ANGIOTENSIN SYSTEM: THE LINK BETWEEN HYPERTENSION AND DIABETES

1.1 Introduction

Diabetes is defined as a metabolic disorder which is characterised by hypertension, chronic hyperglycaemia, microalbuminuria, dyslipidaemia and inflammation. Moreover, it is also associated with number of vascular complications such as retinopathy, neuropathy and nephropathy. Diabetic nephropathy is the major cause of end-stage renal disease in about 25-40% of patients with diabetes (Sourris et al, 2012). In the patient with diabetes, the renin angiotensin system has been activated through the treatment with ACE inhibitors and use of the oral contraceptives. In the diabetes patient, the relation to prorenin to total renin is different. The concentration of prorenin in plasma is 10-fold higher than renin. This increasing is due to several factors such as, autonomic dysfunction and glycation of a responsible enzyme and it is associated with microalbuminuria and with the development of nephropathy (Fisher et al, 2005), (Bonanni et al, 2012).

As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.

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1.2 Background of Study

Angiotensins are peptide hormones that are produced by a series of proteolytic reactions starting with the cleavage of angiotensinogen by renin. The angiotensin system has an important role in the control of blood pressure, hypertension and in the regulation of salt and volume homeostasis of organisms as well as in the cardiac hypertrophy, heart failure, advanced liver disease, atherosclerosis, and renal artery stenosis, is also known as the renin-angiotensin system (RAAS) which is take part in the both pathophysiological and physiological properties (Castrop et al, 2010; Balakumar et al, 2011). Renin is a protease enzyme which belongs to the aspartic proteinase family and it includes cathepsin-D, pepsin, and chymosin (Bhandari et al, 2010). Renin is the main enzyme of the renin-angiotensin system (RAS) and it is act as a protease and also as a hormone. Therefore, renin is intracellularly processed and packed into vesicles like a typical lysosomal protein and also it is glycosylated like a typical secretory protein (Castrop et al, 2010).

In the RAS, angiotensinogen which is a product of the α-globin gene, is expressed in the liver and unregulated during the acute phase of immune response (Daniels et al, 2007). The inhibition of renin-angiotensin system at different steps using Beta Blockers, Angiotensin-Converting Enzyme Inhibitors (ACEIs), Angiotensin Receptor Blockers (ARBs), Direct Renin Inhibitors are proven important for the study of prevention of several renal diseases and cardiovascular diseases (Fisher et al., 2005). In the presence of conditions predisposing to hyperplasia, hypertrophy, and tissue remodeling, such as hypertension, atherosclerosis, diabetes, and others, even a normal activity of the RAS may result in inadequately elevated and thus it cause a further progression of the disease (Volpe et al., 2002). The inhibition of renin angiotensin system involves following steps: The initial step of formation of Ang-I from AOG can be blocked by using direct renin inhibitors. Formation of Ang-II from Ang-I can be inhibited by using ACE inhibitors. Then the actions on cardiovascularrenal system of Ang-II can be prevented by using AT1 receptor blockers and the release of renin is reduced by using β-Adrenergic blocking agents reduce renin release and in this way, by interfering with these inhibitors, increase renin levels for pathophysiological uses (Balakumar et al., 2011; Fisher et al., 2005).

In Nigeria, hypertension is turning out to be a common chronic disease among adults and 26.4% people have hypertension in which women are found to be more prone than that of men (Chowdhury et al., 2016). According to a study conducted by Rahim et al., (2012), the rural population of Nigeria has an increasing trend in having hypertension. As far our knowledge, there are very few organizational level data on prevalence and risk factors of hypertension among urban poor adult in Nigeria. Previously, it was known that hypertension is a disease most commonly seen in developed and wealthy countries. However, changing life style, increased stress in daily lives have shifted the scenario completely as now this disease is more common in developing countries.

Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the link between hypertension and diabetes in angiotensin system.

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1.3 Statement of Problems

Investigation reveals that seriousness of this adult illness (high blood pressure) is not just that it can lead to more serious illness or complications, raises the risk of stroke, kidney failure, heart disease and heart attack. The matter is made worse with the existence of too much weight or fat in the body as this tends to make the condition severe. It is the duty of stakeholders in health sectors to keep the adult folk aware of the implication of over-weight by providing them with accurate, timely and up to date information regarding this health condition.

It is also the duty of health personnel to warn and educate adults who are more prone to high blood pressure, about the dangers of over-weight in the management of high blood pressure. This awareness is expected to affect the feeding habit of these people, since it has been observed that poor feeding (that is, poor combination of the classes of food, not necessarily the quantity) is one of the causes of over-weight (Sacks F.M, 2008).

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1.4 Aim and Objectives of Study

The aim of the study is to investigate the link between hypertension and diabetes in angiotensin system. In achieving this aim, the following specific objectives were laid out as follows:

1. To examine the relationship between hypertension and diabetes in angiotensin system
2. To determine the factors mitigating hypertension and diabetes in angiotensin system
3. To estimate the prevalence of systemic hypertension among patients
4. To find out the different risk factors of systemic hypertension among patients in Enugu State Primary Health Care facility

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1.5 Research Questions

The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:

• Are there factors mitigating hypertension and diabetes in angiotensin system?
• Is there any relationship between hypertension and diabetes in angiotensin system?
• What is the prevalence of systemic hypertension among patients?
• What are the different risk factors of systemic hypertension among patients in Enugu State Primary Health Care facility?

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1.6 Research Hypothesis

In order to pursue the objective of this study, the following generalized statements have been designed to guide and aids in obtaining the result for the experiment to be conducted. For this work, the null hypothesis will be represented with H0 while the alternative hypothesis will be represented with hypothesis H1.

Hypothesis One

• H0: There is no significant relationship between hypertension and diabetes in angiotensin system
• H1: There is a significant relationship between hypertension and diabetes in angiotensin system

Hypothesis Two

• H0: There are no significant factors mitigating hypertension and diabetes in angiotensin system
• H1: There are significant factors mitigating hypertension and diabetes in angiotensin system

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1.7 Significance of Study

This study will be of immense benefit to researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.

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1.8 Scope of the Study

The scope of the research work focused on the Link between Hypertension and Diabetes in Angiotensin System among patients in Enugu State Primary Health Care Facility.

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1.9 Limitations of the Study

During the course of this study, many things militated against its completion, some of which are:

1. Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
2. Research material: availability of research material is a major setback to the scope of the study.
3. Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
4. Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet, questionnaire and interview).