Bioactives from Marine Organisms and their Potential Role as Matrix Metalloproteinase Inhibitors

Recent research has revealed the role of metalloproteinases in a number of severe pathological illnesses, including cardiac, cartilage, neurological, and cancer-related diseases that are fatal to humans. Metalloproteinases are a subclass of endopeptidases that comprise structurally identical enzymes known as Matrix Metalloproteinases (MMPs) that are solely involved in extracellular matrix degradation and play a significant regulatory function in tissue remodeling. Improper regulation and expression of MMPs have been linked to several life-threatening pathological conditions in humans. Hence there is an ever-growing interest in various research communities to identify and report the Matrix Metalloproteinase Inhibitors (MMPIs). In spite of several chemically synthesized MMPIs being available currently, several unpleasant side effects, un-successful clinical trials have made use of synthetic MMPIs as a risky strategy. Several natural product researchers have strongly recommended and reported many natural resources like plants, microorganisms, and animals as greater resources to screen for bioactives that can function as potential natural MMPIs. Marine environment is one of the vast and promising resources that harbor diverse forms of life known to synthesize biologically active compounds. These bioactive compounds from marine organisms have been reported for their unparalleled biological effects and have profound applications in cosmeceutical, nutraceutical, and pharmaceutical research. Several research groups have reported an umpteen number of medicinally unmatched compounds from marine flora and fauna, thus driving researchers to screen marine organisms for natural MMPIs. In this review, our group has reported the potential MMPIs from marine organisms.

Post-Tonsillectomy Ibuprofen: Is There a Dose-Dependent Bleeding Risk?

OBJECTIVES/HYPOTHESIS

Post-tonsillectomy hemorrhage (PTH) is a potentially life-threatening complication. A recent meta-analysis suggests that ibuprofen may increase the risk of PTH. The aims of this study were to 1) re-evaluate the effect of ibuprofen on PTH given additional recent evidence and 2) to evaluate a potential dose effect of ibuprofen.

STUDY DESIGN

Meta-analysis and meta-regression; single-institution retrospective review.

METHODS

We conducted a systematic review of the literature and a meta-analysis of 12 studies comparing postoperative ibuprofen analgesia to non-nonsteroidal anti-inflammatory drug (NSAID) controls. Next, we performed a meta-regression analysis to assess for an effect of dose, if any, on rates of PTH. Five studies specifying a dose of 5 mg/kg (828 patients, 1,411 controls) and 7 studies using 10 mg/kg (5,633 patients, 7,656 controls) were included. We then conducted a novel single-institution, retrospective review of data for 1,046 patients prescribed intermediate-dose 7.5 mg/kg ibuprofen.

RESULTS

Ibuprofen was not associated with an increased rate of PTH (log odds ratio [OR], 0.21; 95% confidence interval [CI] -0.15, 0.57). Meta-regression showed that ibuprofen dose (5 and 10 mg/kg) did not have a statistically significant effect on PTH (OR, 1.32; 95% CI 0.30, 5.84). Uncontrolled, aggregate rates of PTH across all studies were 2.29% (N = 828) for 5 mg/kg and 4.65% (N = 5,633) for 10 mg/kg dosing. The rate of secondary hemorrhage in patients prescribed 7.5 mg/kg ibuprofen was 3.10% (N = 1,046).

CONCLUSION

We found no statistically significant increased risk of PTH when ibuprofen is prescribed at the low or high range of commonly used clinical dosages, compared to a non-ibuprofen regimen. Further studies with less heterogeneity are needed to determine if there is a clinically relevant dose-dependent difference in PTH with ibuprofen.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

A comparative study of thermal calcination and an alkaline hydrolysis method in the isolation of hydroxyapatite from Thunnus obesus bone

In the present study, hydroxyapatite (HAp) was isolated from Thunnus obesus bone using alkaline hydrolysis and thermal calcination methods. The obtained ceramic has been characterized by thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), powder x-ray diffraction analysis (XRD), field-emission scanning electron microscopy, energy-dispersive x-ray analysis, transmission electron microscopy (TEM), selected area diffraction analysis, cytotoxic analysis and cell proliferation analysis. The results indicate that there are significant differences between the ceramics and T. obesus bone. FT-IR and TGA results affirmed that the collagen and organic moieties have been eliminated by both the proposed methods. XRD results were in agreement with JCPDS data. TEM and selective area diffraction images have signified that the thermal calcination method produces good crystallinity with dimensions 0.3-1.0 µm, whereas the alkaline hydrolysis method produces nanostructured HAp crystals with 17-71 nm length and 5-10 nm width. Biocompatibility of HAp crystals was evaluated by cytotoxicity and cell proliferation with human osteoblast-like cell MG-63.

Effects of cigarette smoking and smoking cessation on plasma constituents and enzyme activities related to oxidative stress

In order to study effects of cigarette smoking and smoking cessation on plasma constituents and enzyme activities related to oxidative stress, 1255 smokers and 524 healthy non-smokers were investigated in terms of plasma levels of lipoperoxides (LPO), nitric oxide (NO), vitamin C (VC), vitamin E (VE) and beta-carotene (beta-CAR). Additionally, erythrocytes were examined to determine the level of LPO, the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). The results showed that, when compared with the average values of the non-smoker group, the average plasma values of LPO, NO and the average erythrocyte value of LPO in the smoker group were significantly increased (P < 0. 001), while the average plasma values of VC, VE, beta-CAR, and the average erythrocyte activities of SOD, CAT, GSH-Px were significantly decreased (P < 0.001). A linear regression and correlation analysis for 65 male smokers who were all 40 years old showed that with longer smoking duration and greater daily smoking quantity, the plasma values of LPO, NO and the erythrocyte value of LPO were elevated, while the plasma values of VC, VE, beta-CAR and erythrocyte values of SOD, CAT, GSH-Px were decreased. In a group of 73 smokers who stopped smoking completely for six months, the average plasma values of LPO, NO and the average erythrocyte value of LPO decreased, although they were still significantly higher than those in the matched non-smoker group (P < 0.05). Additionally, the average plasma values of VC, VE, beta-CAR and the average erythrocyte values of SOD, CAT, GSH-Px increased, although they were still significantly lower than those in the matched non-smoker group (P < 0.05). However, after smoking cessation for one year the above average values were not significantly different from those in the matched non-smoker group (P > 0.05). This finding indicates that the markedly increased oxidative stress in smokers might gradually return to normal but only after a long period of smoking cessation. In conclusion, in the bodies of smokers a series of free radical chain reactions were gravely aggravated, the dynamic balance between oxidation and antioxidation was seriously disrupted, and oxidative stress was clearly exacerbated, which is closely related to many disorders or diseases in smokers. The present study underscored the need, urgency and importance of complete smoking cessation.