Anti-apoptotic effect of morphine-induced delayed preconditioning on pulmonary artery endothelial cells with anoxia/reoxygenation injury:

Petechial hemorrhages, ethanol, and opioids in victims from intoxication

Petechial hemorrhages are of interest to forensic pathologists because of their association with pressure on the neck. This study shows the associations between ethanol, opioids in blood and the risk of petechiae in conjunctivae and eye lids of 865 medico-legally examined victims from intoxication, 112 (12.9 %) with petechiae. Livor mortis on the front, face down body position, higher body weight, and younger age of the victims were independently associated with higher risk of petechiae. These variables were used for adjustment in the logistic regression analyzes. We found associations between ethanol, opioids, and the risk of petechiae when analyzed simultaneously. The association between ethanol and the risk of petechiae differed in opioid negative and positive victims (interaction, p = 0.028). In the opioid negative group, the association was J-formed, victims with low to medium level ethanol having lower risk (OR = 0.77) than those without ethanol or opioids, whereas high ethanol level gave a 4-fold higher risk (OR = 3.97). In the opioid positive group, the J-formed pattern was reversed. Victims with low to medium level ethanol had more than 4 times higher risk (OR = 4.65), whereas high level ethanol gave a slightly elevated risk (OR = 1.34) only compared to no ethanol or opioids. The results suggest that ethanol and opioids have a complex association with the risk of petechiae independent of livor mortis, initial body position, body weight, and age in victims from intoxication. Of practical value for the post-mortem examination is that the pathologist must consider both the ethanol level and the presence of opioids when judging the significance of petechiae in the eye regions.

NADPH oxidase-mediated endothelial injury in HIV- and opioid-induced pulmonary arterial hypertension

We previously demonstrated that the combined exposure of human pulmonary microvascular endothelial cells (HPMECs) to morphine and viral protein(s) results in the oxidative stress-mediated induction of autophagy, leading to shift in the cells from early apoptotic to apoptosis-resistant proliferative status associated with the angioproliferative remodeling observed in pulmonary arterial hypertension (PAH). In this study, we tried to delineate the major source of HIV-1 protein Tat and morphine induced oxidative burst in HPMECs and its consequences on vascular remodeling and PAH in an in vivo model. We observed switch from the initial increased expression of NADPH oxidase (NOX) 2 in response to acute treatment of morphine and HIV-Tat to later increased expression of NOX4 on chronic treatment in the endoplasmic reticulum of HPMECs without any alterations in the mitochondria. Furthermore, NOX-dependent induction of autophagy was observed to play a pivotal role in regulating the endothelial cell survival. Our in vivo findings showed significant increase in pulmonary vascular remodeling, right ventricular systolic pressure, and Fulton index in HIV-transgenic rats on chronic administration of morphine. This was associated with increased oxidative stress in lung tissues and rat pulmonary microvascular endothelial cells. Additionally, endothelial cells from morphine-treated HIV-transgenic rats demonstrated increased expression of NOX2 and NOX4 proteins, inhibition of which ameliorated their increased survival upon serum starvation. In conclusion, this study describes NADPH oxidases as one of the main players in the oxidative stress-mediated endothelial dysfunction on the dual hit of HIV-viral protein(s) and opioids.

Sugen-morphine model of pulmonary arterial hypertension

Pulmonary arterial hypertension is a fatal disease associated with pulmonary vascular remodeling and right ventricular hypertrophy. Pre-clinical animal models that reproduce the human pulmonary arterial hypertension process and pharmacological response to available therapies are critical for future drug development. The most prevalent animal model reproducing many aspects of angioobliterative forms of pulmonary arterial hypertension is the rat Sugen/hypoxia model in which Sugen, a vascular endothelial growth factor receptor antagonist, primarily causes initiation of endothelial injury and later in the presence of hypoxia promotes proliferation of apoptosis-resistant endothelial cells. We previously demonstrated that exposure of human pulmonary microvascular endothelium to morphine and HIV-proteins results in initial apoptosis followed by increased proliferation. Here, we demonstrate that the double-hit of morphine and Sugen 5416 (Sugen–morphine) in rats leads to the development of pulmonary arterial hypertension with significant medial hypertrophy of pre-acinar pulmonary arteries along with neo-intimal thickening of intra-acinar vessels. In addition, the pulmonary smooth muscle and endothelial cells isolated from Sugen–morphine rats showed hyperproliferation and apoptotic resistance, respectively, in response to serum starvation. Our findings support that the dual hit model of Sugen 5416 and morphine provides another experimental strategy to induce significant pulmonary vascular remodeling and development of severe pulmonary arterial hypertension pathology in rats without exposure to hypoxia.

Drug abuse and HIV-related pulmonary hypertension: double hit injury

: Improved survival among HIV-1-infected individuals with the advent of antiretroviral therapy has clearly led to a greater prevalence of noninfectious complications. One of the most devastating sequelae in these individuals is the development of pulmonary arterial hypertension (PAH). Various epidemiological studies suggest worse survival of HIV-PAH patients when compared with other forms of PAH. Given that only a subset and not all HIV-infected individuals develop HIV-PAH, it is suggested that an additional second-hit of genetic or environmental trigger is needed for the development of PAH. In this context, it has been well documented that HIV patients who abuse illicit drugs such as stimulants, opioids, and the like, are more susceptible to develop PAH. In this review, we highlight the studies that support the significance of a double hit of HIV and drug abuse in the incidence of PAH and focus on the research that has been undertaken to unravel the pathobiology and vascular remodeling mechanisms underlying the deleterious synergy between HIV infection and drugs of abuse in orchestrating the development of PAH.

Enhanced autophagy in pulmonary endothelial cells on exposure to HIV-Tat and morphine: Role in HIV-related pulmonary arterial hypertension

Intravenous drug use is one of the major risk factors for HIV-infection in HIV-related pulmonary arterial hypertension patients. We previously demonstrated exaggerated pulmonary vascular remodeling with enhanced apoptosis followed by increased proliferation of pulmonary endothelial cells on simultaneous exposure to both opioids and HIV protein(s). Here we hypothesize that the exacerbation of autophagy may be involved in the switching of endothelial cells from an early apoptotic state to later hyper-proliferative state. Treatment of human pulmonary microvascular endothelial cells (HPMECs) with both the HIV-protein Tat and morphine resulted in an oxidative stress-dependent increase in the expression of various markers of autophagy and formation of autophagosomes when compared to either Tat or morphine monotreatments as demonstrated by western blot, transmission electron microscopy and immunofluorescence. Autophagy flux experiments suggested increased formation rather than decreased clearance of autolysosomes. Inhibition of autophagy resulted in a significant increase in apoptosis and reduction in proliferation of HPMECs with combined morphine and Tat (M+T) treatment compared to monotreatments whereas stimulation of autophagy resulted in opposite effects. Significant increases in the expression of autophagy markers as well as the number of autophagosomes and autolysosomes was observed in the lungs of SIV-infected macaques and HIV-infected humans exposed to opioids. Overall our findings indicate that morphine in combination with viral protein(s) results in the induction of autophagy in pulmonary endothelial cells that may lead to an increase in severity of angio-proliferative remodeling of the pulmonary vasculature on simian and human immunodeficiency virus infection in the presence of opioids.

Desflurane preconditioning protects human umbilical vein endothelial cells against anoxia/reoxygenation by upregulating NLRP12 and inhibiting non-canonical nuclear factor-κB signaling

Volatile anesthetics modulate endothelial cell apoptosis and inhibit nuclear factor-κB (NF-κB) signaling. In this study, we aimed to assess whether desflurane preconditioning protects human umbilical vein endothelial cells (HUVECs) agaist anoxia/reoxygenation (A/R) injury. HUVECs were pre-conditioned with desflurane (1.0 MAC) for 30 min, followed by a 15-min washout, then exposed to 60 min anoxia and 60 min reoxygenation (A/R), and incubated with 10 ng/ml tumor necrosis factor (TNF)-α for 60 min. HUVEC viability and apoptosis were measured by MTT assay and annexin V staining, and immunoblot analysis was used to measure the levels of Smac and cellular inhibitor of apoptosis 1 (cIAP1). NF-κB activation was assessed using the NF-κB signaling pathway real‑time PCR array, and the levels of NF-κB inducing kinase (NIK), p52, IκB kinase (IKK)α, p100, RelB and NLR family, pyrin domain containing 12 (NLRP12) were assessed by immunoblot analysis. Desflurane preconditioning attenuated the effects of A/R and/or A/R plus TNF-α on cell viability, decreasing the levels of Smac and enhancing the levels of of cIAP1 (P<0.05). Preconditioning with desflurane also enhanced the mRNA levels of interleukin (IL)-10 and NLRP12 in the cells exposed to A/R by 2.40- and 2.16‑fold, respectively. The HUVECs exposed to A/R had greater levels of NIK and p100 and reduced levels of p52 and IKKα. Desflurance preconditioning further increased p100 levels, decreased the level of NIK, further decreased p52 levels and further reduced IKKα levels. A/R in combination with TNF-α increased the NIK, IKKα, p100 and RelB levels, and this increase was significantly attenuated by desflurance preconditioning (all P<0.05). Desflurane preconditioning enhanced HUVEC survival and protected the cells against A/R injury, and our results suggested that this process involved the upregulation of NLRP12 and the inhibition of non-canonical NF-κB signaling.

Enhanced pulmonary arteriopathy in simian immunodeficiency virus-infected macaques exposed to morphine

RATIONALE

HIV-associated pulmonary arterial hypertension (PAH) is likely a more prevalent noninfectious complication of AIDS than previously recognized. Furthermore, the majority of HIV-PAH cases occur in individuals with a history of intravenous drug use. In this study we used a simian immunodeficiency (SIV) macaque model and a primary cell-culture system to investigate the association between drug abuse and HIV infection in HIV-PAH development.

METHODS

The archival lung tissues from macaques previously used to study the effect of morphine on SIV infection-associated neuropathogenesis were analyzed for pulmonary vascular changes. The direct effect of HIV proteins and illicit drugs was investigated on oxidative stress, survival, and proliferation of human pulmonary microvascular endothelial cells.

MEASUREMENTS AND MAIN RESULTS

SIVmacR71/17E-infected rhesus macaques treated with morphine (VM group) demonstrated significant pulmonary vascular remodeling, including the presence of early and advanced complex (plexiform) lesions, when compared with either the SIV-infected (V group) or morphine-treated uninfected (M group) macaques. However, both the V (two of five) and VM (two of six) groups included some animals with Pneumocystis jirovecii pneumonia. The endothelial cells lining the vessels with medial hypertrophy or initial-stage intimal lesions in lung sections from VM macaques demonstrated an increase in positivity for both terminal dUTP nick-end labeling and Ki67. Oxidative stress-mediated enhanced apoptosis followed by enhanced proliferation of endothelial cells was observed on simultaneous treatment with viral proteins and drugs of abuse compared with either treatment alone.

CONCLUSIONS

Our findings suggest that SIV/HIV protein(s) and morphine interact to cause the proliferation of apoptosis-resistant endothelial cells leading to angio-obliteration.

Endogenous opiates and behavior: 2008

This paper is the 31st consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2008 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).