Faculty Bibliography

Despite the existence of Hepatitis B vaccination, hepatitis B virus (HBV) infection is still prevalent worldwide and accounts for significant morbidity and mortality. It is encouraging that majority of patients do recover from the acute infection, however, those that progress to chronic disease state is at great risk of developing complications such as hepatocellular carcinoma, cirrhosis and liver failure. Hepatitis B virus infection can be influenced by many factors such as host immune status, age at infection, and level of viral replication. The discovery about the existence of various genotypes and its association with different geographic distribution as well as the knowledge regarding mutant species has aid us in better understanding the nature of HBV infection and in delivering better care for patients. It is especially important to recognize those individuals with HBeAg-negative chronic HBV as they have a poorer prognosis compare with their counterparts, HBeAg-positive. Tremendous progress has been made over the years in understanding the behavior and clinical course of the disease; however, the natural history of HBV is complex and we still have much to explore and learn.

The glomerular mesangium is an important site of activity in patients with heroin addiction. We studied the effect of morphine, a metabolite of heroin, on the mesangial immunoglobulin G aggregate uptake in a model of specific mesangial cell injury. Isolated specific mesangial cell injury was developed in Lewis rats by injecting intravenously antithymocyte serum (ATS). Forty-eight hours later, radioiodinated, heat aggregated immunoglobulin G (AHIgG125I) was administered (20 mg/100 g i.v.) by tail vein. At 4 and 24 h, kidneys, liver, and spleen were removed, glomeruli isolated, and the radioactivity measured. Blood levels of AHIgG125I were measured at 0, 4 and 24 h. For ultrastructural studies, IgG-coated gold particles were injected, and the mesangial circulation was studied. At 4 h, ATS-treated rats showed a lower (p < 0.02) accumulation of AHIgG125I in the mesangium when compared with control rats (controls 511,012 +/- 10,807 vs. ATS 464,614 +/- 7,944 cpm/g glomerular protein). ATS plus morphine treated rats showed a higher (p < 0.01) accumulation of of AHIgG125I when compared with rats treated with AS alone. Even at 24, h morphine-treated ATS rats showed a higher accumulation of AHIgG125I when compared with those treated with ATS alone. Ultrastructural studies showed aggregation of IgG-coated gold particles in the mesangial cell endolysosomes of control rats. Our results suggest that macromolecules may dwell longer in the mesangium of rats with intact mesangial cells. This increase in transit time may be related to the uptake of these macromolecules by mesangial cells. Morphine seems to enhance the accumulation of macromolecules in the mesangium, independent of its action on mesangial cells.

Since increased mesangial accumulation of matrix has been considered to be an important event in the development of focal glomerulosclerosis, we investigated whether morphine, an active metabolite of heroin, can modulate mesangial accumulation of immune complexes. Control or morphine-dependent rats were administered intraperitoneal ferritin (8 mg/100 g body weight) daily for 6 weeks. Body weight, blood pressure, serum creatinine, 24-hour urinary protein and creatinine excretion rates were measured at 3-week intervals. Rats were sacrificed at the end of 6 weeks and kidney tissue was studied by light, immunofluorescence and electron microscopy. Serum creatinine levels and urinary protein excretion rates were not different between control and morphine-dependent rats. All morphine-dependent rats developed hematuria, whereas only 1 control rat developed hematuria. Light microscopy revealed no proliferation of mesangial cells and only a minimal increase in the mesangial matrix. Electron-microscopic studies showed deposition of immune complexes in the mesangial region. Mesangial cells showed aggregation of ferritin in lysosomes. Immunofluorescence studies revealed the presence of IgG staining predominantly in the mesangial region. The majority (60%) of morphine-dependent rats showed a diffuse mesangial deposition of IgG when compared to control rats (83%) who showed only focal deposition. These results indicate that morphine enhances deposition of immune complexes in the mesangium. Morphine-induced matrix but may also change its quality. This may play a pathogenic role in the development of glomerular lesions in patients who abuse opiates.

Focal glomerulosclerosis is the predominant glomerular lesion in patients with drug addiction. Since mesangial expansion has been considered a precursor of glomerulosclerosis we investigated whether the use of these drugs can cause accumulation of macromolecules into mesangium which may contribute to the expansion of mesangium. The majority of drug addicts at times take drugs in groups and may thus be exposed to a variety of drugs (cocaine, alcohol, and heroin). Therefore, we studied the effect of cocaine, alcohol, and morphine alone or in combination on the accumulation of radiolabeled human immunoglobulin-G (IgG) aggregates (AHIgG125I) into glomeruli/mesangium. Cocaine enhanced accumulation of AHIgG125I at 8 hr. Glomerular levels of AHIgG125I levels were also higher in morphine treated rats when compared with untreated animals. Alcohol did not alter the deposition of AHIgG125I. But at an earlier time (4 hr) alcohol enhanced the effect of cocaine on accumulation of IgG aggregates into the mesangium. The combined effects of morphine and cocaine, or morphine and alcohol were not different than the effect of morphine alone. The enhanced accumulation of phlogogenic macromolecules into the mesangium may not only increase the quantity of mesangial matrix but may also alter the quality of matrix. This may be playing an important role in the development of glomerular injury.

Because mesangial expansion is considered a precursor of focal glomerulosclerosis, we studied whether morphine can cause mesangial expansion. We used radiolabeled human immunoglobulin G aggregates (125I-ahIgG) to study mesangial kinetics in control and experimental (morphine-treated) rats. Control and experimental rats were administered 125I-ahIgG by tail vein. Serum levels of 125I-ahIgG and uptake of 125I-ahIgG by liver, spleen, and mesangium were determined at 4, 8, 12, 24, and 36 h after 125I-ahIgG administration. Mesangial 125I-ahIgG levels were higher (P < 0.05) at 4 h and at later periods in morphine-treated vs. control rats. Naloxone, an opioid antagonist, did not attenuate the morphine-induced mesangial accumulation of 125I-ahIgG. The mean uptake of IgG aggregates was lower in the liver and spleen of morphine-treated rats at 36 h (P < 0.05). In both in vivo and in vitro experiments, ultrastructural studies showed accumulation of IgG-coated gold particles in vesicles, endosomes, and lysosomes. Morphine may have increased the accumulation of 125I-ahIgG in the glomeruli either by increasing the delivery of macromolecules into the mesangium or by altering the exit of macromolecules from the mesangium.

Focal glomerular sclerosis is the predominant renal lesion in heroin addicts. We studied whether morphine, a metabolite of heroin, could directly affect the uptake of immunoglobulin G (IgG) complexes by cultured mesangial cells (MC) and macrophages (MP). Pre-incubation of morphine (10(-6) M) decreased uptake of IgG complexes [morphine, 66,577 +/- 6,248 vs. control, 95,735 +/- 5,227 counts.min-1 (cpm).mg protein-1; P < 0.02] by MC. Morphine (10(-4)-10(-6) M) also inhibited (P < 0.01) uptake of 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate-labeled low-density lipoprotein by MC. MP pretreated with morphine (10(-6) M) also showed significantly (P < 0.02) lower uptake of IgG complexes (control 94,959 +/- 4,980 vs. morphine, 58,360 +/- 11,608 cpm/mg protein). Binding studies carried out at 4 degrees C on MC and MP indicated that morphine did not modulate surface binding of IgG complexes. Naloxone, a morphine antagonist, also produced a rather decreased (P < 0.05) uptake of IgG complexes by both MP and MC and did not inhibit the effect of morphine on the uptake of IgG complexes. In vivo studies indicated that morphine-treated rats had a higher (P < 0.05) accumulation of aggregated human IgG complexes (125I-labeled ahIgG) in their glomeruli when compared with untreated rats (control rats, 256,929 +/- 40,008 cpm/g protein vs. experimental rats, 398,317 + 51,512 cpm/g). Increased accumulation of 125I-ahIgG in the glomeruli from morphine-treated rats may either be related to increased delivery of 125I-ahIgG into the mesangium or be a result of decreased drainage of 125I-ahIgG from the mesangium.(ABSTRACT TRUNCATED AT 250 WORDS)