengue, a mosquito-borne viral infection, is one of the major public health concerns in the tropical and subtropical regions of the world. Approximately, 2.5 billion people across the world are at risk from dengue and 50 to 100 million new infections of dengue occur annually. There is yet no vaccine or medicine available against dengue, and treatment remains only supportive. Targeting its vector by a combination of biological and chemical approaches and management of breeding sites are currently the only existing approaches to control or eliminate dengue. Chlorophyll derivatives like chlorophyllin and pheophorbide have been reported as effective natural photosensitizers against larvae of several insects including flies. Chlorophyll derivatives were also reported effective against larval stages of freshwater snails as well as against certain parasites of fish. This article briefly discusses the possible application of chlorophyll derivatives in controlling dengue vectors and hence the disease itself. Chlorophyll derivatives can prove to be a good contributor in an integrated approach against dengue.     

The effects of fetal allogeneic umbilical cord tissue transplant following experimental spinal cord injury on urinary bladder morphology

Background and purposeIn continuation of our previous experimental study on spinal cord injury (SCI) using fetal stem cells, we investigated here the effects of fetal allogeneic umbilical cord tissue transplant on the urinary bladder morphology in a rat SCI model.Material and methodsFive pregnant albino Wistar rats at 12 days of gestation were used to obtain the umbilical cord cell graft. In Group 1 (n = 5), Th8-Th9 laminectomy was performed. Group 2 (n = 5) received spinal cord injury. In Group 3 (n = 5), the cultured fetal umbilical cord cells coated with alginate gel were placed into the lesion cavity. In Group 4 (n = 5), only alginate sponges without umbilical cord cells were placed into the injury cavity. The bladders of animals were analyzed pathologically at 21 days after surgery.ResultsThe thickness of the epithelium and the lamina propria did not differ among studied groups (p > 0.05). The lamina muscularis thickness was significantly higher in Group 2 and Group 4 than the others (p < 0.05). The bladder weight was similar among Groups 1, 2, and 3 (p > 0.05). Fibrosis was significantly increased in Group 2 (p < 0.05); it was greater in Group 2 than in Group 3 (p < 0.05) but did not differ between Groups 1 and 3 (p > 0.05).ConclusionsThis study suggests that allogeneic umbilical cord tissue transplantation after SCI may prevent bladder wall hypertrophy and fibrosis in the rat SCI model.