Identification and Characterization of Edible Cricket Peptides on Hypertensive and Glycemic In Vitro Inhibition and Their Anti-Inflammatory Activity on RAW 264.7 Macrophage Cells

Recent studies continue to demonstrate the potential of edible insects as a protein base to obtain bioactive peptides applicable for functional food development. This study aimed at identifying antihypertensive, anti-glycemic, and anti-inflammatory peptides derived from the in vitro gastrointestinal digests of cricket protein hydrolysates. After sequential fractionation, the protein digest subfraction containing the lowest molecular weight (<0.5 kDa), hydrophobic (C18) and cationic peptides (IEX) was found responsible for the most bioactivity. The cationic peptide fraction significantly reduced (p < 0.05) α-amylase, α-glucosidase, and angiotensin converting enzyme (ACE) activity in vitro, and also inhibited the expression of NF-κB in RAW 264.7 macrophage cells. A total of 28 peptides were identified with mass spectrometry (LC–MS/MS) and de novo sequencing from the potent fraction. Three novel peptides YKPRP, PHGAP, and VGPPQ were chosen for the molecular docking studies. PHGAP and VGPPQ exhibited a higher degree of non-covalent interactions with the enzyme active site residues and binding energies comparable to captopril. Results from this study demonstrate the bioactive potential of edible cricket peptides, especially as ACE inhibitors.     

Human TRPA1 is intrinsically cold- and chemosensitive with and without its N-terminal ankyrin repeat domain

We have purified and reconstituted human transient receptor potential (TRP) subtype A1 (hTRPA1) into lipid bilayers and recorded single-channel currents to understand its inherent thermo- and chemosensory properties as well as the role of the ankyrin repeat domain (ARD) of the N terminus in channel behavior. We report that hTRPA1 with and without its N-terminal ARD (Δ1–688 hTRPA1) is intrinsically cold-sensitive, and thus, cold-sensing properties of hTRPA1 reside outside the N-terminal ARD. We show activation of hTRPA1 by the thiol oxidant 2-((biotinoyl)amino)ethyl methanethiosulfonate (MTSEA-biotin) and that electrophilic compounds activate hTRPA1 in the presence and absence of the N-terminal ARD. The nonelectrophilic compounds menthol and the cannabinoid Δ⁹-tetrahydrocannabiorcol (C16) directly activate hTRPA1 at different sites independent of the N-terminal ARD. The TRPA1 antagonist {"type":"entrez-nucleotide","attrs":{"text":"HC030031","term_id":"262060681","term_text":"HC030031"}}HC030031 inhibited cold and chemical activation of hTRPA1 and Δ1–688 hTRPA1, supporting a direct interaction with hTRPA1 outside the N-terminal ARD. These findings show that hTRPA1 is an intrinsically cold- and chemosensitive ion channel. Thus, second messengers, including Ca²⁺, or accessory proteins are not needed for hTRPA1 responses to cold or chemical activators. We suggest that conformational changes outside the N-terminal ARD by cold, electrophiles, and nonelectrophiles are important in hTRPA1 channel gating and that targeting chemical interaction sites outside the N-terminal ARD provides possibilities to fine tune TRPA1-based drug therapies (e.g., for treatment of pain associated with cold hypersensitivity and cardiovascular disease).A number of vertebrate and invertebrate transient receptor potential (TRP) ion channels have been implicated in temperature sensation (1–3), but only the rat menthol receptor TRP subtype M8 (TRPM8) and the rat capsaicin receptor TRP subtype V1 (TRPV1) have been shown to possess intrinsic thermosensitivity (4, 5). In 2003, Story et al. (6) proposed that the mouse TRPA1 is a noxious cold sensor. Story et al. (6) showed that TRPA1 was present in nociceptive primary sensory neurons and that CHO cells heterologously expressing the mouse TRPA1 displayed cold sensitivity. Most subsequent studies of cold responses in heterologous TRPA1 expression systems, isolated primary sensory neurons, and whole animals have provided evidence in support of mouse and rat TRPA1 being involved in noxious cold transduction (7). Interestingly, a familial episodic pain syndrome triggered by cold is caused by a gain-of-function mutation in the TRPA1 gene, indicating that TRPA1 may have a key role in human noxious cold sensation (8). Thus, human TRPA1 (hTRPA1) may be a relevant drug target for treatment of this condition and other pathological conditions, such as inflammation, nerve injury, and chemotherapy-induced neuropathy, that are characterized by TRPA1-dependent cold allodynia or hypersensitivity (7). However, in vitro studies of the expressed hTRPA1 have generated conflicting findings (8–15), and no study has provided evidence that mammalian TRPA1 channels are, indeed. intrinsically cold-sensitive proteins, which would require examination of the purified protein in a defined membrane environment.Heterologous expression studies of chimeric or mutated TRPA1 channels have proposed that the N-terminal region plays an important role in thermal and chemical sensitivity of both mammalian and insect TRPA1 (14, 16–19). Initial studies indicated that mammalian TRPA1 is activated by cysteine-reactive electrophilic compounds and oxidants, such as diallyl disulfide in garlic (9, 10, 20, 21). Targeted gene mutations have identified cysteines present in the N terminus of TRPA1 as important for electrophilic and oxidative TRPA1 channel activation (22, 23). Because several of these cysteines are involved in protein disulfide formation (24–26), it is not unlikely that such mutations will have pronounced effects on the overall TRPA1 channel structure and function (7). Electrophilic compounds can also covalently bind to cysteines in the transmembrane segments and the C-terminal domain of mammalian TRPA1 (23, 26), and the electrophiles p-benzoquinone, isovelleral, and polygodial robustly activate the heterologously expressed triple mutant hTRPA1-3C (27, 28) that was initially used to identify certain N-terminal cysteine residues in hTRPA1 as key targets for electrophiles (22). However, it is yet to be shown that covalent binding sites outside the N-terminal ankyrin repeat domain (ARD) contribute to the regulation of channel gating.Another key feature of mammalian TRPA1 is the responsiveness to nonelectrophilic compounds with very different chemical structures, such as menthol and the cannabinoids Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and Δ⁹-tetrahydrocannabiorcol (C16) (7). However, if nonelectrophilic compounds activate TRPA1 directly and at the same site on TRPA1 is not known. The site of action of nonelectrophilic TRPA1 activators is important to clarify, because some TRPA1 activators are antinoiceptive (29, 30), and nontissue-damaging TRPA1 activators may be used clinically for pharmacological regulation of TRPA1 channel activity (29).Here, we have purified and inserted hTRPA1 with and without its N-terminal ARD (Δ1–688 hTRPA1) into lipid bilayers for functional studies using patch-clamp electrophysiology to explore the inherent thermo- and chemosensitivity of hTRPA1. Because of the great potential of TRPA1 as a drug target for treatment of human pain and the existence of mammalian TRPA1 species differences (7), the human variant of TRPA1 was chosen for these studies. We addressed the role of the N-terminal ARD in cold and chemical sensitivity by deleting the N-terminal ARD, something that cannot be studied in cells heterologously expressing TRPA1, because the N-terminal ARD is needed for insertion of the ion channel into the plasma membrane (31). Our findings consolidate hTRPA1 as a multimodal nocisensor responding to cold and chemicals. It is suggested that conformational changes outside the N-terminal ARD by cold, electrophiles, and nonelectrophilic compounds are important in hTRPA1 channel gating. Targeting chemical interaction sites outside the N-terminal ARD may provide possibilities to fine tune TRPA1-based drug therapies [e.g., for treatment of pain associated with cold hypersensitivity (7) and cardiovascular disease (32)].     

Regulation of cardiac oxidative stress and lipid peroxidation in streptozotocin-induced diabetic rats treated with aqueous extract of Pimpinella tirupatiensis tuberous root

Plants with antidiabetic activities provide important source for the development of new drugs in the management of diabetes mellitus. The main aim of this study was to evaluate the protective effect of aqueous extract (AE) of Pimpinella tirupatiensis (Pt) tuberous root on cardiac oxidative stress and lipid peroxidation (LPO) in non-diabetic and streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in male Wistar rats by a single administration of STZ (40 mg/kg intraperitoneal (i.p). AE (750 mg/kg/b.w./day) and glibenclamide (GLB) (20 mg/kg/b.w./day) were administrated orally by intra oral gastric tube for 30 days. After 4 weeks of hyperglycaemia the enzymatic and non-enzymatic factors were measured in cardiac tissue of diabetic and control groups. Xanthine oxidase activity (XOD), Uric acid (UA) and malondialdehyde (MDA) content were significantly (p < 0.01) elevated by 48, 48 and 50% respectively and the contents of glutathione (GSH), ascorbic acid (AA) were significantly (p < 0.01) diminished by 45 and 42% respectively in diabetic rats when compared to normal. Treatment with AE and GLB normalized the content of UA, GSH, AA, MDA and the activity of XOD. No significant changes were observed in control rats treated with AE. This data suggests that hyperglycemia induces oxidative stress in the heart, but the oxidative stress defense mechanisms in the heart tissue are fairly efficacious against oxidative injury by the treatment with AE and GLB. The present study reveals that AE may provide a useful therapeutic option in the reversal of oxidative stress induced cardiac dysfunction in diabetes mellitus.     

Effect of body mass index on bone mineral density is age-specific

Background and aimsObesity and osteoporosis are two important and growing public health problems worldwide. Body mass index (BMI) has been found to be inversely related to the risk of osteoporotic fracture. We aimed to assess the association of BMI with thoracic vertebral bone mineral density (BMD) measured from a quantitative computed tomography (QCT).Methods and resultsWe retrospectively evaluated the data from 15,758 consecutive patients (5675 females and 10,083 males) between age 20–90 years, who underwent Coronary Artery Calcium (CAC) scoring. Quantitative data analyses of thoracic trabecular BMD (mg/cm³) was performed with a phantom system or phantomless using validated software. The gender-specific subgroup was divided based on age (<45, 45–55, 55–65, >65 yrs in females; <40,40–60,>60 yrs in Males) and weight by BMI (kg/m²) as < 25 (normal or low weight), >25 - <30 (overweight) and >30 (obesity). Analysis of variance (ANOVA) and Scheffe's post hoc procedure tested the association of body weight/BMI on BMD. A significant positive association between the body weight and BMD existed in obese population in elder groups in both genders (p < 0.05). There was no significant difference in BMD in 40–60 years in men and <55 years in women with normal or low weight compared to overweight or obese cohorts.ConclusionsWe concluded that the effect of weight on BMD is age-specific and the BMD should be monitored routinely with a cardiac CT scan in the senile population.     

Age-related macular degeneration and 5-year incidence of impaired activities of daily living

Objectives

We aimed to assess the prospective association between age-related macular degeneration (AMD) and impaired activities of daily living (ADL) among a large cohort of older adults.

Study design

Functional status was determined by the Older Americans Resources and Services ADL scale from 2002–2004 to 2007–2009 among 761 participants aged 60+ years. AMD was assessed from retinal photographs.

Results

After adjusting for age, sex, living status, self-rated poor health, smoking, body mass index, visual impairment, hypertension, diabetes, hospital admissions in the past year, walking disability, probable depression, mini-mental state examination scores, having any AMD or late AMD increased the risk of incident impaired total ADL 5 years later, odds ratio, OR 2.87 (95% confidence intervals, CI 1.44–5.71) and OR 12.95 (95% CI 3.78–44.35), respectively. Having any AMD increased the risk of developing instrumental ADL disability over the 5 years, multivariable-adjusted OR 2.06 (95% CI 1.11–3.83).

Conclusions

This study shows that the presence of AMD could independently signal an increased risk of functional disability, particularly in performing instrumental ADL tasks.     

Associations between retinal microvascular structure and the severity and extent of coronary artery disease

Objective

Microvascular mechanisms are increasingly recognized as being involved in a significant proportion of coronary artery disease (CAD) cases, but their exact contribution or role is unclear. We aimed to define the association between retinal microvascular signs and both CAD extent and severity.

Methods

1120 participants of the Australian Heart Eye Study were included. Retinal vessel caliber was measured from digital retinal images. Extent and severity of CAD was assessed using several approaches. First, a simple scoring classifying participants as having one-vessel, two-vessel, and three-vessel disease was used. Gensini and Extent scores were calculated using angiography findings.

Results

After multivariable adjustment, significantly narrower retinal arteriolar caliber in women (comparing lowest versus highest quartile or reference) and wider venular caliber in men (comparing highest versus lowest quartile or reference) were associated with 2-fold and 54% higher odds of having at least one stenosis ≥50% in the epicardial coronary arteries, respectively. Women in the third versus first tertile of retinal venular caliber had 92% and ∼2-fold higher likelihood of having higher Gensini and Extent scores, respectively. Women in the lowest versus highest tertile of retinal arteriolar caliber had greater odds of having higher Extent scores, OR 2.99 (95% CI 1.45–6.16). In men, non-significant associations were observed between retinal vascular caliber and Gensini and Extent scores.

Conclusions

An unhealthy retinal microvascular profile, namely, narrower retinal arterioles and wider venules was associated with more diffuse and severe CAD among women.     

Differential association of retinal arteriolar and venular caliber with diabetes and retinopathy

Aims

To describe the relationship of retinal arteriolar and venular caliber with diabetes, retinopathy and hyperglycemia, in an Asian Indian population.

Methods

This was a population-based cross-sectional study of 3400 (75.6% response rate) Singapore ethnic Indians aged 40-80 years. Central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were obtained using a validated computer-assisted program. Diabetes mellitus was identified using standardized criteria. Diabetic retinopathy was graded based on the modified Airlie House Classification System.

Results

There were 980 (32.2%) participants with diabetes. Of these, 327 (33.4%) had diabetic retinopathy. After multivariate adjustment, diabetic persons had a wider CRAE (145.23 μm vs 142.38 μm, P < 0.001). This relationship was stronger in persons without hyperlipidemia (P-interaction < 0.1). Among diabetic participants, wider CRVE was related to increasing severity of retinopathy (P for trend < 0.05) and this association may be altered by hypertensive status. Retinal arteriolar caliber widened with increasing glucose (P < 0.001) and HbA1C (P < 0.001) levels.

Conclusions

In Indian adults, wider retinal arteriolar caliber is associated with diabetes and hyperglycemia, while wider retinal venular caliber is associated with diabetic retinopathy. This is consistent with white populations and confirms the differential systemic association of retinal vascular caliber in Asian Indians.