Mitochondrial-targeted curcumin inhibits T-cell activation via Nrf2 and inhibits graft-versus-host-disease in a mouse model

Anti-inflammatory and immune suppressive agents are required to moderate hyper-activation of lymphocytes under disease conditions or organ transplantation. However, selective disruption of mitochondrial redox has not been evaluated as a therapeutic strategy for suppression of T-cell-mediated pathologies. Using mitochondrial targeted curcumin (MitoC), we studied the effect of mitochondrial redox modulation on T-cell responses by flow cytometry, transmission electron microscopy, transcriptomics, and proteomics, and the role of Nrf2 was studied using Nrf2- /- mice. MitoC decreased mitochondrial TrxR activity, enhanced mitochondrial ROS (mROS) production, depleted mitochondrial glutathione, and suppressed activation-induced increase in mitochondrial biomass. This led to suppression of T-cell responses and metabolic reprogramming towards Treg differentiation. MitoC induced nuclear translocation and DNA binding of Nrf2, leading to upregulation of Nrf2-dependent genes and proteins. MitoC-mediated changes in mitochondrial redox and modulation of T-cell responses are abolished in Nrf2- /- mice. Restoration of mitochondrial thiols abrogated inhibition of T-cell responses. MitoC suppressed alloantigen-induced lymphoblast formation, inflammatory cytokines, morbidity, and mortality in acute graft-versus-host disease mice. Disruption of mitochondrial thiols but not mROS increase inculcates an Nrf2-dependent immune-suppressive disposition in T cells for the propitious treatment of graft-versus-host disease.

Design, synthesis and development of a dual inhibitor of Topoisomerase 1 and poly (ADP-ribose) polymerase 1 for efficient killing of cancer cells

Combinatorial inhibition of Topoisomerase 1 (TOP1) and Poly (ADP-ribose) polymerase 1 (PARP1) is an attractive therapeutic strategy which is under active investigation to address chemoresistance to TOP1 inhibitors. However, this combinatorial regimen suffers from severe dose limiting toxicities. Dual inhibitors often offer significant advantages over combinatorial therapies involving individual agents by minimizing toxicity and providing conducive pharmacokinetic profiles. In this study, we have designed, synthesized and evaluated a library of 11 candidate conjugated dual inhibitors for PARP1 and TOP1, named as DiPT-1 to DiPT-11. Our extensive screening showed that one of the hits i.e.DiPT-4 has promising cytotoxicity profile against multiple cancers with limited toxicities towards normal cells. DiPT-4 induces extensive DNA double stand breaks (DSBs), cell cycle arrest and apoptosis in cancer cells. Mechanistically, DiPT-4 has the propensity to bind catalytic pockets of TOP1 and PARP1, leading to significant inhibition of both TOP1 and PARP1 at in vitro and cellular level. Interestingly, DiPT-4 causes extensive stabilization of TOP1-DNA covalent complex (TOP1cc), a key lethal intermediate associated with induction of DSBs and cell death. Moreover, DiPT-4 inhibited poly (ADP-ribosylation) i.e. PARylation of TOP1cc, leading to long lived TOP1cc with a slower kinetics of degradation. This is one of the important molecular processes which helps in overcoming resistance in cancer in response to TOP1 inhibitors. Together, our investigation showed DiPT-4 as a promising dual inhibitor of TOP1 and PARP1, which may have the potential to offer significant advantages over combinatorial therapy in clinical settings.

Triple drug therapy to manage uncontrolled BP in hypertensive patients during Covid-19 lockdown: perspectives from India

Funding Acknowledgements

Type of funding sources: None.

Background

Reportedly, hypertension (HTN) independently increases the risk of Covid-19 severity and doubles the risk of Covid-19 mortality. Also, individuals with untreated HTN remain at high risk of covid-19 complications in comparison to those managed with antihypertensive treatment.

Objective

The survey was carried out to seek the opinion of healthcare practitioners (HCPs) on the impact of Covid-19 lockdown on the blood pressure (BP) control, and the role of triple drug therapy in management of uncontrolled BP.

Method

This PAN India study was carried out through a structured web-based objective questionnaire survey involving 479 HCPs. The survey comprised questions related to the prevalence and causes of uncontrolled BP during the Covid-19 lockdown, and the use of triple drug therapy in the management of uncontrolled BP.

Results

The respondent pool of 479 HCPs consisted of consulting physicians (51.5%), family physicians (19%), diabetologists (15%), cardiologists (14%) and nephrologists (0.5%). In this study a majority (40%) of HCPs agreed that stress was the most common reason behind uncontrolled BP during Covid-19 lockdown followed by non-compliance of treatment and sedentary lifestyle, each opined by 30% of HCPs. Almost 54% and 40% of the HCPs respectively, mentioned that 10-40% and 40-80% of their patients with hypertension have reported uncontrolled BP levels following the Covid-19 lockdown. 4% of the HCPs reported that all of their patients lost BP control, while 2% of HCPs mentioned that none of their patients reported uncontrolled BP after the Covid-19 lockdown. Of all the HCPs, 12% opined that they will choose a triple drug combination (TDC) for patients uncontrolled with high dose monotherapy, ∼75% opined that they will chose TDC for patients uncontrolled with dual therapy while 13% mentioned that they will chose TDC for patients at high risk. Regarding the TDC of choice, more than half (51%) of the HCPs opted for Telmisartan + Amlodipine + Hydrochlorothiazide as the preferred combination. Among other TDCs, Telmisartan + Amlodipine + Chlorthalidone, Telmisartan + Cilnidipine + Chlorthalidone, and Olmesartan + Amlodipine + Hydrochlorothiazide were ranked as the next three choices opted by 28%, 17.5% and 2.5% of HCPs for the management of uncontrolled BP. A majority of HCPs (58%) also agreed that they would adopt TDC early in the treatment, during the ongoing Covid-19 pandemic.

Conclusion

This study underlined the negative impact of Covid-19 lockdown on the blood pressure control in patients with hypertension. It also highlighted the HCPs perspectives on the early use of TDC, and that Telmisartan + Amlodipine + Hydrochlorothiazide is the most commonly preferred TDC in patients with uncontrolled BP levels in Indian settings.

An indian clinician outlook on hypertension care during Covid-19 pandemic

Funding Acknowledgements

Type of funding sources: None.

Background

Hypertension (HTN) has been found to increase the risk of Covid-19 mortality when compared with normotensives, and those discontinuing the antihypertensive treatment have an additional fatality risk.

Objective

The survey was carried out to seek the opinion of Indian healthcare practitioners (HCPs) on the risk factors, challenges and management of HTN during the ongoing Covid-19 pandemic.

Method

This was a structured web-based objective questionnaire survey involving 2545 HCPs PAN-India. The survey comprised questions related to the risk factors for HTN, home blood pressure monitoring (HBPM), BP control, treatment, complications and challenges of uncontrolled HTN during Covid-19.

Results

This study showed that tobacco use, obesity and comorbidities are top three modifiable risk factors for HTN followed by emotional stress, during Covid-19 pandemic. A majority of HCPs (44%) reported that <30% of their hypertensive patients check BP at home while 36% and 20% reported that 30-50% and >50% of their patients respectively, practice HBPM. 20%, 63%, and 17% of HCPs respectively, reported that <20%, 20-40% and >40% of their patients presented with BP > 150/100 mmHg during lockdown. Of all the HCPs, 53% and 33% respectively, reported BP increase in <20% and 20-40% of their patients on monotherapy while 14% of HCPs reported BP increase in >40% of their patients on monotherapy during the lockdown. As compared to high dose monotherapy, dual and triple combination therapies (TDC) were selected as most preferred for the management of uncontrolled BP opted by 56% and 34% of the HCPs, respectively. The dual combination antihypertensives were ranked as angiotensin receptor blockers (ARB) + diuretic (DU) > ARB + calcium channel blockers (CCB) > ARB + beta-blocker. The TDC with ARB + CCB + DU was the most favored TDC antihypertensive therapy during Covid-19 era. Acute coronary syndrome was anticipated as the most common complication of HTN in the Covid-19 pandemic, followed by renal dysfunction, cerebral ischemia and cerebral hemorrhage reported by 47%, 17%, 14% and 14% of HCPs, respectively. Multiple challenges in HTN care during Covid-19 as opined by HCPs included BP measurement while avoiding the risk of infection (57%), advising treatment via teleconsultation (48%), dose modification (41%), patient compliance (32%) and transport-related issues (30%). Most of the HCPs believed that self-monitoring of BP (32%) and economical medicines (24%) can improve medication adherence in patients with HTN.

Conclusion

The study underlined that the provision of economic medicines, single pill combinations, doctor-patient digital connect, and patient education can help in improving medication adherence leading to better outcomes in patients with HTN during Covid-19.  The study also suggested the need to enhance HBPM and the use of ARB-based dual and triple combination therapies to improve BP control in patients uncontrolled on monotherapy during Covid-19 pandemic.

Differential expression of virulence genes and role of gyrA mutations in quinolone resistant and susceptible strains of Salmonella Weltevreden and Newport isolated from seafood

AIMS

To investigate the differential expression of virulence genes and role of gyrA mutations in quinolone resistant and susceptible strains of Salmonella isolated from seafood.

METHODS AND RESULTS

Forty Salmonella isolates from seafood were tested for antibiotic sensitivity. Minimal inhibitory concentration (MIC) was determined and two nalidixic acid-resistant isolates, viz Salmonella Weltevreden (SW9) and Salmonella Newport (SN36) were selected for identifying the mechanism of resistance. SW9 showed mutation in the gyrA gene at codon 83 (Ser to Tyr) while SN36 presented at codon 87 (Asp to Asn). Experimental induction of resistance to a sensitive Salm. Newport (SN71) showed point mutation at codon 87 (Asp to Gly) in the gyrA gene, and was designated SN71R. All the isolates resistant to nalidixic acid had a single mutation at different positions in the gyrA gene. However, induction of resistance to a sensitive Salm. Weltevreden (SW30) was exceptional in that it did not show any mutation in the gyrA region. Use of Phe-Arg-β-naphthylamide (PAβN) also could not reduce MIC below the Clinical and Laboratory Standards Institute guidelines revealing the absence of efflux mediated resistance. Thus, the resistance mechanism in SW30R is unknown. The growth rate of quinolone resistant isolates was slower than the susceptible ones. The resistant isolates showed decreased epithelial cell invasion and intracellular replication. The mRNA expression levels of some of the genes were significantly (P < 0·005) reduced in SN71R compared to the sensitive strain (SN71).

CONCLUSIONS

Nalidixic acid-resistant Salmonella strains are associated with lower virulence and pathogenicity than the sensitive strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provided valuable information on the difference in the growth, cytotoxicity, infectivity and expression of virulence genes in resistant and susceptible strains. Furthermore, the gyrA mutation was shown to be the main mechanism of quinolone resistance in Salmonella other than the overexpression of efflux pumps or the presence of plasmid mediated quinolone resistance genes.

Presence of T3SS2β genes in trh⁺ Vibrio parahaemolyticus isolated from seafood harvested along Mangalore coast, India

Vibrio parahaemolyticus is a seafood-borne pathogen autochthonous to the marine and estuarine ecosystem, responsible for gastroenteritis when contaminated raw seafood is consumed. The pathogenicity has been associated with thermostable direct haemolysin (TDH) and TDH-related haemolysin (TRH). Of late, the presence of T3SS2α and T3SS2β gene clusters has been well documented in clinical isolates of Vibrio parahaemolyticus and known to play an essential role in pathogenesis. However, reports on the presence of T3SSβ genes in V. parahaemolyticus isolated from the seafood and/or environmental samples are scanty. In this study, we have identified and analysed the distribution of the T3SS2β genes in V. parahaemolyticus isolated from seafood harvested along southwest coast of India. Results showed that T3SS2β genes are solely associated with trh⁺ and tdh⁺ /trh⁺ strains of V. parahaemolyticus. Reverse transcriptase PCR (RT-PCR) showed that the T3SS2β genes identified in trh⁺ V. parahaemolyticus were transcriptionally active. To our knowledge, this study appears to be the first description on the presence of T3SS2β-positive V. parahaemolyticus isolated from seafood in India. The study of T3SS2 along with other virulence factors will help in better understanding of the risk of seafood-borne illness due to V. parahaemolyticus.

SIGNIFICANCE AND IMPACT OF THE STUDY

T3SSs (α or β) are the important virulence factors of Vibrio parahaemolyticus that contribute to their pathogenicity in humans. This study demonstrated the presence of T3SS2β genes in V. parahaemolyticus isolated from the seafood harvested along Mangalore coast. RT-PCR showed that the T3SS2β genes identified in seafood isolates of V. parahaemolyticus were found to be functional. To the best of our knowledge, this is the first description of T3SS2β genes in trh⁺ V. parahaemolyticus isolated from seafood in India. The presence of T3SS2 along with other virulence factors such as TDH and/or TRH highlights a potential health risk for seafood consumers.

Psychological Correlates of Outcome after Coronary Artery Bypass Graft

BACKGROUND

Psychological effects of Coronary Artery Bypass graft (CABG) have been of interest all over the world but there is a paucity of Indian work.

METHODS

30 patients undergoing CABG at a service hospital were included. All patients filled a specially designed proforma. Mini Mental Status Examination, Hospital anxiety and depression scale, Coronary scale, Seattle angina questionnaire and Euro-QOL 5D were performed before and seven days after CABG.

RESULTS

43.3% had significant anxiety and 30% had significant depression before CABG. Following CABG, 36.67% of the patients had significant anxiety while 40% had significant depression. On the Seattle angina questionnaire, physical limitation reduced from 71.6 ± 7.9 to 53.1 ± 14.6. There was significant improvement in treatment satisfaction from 37.8 ± 6.1 to 59.4 ± 4.2 following CABG. On th euro quality of life scale (EQ5D) health status improved from 38.17 ± 9.51 before CABG to 68.5 ± 5.28 after CABG.

CONCLUSION

There is a significant incidence of anxiety and depression in patients undergoing CABG, both before and after surgery.

Modelling epidemiology of leprosy

A simulation model for leprosy transmission and control has been developed with specific objectives. Several sensitivity experiments have been carried out by altering the various inputs based on empirical data combined with intelligent guessing. The outputs generated through these exercises were on the expected lines. While incremental exercises would improve the model, it can be used even at the existing stage as a tool for programme managers.

Stochastic compartmental models with Prendville growth mechanisms

We consider a stochastic compartmental model in which cells reproduce in accordance with a regulated birth and death process. We find expressions for the mean vector and covariance matrix for the number of cells in these compartments. We obtain the asymptotic behavior of the mean vector in the general case and explicit expressions for two compartmental and mammillary systems.

Efficacy and limitations of QBC acridine orange staining as a routine diagnostic technique for malaria in developing countries

The recently developed QBC technique has been reported to be rapid, sensitive and specific for the detection of malaria infection. We evaluated this technique in comparison with thin and thick Giemsa stained blood films for the diagnosis of malaria in acute fever and PUO cases. The technique was slightly more sensitive than thin blood film but equal to thick blood film examination. Identification of species of malaria posed some difficulties. Due to its high cost and requirement for a fluorescent microscope this technique, in spite of its speed and sensitivity, may not have the potential to be a substitute for the conventional blood film examination for the diagnosis of malaria, especially in developing countries.