Indian Society of Critical Care Medicine and Indian Association of Palliative Care Expert Consensus and Position Statements for End-of-life and Palliative Care in the Intensive Care Unit.

End-of-life care (EOLC) exemplifies the joint mission of intensive and palliative care (PC) in their human-centeredness. The explosion of technological advances in medicine must be balanced with the culture of holistic care. Inevitably, it brings together the science and the art of medicine in their full expression. High-quality EOLC in the ICU is grounded in evidence, ethical principles, and professionalism within the framework of the Law. Expert professional statements over the last two decades in India were developed while the law was evolving. Recent landmark Supreme Court judgments have necessitated a review of the clinical pathway for EOLC outlined in the previous statements. Much empirical and interventional evidence has accumulated since the position statement in 2014. This iteration of the joint Indian Society of Critical Care Medicine-Indian Association of Palliative Care (ISCCM-IAPC) Position Statement for EOLC combines contemporary evidence, ethics, and law for decision support by the bedside in Indian ICUs. How to cite this article: Mani RK, Bhatnagar S, Butola S, Gursahani R, Mehta D, Simha S, et al. Indian Society of Critical Care Medicine and Indian Association of Palliative Care Expert Consensus and Position Statements for End-of-life and Palliative Care in the Intensive Care Unit. Indian J Crit Care Med 2024;28(3):200-250.

Terminal Extubation or Terminal Weaning: Is it Feasible in Indian Intensive Care Units?

Terminal extubation (TE) and weaning have long been suggested as a modality of intervention when the continuation of mechanical ventilation is not expected to achieve its therapeutic aim and is merely prolonging the dying process. The decision, however, is complex considering limited evidence regarding the best practices and is often defied due to inherent ethical, legal, and medical dilemmas. The article attempts a brief overview of available literature on this subject and discusses its feasibility in Indian intensive care units (ICUs). How to cite this article: Kumar A, Bhat RS, Mani RK. Terminal Extubation or Terminal Weaning: Is it Feasible in Indian Intensive Care Units? Indian J Crit Care Med 2024;28(2):103-105.

Targeting Cariogenic Streptococcus mutans in Oral Biofilms with Charge-Switching Smart Antimicrobial Polymers.

Cariogenic biofilms produce strong acidic microenvironments, which is the primary cause of dental caries. Streptococcus mutans is a dominant species in cariogenic biofilms. Herein, we report a pH-responsive, charge-switching smart copolymer to selectively target and eradicate bacteria in cariogenic biofilms. To that end, the copolymer is designed to be activated in an acidic environment. The smart copolymer, Poly-1A, consists of ternary compositions of monomers with a cationic ethyl ammonium group, a carboxylic group, and a hydrophobic group in the side chains. The net charge of Poly-1A was charge neutral at neutral pH, but it switched to be cationic because the acidic carboxylate side chains were protonated and became neutral; however, the ammonium groups remained positive. Poly-1A with a net positive charge bound to the anionic surface of oral bacteria by electrostatic interactions and disrupted the bacterial membranes, causing bacterial death. Poly-1A reduced the cell viability of planktonic and biofilm S. mutans at pH 4.5, while it was not bactericidal at pH 7.4. Poly-1A did not reduce the cell viability of human gingival fibroblasts and periodontal ligament stem cells for a 1 h incubation.

Clinico-Epidemiologic Characteristics of Patients Reported in the Mycotic Infections in COVID-19 Registry.

We update results from the Mycotic Infections in COVID-19 (MUNCO) Registry, May-September 2021. Data collection from May to September 2021 yielded 728 cases from India, Nepal, Bangladesh, Thailand, and the United States. The cases consisted of mostly mucormycosis (97.6%), primarily rhinocerebral, and were analyzed to investigate clinical characteristics associated with negative outcomes. Patients were mostly diabetic (85%) and male (76%), with significant mortality (11.7%). All patients received treatment of coronavirus disease 2019 (COVID-19) as well as antifungal treatment. The crude mortality rate was 11.3% for mucormycosis and 22.7% formixed infections. This study demonstrates the utility of online databases in the collection of high-caliber data.

Factors Associated with Mortality in Coronavirus-Associated Mucormycosis: Results from Mycotic Infections in COVID-19 (MUNCO) Online Registry.

BACKGROUND: COVID-19-associated mucormycosis (CAM) is associated with high morbidity and mortality. MUNCO is an international database used to collect clinical data on cases of CAM in real time. Preliminary data from the Mycotic Infections in COVID-19 (MUNCO) online registry yielded 728 cases from May to September 2021 in four South Asian countries and the United States. A majority of the cases (694; 97.6%) consisted of a mucormycosis infection. The dataset allowed for the analysis of the risk factors for adverse outcomes from CAM and this analysis is presented in this paper. METHODS: The submission of cases was aided by a direct solicitation and social media online. The primary endpoints were full recovery or death measured on day 42 of the diagnosis. All patients had histopathologically confirmed CAM. The groups were compared to determine the contribution of each patient characteristic to the outcome. Multivariable logistic regression models were used to model the probability of death after a CAM diagnosis. RESULTS: The registry captured 694 cases of CAM. Within this, 341 could be analyzed as the study excluded patients with an unknown CAM recovery status due to either an interruption or a lack of follow up. The 341 viable cases consisted of 258 patients who survived after the completion of treatment and 83 patients who died during the period of observation. In a multivariable logistic regression model, the factors associated with an increased risk of mortality include old age (OR = 1.04, 95% CI 1.02-1.07, p = 0.001), history of diabetes mellitus (OR 3.5, 95% CI 1.01-11.9, p = 0.02) and a lower BMI (OR 0.9, 95% CI 0.82-0.98, p = 0.03). Mucor localized to sinus disease was associated with 77% reduced odds of death (OR = 0.23, 95% CI 0.09-0.57, p = 0.001), while cerebral mucor was associated with an increased odds of death (OR = 10.96, 95% CI 4.93-24.36, p = ≤0.0001). CONCLUSION: In patients with CAM, older age, a history of diabetes and a lower body mass index is associated with increased mortality. Disease limited to the sinuses without a cerebral extension is associated with a lower risk of mortality. Interestingly, the use of zinc and azithromycin were not associated with increased mortality in our study.

Molecular weight tuning optimizes poly(2-methoxyethyl acrylate) dispersion to enhance the aging resistance and anti-fouling behavior of denture base resin.

Poly(methyl methacrylate) (PMMA)-based denture base resins easily develop oral bacterial and fungal biofilms, which may constitute a significant health risk. Conventional bacterial-resistant additives and coatings often cause undesirable changes in the resin. Reduced bacterial resistance over time in the harsh oral environment is a major challenge in resin development. Poly(2-methoxyethyl acrylate) (PMEA) has anti-fouling properties; however, due to the oily/rubbery state of this polymer, and its surface aggregation tendency in a resin mixture, its direct use as a resin additive is limited. This study aimed to optimize the use of PMEA in dental resins. Acrylic resins containing a series of PMEA polymers with various molecular weights (MWs) at different concentrations were prepared, and the mechanical properties, surface gloss, direct transmittance, and cytotoxicity were evaluated, along with the distribution of PMEA in the resin. Resins with low-MW PMEA (2000 g mol-1) (PMEA-1) at low concentrations satisfied the clinical requirements for denture resins, and the PMEA was homogeneously distributed. The anti-fouling performance of the resin was evaluated for protein adsorption, bacterial and fungal attachment, and saliva-derived biofilm formation. The PMEA-1 resin most effectively inhibited biofilm formation (∼50% reduction in biofilm mass and thickness compared to those of the control). Post-aged resins maintained their mechanical properties and anti-fouling activity, and polished surfaces had the same anti-biofilm behavior. Based on wettability and tribological results, we propose that the PMEA additive creates a non-stick surface to inhibit biofilm formation. This study demonstrated that PMEA additives can provide a stable and biocompatible anti-fouling surface, without sacrificing the mechanical properties and aesthetics of denture resins.

Conventional flexible bronchoscopy during the COVID pandemic: A consensus statement from the Indian Association for Bronchology.

During the times of the ongoing COVID pandemic, aerosol-generating procedures such as bronchoscopy have the potential of transmission of severe acute respiratory syndrome coronavirus 2 to the healthcare workers. The decision to perform bronchoscopy during the COVID pandemic should be taken judiciously. Over the years, the indications for bronchoscopy in the clinical practice have expanded. Experts at the Indian Association for Bronchology perceived the need to develop a concise statement that would assist a bronchoscopist in performing bronchoscopy during the COVID pandemic safely. The current Indian Association for Bronchology Consensus Statement provides specific guidelines including triaging, indications, bronchoscopy area, use of personal protective equipment, patient preparation, sedation and anesthesia, patient monitoring, bronchoscopy technique, sample collection and handling, bronchoscope disinfection, and environmental disinfection concerning the coronavirus disease-2019 situation. The suggestions provided herewith should be adopted in addition to the national bronchoscopy guidelines that were published recently. This statement summarizes the essential aspects to be considered for the performance of bronchoscopy in COVID pandemic, to ensure safety for both for patients and healthcare personnel.

Use of an Extended Working Channel in High-Risk Transbronchial Biopsy: An Innovative Use of an Existing Modality to Minimize Bleeding and Hypoxia.

OBJECTIVE: Bleeding is one of the main complications of transbronchial lung biopsy (TBBx) more so with conditions such as azotaemia and coagulopathy. Baseline hypoxia worsens the consequences of TBBx bleeding and can lead to escalation of care. In our experience, TBBx performed through a guide sheath (GS) using it as an extended working channel (EWC) helps minimize bleeding risk. We hypothesized that the EWC produces a tamponade effect in the close vicinity of the biopsy site, both reducing bleeding risk and restricting bleeding to a smaller segment. In this study, we assessed the impact of an additional EWC in high-risk (HR) patients undergoing TBBx, to reduce bleeding and enhance safety. METHODS: Retrospective study between January 2014 and December 2018 looking at the risk of bleeding following TBBx performed through a GS (EWC) in patients at high risk for bleeding-related complications. Bleeding incidence and consequent hypoxic events requiring escalation of care were noted. The specimen diagnostic yield was also analyzed. SPSS statistics were used-data are reported as mean and standard deviation for continuous variables, and number and percentage for discrete variables. RESULTS: Eight hundred four TBBxs were performed during the study period, and 105 (13.1%) procedures were done in the HR individuals using a GS as an EWC. No significant bleeding requiring escalation of care was seen with the use of EWC-GS. Histopathology revealed adequate sampling in all cases. CONCLUSIONS: A GS as an EWC was used to reduce the bleeding risk, consequent hypoxia, and prevent escalation of care in TBBx in HR patients. Adequate tissue was obtained without any complications. Though prospective, randomized, multicenter trials using an EWC in HR-TBBx are important, they are challenging to do due to the HR population under study.

The function of peptide-mimetic anionic groups and salt bridges in the antimicrobial activity and conformation of cationic amphiphilic copolymers.

Herein we report the synthesis of ternary statistical methacrylate copolymers comprising cationic ammonium (amino-ethyl methacrylate: AEMA), carboxylic acid (propanoic acid methacrylate: PAMA) and hydrophobic (ethyl methacrylate: EMA) side chain monomers, to study the functional role of anionic groups on their antimicrobial and hemolytic activities as well as the conformation of polymer chains. The hydrophobic monomer EMA was maintained at 40 mol% in all the polymers, with different percentages of cationic ammonium (AEMA) and anionic carboxylate (PAMA) side chains, resulting in different total net charge for the polymers. The antimicrobial and hemolytic activities of the copolymer were determined by the net charge of +3 or larger, suggesting that there was no distinct effect of the anionic carboxylate groups on the antimicrobial and hemolytic activities of the copolymers. However, the pH titration and atomic molecular dynamics simulations suggest that anionic groups may play a strong role in controlling the polymer conformation. This was achieved via formation of salt bridges between cationic and anionic groups, transiently crosslinking the polymer chain allowing dynamic switching between compact and extended conformations. These results suggest that inclusion of functional groups in general, other than the canonical hydrophobic and cationic groups in antimicrobial agents, may have broader implications in acquiring functional structures required for adequate antimicrobial activity. In order to explain the implications, we propose a molecular model in which formation of intra-chain, transient salt bridges, due to the presence of both anionic and cationic groups along the polymer, may function as "adhesives" which facilitate compact packing of the polymer chain to enable functional group interaction but without rigidly locking down the overall polymer structure, which may adversely affect their functional roles.

A Novel Technique for the Management of Massive Hemoptysis: The Customized Endobronchial Silicone Blocker.

OBJECTIVE: Massive hemoptysis (MH) has a high mortality rate. Therapeutic options include bronchoscopy for endobronchial lesions, bronchial artery embolization (BAE), and emergency surgery. Scant options exist for patients who are not candidates for these modalities. Culprit bronchial segment occlusion is an option to prevent "spillover flooding → hypoxia." Applying this concept, we describe a case series of MH control using a novel bronchoscopically inserted customized endobronchial silicone blocker (CESB). We analyzed the safety and efficacy of CESBs in a select subset of patients with MH. METHODS: Inclusion criteria were patients with MH who were unstable for surgery/BAE, failed BAE, or relatively contraindicated/refused BAE. CESBs were manufactured on-site by modifying silicone stents, inserted using rigid bronchoscopy and reinforced with glue. The CESB was removed after 6 weeks when possible. A successful outcome was defined as immediate bleeding control with no recurrence after removal. RESULTS: Over 4.5 years, 13 episodes of MH in 12 patients meeting the criteria specified earlier were treated with CESBs. Seven of 12 patients had tuberculosis, 4 active and 3 inactive. One patient had mucormycosis, 1 post-lobectomy, 1 endobronchial renal cell carcinoma, 1 fibrosing mediastinitis, and 1 patient had metastatic laryngeal Ca. Eight of 12 patients were taken for primary-CESB placement. Four of 12 patients were sent for BAE, which was unsuccessful, and rescue-CESB was done for definitive management. The success rate, as defined earlier, was 92.3%, with no deaths from MH. CONCLUSIONS: Innovative bronchoscopically inserted CESBs are an effective strategy in MH when patients are unstable or fail conventional management.

Decoupling the Functional Roles of Cationic and Hydrophobic Groups in the Antimicrobial and Hemolytic Activities of Methacrylate Random Copolymers.

In this study, we report the antimicrobial and hemolytic activities of ternary statistical methacrylate copolymers consisting of cationic ammonium (amino-ethyl methacrylate: AEMA), hydrophobic alkyl (ethyl methacrylate: EMA), and neutral hydroxyl (hydroxyethyl methacrylate: HEMA) side chain monomers. The cationic and hydrophobic functionalities of copolymers mimic the cationic amphiphilicity of naturally occurring antimicrobial peptides (AMPs). The HEMA monomer units were used to separately modulate the compositions of cationic and hydrophobic monomers, and we investigated the effect of each component on the antimicrobial and hemolytic activities of copolymers. Our data indicated that increasing the number of cationic groups of the copolymers to be more than 30 mol % did not increase their antimicrobial activity against Escherichia coli. The number of cationic side chains in a polymer chain at this threshold is 5.5-7.7, which is comparable to those of natural antimicrobial peptides such as maginin (+6). The MIC values of copolymers with >30 mol % of AEMA depend on only the mol % of EMA, indicating that the hydrophobic interactions of the copolymers with E. coli cell membranes determine the antimicrobial activity of copolymers. These results suggest that the roles of cationic and hydrophobic groups can be controlled independently by design in the ternary copolymers studied here.

An Innovative Solution for Prolonged Air Leaks: The Customized Endobronchial Silicone Blocker.

BACKGROUND: Prolonged air leak (PAL) is a life-threatening condition that can present either as bronchopleural fistula, or alveolar-pleural fistula (APF). Although numerous bronchoscopic treatments are described, they are either expensive, not widely available in the developing world or have limited success. We describe our experience with a novel customized endobronchial silicone blocker (CESB) for PAL treatment. METHODS: This is a retrospective study of PAL patients who underwent CESB placement. The air leak was localized using a balloon occlusion test. The CESB was uniquely designed by molding silicone stent pieces into a conical shape, deployed with rigid bronchoscopy into the appropriate segment, and reinforced with cyanoacrylate glue to prevent migration. In patients with APF, pleurodesis was performed after leak resolution to prevent recurrence. Following this, the CESB was removed after 6 weeks. RESULTS: Forty-nine CESBs were placed in 31 patients (25 male individuals, 6 female individuals) with mean age of 49.7±19.7 years. The PALs included APF (n=16), bronchopleural fistula (n=14), and airway-mediastinal fistula (n=1). The average diameter of the CESB used was 7.9±2.9 mm. There was resolution of the PAL in 26 of 31 patients (84%). The CESB migrated in 5 patients with no adverse events. Pleurodesis was performed in 13 of 16 patients with APF, to prevent recurrence. No other significant complications were observed. CONCLUSIONS: CESBs represent a safe, effective, and innovative approach in the management of PAL. They should be considered in patients who are not surgical candidates, fail surgery, or those who have a recurrence following surgery.

An innovative solution for T-tube obstruction: The tracheostomy-customized stent combination.

The Montgomery T-tube (MTT) is a useful tool for post-tracheostomy tracheal stenosis. However, MTTs can get blocked. We present a case series of life-threatening MTT blockage, wherein a split-function option was implemented, which was a customized silicone Dumon stent above the tracheostomy to maintain both airway and phonation. This tracheostomy-customized stent combination serves the same function as an MTT, with a greater margin of safety due to the easy suctioning capacity of the tracheostomy. With a fenestrated tracheostomy and stent above, speech is effectively preserved. We recommend this strategy in severe MTT blockage as a superior option to regular tracheostomy. Laryngoscope, 1795-1797, 2018.

Conventional Transbronchial Needle Aspiration: The Original Guard Who Still Has a Role in Mediastinal Lymph Node Sampling.

INTRODUCTION: Conventional transbronchial needle aspiration (C-TBNA) is the originally described method for sampling mediastinal lymph nodes (MLN). After the advent of endobronchial ultrasound, the practice and reports of C-TBNA have dwindled. We report a large series of C-TBNA from the Indian subcontinent, highlighting aspects such as pathological spectrum, yield and complications, and reiterating its relevance in MLN sampling. METHODS: The study population included 400 consecutive patients over 6.8 years who had C-TBNA done for MLN ≥1 cm in size. C-TBNA was done using a 19-G needle, with conscious sedation. A maximum of 7 passes per node were done. Rapid-on-site evaluation was done in >95% cases. Lymph nodes sampled were labeled "adequate" if lymphocytes were present, and "diagnostic" if a definitive diagnosis was made. RESULTS: The study included 228 males and 172 females, mean age 49.4±14.7 years. The "adequacy" rate was 383/400 (95.75%), and "diagnostic" yield was 347/400 (86.75%). C-TBNA was the sole diagnostic modality in 215/400 (53.75%) patients. The diagnoses included tuberculosis (43%), sarcoidosis (25.5%) and malignancy (18.25%). Complications were rare. CONCLUSIONS: This is one of the largest studies of C-TBNA in literature, and one of the few studies to define accurate pathologic diagnosis of enlarged MLN in India. This is also the one of the largest series to define the yield of TBNA with rapid-on-site evaluation in MLN sampling. Currently, in many parts of the world, C-TBNA is still the most common MLN sampling procedure, from an availability, expertise, economic, and safety perspective.

Tunable thermoresponsive pyrrolidone-based polymers from pyroglutamic acid, a bio-derived resource.

A series of pyrrolidone-based polymers is prepared from pyroglutamic acid, a bio-derived resource. Polymers bearing simple alkoxy substituents (e.g., methoxy, ethoxy, and butoxy) are soluble in common organic solvents and possess glass transition temperatures that are dependent on the length of the alkoxy residue. Replacing these substituents with an ether moiety (CH3 OCH2 CH2 O-) affords a highly sensitive and reversible thermoresponsive polymer with a lower critical solution temperature (LCST) of 42 °C in water. Copolymers composed of repeat units bearing both the ether and simple alkoxy residues are found to exhibit LCSTs that are highly dependent on the nature of the hydrophobic alkoxy residue suggesting that the LCSTs of these polymers can be successfully tuned by simply tailoring the copolymer structure.

Investigation of the urge-to-cough sensation in healthy volunteers.

BACKGROUND AND OBJECTIVE: Recently, there has been interest in the sensation of irritation that precedes the motor act of coughing, which has been termed the urge-to-cough (UTC). The aim of this study was to perform the largest evaluation to date of the UTC threshold (C(u)) in a healthy population. The specific aims were to investigate the relationship between C(u) and cough reflex sensitivity, to evaluate gender differences in the UTC and to assess the reproducibility of measurements of C(u). METHODS: Standard capsaicin cough challenge methodology was employed to measure cough reflex sensitivity in 100 healthy adult non-smokers (50 females) with the additional measurement of C(u). A subgroup of 40 subjects (20 males) underwent repeat cough challenges after 1 week to examine the reproducibility of the measurements. RESULTS: All 100 subjects demonstrated motor cough in response to capsaicin. Twenty-one subjects (10 females) did not show a discernible C(u), as the motor cough event preceded a UTC sensation unaccompanied by cough. Although cough reflex sensitivity, as measured by the concentration of capsaicin inducing five or more coughs (C(5)), was enhanced in women, there was no gender difference in C(u). Similar to standard cough reflex sensitivity measurements, the measurement of C(u) was highly reproducible. CONCLUSIONS: These results demonstrate that the UTC threshold can be effectively and reproducibly measured using a modification of standard cough challenge methodology. Given its clinical significance as a prevalent symptom, UTC, as measured by C(u), represents an additional relevant end point for studies investigating the effects of pharmacological and other interventions in cough and cough reflex sensitivity.

Effect of viral upper respiratory tract infection on the urge-to-cough sensation.

BACKGROUND: Recently, interest has emerged in the sensation of irritation that precedes the motor act of coughing; this phenomenon has been termed the urge-to-cough (UTC). Although one previous study has demonstrated a transient enhancement of cough reflex sensitivity during acute upper respiratory tract infection (URI), the effect of URI on UTC has not previously been investigated. METHODS: Employing standard cough challenge methodology, we measured cough reflex sensitivity in 24 otherwise healthy adult nonsmokers during URI and again after recovery (4-8 weeks later) by determining C(2) and C(5), the concentrations of capsaicin inducing 2 or more and 5 or more coughs, respectively. In addition, we determined the capsaicin concentration at which the UTC sensation first occurred, without an associated motor cough, and termed it C(u). Furthermore, we determined the difference between concentrations of capsaicin inducing the first motor event of cough (C(1)) and C(u), and have termed it C(Δ). RESULTS: During URI, cough reflex sensitivity as measured by C(1) (p = 0.033) and C(5) (p = 0.001), as well as the urge-to-cough threshold, C(u) (p = 0.046), were significantly enhanced compared to the post-recovery state. The degree of change in cough reflex sensitivity (C(5)) was significantly greater than that of the urge-to-cough threshold, C(u) (p = 0.044). CONCLUSION: Our results demonstrate that the UTC sensation is transiently enhanced during URI. We also confirm the results of the lone previous study that demonstrated transient enhancement of cough reflex sensitivity during URI. The UTC threshold may represent an additional relevant end point to measure in future studies evaluating potential antitussive agents.

Morphine-induced degradation of the host defense barrier role of intestinal mucosal injury.

The effect of morphine on intestinal ulcer formation and on the degradation of the host defense barrier was studied. Mice receiving morphine (MRM) showed mucosal ulcer formation in the ileum and in the upper third of the colon. In in vitro studies, morphine enhanced apoptosis of cultured human colonic cells (HCC). Nitric oxide synthase (NOS) inhibitors attenuated the proapoptotic effect of morphine. Moreover, morphine stimulated NO generation by HCCs. MRM also showed a breach in the host defense barrier as well as injury to peritoneal macrophages. Although NOS inhibitors completely prevented morphine-induced intestinal ulcer formation, it provided only partial protection against a breach in the host defense barrier and peritoneal macrophage injury. Propranolol did not inhibit the induction of intestinal ulcer formation in MRM; nevertheless, propranolol prevented a breach in the host defense barrier as well as macrophage injury in MRM, whereas hemin exacerbated macrophage injury as well as the breach in the host defense barrier of MRM. These findings suggest that morphine-induced intestinal injury is mediated through NO generation. However, the degradation of the host defense barrier correlates with macrophage injury, but not intestinal injury.

Morphine-induced macrophage apoptosis: oxidative stress and strategies for modulation.

Occurrence of macrophage apoptosis has been implicated for the altered immune function found in an opiate milieu. In the present study, we evaluated the role of oxidative stress in morphine-induced macrophage apoptosis. Morphine promoted the apoptosis of macrophages. This effect of morphine was associated with the production of superoxide and nitric oxide (NO). Antioxidants provided protection against morphine-induced macrophage injury. In addition, diphenyleneiodonium chloride, an inhibitor of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation, attenuated the proapoptotic effect of morphine. Antitransforming growth factor-beta (anti-TGF-beta) antibody and propranolol (an inhibitor of the phospholipase D pathway) inhibited morphine-induced superoxide generation as well as apoptosis. N'-Tetraacetic acid tetra (acetoxymethyl) ester, a calcium-chelating agent, inhibited morphine-induced apoptosis, whereas thapsigargin (a calcium agonist) stimulated macrophage apoptosis under basal as well as morphine-stimulated states. These studies suggest that morphine-induced macrophage apoptosis is mediated through downstream signaling involving TGF-beta and NO production. Moreover, there is NADPH oxidation activation involving phospholipase D and Ca(2+), leading to the generation of superoxide. In in vivo studies, administration of N-acetyl cysteine and preinduction of heme oxygenase activity and epoetin alpha prevented morphine-induced peritoneal macrophage apoptosis, thus further confirming the role of oxidative stress in morphine-induced macrophage apoptosis.

Role of oxidative stress and heme oxygenase activity in morphine-induced glomerular epithelial cell growth.

Opiate addiction has been reported to contribute to the progression of renal injury. In addition, opiate addiction is a major risk factor for the development of human immunodeficiency virus-associated nephropathy. In the present study, we evaluated the effects of morphine, an active metabolite of heroin, on glomerular epithelial cell (GEC) growth and the involved molecular mechanism. At lower concentrations, morphine promoted GEC proliferation; however, at higher concentrations, morphine triggered apoptosis. Antioxidants inhibited morphine-induced proliferation as well as apoptosis. Similarly, free radical scavengers prevented morphine-induced GEC proliferation and apoptosis. Because proliferative and proapoptotic effects of morphine were inhibited by free radical scavengers as well as antioxidants, it appears that these effects of morphine are mediated through oxidative stress. Hemin, an inducer of heme oxygenase (HO) activity, inhibited GEC proliferation and promoted GEC apoptosis under basal and morphine-stimulated conditions. On the other hand, zinc protoporphyrin, an inhibitor of HO activity, promoted GEC proliferation and inhibited GEC apoptosis under basal as well as morphine-stimulated conditions. These findings suggest that HO activity is directly related to GEC apoptosis and inversely related to GEC proliferation. Morphine, de novo, had bimodal effects on HO activity: lower concentrations increased and higher concentrations decreased HO activity. It appears that HO activity may be modifying morphine-induced GEC growth.