Protein kinase C mRNA and protein expressions in hypobaric hypoxia-induced cardiac hypertrophy in rats

AIM

Protein kinase C (PKC), cloned as a serine/threonine kinase, plays key roles in diverse intracellular signalling processes and in cardiovascular remodelling during pressure overload or volume overload. We looked for correlations between changes in PKC isoforms (levels and/or subcellular distributions) and cardiac remodelling during experimental hypobaric hypoxic environment (HHE)-induced pulmonary hypertension.

METHODS

To study the PKC system in the heart during HHE, 148 male Wistar rats were housed for up to 21 days in a chamber at the equivalent of 5500 m altitude level (10% O(2)).

RESULTS

At 14 or more days of exposure to HHE, pulmonary arterial pressure (PAP) was significantly increased. In the right ventricle (RV): (1) the expression of PKC-alpha protein in the cytosolic and membrane fractions was increased at 3-14 days and at 5-7 days of exposure respectively; (ii) the cytosolic expression of PKC-delta protein was increased at 1-5, 14 and 21 days of exposure; (3) the membrane expressions of the proteins were decreased at 14-21 (PKC-betaII), 14-21 (PKC-gamma), and 0.5-5 and 21 (PKC-epsilon) days of exposure; (4) the expression of the active form of PKC-alpha protein on the plasma membrane was increased at 3 days of exposure (based on semiquantitative analysis of the immunohistochemistry). In the left ventricle, the expressions of the PKC mRNAs, and of their cytosolic and membrane proteins, were almost unchanged. The above changes in PKC-alpha, which were strongly evident in the RV, occurred alongside the increase in PAP.

CONCLUSION

PKC-alpha may help to modulate the right ventricular hypertrophy caused by pulmonary hypertension in HHE.

Osteopontin expression in normal and hypobaric hypoxia-exposed rats

AIM

Experimental pulmonary hypertension induced in a hypobaric hypoxic environment (HHE) is characterized by structural remodelling of the heart and pulmonary arteries. Osteopontin (OPN) has emerged as a key factor in cardiovascular remodelling in response to pressure or volume overload. We studied the possible effects of HHE on the OPN synthesis system.

METHODS

One hundred and forty-eight male Wistar rats were housed in a chamber with conditions equivalent of an altitude of 5500 m for up to 21 days.

RESULTS

Plasma OPN protein level was found to be significantly decreased on day 0.5 of exposure to HHE, as was the level in the adrenal gland (which secreted highest levels of OPN protein). In the right ventricle of the heart (mRNA) and the lung (protein), OPN expression was found to be significantly increased only on day 1 and day 5, respectively, of exposure to HHE. By immunohistochemistry, the distribution and intensity of OPN protein in several organs were found to alter during exposure to HHE. However, these changes in OPN synthesis did not coincide with the moderate increase in pulmonary arterial pressure (PAP) (maximal mean PAP, 24.5 mmHg) during HHE.

CONCLUSION

Pulmonary hypertension in HHE with conditions equivalent of an altitude of 5500 m may induce little or no OPN in heart and lung. Sustained induction may require a more severe PAP overload.

Antidepressant treatment of patients with diffuse esophageal spasm: a psychosomatic approach

The cause of diffuse esophageal spasm (DES) has not been clearly established, and effective treatment is lacking. To determine whether a psychosomatic approach can be effective in treating DES patients, nine patients and 26 healthy volunteers were studied. Esophageal manometry and psychological testing were performed in both groups. The psychological background of the DES patients was investigated. Psychiatric diagnoses were made according to the criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders, 3rd edition, revised. The authors started psychosomatic treatment with isosorbide dinitrate for 1 month, then prescribed serotonin reuptake inhibitor antidepressants for an additional month. Anxiety and depression scores were substantially higher for the DES group than for the control group. Five of the nine DES patients (56%) were diagnosed as having major psychiatric disorders. Only one patient showed improvement with isosorbide dinitrate, and eight patients improved with antidepressants. These initial observations suggest that psychosomatic treatment with antidepressants may be effective in the treatment of DES.

Treating nonulcer dyspepsia considering both functional disorders of the digestive system and psychiatric conditions

Nonulcer dyspepsia (NUD) is a common syndrome, but the optimal treatments have yet to be established. This study was performed to determine the most effective treatment for NUD. Subjects were recruited through the Department of General Internal Medicine at the Kyushu University Hospital because of their somatic symptoms. When no organic lesions were found, the patients were directed to consult our department (Psychosomatic Medicine); 194 consecutive NUD patients were studied. All subjects were assessed psychiatrically with the Structured Clinical Interview for DSM-III-R(SCID). Patients with serious NUD were hospitalized, and randomly divided into control (N = 42) and experimental groups (N = 86). The controls were treated with physical treatment alone. The experimental group received psychiatric treatment in addition, based on the results of SCID. The experimental group showed a significant improvement compared with the controls (P < 0.0001). The treatment for NUD taking into consideration both the physical and psychiatric conditions is highly effective.

Alterations in lymphocyte subsets and pituitary-adrenal gland-related hormones during fasting

We investigated changes in the immunoendocrine system during fasting. Ten hospitalized patients aged 14-46 y with psychosomatic disorders fasted for 7 or 10 d. Blood samples were collected before and on days 3 and 7 of the 7-d fasts. When fasting continued to 10 d, an additional sample was taken on day 10. We measured blood cellularity (white blood cells and total lymphocytes), the total number and percentage of lymphocyte subsets (CD2, CD3, CD4, CD8, and CD19), natural killer (NK) cell activity, cytokines (interleukin 1 beta, interleukin 2, interleukin 6, granulocyte-macrophage colony stimulating factor, tumor necrosis factor alpha, and interferon gamma), and soluble interleukin 2 receptors. Corticotropin, cortisol, and dehydroepiandrosterone sulfate (DHEAS) concentrations were also determined. Although the total number of lymphocytes decreased during fasting, NK cell activity increased significantly. Plasma cortisol and DHEAS concentrations also increased significantly whereas changes in corticotropin concentrations were not significant. The total number and percentage of CD4 cells decreased significantly during fasting but no other lymphocyte subsets changed significantly. The percentage of CD4 cells was negatively correlated with cortisol concentrations during fasting. No detectable changes occurred in cytokines or soluble interleukin 2 receptors during the study. All measured immunoendocrine values that changed during fasting returned to prefasting values during the refeeding period. These findings indicate that fasting affects immune variables such as T cell subsets and NK cell activity at least in part through changes in adrenal gland-related hormones.

[A depressive disorder in patients with irritable bowel syndrome and non-ulcer dyspepsia]

The relationships between psychiatric disorders and the symptoms of both irritable bowel syndrome (IBS) and non-ulcer dyspepsia (NUD) are herein investigated and discussed. Functional disorders of the small and large intestine induce irritable bowel syndrome. NUD is a syndrome that displays symptoms that might originate in the upper digestive system despite the absence of any organic disorder. In addition, it has also been suggested that the occurrence of NUD is based on a functional disorder of the upper digestive systems. Based on our studies of serious cases with both NUD and IBS, in approximately 50% of the NUD patients as well as about 50% of the IBS cases, a depressive disorder was found to be most closely related to the onset and continuance of the symptoms of either NUD or IBS. According to the evaluations of NUD and IBS as functional disorders and psychiatric disorders, the patients underwent treatment and all demonstrated a good response to the various treatment regimens. It is thus considered that NUD and IBS should be evaluated as both functional digestive disorders and psychiatric disorders.

[The relation between irritable bowel syndrome and a major depression]

It has been demonstrated that physical or psychological stress induces dysfunction of bowel movement and intestinal transit in rodents and human. There have been several reports concerning the psychiatric factors involved in the onset and clinical course of irritable bowel syndrome (IBS). We investigated patients with IBS who had been markedly disturbed in their daily life, and it was concluded that the most important psychiatric factor related to the onset and the clinical course of severely impaired IBS is a major depression, fulfilling the criteria of the DSM-III-R. Especially, in diarrhea predominant type of IBS, a major depression was considered to be strongly involved in the onset and the clinical course of IBS. Most of IBS patients with a major depression can be effectively treated with antidepressants and brief psychotherapy. Concerning treatment, the psychological background should be carefully considered.

[A study of the dynamics of gallbladder contraction in irritable bowel syndrome]

We examined gallbladder motility function after intramuscular injection of caerulein (0.2 micrograms/kg) to the cases of irritable bowel syndrome (IBS) by using ultrasonography. We measured gallbladder area pre and after caerulein injection (0' 5' 10' 15' 20' 25' 30' 40' 50' 60') and calculated contraction rate of gallbladder in each time. We applied one way analysis of variance among the four groups [diarrhea group (N = 9), alternative group (N = 8), constipation group (N = 8), control group (N = 15)]. Gallbladder contraction rate was low in diarrhea group and high in constipation group (p less than 0.05). And then we classified gallbladder contraction pattern to three groups (hyperkinetic, intermediate, hypokinetic). These three groups correlated bowel habits and biliary knocked pain. Therefore, constipation group showed hyperkinetic tendency and diarrhea group showed hypokinetic tendency (chi 2 analysis: p = 0.004 CMH analysis: p = 0.001). And biliary knocked pain significantly appeared in constipation group and hyperkinetic type of gallbladder (chi 2 analysis: p = 0.026, CMH analysis: p = 0.019). Consequently, it was suggested that bowel habits concerned with abnormality of gallbladder motility function in IBS.